Update to trunk r13638

(bzr r13341.1.286)

20 files changed, 1092 insertions, 802 deletions

diff --git a/src/box3d-side.cpp b/src/box3d-side.cpp
index dfccb63bf..3058eab2d 100644
--- a/src/box3d-side.cpp
+++ b/src/box3d-side.cpp
@@ -4,6 +4,7 @@
  * Authors:
  *   Maximilian Albert <Anhalter42@gmx.de>
  *   Abhishek Sharma
+ *   Jon A. Cruz <jon@joncruz.org>
  *
  * Copyright (C) 2007  Authors
  *
@@ -166,13 +167,12 @@ void Box3DSide::set_shape() {
 
     SPObject *parent = this->parent;
 
-    if (!SP_IS_BOX3D(parent)) {
+    SPBox3D *box = dynamic_cast<SPBox3D *>(parent);
+    if (!box) {
         g_warning("Parent of 3D box side is not a 3D box.\n");
         return;
     }
 
-    SPBox3D *box = SP_BOX3D(parent);
-
     Persp3D *persp = box3d_side_perspective(this);
 
     if (!persp) {
@@ -259,7 +259,8 @@ box3d_side_compute_corner_ids(Box3DSide *side, unsigned int corners[4]) {
 
 Persp3D *
 box3d_side_perspective(Box3DSide *side) {
-    return SP_BOX3D(side->parent)->persp_ref->getObject();
+    SPBox3D *box = side ? dynamic_cast<SPBox3D *>(side->parent) : NULL;
+    return box ? box->persp_ref->getObject() : NULL;
 }
 
 Inkscape::XML::Node *box3d_side_convert_to_path(Box3DSide *side) {
diff --git a/src/box3d.cpp b/src/box3d.cpp
index 5f60766f4..3c0cbb675 100644
--- a/src/box3d.cpp
+++ b/src/box3d.cpp
@@ -66,27 +66,23 @@ SPBox3D::~SPBox3D() {
 }
 
 void SPBox3D::build(SPDocument *document, Inkscape::XML::Node *repr) {
-	SPBox3D* object = this;
-
     SPGroup::build(document, repr);
 
-    SPBox3D *box = SP_BOX3D (object);
-    box->my_counter = counter++;
+    my_counter = counter++;
 
     /* we initialize the z-orders to zero so that they are updated during dragging */
     for (int i = 0; i < 6; ++i) {
-        box->z_orders[i] = 0;
+        z_orders[i] = 0;
     }
 
     // TODO: Create/link to the correct perspective
 
-    SPDocument *doc = box->document;
-    if ( doc ) {
-        box->persp_ref->changedSignal().connect(sigc::bind(sigc::ptr_fun(box3d_ref_changed), box));
+    if ( document ) {
+        persp_ref->changedSignal().connect(sigc::bind(sigc::ptr_fun(box3d_ref_changed), this));
 
-        object->readAttr( "inkscape:perspectiveID" );
-        object->readAttr( "inkscape:corner0" );
-        object->readAttr( "inkscape:corner7" );
+        readAttr( "inkscape:perspectiveID" );
+        readAttr( "inkscape:corner0" );
+        readAttr( "inkscape:corner7" );
     }
 }
 
@@ -188,11 +184,15 @@ box3d_ref_changed(SPObject *old_ref, SPObject *ref, SPBox3D *box)
 {
     if (old_ref) {
         sp_signal_disconnect_by_data(old_ref, box);
-        persp3d_remove_box (SP_PERSP3D(old_ref), box);
+        Persp3D *oldPersp = dynamic_cast<Persp3D *>(old_ref);
+        if (oldPersp) {
+            persp3d_remove_box(oldPersp, box);
+        }
     }
-    if ( SP_IS_PERSP3D(ref) && ref != box ) // FIXME: Comparisons sane?
+    Persp3D *persp = dynamic_cast<Persp3D *>(ref);
+    if ( persp && (ref != box) ) // FIXME: Comparisons sane?
     {
-        persp3d_add_box (SP_PERSP3D(ref), box);
+        persp3d_add_box(persp, box);
     }
 }
 
@@ -273,9 +273,6 @@ void box3d_position_set(SPBox3D *box)
 }
 
 Geom::Affine SPBox3D::set_transform(Geom::Affine const &xform) {
-	SPBox3D* item = this;
-    SPBox3D *box = item;
-
     // We don't apply the transform to the box directly but instead to its perspective (which is
     // done in sp_selection_apply_affine). Here we only adjust strokes, patterns, etc.
 
@@ -283,10 +280,9 @@ Geom::Affine SPBox3D::set_transform(Geom::Affine const &xform) {
     gdouble const sw = hypot(ret[0], ret[1]);
     gdouble const sh = hypot(ret[2], ret[3]);
 
-    for ( SPObject *child = box->firstChild(); child; child = child->getNext() ) {
-        if (SP_IS_ITEM(child)) {
-            SPItem *childitem = SP_ITEM(child);
-
+    for ( SPObject *child = firstChild(); child; child = child->getNext() ) {
+        SPItem *childitem = dynamic_cast<SPItem *>(child);
+        if (childitem) {
             // Adjust stroke width
             childitem->adjust_stroke(sqrt(fabs(sw * sh)));
 
@@ -1220,9 +1216,10 @@ box3d_check_for_swapped_coords(SPBox3D *box) {
 }
 
 static void box3d_extract_boxes_rec(SPObject *obj, std::list<SPBox3D *> &boxes) {
-    if (SP_IS_BOX3D(obj)) {
-        boxes.push_back(SP_BOX3D(obj));
-    } else if (SP_IS_GROUP(obj)) {
+    SPBox3D *box = dynamic_cast<SPBox3D *>(obj);
+    if (box) {
+        boxes.push_back(box);
+    } else if (dynamic_cast<SPGroup *>(obj)) {
         for ( SPObject *child = obj->firstChild(); child; child = child->getNext() ) {
             box3d_extract_boxes_rec(child, boxes);
         }
@@ -1306,7 +1303,9 @@ SPGroup *box3d_convert_to_group(SPBox3D *box)
 
     grepr->setAttribute("id", id);
 
-    return SP_GROUP(doc->getObjectByRepr(grepr));
+    SPGroup *group = dynamic_cast<SPGroup *>(doc->getObjectByRepr(grepr));
+    g_assert(group != NULL);
+    return group;
 }
 
 const char *SPBox3D::displayName() const {
diff --git a/src/box3d.h b/src/box3d.h
index 60b966187..85f481e5b 100644
--- a/src/box3d.h
+++ b/src/box3d.h
@@ -8,6 +8,7 @@
  *   Lauris Kaplinski <lauris@kaplinski.com>
  *   Maximilian Albert <Anhalter42@gmx.de>
  *   Abhishek Sharma
+ *   Jon A. Cruz <jon@joncruz.org.
  *
  * Copyright (C) 2007      Authors
  * Copyright (C) 1999-2002 Lauris Kaplinski
@@ -21,8 +22,6 @@
 #include "axis-manip.h"
 
 #define SP_TYPE_BOX3D            (box3d_get_type ())
-#define SP_BOX3D(obj) (dynamic_cast<SPBox3D*>((SPObject*)obj))
-#define SP_IS_BOX3D(obj) (dynamic_cast<const SPBox3D*>((SPObject*)obj) != NULL)
 
 class Persp3D;
 class Persp3DReference;
diff --git a/src/document.cpp b/src/document.cpp
index 64ccb8c36..e5b827937 100644
--- a/src/document.cpp
+++ b/src/document.cpp
@@ -618,7 +618,10 @@ Inkscape::Util::Quantity SPDocument::getWidth() const
 
 void SPDocument::setWidth(const Inkscape::Util::Quantity &width)
 {
-    gdouble old_computed = root->width.computed;
+    Inkscape::Util::Unit const *old_units = unit_table.getUnit("px");
+    if (root->width.unit)
+        old_units = unit_table.getUnit(root->width.unit);
+    gdouble old_converted = Inkscape::Util::Quantity::convert(root->width.value, old_units, width.unit);
     root->width.computed = width.value("px");
     /* SVG does not support meters as a unit, so we must translate meters to
      * cm when writing */
@@ -631,7 +634,7 @@ void SPDocument::setWidth(const Inkscape::Util::Quantity &width)
     }
 
     if (root->viewBox_set)
-        root->viewBox.setMax(Geom::Point(root->viewBox.left() + (root->width.computed / old_computed) * root->viewBox.width(), root->viewBox.bottom()));
+        root->viewBox.setMax(Geom::Point(root->viewBox.left() + (root->width.value / old_converted) * root->viewBox.width(), root->viewBox.bottom()));
 
     root->updateRepr();
 }
@@ -656,7 +659,10 @@ Inkscape::Util::Quantity SPDocument::getHeight() const
 
 void SPDocument::setHeight(const Inkscape::Util::Quantity &height)
 {
-    gdouble old_computed = root->height.computed;
+    Inkscape::Util::Unit const *old_units = unit_table.getUnit("px");
+    if (root->height.unit)
+        old_units = unit_table.getUnit(root->height.unit);
+    gdouble old_converted = Inkscape::Util::Quantity::convert(root->height.value, old_units, height.unit);
     root->height.computed = height.value("px");
     /* SVG does not support meters as a unit, so we must translate meters to
      * cm when writing */
@@ -669,7 +675,7 @@ void SPDocument::setHeight(const Inkscape::Util::Quantity &height)
     }
 
     if (root->viewBox_set)
-        root->viewBox.setMax(Geom::Point(root->viewBox.right(), root->viewBox.top() + (root->height.computed / old_computed) * root->viewBox.height()));
+        root->viewBox.setMax(Geom::Point(root->viewBox.right(), root->viewBox.top() + (root->height.value / old_converted) * root->viewBox.height()));
 
     root->updateRepr();
 }
diff --git a/src/knotholder.cpp b/src/knotholder.cpp
index b8d941bf7..f46daa09e 100644
--- a/src/knotholder.cpp
+++ b/src/knotholder.cpp
@@ -6,6 +6,7 @@
  *   bulia byak <buliabyak@users.sf.net>
  *   Maximilian Albert <maximilian.albert@gmail.com>
  *   Abhishek Sharma
+ *   Jon A. Cruz <jon@joncruz.org>
  *
  * Copyright (C) 2001-2008 authors
  *
@@ -58,8 +59,7 @@ KnotHolder::KnotHolder(SPDesktop *desktop, SPItem *item, SPKnotHolderReleasedFun
     local_change(FALSE),
     dragging(false)
 {
-
-    if (!desktop || !item || !SP_IS_ITEM(item)) {
+    if (!desktop || !item) {
         g_print ("Error! Throw an exception, please!\n");
     }
 
@@ -128,29 +128,37 @@ KnotHolder::knot_clicked_handler(SPKnot *knot, guint state)
         }
     }
 
-    if (SP_IS_SHAPE(saved_item)) {
-        SP_SHAPE(saved_item)->set_shape();
+    {
+        SPShape *savedShape = dynamic_cast<SPShape *>(saved_item);
+        if (savedShape) {
+            savedShape->set_shape();
+        }
     }
 
     knot_holder->update_knots();
 
     unsigned int object_verb = SP_VERB_NONE;
 
-    if (SP_IS_RECT(saved_item))
+    // TODO extract duplicated blocks;
+    if (dynamic_cast<SPRect *>(saved_item)) {
         object_verb = SP_VERB_CONTEXT_RECT;
-    else if (SP_IS_BOX3D(saved_item))
+    } else if (dynamic_cast<SPBox3D *>(saved_item)) {
         object_verb = SP_VERB_CONTEXT_3DBOX;
-    else if (SP_IS_GENERICELLIPSE(saved_item))
+    } else if (dynamic_cast<SPGenericEllipse *>(saved_item)) {
         object_verb = SP_VERB_CONTEXT_ARC;
-    else if (SP_IS_STAR(saved_item))
+    } else if (dynamic_cast<SPStar *>(saved_item)) {
         object_verb = SP_VERB_CONTEXT_STAR;
-    else if (SP_IS_SPIRAL(saved_item))
+    } else if (dynamic_cast<SPSpiral *>(saved_item)) {
         object_verb = SP_VERB_CONTEXT_SPIRAL;
-    else if (SP_IS_OFFSET(saved_item)) {
-        if (SP_OFFSET(saved_item)->sourceHref)
-            object_verb = SP_VERB_SELECTION_LINKED_OFFSET;
-        else
-            object_verb = SP_VERB_SELECTION_DYNAMIC_OFFSET;
+    } else {
+        SPOffset *offset = dynamic_cast<SPOffset *>(saved_item);
+        if (offset) {
+            if (offset->sourceHref) {
+                object_verb = SP_VERB_SELECTION_LINKED_OFFSET;
+            } else {
+                object_verb = SP_VERB_SELECTION_DYNAMIC_OFFSET;
+            }
+        }
     }
 
     // for drag, this is done by ungrabbed_handler, but for click we must do it here
@@ -184,8 +192,9 @@ KnotHolder::knot_moved_handler(SPKnot *knot, Geom::Point const &p, guint state)
         }
     }
 
-    if (SP_IS_SHAPE (item)) {
-        SP_SHAPE (item)->set_shape();
+    SPShape *shape = dynamic_cast<SPShape *>(item);
+    if (shape) {
+        shape->set_shape();
     }
 
     this->update_knots();
@@ -210,45 +219,42 @@ KnotHolder::knot_ungrabbed_handler(SPKnot */*knot*/, guint)
         /* do cleanup tasks (e.g., for LPE items write the parameter values
          * that were changed by dragging the handle to SVG)
          */
-        if (dynamic_cast<SPLPEItem*> (object)) {
+        SPLPEItem *lpeItem = dynamic_cast<SPLPEItem *>(object);
+        if (lpeItem) {
             // This writes all parameters to SVG. Is this sufficiently efficient or should we only
             // write the ones that were changed?
-            SPLPEItem * lpeitem = SP_LPE_ITEM(object);
-            if (lpeitem) {
-                Inkscape::LivePathEffect::Effect *lpe = lpeitem->getCurrentLPE();
-                if (lpe) {
-                    LivePathEffectObject *lpeobj = lpe->getLPEObj();
-                    lpeobj->updateRepr();
-                }
+            Inkscape::LivePathEffect::Effect *lpe = lpeItem->getCurrentLPE();
+            if (lpe) {
+                LivePathEffectObject *lpeobj = lpe->getLPEObj();
+                lpeobj->updateRepr();
             }
         }
 
         unsigned int object_verb = SP_VERB_NONE;
 
-        if (SP_IS_RECT(object))
+        // TODO extract duplicated blocks:
+        if (dynamic_cast<SPRect *>(object)) {
             object_verb = SP_VERB_CONTEXT_RECT;
-        else if (SP_IS_BOX3D(object))
+        } else if (dynamic_cast<SPBox3D *>(object)) {
             object_verb = SP_VERB_CONTEXT_3DBOX;
-        else if (SP_IS_GENERICELLIPSE(object))
+        } else if (dynamic_cast<SPGenericEllipse *>(object)) {
             object_verb = SP_VERB_CONTEXT_ARC;
-        else if (SP_IS_STAR(object))
+        } else if (dynamic_cast<SPStar *>(object)) {
             object_verb = SP_VERB_CONTEXT_STAR;
-        else if (SP_IS_SPIRAL(object))
+        } else if (dynamic_cast<SPSpiral *>(object)) {
             object_verb = SP_VERB_CONTEXT_SPIRAL;
-        else if (SP_IS_OFFSET(object)) {
-            if (SP_OFFSET(object)->sourceHref)
-                object_verb = SP_VERB_SELECTION_LINKED_OFFSET;
-            else
-                object_verb = SP_VERB_SELECTION_DYNAMIC_OFFSET;
-        }
-        if (object) { //increasingly aggressive sanity checks
-            if (object->document) {
-                if (object_verb <= SP_VERB_LAST && object_verb >= SP_VERB_INVALID) {
-                    DocumentUndo::done(object->document, object_verb,
-                                       _("Move handle"));
+        } else {
+            SPOffset *offset = dynamic_cast<SPOffset *>(object);
+            if (offset) {
+                if (offset->sourceHref) {
+                    object_verb = SP_VERB_SELECTION_LINKED_OFFSET;
+                } else {
+                    object_verb = SP_VERB_SELECTION_DYNAMIC_OFFSET;
                 }
             }
-        } //else { abort(); }
+        }
+
+        DocumentUndo::done(object->document, object_verb, _("Move handle"));
     }
 }
 
@@ -261,7 +267,7 @@ void KnotHolder::add(KnotHolderEntity *e)
 
 void KnotHolder::add_pattern_knotholder()
 {
-    if ((item->style->fill.isPaintserver()) && SP_IS_PATTERN(item->style->getFillPaintServer())) {
+    if ((item->style->fill.isPaintserver()) && dynamic_cast<SPPattern *>(item->style->getFillPaintServer())) {
         PatternKnotHolderEntityXY *entity_xy = new PatternKnotHolderEntityXY(true);
         PatternKnotHolderEntityAngle *entity_angle = new PatternKnotHolderEntityAngle(true);
         PatternKnotHolderEntityScale *entity_scale = new PatternKnotHolderEntityScale(true);
@@ -283,7 +289,7 @@ void KnotHolder::add_pattern_knotholder()
         entity.push_back(entity_scale);
     }
 
-    if ((item->style->stroke.isPaintserver()) && SP_IS_PATTERN(item->style->getStrokePaintServer())) {
+    if ((item->style->stroke.isPaintserver()) && dynamic_cast<SPPattern *>(item->style->getStrokePaintServer())) {
         PatternKnotHolderEntityXY *entity_xy = new PatternKnotHolderEntityXY(false);
         PatternKnotHolderEntityAngle *entity_angle = new PatternKnotHolderEntityAngle(false);
         PatternKnotHolderEntityScale *entity_scale = new PatternKnotHolderEntityScale(false);
diff --git a/src/path-chemistry.cpp b/src/path-chemistry.cpp
index fe241381f..0c3f9cde7 100644
--- a/src/path-chemistry.cpp
+++ b/src/path-chemistry.cpp
@@ -66,8 +66,9 @@ sp_selected_path_combine(SPDesktop *desktop)
     GSList *to_paths = NULL;
     for (GSList *i = items; i != NULL; i = i->next) {
         SPItem *item = (SPItem *) i->data;
-        if (!SP_IS_PATH(item) && !SP_IS_GROUP(item))
+        if (!dynamic_cast<SPPath *>(item) && !dynamic_cast<SPGroup *>(item)) {
             to_paths = g_slist_prepend(to_paths, item);
+        }
     }
     GSList *converted = NULL;
     bool did = sp_item_list_to_curves(to_paths, &items, &converted);
@@ -99,7 +100,8 @@ sp_selected_path_combine(SPDesktop *desktop)
     for (GSList *i = items; i != NULL; i = i->next) {  // going from top to bottom
 
         SPItem *item = (SPItem *) i->data;
-        if (!SP_IS_PATH(item)) {
+        SPPath *path = dynamic_cast<SPPath *>(item);
+        if (!path) {
             continue;
         }
 
@@ -108,7 +110,7 @@ sp_selected_path_combine(SPDesktop *desktop)
             did = true;
         }
 
-        SPCurve *c = SP_PATH(item)->get_curve_for_edit();
+        SPCurve *c = path->get_curve_for_edit();
         if (first == NULL) {  // this is the topmost path
             first = item;
             parent = first->getRepr()->parent();
@@ -204,12 +206,11 @@ sp_selected_path_break_apart(SPDesktop *desktop)
 
         SPItem *item = (SPItem *) items->data;
 
-        if (!SP_IS_PATH(item)) {
+        SPPath *path = dynamic_cast<SPPath *>(item);
+        if (!path) {
             continue;
         }
 
-        SPPath *path = SP_PATH(item);
-
         SPCurve *curve = path->get_curve_for_edit();
         if (curve == NULL) {
             continue;
@@ -366,17 +367,20 @@ sp_item_list_to_curves(const GSList *items, GSList **selected, GSList **to_selec
          items != NULL;
          items = items->next) {
 
-        SPItem *item = SP_ITEM(items->data);
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(items->data));
+        g_assert(item != NULL);
         SPDocument *document = item->document;
 
+        SPGroup *group = dynamic_cast<SPGroup *>(item);
         if ( skip_all_lpeitems &&
-             SP_IS_LPE_ITEM(item) && 
-             !SP_IS_GROUP(item) ) // also convert objects in an SPGroup when skip_all_lpeitems is set.
+             dynamic_cast<SPLPEItem *>(item) && 
+             !group ) // also convert objects in an SPGroup when skip_all_lpeitems is set.
         { 
             continue;
         }
 
-        if (SP_IS_PATH(item) && !SP_SHAPE(item)->_curve_before_lpe) {
+        SPPath *path = dynamic_cast<SPPath *>(item);
+        if (path && !path->_curve_before_lpe) {
             // remove connector attributes
             if (item->getAttribute("inkscape:connector-type") != NULL) {
                 item->removeAttribute("inkscape:connection-start");
@@ -388,9 +392,10 @@ sp_item_list_to_curves(const GSList *items, GSList **selected, GSList **to_selec
             continue; // already a path, and no path effect
         }
 
-        if (SP_IS_BOX3D(item)) {
+        SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+        if (box) {
             // convert 3D box to ordinary group of paths; replace the old element in 'selected' with the new group
-            Inkscape::XML::Node *repr = box3d_convert_to_group(SP_BOX3D(item))->getRepr();
+            Inkscape::XML::Node *repr = box3d_convert_to_group(box)->getRepr();
             
             if (repr) {
                 *to_select = g_slist_prepend (*to_select, repr);
@@ -401,9 +406,9 @@ sp_item_list_to_curves(const GSList *items, GSList **selected, GSList **to_selec
             continue;
         }
         
-        if (SP_IS_GROUP(item)) {
-            SP_LPE_ITEM(item)->removeAllPathEffects(true);
-            GSList *item_list = sp_item_group_item_list(SP_GROUP(item));
+        if (group) {
+            group->removeAllPathEffects(true);
+            GSList *item_list = sp_item_group_item_list(group);
             
             GSList *item_to_select = NULL;
             GSList *item_selected = NULL;
@@ -480,7 +485,7 @@ sp_selected_item_to_curved_repr(SPItem *item, guint32 /*text_grouping_policy*/)
 
     Inkscape::XML::Document *xml_doc = item->getRepr()->document();
 
-    if (SP_IS_TEXT(item) || SP_IS_FLOWTEXT(item)) {
+    if (dynamic_cast<SPText *>(item) || dynamic_cast<SPFlowtext *>(item)) {
         // Special treatment for text: convert each glyph to separate path, then group the paths
         Inkscape::XML::Node *g_repr = xml_doc->createElement("svg:g");
         g_repr->setAttribute("transform", item->getRepr()->attribute("transform"));
@@ -497,7 +502,7 @@ sp_selected_item_to_curved_repr(SPItem *item, guint32 /*text_grouping_policy*/)
         g_repr->setAttribute("inkscape:transform-center-y", item->getRepr()->attribute("inkscape:transform-center-y"), false);
         /* Whole text's style */
         gchar *style_str = sp_style_write_difference(item->style,
-                                                     item->parent->style);
+                                                     item->parent ? item->parent->style : NULL); // TODO investigate posibility
         g_repr->setAttribute("style", style_str);
         g_free(style_str);
         Inkscape::Text::Layout::iterator iter = te_get_layout(item)->begin(); 
@@ -514,11 +519,11 @@ sp_selected_item_to_curved_repr(SPItem *item, guint32 /*text_grouping_policy*/)
             if (!rawptr || !SP_IS_OBJECT(rawptr)) // no source for glyph, abort
                 break;
             pos_obj = SP_OBJECT(rawptr);
-            while (SP_IS_STRING(pos_obj) && pos_obj->parent) {
+            while (dynamic_cast<SPString const *>(pos_obj) && pos_obj->parent) {
                pos_obj = pos_obj->parent;   // SPStrings don't have style
             }
             gchar *style_str = sp_style_write_difference(pos_obj->style,
-                                                         pos_obj->parent->style);
+                                                         pos_obj->parent ? pos_obj->parent->style : NULL); // TODO investigate posibility
 
             // get path from iter to iter_next:
             SPCurve *curve = te_get_layout(item)->convertToCurves(iter, iter_next);
@@ -555,8 +560,11 @@ sp_selected_item_to_curved_repr(SPItem *item, guint32 /*text_grouping_policy*/)
     }
 
     SPCurve *curve = NULL;
-    if (SP_IS_SHAPE(item)) {
-        curve = SP_SHAPE(item)->getCurve();
+    {
+        SPShape *shape = dynamic_cast<SPShape *>(item);
+        if (shape) {
+            curve = shape->getCurve();
+        }
     } 
 
     if (!curve)
@@ -575,7 +583,7 @@ sp_selected_item_to_curved_repr(SPItem *item, guint32 /*text_grouping_policy*/)
     repr->setAttribute("transform", item->getRepr()->attribute("transform"));
     /* Style */
     gchar *style_str = sp_style_write_difference(item->style,
-                                                 item->parent->style);
+                                                 item->parent ? item->parent->style : NULL); // TODO investigate posibility
     repr->setAttribute("style", style_str);
     g_free(style_str);
 
@@ -622,12 +630,12 @@ sp_selected_path_reverse(SPDesktop *desktop)
 
     for (GSList *i = items; i != NULL; i = i->next) {
 
-        if (!SP_IS_PATH(i->data)) {
+        SPPath *path = dynamic_cast<SPPath *>(static_cast<SPObject *>(i->data));
+        if (!path) {
             continue;
         }
 
         did = true;
-        SPPath *path = SP_PATH(i->data);
 
         SPCurve *rcurve = path->get_curve_reference()->create_reverse();
 
diff --git a/src/selection-chemistry.cpp b/src/selection-chemistry.cpp
index 77fa78967..6a091bd12 100644
--- a/src/selection-chemistry.cpp
+++ b/src/selection-chemistry.cpp
@@ -284,11 +284,12 @@ void SelectionHelper::fixSelection(SPDesktop *dt)
     GSList const *selList = selection->itemList();
 
     for( GSList const *i = selList; i; i = i->next ) {
-        if( SP_IS_ITEM(i->data) &&
-            !dt->isLayer(SP_ITEM(i->data)) &&
-            (!SP_ITEM(i->data)->isLocked()))
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(i->data));
+        if( item &&
+            !dt->isLayer(item) &&
+            (!item->isLocked()))
         {
-            items = g_slist_prepend(items, SP_ITEM(i->data));
+            items = g_slist_prepend(items, item);
         }
     }
 
@@ -332,18 +333,27 @@ static void sp_selection_copy_impl(GSList const *items, GSList **clip, Inkscape:
     sorted_items = g_slist_sort(static_cast<GSList *>(sorted_items), (GCompareFunc) sp_object_compare_position);
 
     // Copy item reprs:
-    for (GSList *i = (GSList *) sorted_items; i != NULL; i = i->next) {
-        sp_selection_copy_one(SP_OBJECT(i->data)->getRepr(), SP_ITEM(i->data)->i2doc_affine(), clip, xml_doc);
+    for (GSList *i = sorted_items; i != NULL; i = i->next) {
+        SPItem *item = dynamic_cast<SPItem *>(SP_OBJECT(i->data));
+        if (item) {
+            sp_selection_copy_one(item->getRepr(), item->i2doc_affine(), clip, xml_doc);
+        } else {
+            g_assert_not_reached();
+        }
     }
 
     *clip = g_slist_reverse(*clip);
     g_slist_free(static_cast<GSList *>(sorted_items));
 }
 
+// TODO check if parent parameter should be changed to SPItem, of if the code should handle non-items.
 static GSList *sp_selection_paste_impl(SPDocument *doc, SPObject *parent, GSList **clip)
 {
     Inkscape::XML::Document *xml_doc = doc->getReprDoc();
 
+    SPItem *parentItem = dynamic_cast<SPItem *>(parent);
+    g_assert(parentItem != NULL);
+
     GSList *copied = NULL;
     // add objects to document
     for (GSList *l = *clip; l != NULL; l = l->next) {
@@ -351,7 +361,7 @@ static GSList *sp_selection_paste_impl(SPDocument *doc, SPObject *parent, GSList
         Inkscape::XML::Node *copy = repr->duplicate(xml_doc);
 
         // premultiply the item transform by the accumulated parent transform in the paste layer
-        Geom::Affine local(SP_ITEM(parent)->i2doc_affine());
+        Geom::Affine local(parentItem->i2doc_affine());
         if (!local.isIdentity()) {
             gchar const *t_str = copy->attribute("transform");
             Geom::Affine item_t(Geom::identity());
@@ -428,7 +438,7 @@ static void add_ids_recursive(std::vector<const gchar *> &ids, SPObject *obj)
     if (obj) {
         ids.push_back(obj->getId());
 
-        if (SP_IS_GROUP(obj)) {
+        if (dynamic_cast<SPGroup *>(obj)) {
             for (SPObject *child = obj->firstChild() ; child; child = child->getNext() ) {
                 add_ids_recursive(ids, child);
             }
@@ -484,8 +494,9 @@ void sp_selection_duplicate(SPDesktop *desktop, bool suppressDone)
 
         if (fork_livepatheffects) {
             SPObject *new_obj = doc->getObjectByRepr(copy);
-            if (new_obj && SP_IS_LPE_ITEM(new_obj)) {
-                SP_LPE_ITEM(new_obj)->forkPathEffectsIfNecessary(1);
+            SPLPEItem *newLPEObj = dynamic_cast<SPLPEItem *>(new_obj);
+            if (newLPEObj) {
+                newLPEObj->forkPathEffectsIfNecessary(1);
             }
         }
 
@@ -501,8 +512,9 @@ void sp_selection_duplicate(SPDesktop *desktop, bool suppressDone)
         for (unsigned int i = 0; i < old_ids.size(); i++) {
             const gchar *id = old_ids[i];
             SPObject *old_clone = doc->getObjectById(id);
-            if (SP_IS_USE(old_clone)) {
-                SPItem *orig = SP_USE(old_clone)->get_original();
+            SPUse *use = dynamic_cast<SPUse *>(old_clone);
+            if (use) {
+                SPItem *orig = use->get_original();
                 if (!orig) // orphaned
                     continue;
                 for (unsigned int j = 0; j < old_ids.size(); j++) {
@@ -516,13 +528,16 @@ void sp_selection_duplicate(SPDesktop *desktop, bool suppressDone)
                         g_free(newref);
                     }
                 }
-            } else if (SP_IS_OFFSET(old_clone)) {
-                for (guint j = 0; j < old_ids.size(); j++) {
-                gchar *source_href = SP_OFFSET(old_clone)->sourceHref;
-                    if (source_href && source_href[0]=='#' && !strcmp(source_href+1, old_ids[j])) {
-                        gchar *newref = g_strdup_printf("#%s", new_ids[j]);
-                        doc->getObjectById(new_ids[i])->getRepr()->setAttribute("xlink:href", newref);
-                        g_free(newref);
+            } else {
+                SPOffset *offset = dynamic_cast<SPOffset *>(old_clone);
+                if (offset) {
+                    for (guint j = 0; j < old_ids.size(); j++) {
+                        gchar *source_href = offset->sourceHref;
+                        if (source_href && source_href[0]=='#' && !strcmp(source_href+1, old_ids[j])) {
+                            gchar *newref = g_strdup_printf("#%s", new_ids[j]);
+                            doc->getObjectById(new_ids[i])->getRepr()->setAttribute("xlink:href", newref);
+                            g_free(newref);
+                        }
                     }
                 }
             }
@@ -548,8 +563,9 @@ void sp_edit_clear_all(Inkscape::Selection *selection)
     SPDocument *doc = selection->layers()->getDocument();
     selection->clear();
 
-    g_return_if_fail(SP_IS_GROUP(selection->layers()->currentLayer()));
-    GSList *items = sp_item_group_item_list(SP_GROUP(selection->layers()->currentLayer()));
+    SPGroup *group = dynamic_cast<SPGroup *>(selection->layers()->currentLayer());
+    g_return_if_fail(group != NULL);
+    GSList *items = sp_item_group_item_list(group);
 
     while (items) {
         reinterpret_cast<SPObject*>(items->data)->deleteObject();
@@ -573,17 +589,18 @@ void sp_edit_clear_all(Inkscape::Selection *selection)
 GSList *get_all_items(GSList *list, SPObject *from, SPDesktop *desktop, bool onlyvisible, bool onlysensitive, bool ingroups, GSList const *exclude)
 {
     for ( SPObject *child = from->firstChild() ; child; child = child->getNext() ) {
-        if (SP_IS_ITEM(child) &&
-            !desktop->isLayer(SP_ITEM(child)) &&
-            (!onlysensitive || !SP_ITEM(child)->isLocked()) &&
-            (!onlyvisible || !desktop->itemIsHidden(SP_ITEM(child))) &&
+        SPItem *item = dynamic_cast<SPItem *>(child);
+        if (item &&
+            !desktop->isLayer(item) &&
+            (!onlysensitive || !item->isLocked()) &&
+            (!onlyvisible || !desktop->itemIsHidden(item)) &&
             (!exclude || !g_slist_find(const_cast<GSList *>(exclude), child))
             )
         {
-            list = g_slist_prepend(list, SP_ITEM(child));
+            list = g_slist_prepend(list, item);
         }
 
-        if (ingroups || (SP_IS_ITEM(child) && desktop->isLayer(SP_ITEM(child)))) {
+        if (ingroups || (item && desktop->isLayer(item))) {
             list = get_all_items(list, child, desktop, onlyvisible, onlysensitive, ingroups, exclude);
         }
     }
@@ -598,7 +615,7 @@ static void sp_edit_select_all_full(SPDesktop *dt, bool force_all_layers, bool i
 
     Inkscape::Selection *selection = sp_desktop_selection(dt);
 
-    g_return_if_fail(SP_IS_GROUP(dt->currentLayer()));
+    g_return_if_fail(dynamic_cast<SPGroup *>(dt->currentLayer()));
 
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     PrefsSelectionContext inlayer = (PrefsSelectionContext) prefs->getInt("/options/kbselection/inlayer", PREFS_SELECTION_LAYER);
@@ -617,14 +634,14 @@ static void sp_edit_select_all_full(SPDesktop *dt, bool force_all_layers, bool i
 
     switch (inlayer) {
         case PREFS_SELECTION_LAYER: {
-        if ( (onlysensitive && SP_ITEM(dt->currentLayer())->isLocked()) ||
-             (onlyvisible && dt->itemIsHidden(SP_ITEM(dt->currentLayer()))) )
+        if ( (onlysensitive && dynamic_cast<SPItem *>(dt->currentLayer())->isLocked()) ||
+             (onlyvisible && dt->itemIsHidden(dynamic_cast<SPItem *>(dt->currentLayer()))) )
         return;
 
-        GSList *all_items = sp_item_group_item_list(SP_GROUP(dt->currentLayer()));
+        GSList *all_items = sp_item_group_item_list(dynamic_cast<SPGroup *>(dt->currentLayer()));
 
         for (GSList *i = all_items; i; i = i->next) {
-            SPItem *item = SP_ITEM(i->data);
+            SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(i->data));
 
             if (item && (!onlysensitive || !item->isLocked())) {
                 if (!onlyvisible || !dt->itemIsHidden(item)) {
@@ -703,7 +720,7 @@ static void sp_selection_group_impl(GSList *p, Inkscape::XML::Node *group, Inksc
             Geom::Affine item_t(Geom::identity());
             if (t_str)
                 sp_svg_transform_read(t_str, &item_t);
-            item_t *= SP_ITEM(doc->getObjectByRepr(current->parent()))->i2doc_affine();
+            item_t *= dynamic_cast<SPItem *>(doc->getObjectByRepr(current->parent()))->i2doc_affine();
             // FIXME: when moving both clone and original from a transformed group (either by
             // grouping into another parent, or by cut/paste) the transform from the original's
             // parent becomes embedded into original itself, and this affects its clones. Fix
@@ -794,7 +811,7 @@ void sp_selection_ungroup(Inkscape::Selection *selection, SPDesktop *desktop)
     GSList *groups = NULL;
     for (GSList *item = old_select; item; item = item->next) {
         SPItem *obj = static_cast<SPItem*>(item->data);
-        if (SP_IS_GROUP(obj)) {
+        if (dynamic_cast<SPGroup *>(obj)) {
             groups = g_slist_prepend(groups, obj);
         }
     }
@@ -815,8 +832,8 @@ void sp_selection_ungroup(Inkscape::Selection *selection, SPDesktop *desktop)
         SPUse *use = dynamic_cast<SPUse *>(static_cast<SPItem *>(item->data));
 
         SPItem *original = use;
-        while (SP_IS_USE(original)) {
-            original = SP_USE(original)->get_original();
+        while (dynamic_cast<SPUse *>(original)) {
+            original = dynamic_cast<SPUse *>(original)->get_original();
         }
 
         if (g_slist_find(groups, original) != NULL) {
@@ -843,7 +860,7 @@ void sp_selection_ungroup(Inkscape::Selection *selection, SPDesktop *desktop)
         // ungroup only the groups marked earlier
         if (g_slist_find(groups, item->data) != NULL) {
             GSList *children = NULL;
-            sp_item_group_ungroup(SP_GROUP(obj), &children, false);
+            sp_item_group_ungroup(dynamic_cast<SPGroup *>(obj), &children, false);
             // add the items resulting from ungrouping to the selection
             new_select = g_slist_concat(new_select, children);
             item->data = NULL; // zero out the original pointer, which is no longer valid
@@ -868,11 +885,12 @@ sp_degroup_list(GSList *items)
     GSList *out = NULL;
     bool has_groups = false;
     for (GSList *item = items; item; item = item->next) {
-        if (!SP_IS_GROUP(item->data)) {
+        SPGroup *group = dynamic_cast<SPGroup *>(static_cast<SPObject *>(item->data));
+        if (!group) {
             out = g_slist_prepend(out, item->data);
         } else {
             has_groups = true;
-            GSList *members = sp_item_group_item_list(SP_GROUP(item->data));
+            GSList *members = sp_item_group_item_list(group);
             for (GSList *member = members; member; member = member->next) {
                 out = g_slist_prepend(out, member->data);
             }
@@ -899,7 +917,7 @@ sp_item_list_common_parent_group(GSList const *items)
     }
     SPObject *parent = SP_OBJECT(items->data)->parent;
     // Strictly speaking this CAN happen, if user selects <svg> from Inkscape::XML editor
-    if (!SP_IS_GROUP(parent)) {
+    if (!dynamic_cast<SPGroup *>(parent)) {
         return NULL;
     }
     for (items = items->next; items; items = items->next) {
@@ -908,7 +926,7 @@ sp_item_list_common_parent_group(GSList const *items)
         }
     }
 
-    return SP_GROUP(parent);
+    return dynamic_cast<SPGroup *>(parent);
 }
 
 /** Finds out the minimum common bbox of the selected items. */
@@ -928,7 +946,7 @@ enclose_items(GSList const *items)
 static SPObject *prev_sibling(SPObject *child)
 {
     SPObject *prev = 0;
-    if ( child && SP_IS_GROUP(child->parent) ) {
+    if ( child && dynamic_cast<SPGroup *>(child->parent) ) {
         prev = child->getPrev();
     }
     return prev;
@@ -965,8 +983,9 @@ sp_selection_raise(Inkscape::Selection *selection, SPDesktop *desktop)
             // for each selected object, find the next sibling
             for (SPObject *newref = child->next; newref; newref = newref->next) {
                 // if the sibling is an item AND overlaps our selection,
-                if (SP_IS_ITEM(newref)) {
-                    Geom::OptRect newref_bbox = SP_ITEM(newref)->desktopVisualBounds();
+                SPItem *newItem = dynamic_cast<SPItem *>(newref);
+                if (newItem) {
+                    Geom::OptRect newref_bbox = newItem->desktopVisualBounds();
                     if ( newref_bbox && selected->intersects(*newref_bbox) ) {
                         // AND if it's not one of our selected objects,
                         if (!g_slist_find(const_cast<GSList *>(items), newref)) {
@@ -1050,8 +1069,9 @@ void sp_selection_lower(Inkscape::Selection *selection, SPDesktop *desktop)
             // for each selected object, find the prev sibling
             for (SPObject *newref = prev_sibling(child); newref; newref = prev_sibling(newref)) {
                 // if the sibling is an item AND overlaps our selection,
-                if (SP_IS_ITEM(newref)) {
-                    Geom::OptRect ref_bbox = SP_ITEM(newref)->desktopVisualBounds();
+                SPItem *newItem = dynamic_cast<SPItem *>(newref);
+                if (newItem) {
+                    Geom::OptRect ref_bbox = newItem->desktopVisualBounds();
                     if ( ref_bbox && selected->intersects(*ref_bbox) ) {
                         // AND if it's not one of our selected objects,
                         if (!g_slist_find(const_cast<GSList *>(items), newref)) {
@@ -1105,9 +1125,9 @@ void sp_selection_lower_to_bottom(Inkscape::Selection *selection, SPDesktop *des
         Inkscape::XML::Node *repr = static_cast<Inkscape::XML::Node *>(l->data);
         pp = document->getObjectByRepr(repr->parent());
         minpos = 0;
-        g_assert(SP_IS_GROUP(pp));
+        g_assert(dynamic_cast<SPGroup *>(pp));
         pc = pp->firstChild();
-        while (!SP_IS_ITEM(pc)) {
+        while (!dynamic_cast<SPItem *>(pc)) {
             minpos += 1;
             pc = pc->next;
         }
@@ -1162,8 +1182,8 @@ take_style_from_item(SPObject *object)
     if (css == NULL)
         return NULL;
 
-    if ((SP_IS_GROUP(object) && object->children) ||
-        (SP_IS_TEXT(object) && object->children && object->children->next == NULL)) {
+    if ((dynamic_cast<SPGroup *>(object) && object->children) ||
+        (dynamic_cast<SPText *>(object) && object->children && object->children->next == NULL)) {
         // if this is a text with exactly one tspan child, merge the style of that tspan as well
         // If this is a group, merge the style of its topmost (last) child with style
         for (SPObject *last_element = object->lastChild(); last_element != NULL; last_element = last_element->getPrev()) {
@@ -1178,14 +1198,16 @@ take_style_from_item(SPObject *object)
         }
     }
 
-    if (!(SP_IS_TEXT(object) || SP_IS_TSPAN(object) || SP_IS_TREF(object) || SP_IS_STRING(object))) {
+    if (!(dynamic_cast<SPText *>(object) || dynamic_cast<SPTSpan *>(object) || dynamic_cast<SPTRef *>(object) || dynamic_cast<SPString *>(object))) {
         // do not copy text properties from non-text objects, it's confusing
         css = sp_css_attr_unset_text(css);
     }
 
-    if (SP_IS_ITEM(object)) {
+
+    SPItem *item = dynamic_cast<SPItem *>(object);
+    if (item) {
         // FIXME: also transform gradient/pattern fills, by forking? NO, this must be nondestructive
-        double ex = SP_ITEM(object)->i2doc_affine().descrim();
+        double ex = item->i2doc_affine().descrim();
         if (ex != 1.0) {
             css = sp_css_attr_scale(css, ex);
         }
@@ -1425,22 +1447,23 @@ selection_contains_original(SPItem *item, Inkscape::Selection *selection)
 {
     bool contains_original = false;
 
-    bool is_use = SP_IS_USE(item);
     SPItem *item_use = item;
     SPItem *item_use_first = item;
-    while (is_use && item_use && !contains_original)
+    SPUse *use = dynamic_cast<SPUse *>(item_use);
+    while (use && item_use && !contains_original)
     {
-        item_use = SP_USE(item_use)->get_original();
+        item_use = use->get_original();
+        use = dynamic_cast<SPUse *>(item_use);
         contains_original |= selection->includes(item_use);
         if (item_use == item_use_first)
             break;
-        is_use = SP_IS_USE(item_use);
     }
 
     // If it's a tref, check whether the object containing the character
     // data is part of the selection
-    if (!contains_original && SP_IS_TREF(item)) {
-        contains_original = selection->includes(SP_TREF(item)->getObjectReferredTo());
+    SPTRef *tref = dynamic_cast<SPTRef *>(item);
+    if (!contains_original && tref) {
+        contains_original = selection->includes(tref->getObjectReferredTo());
     }
 
     return contains_original;
@@ -1452,10 +1475,12 @@ selection_contains_both_clone_and_original(Inkscape::Selection *selection)
 {
     bool clone_with_original = false;
     for (GSList const *l = selection->itemList(); l != NULL; l = l->next) {
-        SPItem *item = SP_ITEM(l->data);
-        clone_with_original |= selection_contains_original(item, selection);
-        if (clone_with_original)
-            break;
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(l->data));
+        if (item) {
+            clone_with_original |= selection_contains_original(item, selection);
+            if (clone_with_original)
+                break;
+        }
     }
     return clone_with_original;
 }
@@ -1495,9 +1520,9 @@ void sp_selection_apply_affine(Inkscape::Selection *selection, Geom::Affine cons
     }
 
     for (GSList const *l = selection->itemList(); l != NULL; l = l->next) {
-        SPItem *item = SP_ITEM(l->data);
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(l->data));
 
-        if( SP_IS_ROOT(item) ) {
+        if( dynamic_cast<SPRoot *>(item) ) {
             // An SVG element cannot have a transform. We could change 'x' and 'y' in response
             // to a translation... but leave that for another day.
             selection->desktop()->messageStack()->flash(Inkscape::WARNING_MESSAGE, _("Cannot transform an embedded SVG."));
@@ -1515,24 +1540,32 @@ void sp_selection_apply_affine(Inkscape::Selection *selection, Geom::Affine cons
 
         // we're moving both a clone and its original or any ancestor in clone chain?
         bool transform_clone_with_original = selection_contains_original(item, selection);
+
         // ...both a text-on-path and its path?
-        bool transform_textpath_with_path = (SP_IS_TEXT_TEXTPATH(item) && selection->includes( sp_textpath_get_path_item(SP_TEXTPATH(item->firstChild())) ));
+        bool transform_textpath_with_path = ((dynamic_cast<SPText *>(item) && item->firstChild() && dynamic_cast<SPTextPath *>(item->firstChild()))
+                                             && selection->includes( sp_textpath_get_path_item(dynamic_cast<SPTextPath *>(item->firstChild())) ));
+
         // ...both a flowtext and its frame?
-        bool transform_flowtext_with_frame = (SP_IS_FLOWTEXT(item) && selection->includes( SP_FLOWTEXT(item)->get_frame(NULL))); // (only the first frame is checked so far)
+        bool transform_flowtext_with_frame = (dynamic_cast<SPFlowtext *>(item) && selection->includes( dynamic_cast<SPFlowtext *>(item)->get_frame(NULL))); // (only the first frame is checked so far)
+
         // ...both an offset and its source?
-        bool transform_offset_with_source = (SP_IS_OFFSET(item) && SP_OFFSET(item)->sourceHref) && selection->includes( sp_offset_get_source(SP_OFFSET(item)) );
+        bool transform_offset_with_source = (dynamic_cast<SPOffset *>(item) && dynamic_cast<SPOffset *>(item)->sourceHref) && selection->includes( sp_offset_get_source(dynamic_cast<SPOffset *>(item)) );
 
         // If we're moving a connector, we want to detach it
         // from shapes that aren't part of the selection, but
         // leave it attached if they are
         if (Inkscape::UI::Tools::cc_item_is_connector(item)) {
-            SPItem *attItem[2];
-            SP_PATH(item)->connEndPair.getAttachedItems(attItem);
-
-            for (int n = 0; n < 2; ++n) {
-                if (!selection->includes(attItem[n])) {
-                    sp_conn_end_detach(item, n);
+            SPPath *path = dynamic_cast<SPPath *>(item);
+            if (path) {
+                SPItem *attItem[2] = {0, 0};
+                path->connEndPair.getAttachedItems(attItem);
+                for (int n = 0; n < 2; ++n) {
+                    if (!selection->includes(attItem[n])) {
+                        sp_conn_end_detach(item, n);
+                    }
                 }
+            } else {
+                g_assert_not_reached();
             }
         }
 
@@ -1556,10 +1589,11 @@ void sp_selection_apply_affine(Inkscape::Selection *selection, Geom::Affine cons
             // apply the inverse of the region's transform to the <use> so that the flow remains
             // the same (even though the output itself gets transformed)
             for ( SPObject *region = item->firstChild() ; region ; region = region->getNext() ) {
-                if (SP_IS_FLOWREGION(region) || SP_IS_FLOWREGIONEXCLUDE(region)) {
-                    for ( SPObject *use = region->firstChild() ; use ; use = use->getNext() ) {
-                        if ( SP_IS_USE(use) ) {
-                            SP_USE(use)->doWriteTransform(use->getRepr(), item->transform.inverse(), NULL, compensate);
+                if (dynamic_cast<SPFlowregion *>(region) || dynamic_cast<SPFlowregionExclude *>(region)) {
+                    for ( SPObject *item = region->firstChild() ; item ; item = item->getNext() ) {
+                        SPUse *use = dynamic_cast<SPUse *>(item);
+                        if ( use ) {
+                            use->doWriteTransform(use->getRepr(), use->transform.inverse(), NULL, compensate);
                         }
                     }
                 }
@@ -1573,7 +1607,15 @@ void sp_selection_apply_affine(Inkscape::Selection *selection, Geom::Affine cons
             item->readAttr( "transform" );
 
             // calculate the matrix we need to apply to the clone to cancel its induced transform from its original
-            Geom::Affine parent2dt = SP_ITEM(item->parent)->i2dt_affine();
+            Geom::Affine parent2dt;
+            {
+                SPItem *parentItem = dynamic_cast<SPItem *>(item->parent);
+                if (parentItem) {
+                    parent2dt = parentItem->i2dt_affine();
+                } else {
+                    g_assert_not_reached();
+                }
+            }
             Geom::Affine t = parent2dt * affine * parent2dt.inverse();
             Geom::Affine t_inv = t.inverse();
             Geom::Affine result = t_inv * item->transform * t;
@@ -1582,7 +1624,15 @@ void sp_selection_apply_affine(Inkscape::Selection *selection, Geom::Affine cons
                 // we need to cancel out the move compensation, too
 
                 // find out the clone move, same as in sp_use_move_compensate
-                Geom::Affine parent = SP_USE(item)->get_parent_transform();
+                Geom::Affine parent;
+                {
+                    SPUse *use = dynamic_cast<SPUse *>(item);
+                    if (use) {
+                        parent = use->get_parent_transform();
+                    } else {
+                        g_assert_not_reached();
+                    }
+                }
                 Geom::Affine clone_move = parent.inverse() * t * parent;
 
                 if (prefs_parallel) {
@@ -1743,8 +1793,12 @@ void sp_selection_rotate_90(SPDesktop *desktop, bool ccw)
     GSList const *l = selection->itemList();
     Geom::Rotate const rot_90(Geom::Point(0, ccw ? 1 : -1)); // pos. or neg. rotation, depending on the value of ccw
     for (GSList const *l2 = l ; l2 != NULL ; l2 = l2->next) {
-        SPItem *item = SP_ITEM(l2->data);
-        sp_item_rotate_rel(item, rot_90);
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(l2->data));
+        if (item) {
+            sp_item_rotate_rel(item, rot_90);
+        } else {
+            g_assert_not_reached();
+        }
     }
 
     DocumentUndo::done(sp_desktop_document(desktop),
@@ -1802,7 +1856,7 @@ void sp_select_same_fill_stroke_style(SPDesktop *desktop, gboolean fill, gboolea
     Inkscape::Selection *selection = sp_desktop_selection (desktop);
 
     for (GSList const* sel_iter = selection->itemList(); sel_iter; sel_iter = sel_iter->next) {
-        SPItem *sel = SP_ITEM(sel_iter->data);
+        SPItem *sel = dynamic_cast<SPItem *>(static_cast<SPObject *>(sel_iter->data));
         GSList *matches = all_list;
         if (fill) {
             matches = sp_get_same_fill_or_stroke_color(sel, matches, SP_FILL_COLOR);
@@ -1855,8 +1909,12 @@ void sp_select_same_object_type(SPDesktop *desktop)
     Inkscape::Selection *selection = sp_desktop_selection (desktop);
 
     for (GSList const* sel_iter = selection->itemList(); sel_iter; sel_iter = sel_iter->next) {
-        SPItem *sel = SP_ITEM(sel_iter->data);
-        matches = sp_get_same_object_type(sel, matches);
+        SPItem *sel = dynamic_cast<SPItem *>(static_cast<SPObject *>(sel_iter->data));
+        if (sel) {
+            matches = sp_get_same_object_type(sel, matches);
+        } else {
+            g_assert_not_reached();
+        }
     }
 
     selection->clear();
@@ -1893,10 +1951,14 @@ void sp_select_same_stroke_style(SPDesktop *desktop)
     Inkscape::Selection *selection = sp_desktop_selection (desktop);
 
     for (GSList const* sel_iter = selection->itemList(); sel_iter; sel_iter = sel_iter->next) {
-        SPItem *sel = SP_ITEM(sel_iter->data);
-        matches = sp_get_same_stroke_style(sel, matches, SP_STROKE_STYLE_WIDTH);
-        matches = sp_get_same_stroke_style(sel, matches, SP_STROKE_STYLE_DASHES);
-        matches = sp_get_same_stroke_style(sel, matches, SP_STROKE_STYLE_MARKERS);
+        SPItem *sel = dynamic_cast<SPItem *>(static_cast<SPObject *>(sel_iter->data));
+        if (sel) {
+            matches = sp_get_same_stroke_style(sel, matches, SP_STROKE_STYLE_WIDTH);
+            matches = sp_get_same_stroke_style(sel, matches, SP_STROKE_STYLE_DASHES);
+            matches = sp_get_same_stroke_style(sel, matches, SP_STROKE_STYLE_MARKERS);
+        } else {
+            g_assert_not_reached();
+        }
     }
 
     selection->clear();
@@ -1922,45 +1984,49 @@ GSList *sp_get_same_fill_or_stroke_color(SPItem *sel, GSList *src, SPSelectStrok
     SPIPaint *sel_paint = (type == SP_FILL_COLOR) ? &(sel->style->fill) : &(sel->style->stroke);
 
     for (GSList *i = src; i != NULL; i = i->next) {
-        SPItem *iter = SP_ITEM(i->data);
-        SPIPaint *iter_paint = (type == SP_FILL_COLOR) ? &(iter->style->fill) : &(iter->style->stroke);
-        match = false;
-        if (sel_paint->isColor() && iter_paint->isColor() // color == color comparision doesnt seem to work here.
+        SPItem *iter = dynamic_cast<SPItem *>(static_cast<SPObject *>(i->data));
+        if (iter) {
+            SPIPaint *iter_paint = (type == SP_FILL_COLOR) ? &(iter->style->fill) : &(iter->style->stroke);
+            match = false;
+            if (sel_paint->isColor() && iter_paint->isColor() // color == color comparision doesnt seem to work here.
                 && (sel_paint->value.color.toRGBA32(1.0) == iter_paint->value.color.toRGBA32(1.0))) {
-            match = true;
-        } else if (sel_paint->isPaintserver() && iter_paint->isPaintserver()) {
+                match = true;
+            } else if (sel_paint->isPaintserver() && iter_paint->isPaintserver()) {
 
-            SPPaintServer *sel_server =
+                SPPaintServer *sel_server =
                     (type == SP_FILL_COLOR) ? sel->style->getFillPaintServer() : sel->style->getStrokePaintServer();
-            SPPaintServer *iter_server =
+                SPPaintServer *iter_server =
                     (type == SP_FILL_COLOR) ? iter->style->getFillPaintServer() : iter->style->getStrokePaintServer();
 
-            if ((SP_IS_LINEARGRADIENT(sel_server) || SP_IS_RADIALGRADIENT(sel_server) ||
-                    (SP_IS_GRADIENT(sel_server) && SP_GRADIENT(sel_server)->getVector()->isSwatch()))
+                if ((dynamic_cast<SPLinearGradient *>(sel_server) || dynamic_cast<SPRadialGradient *>(sel_server) ||
+                     (dynamic_cast<SPGradient *>(sel_server) && dynamic_cast<SPGradient *>(sel_server)->getVector()->isSwatch()))
                     &&
-                 (SP_IS_LINEARGRADIENT(iter_server) || SP_IS_RADIALGRADIENT(iter_server) ||
-                    (SP_IS_GRADIENT(iter_server) && SP_GRADIENT(iter_server)->getVector()->isSwatch()))) {
-                SPGradient *sel_vector = SP_GRADIENT(sel_server)->getVector();
-                SPGradient *iter_vector = SP_GRADIENT(iter_server)->getVector();
-                if (sel_vector == iter_vector) {
-                    match = true;
-                }
+                    (dynamic_cast<SPLinearGradient *>(iter_server) || dynamic_cast<SPRadialGradient *>(iter_server) ||
+                     (dynamic_cast<SPGradient *>(iter_server) && dynamic_cast<SPGradient *>(iter_server)->getVector()->isSwatch()))) {
+                    SPGradient *sel_vector = dynamic_cast<SPGradient *>(sel_server)->getVector();
+                    SPGradient *iter_vector = dynamic_cast<SPGradient *>(iter_server)->getVector();
+                    if (sel_vector == iter_vector) {
+                        match = true;
+                    }
 
-            } else if (SP_IS_PATTERN(sel_server) && SP_IS_PATTERN(iter_server)) {
-                SPPattern *sel_pat = pattern_getroot(SP_PATTERN(sel_server));
-                SPPattern *iter_pat = pattern_getroot(SP_PATTERN(iter_server));
-                if (sel_pat == iter_pat) {
-                    match = true;
+                } else if (dynamic_cast<SPPattern *>(sel_server) && dynamic_cast<SPPattern *>(iter_server)) {
+                    SPPattern *sel_pat = pattern_getroot(dynamic_cast<SPPattern *>(sel_server));
+                    SPPattern *iter_pat = pattern_getroot(dynamic_cast<SPPattern *>(iter_server));
+                    if (sel_pat == iter_pat) {
+                        match = true;
+                    }
                 }
+            } else if (sel_paint->isNone() && iter_paint->isNone()) {
+                match = true;
+            } else if (sel_paint->isNoneSet() && iter_paint->isNoneSet()) {
+                match = true;
             }
-        } else if (sel_paint->isNone() && iter_paint->isNone()) {
-            match = true;
-        } else if (sel_paint->isNoneSet() && iter_paint->isNoneSet()) {
-            match = true;
-        }
 
-        if (match) {
-            matches = g_slist_prepend(matches, iter);
+            if (match) {
+                matches = g_slist_prepend(matches, iter);
+            }
+        } else {
+            g_assert_not_reached();
         }
     }
 
@@ -1969,35 +2035,35 @@ GSList *sp_get_same_fill_or_stroke_color(SPItem *sel, GSList *src, SPSelectStrok
 
 static bool item_type_match (SPItem *i, SPItem *j)
 {
-    if ( SP_IS_RECT(i)) {
-        return ( SP_IS_RECT(j) );
+    if ( dynamic_cast<SPRect *>(i)) {
+        return ( dynamic_cast<SPRect *>(j) );
 
-    } else if (SP_IS_GENERICELLIPSE(i)) {
-        return (SP_IS_GENERICELLIPSE(j));
+    } else if (dynamic_cast<SPGenericEllipse *>(i)) {
+        return (dynamic_cast<SPGenericEllipse *>(j));
 
-    } else if (SP_IS_STAR(i) || SP_IS_POLYGON(i)) {
-        return (SP_IS_STAR(j) || SP_IS_POLYGON(j)) ;
+    } else if (dynamic_cast<SPStar *>(i) || dynamic_cast<SPPolygon *>(i)) {
+        return (dynamic_cast<SPStar *>(j) || dynamic_cast<SPPolygon *>(j)) ;
 
-    } else if (SP_IS_SPIRAL(i)) {
-        return (SP_IS_SPIRAL(j));
+    } else if (dynamic_cast<SPSpiral *>(i)) {
+        return (dynamic_cast<SPSpiral *>(j));
 
-    } else if (SP_IS_PATH(i) || SP_IS_LINE(i) || SP_IS_POLYLINE(i)) {
-        return (SP_IS_PATH(j) || SP_IS_LINE(j) || SP_IS_POLYLINE(j));
+    } else if (dynamic_cast<SPPath *>(i) || dynamic_cast<SPLine *>(i) || dynamic_cast<SPPolyLine *>(i)) {
+        return (dynamic_cast<SPPath *>(j) || dynamic_cast<SPLine *>(j) || dynamic_cast<SPPolyLine *>(j));
 
-    } else if (SP_IS_TEXT(i) || SP_IS_FLOWTEXT(i) || SP_IS_TSPAN(i) || SP_IS_TREF(i) || SP_IS_STRING(i)) {
-        return (SP_IS_TEXT(j) || SP_IS_FLOWTEXT(j) || SP_IS_TSPAN(j) || SP_IS_TREF(j) || SP_IS_STRING(j));
+    } else if (dynamic_cast<SPText *>(i) || dynamic_cast<SPFlowtext *>(i) || dynamic_cast<SPTSpan *>(i) || dynamic_cast<SPTRef *>(i) || dynamic_cast<SPString *>(i)) {
+        return (dynamic_cast<SPText *>(j) || dynamic_cast<SPFlowtext *>(j) || dynamic_cast<SPTSpan *>(j) || dynamic_cast<SPTRef *>(j) || dynamic_cast<SPString *>(j));
 
-    }  else if (SP_IS_USE(i)) {
-        return (SP_IS_USE(j)) ;
+    }  else if (dynamic_cast<SPUse *>(i)) {
+        return (dynamic_cast<SPUse *>(j)) ;
 
-    } else if (SP_IS_IMAGE(i)) {
-        return (SP_IS_IMAGE(j));
+    } else if (dynamic_cast<SPImage *>(i)) {
+        return (dynamic_cast<SPImage *>(j));
 
-    } else if (SP_IS_OFFSET(i) && SP_OFFSET(i)->sourceHref) {   // Linked offset
-        return (SP_IS_OFFSET(j) && SP_OFFSET(j)->sourceHref);
+    } else if (dynamic_cast<SPOffset *>(i) && dynamic_cast<SPOffset *>(i)->sourceHref) {   // Linked offset
+        return (dynamic_cast<SPOffset *>(j) && dynamic_cast<SPOffset *>(j)->sourceHref);
 
-    }  else if (SP_IS_OFFSET(i) && !SP_OFFSET(i)->sourceHref) { // Dynamic offset
-        return (SP_IS_OFFSET(j) && !SP_OFFSET(j)->sourceHref);
+    }  else if (dynamic_cast<SPOffset *>(i) && !dynamic_cast<SPOffset *>(i)->sourceHref) { // Dynamic offset
+        return (dynamic_cast<SPOffset *>(j) && !dynamic_cast<SPOffset *>(j)->sourceHref);
 
     }
 
@@ -2013,8 +2079,8 @@ GSList *sp_get_same_object_type(SPItem *sel, GSList *src)
     GSList *matches = NULL;
 
     for (GSList *i = src; i != NULL; i = i->next) {
-        SPItem *item = SP_ITEM(i->data);
-        if (item_type_match (sel, item)) {
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(i->data));
+        if (item && item_type_match(sel, item)) {
             matches = g_slist_prepend (matches, item);
         }
     }
@@ -2050,31 +2116,32 @@ GSList *sp_get_same_stroke_style(SPItem *sel, GSList *src, SPSelectStrokeStyleTy
     }
 
     for (GSList *i = src; i != NULL; i = i->next) {
-        SPItem *iter = SP_ITEM(i->data);
-        SPStyle *iter_style = iter->style;
-        match = false;
-
-        if (type == SP_STROKE_STYLE_WIDTH) {
-            match = (sel_style->stroke_width.set == iter_style->stroke_width.set);
-            if (sel_style->stroke_width.set && iter_style->stroke_width.set) {
-                GSList *objects = NULL;
-                objects = g_slist_prepend(objects, iter);
-                SPStyle *iter_style_for_width = sp_style_new (SP_ACTIVE_DOCUMENT);
-                objects_query_strokewidth (objects, iter_style_for_width);
-
-                if (sel_style_for_width) {
-                    match = (sel_style_for_width->stroke_width.computed == iter_style_for_width->stroke_width.computed);
+        SPItem *iter = dynamic_cast<SPItem *>(static_cast<SPObject *>(i->data));
+        if (iter) {
+            SPStyle *iter_style = iter->style;
+            match = false;
+
+            if (type == SP_STROKE_STYLE_WIDTH) {
+                match = (sel_style->stroke_width.set == iter_style->stroke_width.set);
+                if (sel_style->stroke_width.set && iter_style->stroke_width.set) {
+                    GSList *objects = NULL;
+                    objects = g_slist_prepend(objects, iter);
+                    SPStyle *iter_style_for_width = sp_style_new (SP_ACTIVE_DOCUMENT);
+                    objects_query_strokewidth (objects, iter_style_for_width);
+
+                    if (sel_style_for_width) {
+                        match = (sel_style_for_width->stroke_width.computed == iter_style_for_width->stroke_width.computed);
+                    }
+                    g_slist_free(objects);
                 }
-                g_slist_free(objects);
             }
-        }
-        else if (type == SP_STROKE_STYLE_DASHES ) {
-            match = (sel_style->stroke_dasharray.set == iter_style->stroke_dasharray.set);
-            if (sel_style->stroke_dasharray.set && iter_style->stroke_dasharray.set) {
-                match = (sel_style->stroke_dasharray.values == iter_style->stroke_dasharray.values);
+            else if (type == SP_STROKE_STYLE_DASHES ) {
+                match = (sel_style->stroke_dasharray.set == iter_style->stroke_dasharray.set);
+                if (sel_style->stroke_dasharray.set && iter_style->stroke_dasharray.set) {
+                    match = (sel_style->stroke_dasharray.values == iter_style->stroke_dasharray.values);
+                }
             }
-        }
-        else if (type == SP_STROKE_STYLE_MARKERS) {
+            else if (type == SP_STROKE_STYLE_MARKERS) {
                 match = true;
                 int len = sizeof(sel_style->marker)/sizeof(SPIString);
                 for (int i = 0; i < len; i++) {
@@ -2085,10 +2152,13 @@ GSList *sp_get_same_stroke_style(SPItem *sel, GSList *src, SPSelectStrokeStyleTy
                         break;
                     }
                 }
-        }
+            }
 
-        if (match) {
-            matches = g_slist_prepend(matches, iter);
+            if (match) {
+                matches = g_slist_prepend(matches, iter);
+            }
+        } else {
+            g_assert_not_reached();
         }
     }
 
@@ -2435,7 +2505,7 @@ SPItem *next_item_from_list(SPDesktop *desktop, GSList const *items,
 {
     SPObject *current=root;
     while (items) {
-        SPItem *item=SP_ITEM(items->data);
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(items->data));
         if ( root->isAncestorOf(item) &&
              ( !only_in_viewport || desktop->isWithinViewport(item) ) )
         {
@@ -2489,13 +2559,16 @@ SPItem *next_item(SPDesktop *desktop, GSList *path, SPObject *root,
             if (PREFS_SELECTION_LAYER != inlayer) { // recurse into sublayers
                 found = next_item<D>(desktop, NULL, object, only_in_viewport, inlayer, onlyvisible, onlysensitive);
             }
-        } else if ( SP_IS_ITEM(object) &&
-                    ( !only_in_viewport || desktop->isWithinViewport(SP_ITEM(object)) ) &&
-                    ( !onlyvisible || !desktop->itemIsHidden(SP_ITEM(object))) &&
-                    ( !onlysensitive || !SP_ITEM(object)->isLocked()) &&
-                    !desktop->isLayer(SP_ITEM(object)) )
-        {
-            found = SP_ITEM(object);
+        } else {
+            SPItem *item = dynamic_cast<SPItem *>(object);
+            if ( item &&
+                 ( !only_in_viewport || desktop->isWithinViewport(item) ) &&
+                 ( !onlyvisible || !desktop->itemIsHidden(item)) &&
+                 ( !onlysensitive || !item->isLocked()) &&
+                 !desktop->isLayer(item) )
+            {
+                found = item;
+            }
         }
         iter = D::next(iter);
     }
@@ -2613,12 +2686,11 @@ sp_selection_relink(SPDesktop *desktop)
     {
         SPItem *item = static_cast<SPItem *>(items->data);
 
-        if (!SP_IS_USE(item))
-            continue;
-
-        item->getRepr()->setAttribute("xlink:href", newref);
-        item->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
-        relinked = true;
+        if (dynamic_cast<SPUse *>(item)) {
+            item->getRepr()->setAttribute("xlink:href", newref);
+            item->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+            relinked = true;
+        }
     }
 
     g_free(newref);
@@ -2654,7 +2726,7 @@ sp_selection_unlink(SPDesktop *desktop)
     {
         SPItem *item = static_cast<SPItem *>(items->data);
 
-        if (SP_IS_TEXT(item)) {
+        if (dynamic_cast<SPText *>(item)) {
             SPObject *tspan = sp_tref_convert_to_tspan(item);
 
             if (tspan) {
@@ -2666,22 +2738,24 @@ sp_selection_unlink(SPDesktop *desktop)
             unlinked = true;
         }
 
-        if (!(SP_IS_USE(item) || SP_IS_TREF(item))) {
+        if (!(dynamic_cast<SPUse *>(item) || dynamic_cast<SPTRef *>(item))) {
             // keep the non-use item in the new selection
             new_select = g_slist_prepend(new_select, item);
             continue;
         }
 
-        SPItem *unlink;
-        if (SP_IS_USE(item)) {
-            unlink = SP_USE(item)->unlink();
+        SPItem *unlink = NULL;
+        SPUse *use = dynamic_cast<SPUse *>(item);
+        if (use) {
+            unlink = use->unlink();
             // Unable to unlink use (external or invalid href?)
             if (!unlink) {
                 new_select = g_slist_prepend(new_select, item);
                 continue;
             }
         } else /*if (SP_IS_TREF(use))*/ {
-            unlink = SP_ITEM(sp_tref_convert_to_tspan(item));
+            unlink = dynamic_cast<SPItem *>(sp_tref_convert_to_tspan(item));
+            g_assert(unlink != NULL);
         }
 
         unlinked = true;
@@ -2721,24 +2795,39 @@ sp_select_clone_original(SPDesktop *desktop)
     }
 
     SPItem *original = NULL;
-    if (SP_IS_USE(item)) {
-        original = SP_USE(item)->get_original();
-    } else if (SP_IS_OFFSET(item) && SP_OFFSET(item)->sourceHref) {
-        original = sp_offset_get_source(SP_OFFSET(item));
-    } else if (SP_IS_TEXT_TEXTPATH(item)) {
-        original = sp_textpath_get_path_item(SP_TEXTPATH(item->firstChild()));
-    } else if (SP_IS_FLOWTEXT(item)) {
-        original = SP_FLOWTEXT(item)->get_frame(NULL); // first frame only
-    } else if (SP_IS_LPE_ITEM(item)) {
-        // check if the applied LPE is Clone original, if so, go to the refered path
-        Inkscape::LivePathEffect::Effect* lpe = SP_LPE_ITEM(item)->getPathEffectOfType(Inkscape::LivePathEffect::CLONE_ORIGINAL);
-        if (lpe) {
-            Inkscape::LivePathEffect::Parameter *lpeparam = lpe->getParameter("linkedpath");
-            if (Inkscape::LivePathEffect::OriginalPathParam *pathparam = dynamic_cast<Inkscape::LivePathEffect::OriginalPathParam *>(lpeparam)) {
-                original = pathparam->getObject();
+    SPUse *use = dynamic_cast<SPUse *>(item);
+    if (use) {
+        original = use->get_original();
+    } else {
+        SPOffset *offset = dynamic_cast<SPOffset *>(item);
+        if (offset && offset->sourceHref) {
+            original = sp_offset_get_source(offset);
+        } else {
+            SPText *text = dynamic_cast<SPText *>(item);
+            SPTextPath *textpath = (text) ? dynamic_cast<SPTextPath *>(text->firstChild()) : NULL;
+            if (text && textpath) {
+                original = sp_textpath_get_path_item(textpath);
+            } else {
+                SPFlowtext *flowtext = dynamic_cast<SPFlowtext *>(item);
+                if (flowtext) {
+                    original = flowtext->get_frame(NULL); // first frame only
+                } else {
+                    SPLPEItem *lpeItem = dynamic_cast<SPLPEItem *>(item);
+                    if (lpeItem) {
+                        // check if the applied LPE is Clone original, if so, go to the refered path
+                        Inkscape::LivePathEffect::Effect* lpe = lpeItem->getPathEffectOfType(Inkscape::LivePathEffect::CLONE_ORIGINAL);
+                        if (lpe) {
+                            Inkscape::LivePathEffect::Parameter *lpeparam = lpe->getParameter("linkedpath");
+                            if (Inkscape::LivePathEffect::OriginalPathParam *pathparam = dynamic_cast<Inkscape::LivePathEffect::OriginalPathParam *>(lpeparam)) {
+                                original = pathparam->getObject();
+                            }
+                        }
+                    }
+                }
             }
         }
     }
+
     if (original == NULL) { // it's an object that we don't know what to do with
         desktop->messageStack()->flash(Inkscape::WARNING_MESSAGE, error);
         return;
@@ -2749,8 +2838,8 @@ sp_select_clone_original(SPDesktop *desktop)
         return;
     }
 
-    for (SPObject *o = original; o && !SP_IS_ROOT(o); o = o->parent) {
-        if (SP_IS_DEFS(o)) {
+    for (SPObject *o = original; o && !dynamic_cast<SPRoot *>(o); o = o->parent) {
+        if (dynamic_cast<SPDefs *>(o)) {
             desktop->messageStack()->flash(Inkscape::ERROR_MESSAGE, _("The object you're trying to select is <b>not visible</b> (it is in &lt;defs&gt;)"));
             return;
         }
@@ -2826,16 +2915,15 @@ void sp_selection_clone_original_path_lpe(SPDesktop *desktop)
             // add the new clone to the top of the original's parent
             parent->appendChildRepr(clone);
             SPObject *clone_obj = desktop->doc()->getObjectById(clone->attribute("id"));
-            if (SP_IS_LPE_ITEM(clone_obj)) {
+            SPLPEItem *clone_lpeitem = dynamic_cast<SPLPEItem *>(clone_obj);
+            if (clone_lpeitem) {
                 gchar *href = g_strdup_printf("#%s", lpe_id);
-                //sp_lpe_item_add_path_effect( SP_LPE_ITEM(clone_obj), href, false );
-                SP_LPE_ITEM(clone_obj)->addPathEffect(href, false);
+                clone_lpeitem->addPathEffect(href, false);
                 g_free(href);
             }
         }
 
-        DocumentUndo::done(sp_desktop_document(desktop), SP_VERB_EDIT_CLONE_ORIGINAL_PATH_LPE,
-                            _("Fill between strokes"));
+        DocumentUndo::done(sp_desktop_document(desktop), SP_VERB_EDIT_CLONE_ORIGINAL_PATH_LPE, _("Fill between many"));
     } else {
         desktop->messageStack()->flash(Inkscape::WARNING_MESSAGE, _("Select path(s) to fill."));
     }
@@ -2885,7 +2973,15 @@ void sp_selection_to_marker(SPDesktop *desktop, bool apply)
     // bottommost object, after sorting
     SPObject *parent = SP_OBJECT(items->data)->parent;
 
-    Geom::Affine parent_transform(SP_ITEM(parent)->i2doc_affine());
+    Geom::Affine parent_transform;
+    {
+        SPItem *parentItem = dynamic_cast<SPItem *>(parent);
+        if (parent) {
+            parent_transform = parentItem->i2doc_affine();
+        } else {
+            g_assert_not_reached();
+        }
+    }
 
     // Create a list of duplicates, to be pasted inside marker element.
     GSList *repr_copies = NULL;
@@ -2926,8 +3022,9 @@ void sp_selection_to_marker(SPDesktop *desktop, bool apply)
 }
 
 static void sp_selection_to_guides_recursive(SPItem *item, bool wholegroups) {
-    if (SP_IS_GROUP(item) && !SP_IS_BOX3D(item) && !wholegroups) {
-        for (GSList *i = sp_item_group_item_list(SP_GROUP(item)); i != NULL; i = i->next) {
+    SPGroup *group = dynamic_cast<SPGroup *>(item);
+    if (group && !dynamic_cast<SPBox3D *>(item) && !wholegroups) {
+        for (GSList *i = sp_item_group_item_list(group); i != NULL; i = i->next) {
             sp_selection_to_guides_recursive(static_cast<SPItem*>(i->data), wholegroups);
         }
     } else {
@@ -3019,13 +3116,13 @@ void sp_selection_symbol(SPDesktop *desktop, bool /*apply*/ )
 
     // Find out if we have a single group
     bool single_group = false;
-    SPObject *the_group = NULL;
+    SPGroup *the_group = NULL;
     Geom::Affine transform;
     if( g_slist_length( items ) == 1 ) {
         SPObject *object = reinterpret_cast<SPObject *>( items->data );
-        if( SP_IS_GROUP( object ) ) {
+        the_group = dynamic_cast<SPGroup *>(object);
+        if ( the_group ) {
             single_group = true;
-            the_group = object;
 
             if( !sp_svg_transform_read( object->getAttribute("transform"), &transform ))
                 transform = Geom::identity();
@@ -3044,7 +3141,7 @@ void sp_selection_symbol(SPDesktop *desktop, bool /*apply*/ )
                 prefs->setInt("/options/clonecompensation/value", SP_CLONE_COMPENSATION_UNMOVED);
 
                 // Remove transform on group, updating clones.
-                SP_ITEM(object)->doWriteTransform(object->getRepr(), Geom::identity());
+                the_group->doWriteTransform(object->getRepr(), Geom::identity());
 
                 // restore compensation setting
                 prefs->setInt("/options/clonecompensation/value", saved_compensation);
@@ -3138,7 +3235,7 @@ void sp_selection_unsymbol(SPDesktop *desktop)
  
     // Make sure we have only one object in selection.
     // Require that we really have a <symbol>.
-    if( symbol == NULL || !SP_IS_SYMBOL( symbol ))  {
+    if( symbol == NULL || !dynamic_cast<SPSymbol *>( symbol ))  {
         desktop->messageStack()->flash(Inkscape::WARNING_MESSAGE, _("Select only one <b>symbol</b> in Symbol dialog to convert to group."));
         return;
     }
@@ -3157,7 +3254,7 @@ void sp_selection_unsymbol(SPDesktop *desktop)
     // group that only adds a transform to the symbol content).
     if( g_slist_length( children ) == 1 ) {
         SPObject *object = reinterpret_cast<SPObject *>( children->data );
-        if( SP_IS_GROUP( object ) ) {
+        if ( dynamic_cast<SPGroup *>( object ) ) {
             if( object->getAttribute("style") == NULL ||
                 object->getAttribute("class") == NULL ) {
 
@@ -3236,8 +3333,17 @@ sp_selection_tile(SPDesktop *desktop, bool apply)
 
     // bottommost object, after sorting
     SPObject *parent = SP_OBJECT(items->data)->parent;
+    
 
-    Geom::Affine parent_transform(SP_ITEM(parent)->i2doc_affine());
+    Geom::Affine parent_transform;
+    {
+        SPItem *parentItem = dynamic_cast<SPItem *>(parent);
+        if (parentItem) {
+            parent_transform = parentItem->i2doc_affine();
+        } else {
+            g_assert_not_reached();
+        }
+    }
 
     // remember the position of the first item
     gint pos = SP_OBJECT(items->data)->getRepr()->position();
@@ -3342,20 +3448,22 @@ void sp_selection_untile(SPDesktop *desktop)
 
         SPPaintServer *server = item->style->getFillPaintServer();
 
-        if (!SP_IS_PATTERN(server))
+        SPPattern *basePat = dynamic_cast<SPPattern *>(server);
+        if (!basePat) {
             continue;
+        }
 
         did = true;
 
-        SPPattern *pattern = pattern_getroot(SP_PATTERN(server));
+        SPPattern *pattern = pattern_getroot(basePat);
 
-        Geom::Affine pat_transform = pattern_patternTransform(SP_PATTERN(server));
+        Geom::Affine pat_transform = pattern_patternTransform(basePat);
         pat_transform *= item->transform;
 
         for (SPObject *child = pattern->firstChild() ; child != NULL; child = child->next ) {
-            if (SP_IS_ITEM(child)) {
+            if (dynamic_cast<SPItem *>(child)) {
                 Inkscape::XML::Node *copy = child->getRepr()->duplicate(xml_doc);
-                SPItem *i = SP_ITEM(desktop->currentLayer()->appendChildRepr(copy));
+                SPItem *i = dynamic_cast<SPItem *>(desktop->currentLayer()->appendChildRepr(copy));
 
                // FIXME: relink clones to the new canvas objects
                // use SPObject::setid when mental finishes it to steal ids of
@@ -3363,10 +3471,14 @@ void sp_selection_untile(SPDesktop *desktop)
                 // this is needed to make sure the new item has curve (simply requestDisplayUpdate does not work)
                 doc->ensureUpToDate();
 
-                Geom::Affine transform( i->transform * pat_transform );
-                i->doWriteTransform(i->getRepr(), transform);
+                if (i) {
+                    Geom::Affine transform( i->transform * pat_transform );
+                    i->doWriteTransform(i->getRepr(), transform);
 
-                new_select = g_slist_prepend(new_select, i);
+                    new_select = g_slist_prepend(new_select, i);
+                } else {
+                    g_assert_not_reached();
+                }
             }
         }
 
@@ -3584,7 +3696,15 @@ void sp_selection_create_bitmap_copy(SPDesktop *desktop)
     }
 
     // Calculate the matrix that will be applied to the image so that it exactly overlaps the source objects
-    Geom::Affine eek(SP_ITEM(parent_object)->i2dt_affine());
+    Geom::Affine eek;
+    {
+        SPItem *parentItem = dynamic_cast<SPItem *>(parent_object);
+        if (parentItem) {
+            eek = parentItem->i2dt_affine();
+        } else {
+            g_assert_not_reached();
+        }
+    }
     Geom::Affine t;
 
     double shift_x = bbox->min()[Geom::X];
@@ -4042,14 +4162,14 @@ void sp_selection_unset_mask(SPDesktop *desktop, bool apply_clip_path) {
 
         SP_OBJECT(i->data)->getRepr()->setAttribute(attributeName, "none");
 
-        if (ungroup_masked && SP_IS_GROUP(i->data)) {
+        SPGroup *group = dynamic_cast<SPGroup *>(static_cast<SPObject *>(i->data));
+        if (ungroup_masked && group) {
                 // if we had previously enclosed masked object in group,
                 // add it to list so we can ungroup it later
-                SPGroup *item = SP_GROUP(i->data);
 
                 // ungroup only groups we created when setting clip/mask
-                if (item->layerMode() == SPGroup::MASK_HELPER) {
-                    items_to_ungroup = g_slist_prepend(items_to_ungroup, item);
+                if (group->layerMode() == SPGroup::MASK_HELPER) {
+                    items_to_ungroup = g_slist_prepend(items_to_ungroup, group);
                 }
 
         }
@@ -4101,10 +4221,15 @@ void sp_selection_unset_mask(SPDesktop *desktop, bool apply_clip_path) {
 
     // ungroup marked groups added when setting mask
     for (GSList *i = items_to_ungroup ; NULL != i ; i = i->next) {
-        items_to_select = g_slist_remove(items_to_select, SP_GROUP(i->data));
-        GSList *children = NULL;
-        sp_item_group_ungroup(SP_GROUP(i->data), &children, false);
-        items_to_select = g_slist_concat(children, items_to_select);
+        SPGroup *group = dynamic_cast<SPGroup *>(static_cast<SPObject *>(i->data));
+        if (group) {
+            items_to_select = g_slist_remove(items_to_select, group);
+            GSList *children = NULL;
+            sp_item_group_ungroup(group, &children, false);
+            items_to_select = g_slist_concat(children, items_to_select);
+        } else {
+            g_assert_not_reached();
+        }
     }
 
     g_slist_free(items_to_ungroup);
@@ -4212,12 +4337,16 @@ void fit_canvas_to_selection_or_drawing(SPDesktop *desktop) {
 
 static void itemtree_map(void (*f)(SPItem *, SPDesktop *), SPObject *root, SPDesktop *desktop) {
     // don't operate on layers
-    if (SP_IS_ITEM(root) && !desktop->isLayer(SP_ITEM(root))) {
-        f(SP_ITEM(root), desktop);
+    {
+        SPItem *item = dynamic_cast<SPItem *>(root);
+        if (item && !desktop->isLayer(item)) {
+            f(item, desktop);
+        }
     }
     for ( SPObject::SiblingIterator iter = root->firstChild() ; iter ; ++iter ) {
         //don't recurse into locked layers
-        if (!(SP_IS_ITEM(&*iter) && desktop->isLayer(SP_ITEM(&*iter)) && SP_ITEM(&*iter)->isLocked())) {
+        SPItem *item = dynamic_cast<SPItem *>(&*iter);
+        if (!(item && desktop->isLayer(item) && item->isLocked())) {
             itemtree_map(f, iter, desktop);
         }
     }
diff --git a/src/sp-item-group.cpp b/src/sp-item-group.cpp
index b2af3842e..613ace5c1 100644
--- a/src/sp-item-group.cpp
+++ b/src/sp-item-group.cpp
@@ -96,14 +96,14 @@ void SPGroup::child_added(Inkscape::XML::Node* child, Inkscape::XML::Node* ref)
 
     if (last_child && last_child->getRepr() == child) {
         // optimization for the common special case where the child is being added at the end
-        SPObject *ochild = last_child;
-        if ( SP_IS_ITEM(ochild) ) {
+        SPItem *item = dynamic_cast<SPItem *>(last_child);
+        if ( item ) {
             /* TODO: this should be moved into SPItem somehow */
             SPItemView *v;
             Inkscape::DrawingItem *ac;
 
             for (v = this->display; v != NULL; v = v->next) {
-                ac = SP_ITEM (ochild)->invoke_show (v->arenaitem->drawing(), v->key, v->flags);
+                ac = item->invoke_show (v->arenaitem->drawing(), v->key, v->flags);
 
                 if (ac) {
                     v->arenaitem->appendChild(ac);
@@ -111,16 +111,16 @@ void SPGroup::child_added(Inkscape::XML::Node* child, Inkscape::XML::Node* ref)
             }
         }
     } else {    // general case
-        SPObject *ochild = this->get_child_by_repr(child);
-        if ( ochild && SP_IS_ITEM(ochild) ) {
+        SPItem *item = dynamic_cast<SPItem *>(get_child_by_repr(child));
+        if ( item ) {
             /* TODO: this should be moved into SPItem somehow */
             SPItemView *v;
             Inkscape::DrawingItem *ac;
 
-            unsigned position = SP_ITEM(ochild)->pos_in_parent();
+            unsigned position = item->pos_in_parent();
 
             for (v = this->display; v != NULL; v = v->next) {
-                ac = SP_ITEM (ochild)->invoke_show (v->arenaitem->drawing(), v->key, v->flags);
+                ac = item->invoke_show (v->arenaitem->drawing(), v->key, v->flags);
 
                 if (ac) {
                     v->arenaitem->prependChild(ac);
@@ -145,12 +145,12 @@ void SPGroup::order_changed (Inkscape::XML::Node *child, Inkscape::XML::Node *ol
 {
 	SPLPEItem::order_changed(child, old_ref, new_ref);
 
-    SPObject *ochild = this->get_child_by_repr(child);
-    if ( ochild && SP_IS_ITEM(ochild) ) {
+    SPItem *item = dynamic_cast<SPItem *>(get_child_by_repr(child));
+    if ( item ) {
         /* TODO: this should be moved into SPItem somehow */
         SPItemView *v;
-        unsigned position = SP_ITEM(ochild)->pos_in_parent();
-        for ( v = SP_ITEM (ochild)->display ; v != NULL ; v = v->next ) {
+        unsigned position = item->pos_in_parent();
+        for ( v = item->display ; v != NULL ; v = v->next ) {
             v->arenaitem->setZOrder(position);
         }
     }
@@ -177,10 +177,10 @@ void SPGroup::update(SPCtx *ctx, unsigned int flags) {
         l = g_slist_remove (l, child);
 
         if (childflags || (child->uflags & (SP_OBJECT_MODIFIED_FLAG | SP_OBJECT_CHILD_MODIFIED_FLAG))) {
-            if (SP_IS_ITEM (child)) {
-                SPItem const &chi = *SP_ITEM(child);
-                cctx.i2doc = chi.transform * ictx->i2doc;
-                cctx.i2vp = chi.transform * ictx->i2vp;
+            SPItem *item = dynamic_cast<SPItem *>(child);
+            if (item) {
+                cctx.i2doc = item->transform * ictx->i2doc;
+                cctx.i2vp = item->transform * ictx->i2vp;
                 child->updateDisplay((SPCtx *)&cctx, childflags);
             } else {
                 child->updateDisplay(ctx, childflags);
@@ -230,14 +230,11 @@ void SPGroup::modified(guint flags) {
 }
 
 Inkscape::XML::Node* SPGroup::write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags) {
-	SPGroup* object = this;
-    SPGroup *group = SP_GROUP(object);
-
     if (flags & SP_OBJECT_WRITE_BUILD) {
-        GSList *l;
+        GSList *l = NULL;
 
         if (!repr) {
-            if (SP_IS_SWITCH(object)) {
+            if (dynamic_cast<SPSwitch *>(this)) {
                 repr = xml_doc->createElement("svg:switch");
             } else {
                 repr = xml_doc->createElement("svg:g");
@@ -246,8 +243,8 @@ Inkscape::XML::Node* SPGroup::write(Inkscape::XML::Document *xml_doc, Inkscape::
 
         l = NULL;
 
-        for (SPObject *child = object->firstChild(); child; child = child->getNext() ) {
-            if ( !SP_IS_TITLE(child) && !SP_IS_DESC(child) ) {
+        for (SPObject *child = firstChild(); child; child = child->getNext() ) {
+            if ( !dynamic_cast<SPTitle *>(child) && !dynamic_cast<SPDesc *>(child) ) {
                 Inkscape::XML::Node *crepr = child->updateRepr(xml_doc, NULL, flags);
 
                 if (crepr) {
@@ -262,8 +259,8 @@ Inkscape::XML::Node* SPGroup::write(Inkscape::XML::Document *xml_doc, Inkscape::
             l = g_slist_remove (l, l->data);
         }
     } else {
-        for (SPObject *child = object->firstChild() ; child ; child = child->getNext() ) {
-            if ( !SP_IS_TITLE(child) && !SP_IS_DESC(child) ) {
+        for (SPObject *child = firstChild() ; child ; child = child->getNext() ) {
+            if ( !dynamic_cast<SPTitle *>(child) && !dynamic_cast<SPDesc *>(child) ) {
                 child->updateRepr(flags);
             }
         }
@@ -271,9 +268,9 @@ Inkscape::XML::Node* SPGroup::write(Inkscape::XML::Document *xml_doc, Inkscape::
 
     if ( flags & SP_OBJECT_WRITE_EXT ) {
         const char *value;
-        if ( group->_layer_mode == SPGroup::LAYER ) {
+        if ( _layer_mode == SPGroup::LAYER ) {
             value = "layer";
-        } else if ( group->_layer_mode == SPGroup::MASK_HELPER ) {
+        } else if ( _layer_mode == SPGroup::MASK_HELPER ) {
             value = "maskhelper";
         } else if ( flags & SP_OBJECT_WRITE_ALL ) {
             value = "group";
@@ -293,16 +290,16 @@ Geom::OptRect SPGroup::bbox(Geom::Affine const &transform, SPItem::BBoxType bbox
 {
     Geom::OptRect bbox;
 
-    // CPPIFY: replace this const_cast later
+    // TODO CPPIFY: replace this const_cast later
     GSList *l = const_cast<SPGroup*>(this)->childList(false, SPObject::ActionBBox);
 
     while (l) {
         SPObject *o = SP_OBJECT (l->data);
 
-        if (SP_IS_ITEM(o) && !SP_ITEM(o)->isHidden()) {
-            SPItem *child = SP_ITEM(o);
-            Geom::Affine const ct(child->transform * transform);
-            bbox |= child->bounds(bboxtype, ct);
+        SPItem *item = dynamic_cast<SPItem *>(o);
+        if (item && !item->isHidden()) {
+            Geom::Affine const ct(item->transform * transform);
+            bbox |= item->bounds(bboxtype, ct);
         }
 
         l = g_slist_remove (l, o);
@@ -317,8 +314,9 @@ void SPGroup::print(SPPrintContext *ctx) {
     while (l) {
         SPObject *o = SP_OBJECT (l->data);
 
-        if (SP_IS_ITEM(o)) {
-            SP_ITEM(o)->invoke_print (ctx);
+        SPItem *item = dynamic_cast<SPItem *>(o);
+        if (item) {
+            item->invoke_print(ctx);
         }
 
         l = g_slist_remove (l, o);
@@ -365,16 +363,14 @@ Inkscape::DrawingItem *SPGroup::show (Inkscape::Drawing &drawing, unsigned int k
 }
 
 void SPGroup::hide (unsigned int key) {
-    SPItem * child;
-
     GSList *l = g_slist_reverse(this->childList(false, SPObject::ActionShow));
 
     while (l) {
         SPObject *o = SP_OBJECT (l->data);
 
-        if (SP_IS_ITEM (o)) {
-            child = SP_ITEM (o);
-            child->invoke_hide (key);
+        SPItem *item = dynamic_cast<SPItem *>(o);
+        if (item) {
+            item->invoke_hide(key);
         }
 
         l = g_slist_remove (l, o);
@@ -387,8 +383,9 @@ void SPGroup::hide (unsigned int key) {
 void SPGroup::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
     for ( SPObject const *o = this->firstChild(); o; o = o->getNext() )
     {
-        if (SP_IS_ITEM(o)) {
-            SP_ITEM(o)->getSnappoints(p, snapprefs);
+        SPItem const *item = dynamic_cast<SPItem const *>(o);
+        if (item) {
+            item->getSnappoints(p, snapprefs);
         }
     }
 }
@@ -398,14 +395,12 @@ void
 sp_item_group_ungroup (SPGroup *group, GSList **children, bool do_done)
 {
     g_return_if_fail (group != NULL);
-    g_return_if_fail (SP_IS_GROUP (group));
 
     SPDocument *doc = group->document;
     SPRoot *root = doc->getRoot();
     SPObject *defs = root->defs;
 
-    SPItem *gitem = group;
-    Inkscape::XML::Node *grepr = gitem->getRepr();
+    Inkscape::XML::Node *grepr = group->getRepr();
 
     g_return_if_fail (!strcmp (grepr->name(), "svg:g")
                    || !strcmp (grepr->name(), "svg:a")
@@ -413,33 +408,34 @@ sp_item_group_ungroup (SPGroup *group, GSList **children, bool do_done)
                    || !strcmp (grepr->name(), "svg:svg"));
 
     // this converts the gradient/pattern fill/stroke on the group, if any, to userSpaceOnUse
-    gitem->adjust_paint_recursive (Geom::identity(), Geom::identity(), false);
+    group->adjust_paint_recursive (Geom::identity(), Geom::identity(), false);
 
-    SPItem *pitem = SP_ITEM(gitem->parent);
+    SPItem *pitem = dynamic_cast<SPItem *>(group->parent);
+    g_assert(pitem);
     Inkscape::XML::Node *prepr = pitem->getRepr();
 
-	if (SP_IS_BOX3D(gitem)) {
-		group = box3d_convert_to_group(SP_BOX3D(gitem));
-		gitem = group;
-	}
+    {
+        SPBox3D *box = dynamic_cast<SPBox3D *>(group);
+        if (box) {
+            group = box3d_convert_to_group(box);
+        }
+    }
 
-    SP_LPE_ITEM(group)->removeAllPathEffects(false);
+    group->removeAllPathEffects(false);
 
     /* Step 1 - generate lists of children objects */
     GSList *items = NULL;
     GSList *objects = NULL;
     for (SPObject *child = group->firstChild() ; child; child = child->getNext() ) {
 
-        if (SP_IS_ITEM (child)) {
-
-            SPItem *citem = SP_ITEM (child);
-
+        SPItem *citem = dynamic_cast<SPItem *>(child);
+        if (citem) {
             /* Merging of style */
             // this converts the gradient/pattern fill/stroke, if any, to userSpaceOnUse; we need to do
             // it here _before_ the new transform is set, so as to use the pre-transform bbox
             citem->adjust_paint_recursive (Geom::identity(), Geom::identity(), false);
 
-            sp_style_merge_from_dying_parent(child->style, gitem->style);
+            sp_style_merge_from_dying_parent(child->style, group->style);
             /*
              * fixme: We currently make no allowance for the case where child is cloned
              * and the group has any style settings.
@@ -468,20 +464,21 @@ sp_item_group_ungroup (SPGroup *group, GSList **children, bool do_done)
 
             // Merging transform
             Geom::Affine ctrans;
-            Geom::Affine const g(gitem->transform);
-            if (SP_IS_USE(citem) && SP_USE(citem)->get_original() &&
-                SP_USE(citem)->get_original()->parent == SP_OBJECT(group)) {
+            Geom::Affine const g(group->transform);
+            SPUse *useitem = dynamic_cast<SPUse *>(citem);
+            if (useitem && useitem->get_original() &&
+                useitem->get_original()->parent == dynamic_cast<SPObject *>(group)) {
                 // make sure a clone's effective transform is the same as was under group
                 ctrans = g.inverse() * citem->transform * g;
             } else {
                 // We should not apply the group's transformation to both a linked offset AND to its source
-                if (SP_IS_OFFSET(citem)) { // Do we have an offset at hand (whether it's dynamic or linked)?
-                    SPItem *source = sp_offset_get_source(SP_OFFSET(citem));
+                if (dynamic_cast<SPOffset *>(citem)) { // Do we have an offset at hand (whether it's dynamic or linked)?
+                    SPItem *source = sp_offset_get_source(dynamic_cast<SPOffset *>(citem));
                     // When dealing with a chain of linked offsets, the transformation of an offset will be
                     // tied to the transformation of the top-most source, not to any of the intermediate
                     // offsets. So let's find the top-most source
-                    while (source != NULL && SP_IS_OFFSET(source)) {
-                        source = sp_offset_get_source(SP_OFFSET(source));
+                    while (source != NULL && dynamic_cast<SPOffset *>(source)) {
+                        source = sp_offset_get_source(dynamic_cast<SPOffset *>(source));
                     }
                     if (source != NULL && // If true then we must be dealing with a linked offset ...
                         group->isAncestorOf(source) == false) { // ... of which the source is not in the same group
@@ -548,10 +545,14 @@ sp_item_group_ungroup (SPGroup *group, GSList **children, bool do_done)
         // fill in the children list if non-null
         SPItem *item = static_cast<SPItem *>(doc->getObjectByRepr(repr));
 
-        item->doWriteTransform(repr, item->transform, NULL, false);
+        if (item) {
+            item->doWriteTransform(repr, item->transform, NULL, false);
+        } else {
+            g_assert_not_reached();
+        }
 
         Inkscape::GC::release(repr);
-        if (children && SP_IS_ITEM(item)) {
+        if (children && item) {
             *children = g_slist_prepend(*children, item);
         }
 
@@ -570,12 +571,11 @@ sp_item_group_ungroup (SPGroup *group, GSList **children, bool do_done)
 GSList *sp_item_group_item_list(SPGroup * group)
 {
     g_return_val_if_fail(group != NULL, NULL);
-    g_return_val_if_fail(SP_IS_GROUP(group), NULL);
 
     GSList *s = NULL;
 
     for (SPObject *o = group->firstChild() ; o ; o = o->getNext() ) {
-        if ( SP_IS_ITEM(o) ) {
+        if ( dynamic_cast<SPItem *>(o) ) {
             s = g_slist_prepend(s, o);
         }
     }
@@ -649,8 +649,9 @@ void SPGroup::translateChildItems(Geom::Translate const &tr)
 {
     if ( hasChildren() ) {
         for (SPObject *o = firstChild() ; o ; o = o->getNext() ) {
-            if ( SP_IS_ITEM(o) ) {
-                sp_item_move_rel(reinterpret_cast<SPItem *>(o), tr);
+            SPItem *item = dynamic_cast<SPItem *>(o);
+            if ( item ) {
+                sp_item_move_rel(item, tr);
             }
         }
     }
@@ -661,8 +662,10 @@ void SPGroup::scaleChildItemsRec(Geom::Scale const &sc, Geom::Point const &p, bo
 {
     if ( hasChildren() ) {
         for (SPObject *o = firstChild() ; o ; o = o->getNext() ) {
-            if ( SP_IS_ITEM(o) ) {
-                if (SP_IS_GROUP(o) && !SP_IS_BOX3D(o)) {
+            SPItem *item = dynamic_cast<SPItem *>(o);
+            if ( item ) {
+                SPGroup *group = dynamic_cast<SPGroup *>(item);
+                if (group && !dynamic_cast<SPBox3D *>(item)) {
                     /* Using recursion breaks clipping because transforms are applied 
                        in coordinates for draws but nothing in defs is changed
                        instead change the transform on the entire group, and the transform
@@ -673,7 +676,6 @@ void SPGroup::scaleChildItemsRec(Geom::Scale const &sc, Geom::Point const &p, bo
                     */
                     if(noRecurse) {
                         // used for EMF import
-                        SPItem *item = SP_ITEM(o);
                         Geom::Translate const s(p);
                         Geom::Affine final = s.inverse() * sc * s;
                         Geom::Affine tAff = item->i2dt_affine() * final;
@@ -689,30 +691,29 @@ void SPGroup::scaleChildItemsRec(Geom::Scale const &sc, Geom::Point const &p, bo
                         item->doWriteTransform(item->getRepr(), tAff, NULL, true);
                     } else {
                         // used for other import
-                        SPItem *item = NULL;
-                        if (SP_ITEM(o)->clip_ref->getObject()) {
-                            item = SP_ITEM(SP_ITEM(o)->clip_ref->getObject()->firstChild());
+                        SPItem *subItem = NULL;
+                        if (item->clip_ref->getObject()) {
+                            subItem = dynamic_cast<SPItem *>(item->clip_ref->getObject()->firstChild());
                         }
-                        if (item != NULL) {
+                        if (subItem != NULL) {
                             Geom::Affine tdoc2dt = Geom::Scale(1, -1) * Geom::Translate(p); // re-create doc2dt()
-                            Geom::Affine ti2doc = SP_ITEM(o)->i2doc_affine();
-                            item->set_i2d_affine(ti2doc * sc * ti2doc.inverse() * tdoc2dt);
-                            item->doWriteTransform(item->getRepr(), item->transform, NULL, true);
+                            Geom::Affine ti2doc = item->i2doc_affine();
+                            subItem->set_i2d_affine(ti2doc * sc * ti2doc.inverse() * tdoc2dt);
+                            subItem->doWriteTransform(subItem->getRepr(), subItem->transform, NULL, true);
                         }
-                        item = NULL;
-                        if (SP_ITEM(o)->mask_ref->getObject()) {
-                            item = SP_ITEM(SP_ITEM(o)->mask_ref->getObject()->firstChild());
+                        subItem = NULL;
+                        if (item->mask_ref->getObject()) {
+                            subItem = dynamic_cast<SPItem *>(item->mask_ref->getObject()->firstChild());
                         }
-                        if (item != NULL) {
+                        if (subItem != NULL) {
                             Geom::Affine tdoc2dt = Geom::Scale(1, -1) * Geom::Translate(p); // re-create doc2dt()
-                            Geom::Affine ti2doc = SP_ITEM(o)->i2doc_affine();
-                            item->set_i2d_affine(ti2doc * sc * ti2doc.inverse() * tdoc2dt);
-                            item->doWriteTransform(item->getRepr(), item->transform, NULL, true);
+                            Geom::Affine ti2doc = item->i2doc_affine();
+                            subItem->set_i2d_affine(ti2doc * sc * ti2doc.inverse() * tdoc2dt);
+                            subItem->doWriteTransform(item->getRepr(), item->transform, NULL, true);
                         }
-                        SP_GROUP(o)->scaleChildItemsRec(sc, p, false);
+                        group->scaleChildItemsRec(sc, p, false);
                     }
                 } else {
-                    SPItem *item = SP_ITEM(o);
                     Geom::OptRect bbox = item->desktopVisualBounds();
                     if (bbox) {
                         // Scale item
@@ -720,24 +721,33 @@ void SPGroup::scaleChildItemsRec(Geom::Scale const &sc, Geom::Point const &p, bo
                         Geom::Affine final = s.inverse() * sc * s;
                         
                         gchar const *conn_type = NULL;
-                        if (SP_IS_TEXT_TEXTPATH(item)) {
-                            SP_TEXT(item)->optimizeTextpathText();
-                        } else if (SP_IS_FLOWTEXT(item)) {
-                            SP_FLOWTEXT(item)->optimizeScaledText();
-                        } else if (SP_IS_BOX3D(item)) {
-                            // Force recalculation from perspective
-                            box3d_position_set(SP_BOX3D(item));
-                        } else if (item->getAttribute("inkscape:connector-type") != NULL
-                            && (item->getAttribute("inkscape:connection-start") == NULL
-                                || item->getAttribute("inkscape:connection-end") == NULL)) {
-                            // Remove and store connector type for transform if disconnected
-                            conn_type = item->getAttribute("inkscape:connector-type");
-                            item->removeAttribute("inkscape:connector-type");
+                        SPText *textItem = dynamic_cast<SPText *>(item);
+                        bool isTextTextpath = textItem && textItem->firstChild() && dynamic_cast<SPTextPath *>(textItem->firstChild());
+                        if (isTextTextpath) {
+                            textItem->optimizeTextpathText();
+                        } else {
+                            SPFlowtext *flowText = dynamic_cast<SPFlowtext *>(item);
+                            if (flowText) {
+                                flowText->optimizeScaledText();
+                            } else {
+                                SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+                                if (box) {
+                                    // Force recalculation from perspective
+                                    box3d_position_set(box);
+                                } else if (item->getAttribute("inkscape:connector-type") != NULL
+                                           && (item->getAttribute("inkscape:connection-start") == NULL
+                                               || item->getAttribute("inkscape:connection-end") == NULL)) {
+                                    // Remove and store connector type for transform if disconnected
+                                    conn_type = item->getAttribute("inkscape:connector-type");
+                                    item->removeAttribute("inkscape:connector-type");
+                                }
+                            }
                         }
                         
-                        if (SP_IS_PERSP3D(item)) {
-                            persp3d_apply_affine_transformation(SP_PERSP3D(item), final);
-                        } else if (SP_IS_TEXT_TEXTPATH(item) && !item->transform.isIdentity()) {
+                        Persp3D *persp = dynamic_cast<Persp3D *>(item);
+                        if (persp) {
+                            persp3d_apply_affine_transformation(persp, final);
+                        } else if (isTextTextpath && !item->transform.isIdentity()) {
                             // Save and reset current transform
                             Geom::Affine tmp(item->transform);
                             item->transform = Geom::Affine();
@@ -748,7 +758,7 @@ void SPGroup::scaleChildItemsRec(Geom::Scale const &sc, Geom::Point const &p, bo
                             tmp[4] *= sc[0];
                             tmp[5] *= sc[1];
                             item->doWriteTransform(item->getRepr(), tmp, NULL, true);
-                        } else if (SP_IS_USE(item)) {
+                        } else if (dynamic_cast<SPUse *>(item)) {
                             // calculate the matrix we need to apply to the clone
                             // to cancel its induced transform from its original
                             Geom::Affine move = final.inverse() * item->transform * final;
@@ -776,7 +786,7 @@ void SPGroup::scaleChildItemsRec(Geom::Scale const &sc, Geom::Point const &p, bo
 gint SPGroup::getItemCount() const {
     gint len = 0;
     for (SPObject const *o = this->firstChild() ; o ; o = o->getNext() ) {
-        if (SP_IS_ITEM(o)) {
+        if (dynamic_cast<SPItem const *>(o)) {
             len++;
         }
     }
@@ -786,12 +796,11 @@ gint SPGroup::getItemCount() const {
 
 void SPGroup::_showChildren (Inkscape::Drawing &drawing, Inkscape::DrawingItem *ai, unsigned int key, unsigned int flags) {
     Inkscape::DrawingItem *ac = NULL;
-    SPItem * child = NULL;
     GSList *l = g_slist_reverse(this->childList(false, SPObject::ActionShow));
     while (l) {
         SPObject *o = SP_OBJECT (l->data);
-        if (SP_IS_ITEM (o)) {
-            child = SP_ITEM (o);
+        SPItem * child = dynamic_cast<SPItem *>(o);
+        if (child) {
             ac = child->invoke_show (drawing, key, flags);
             if (ac) {
                 ai->appendChild(ac);
@@ -811,8 +820,9 @@ void SPGroup::update_patheffect(bool write) {
     for ( GSList const *iter = item_list; iter; iter = iter->next ) {
         SPObject *subitem = static_cast<SPObject *>(iter->data);
 
-        if (SP_IS_LPE_ITEM(subitem)) {
-        	((SPLPEItem*)subitem)->update_patheffect(write);
+        SPLPEItem *lpeItem = dynamic_cast<SPLPEItem *>(subitem);
+        if (lpeItem) {
+            lpeItem->update_patheffect(write);
         }
     }
 
@@ -833,40 +843,45 @@ void SPGroup::update_patheffect(bool write) {
 static void
 sp_group_perform_patheffect(SPGroup *group, SPGroup *topgroup, bool write)
 {
-    GSList const *item_list = sp_item_group_item_list(SP_GROUP(group));
+    GSList const *item_list = sp_item_group_item_list(group);
 
     for ( GSList const *iter = item_list; iter; iter = iter->next ) {
         SPObject *subitem = static_cast<SPObject *>(iter->data);
 
-        if (SP_IS_GROUP(subitem)) {
-            sp_group_perform_patheffect(SP_GROUP(subitem), topgroup, write);
-        } else if (SP_IS_SHAPE(subitem)) {
-            SPCurve * c = NULL;
+        SPGroup *subGroup = dynamic_cast<SPGroup *>(subitem);
+        if (subGroup) {
+            sp_group_perform_patheffect(subGroup, topgroup, write);
+        } else {
+            SPShape *subShape = dynamic_cast<SPShape *>(subitem);
+            if (subShape) {
+                SPCurve * c = NULL;
 
-            if (SP_IS_PATH(subitem)) {
-                c = SP_PATH(subitem)->get_original_curve();
-            } else {
-                c = SP_SHAPE(subitem)->getCurve();
-            }
+                SPPath *subPath = dynamic_cast<SPPath *>(subShape);
+                if (subPath) {
+                    c = subPath->get_original_curve();
+                } else {
+                    c = subShape->getCurve();
+                }
 
-            // only run LPEs when the shape has a curve defined
-            if (c) {
-                c->transform(i2anc_affine(subitem, topgroup));
-                SP_LPE_ITEM(topgroup)->performPathEffect(c);
-                c->transform(i2anc_affine(subitem, topgroup).inverse());
-                SP_SHAPE(subitem)->setCurve(c, TRUE);
-
-                if (write) {
-                    Inkscape::XML::Node *repr = subitem->getRepr();
-                    gchar *str = sp_svg_write_path(c->get_pathvector());
-                    repr->setAttribute("d", str);
+                // only run LPEs when the shape has a curve defined
+                if (c) {
+                    c->transform(i2anc_affine(subitem, topgroup));
+                    topgroup->performPathEffect(c);
+                    c->transform(i2anc_affine(subitem, topgroup).inverse());
+                    subShape->setCurve(c, TRUE);
+
+                    if (write) {
+                        Inkscape::XML::Node *repr = subitem->getRepr();
+                        gchar *str = sp_svg_write_path(c->get_pathvector());
+                        repr->setAttribute("d", str);
 #ifdef GROUP_VERBOSE
-g_message("sp_group_perform_patheffect writes 'd' attribute");
+                        g_message("sp_group_perform_patheffect writes 'd' attribute");
 #endif
-                    g_free(str);
-                }
+                        g_free(str);
+                    }
 
-                c->unref();
+                    c->unref();
+                }
             }
         }
     }
diff --git a/src/sp-shape.cpp b/src/sp-shape.cpp
index 2259088ba..8b7e735e0 100644
--- a/src/sp-shape.cpp
+++ b/src/sp-shape.cpp
@@ -95,12 +95,12 @@ void SPShape::release() {
         if (this->_marker[i]) {
 
             for (SPItemView *v = this->display; v != NULL; v = v->next) {
-              sp_marker_hide ((SPMarker *) this->_marker[i], v->arenaitem->key() + i);
+                sp_marker_hide(_marker[i], v->arenaitem->key() + i);
             }
 
             this->_release_connect[i].disconnect();
             this->_modified_connect[i].disconnect();
-            this->_marker[i] = sp_object_hunref (this->_marker[i], this);
+            _marker[i] = static_cast<SPMarker *>(sp_object_hunref(_marker[i], this));
         }
     }
     
@@ -170,10 +170,10 @@ void SPShape::update(SPCtx* ctx, guint flags) {
             }
 
             for (int i = 0 ; i < SP_MARKER_LOC_QTY ; i++) {
-                if (this->_marker[i]) {
-                    sp_marker_show_dimension ((SPMarker *) this->_marker[i],
-                                              v->arenaitem->key() + i,
-                                              this->numberOfMarkers (i));
+                if (_marker[i]) {
+                    sp_marker_show_dimension(_marker[i],
+                                             v->arenaitem->key() + i,
+                                             numberOfMarkers(i));
                 }
             }
         }
@@ -290,12 +290,12 @@ sp_shape_update_marker_view(SPShape *shape, Inkscape::DrawingItem *ai)
             if ( shape->_marker[i] ) {
                 Geom::Affine m_auto = m;
                 // Reverse start marker if necessary.
-                if (SP_MARKER(shape->_marker[i])->orient_mode == MARKER_ORIENT_AUTO_START_REVERSE) {
+                if (shape->_marker[i]->orient_mode == MARKER_ORIENT_AUTO_START_REVERSE) {
                     m_auto = Geom::Rotate::from_degrees( 180.0 ) * m;
                 }
-                sp_marker_show_instance ((SPMarker* ) shape->_marker[i], ai,
-                                         ai->key() + i, counter[i], m_auto,
-                                         shape->style->stroke_width.computed);
+                sp_marker_show_instance(shape->_marker[i], ai,
+                                        ai->key() + i, counter[i], m_auto,
+                                        shape->style->stroke_width.computed);
                  counter[i]++;
             }
         }
@@ -311,9 +311,9 @@ sp_shape_update_marker_view(SPShape *shape, Inkscape::DrawingItem *ai)
                 Geom::Affine const m (sp_shape_marker_get_transform_at_start(path_it->front()));
                 for (int i = 0; i < 3; i += 2) {  // SP_MARKER_LOC and SP_MARKER_LOC_MID
                     if ( shape->_marker[i] ) {
-                        sp_marker_show_instance ((SPMarker* ) shape->_marker[i], ai,
-                                                 ai->key() + i, counter[i], m,
-                                                 shape->style->stroke_width.computed);
+                        sp_marker_show_instance(shape->_marker[i], ai,
+                                                ai->key() + i, counter[i], m,
+                                                shape->style->stroke_width.computed);
                          counter[i]++;
                     }
                 }
@@ -331,9 +331,9 @@ sp_shape_update_marker_view(SPShape *shape, Inkscape::DrawingItem *ai)
                     Geom::Affine const m (sp_shape_marker_get_transform(*curve_it1, *curve_it2));
                     for (int i = 0; i < 3; i += 2) {  // SP_MARKER_LOC and SP_MARKER_LOC_MID
                         if (shape->_marker[i]) {
-                            sp_marker_show_instance ((SPMarker* ) shape->_marker[i], ai,
-                                                     ai->key() + i, counter[i], m,
-                                                     shape->style->stroke_width.computed);
+                            sp_marker_show_instance(shape->_marker[i], ai,
+                                                    ai->key() + i, counter[i], m,
+                                                    shape->style->stroke_width.computed);
                             counter[i]++;
                         }
                     }
@@ -348,9 +348,9 @@ sp_shape_update_marker_view(SPShape *shape, Inkscape::DrawingItem *ai)
                 Geom::Affine const m = sp_shape_marker_get_transform_at_end(lastcurve);
                 for (int i = 0; i < 3; i += 2) {  // SP_MARKER_LOC and SP_MARKER_LOC_MID
                     if (shape->_marker[i]) {
-                        sp_marker_show_instance ((SPMarker* ) shape->_marker[i], ai,
-                                                 ai->key() + i, counter[i], m,
-                                                 shape->style->stroke_width.computed);
+                        sp_marker_show_instance(shape->_marker[i], ai,
+                                                ai->key() + i, counter[i], m,
+                                                shape->style->stroke_width.computed);
                         counter[i]++;
                     }
                 }
@@ -372,9 +372,9 @@ sp_shape_update_marker_view(SPShape *shape, Inkscape::DrawingItem *ai)
 
         for (int i = 0; i < 4; i += 3) {  // SP_MARKER_LOC and SP_MARKER_LOC_END
             if (shape->_marker[i]) {
-                sp_marker_show_instance ((SPMarker* ) shape->_marker[i], ai,
-                                         ai->key() + i, counter[i], m,
-                                         shape->style->stroke_width.computed);
+                sp_marker_show_instance(shape->_marker[i], ai,
+                                        ai->key() + i, counter[i], m,
+                                        shape->style->stroke_width.computed);
                 counter[i]++;
             }
         }
@@ -424,26 +424,25 @@ Geom::OptRect SPShape::bbox(Geom::Affine const &transform, SPItem::BBoxType bbox
             // START marker
             for (unsigned i = 0; i < 2; i++) { // SP_MARKER_LOC and SP_MARKER_LOC_START
                 if ( this->_marker[i] ) {
-                    SPMarker* marker = SP_MARKER (this->_marker[i]);
-                    SPItem* marker_item = sp_item_first_item_child( marker );
+                    SPItem* marker_item = sp_item_first_item_child( _marker[i] );
 
                     if (marker_item) {
                         Geom::Affine tr(sp_shape_marker_get_transform_at_start(pathv.begin()->front()));
 
-                        if (marker->orient_mode == MARKER_ORIENT_AUTO_START_REVERSE) {
+                        if (_marker[i]->orient_mode == MARKER_ORIENT_AUTO_START_REVERSE) {
                             // Reverse start marker if necessary
                             tr = Geom::Rotate::from_degrees( 180.0 ) * tr;
-                        } else if (marker->orient_mode == MARKER_ORIENT_ANGLE) {
+                        } else if (_marker[i]->orient_mode == MARKER_ORIENT_ANGLE) {
                             Geom::Point transl = tr.translation();
-                            tr = Geom::Rotate::from_degrees(marker->orient) * Geom::Translate(transl);
+                            tr = Geom::Rotate::from_degrees(_marker[i]->orient) * Geom::Translate(transl);
                         }
 
-                        if (marker->markerUnits == SP_MARKER_UNITS_STROKEWIDTH) {
+                        if (_marker[i]->markerUnits == SP_MARKER_UNITS_STROKEWIDTH) {
                             tr = Geom::Scale(this->style->stroke_width.computed) * tr;
                         }
 
                         // total marker transform
-                        tr = marker_item->transform * marker->c2p * tr * transform;
+                        tr = marker_item->transform * _marker[i]->c2p * tr * transform;
 
                         // get bbox of the marker with that transform
                         bbox |= marker_item->visualBounds(tr);
@@ -457,7 +456,7 @@ Geom::OptRect SPShape::bbox(Geom::Affine const &transform, SPItem::BBoxType bbox
                 	continue;
                 }
 
-                SPMarker* marker = SP_MARKER (this->_marker[i]);
+                SPMarker* marker = _marker[i];
                 SPItem* marker_item = sp_item_first_item_child( marker );
 
                 if ( !marker_item ) {
@@ -495,7 +494,7 @@ Geom::OptRect SPShape::bbox(Geom::Affine const &transform, SPItem::BBoxType bbox
                              * Loop to end_default (so including closing segment), because when a path is closed,
                              * there should be a midpoint marker between last segment and closing straight line segment */
 
-                            SPMarker* marker = SP_MARKER (this->_marker[i]);
+                            SPMarker* marker = _marker[i];
                             SPItem* marker_item = sp_item_first_item_child( marker );
 
                             if (marker_item) {
@@ -541,8 +540,8 @@ Geom::OptRect SPShape::bbox(Geom::Affine const &transform, SPItem::BBoxType bbox
 
             // END marker
             for (unsigned i = 0; i < 4; i += 3) { // SP_MARKER_LOC and SP_MARKER_LOC_END
-                if ( this->_marker[i] ) {
-                    SPMarker* marker = SP_MARKER (this->_marker[i]);
+                if ( _marker[i] ) {
+                    SPMarker* marker = _marker[i];
                     SPItem* marker_item = sp_item_first_item_child( marker );
 
                     if (marker_item) {
@@ -739,10 +738,10 @@ Inkscape::DrawingItem* SPShape::show(Inkscape::Drawing &drawing, unsigned int /*
         }
 
         for (int i = 0; i < SP_MARKER_LOC_QTY; i++) {
-            if (this->_marker[i]) {
-                sp_marker_show_dimension ((SPMarker *) this->_marker[i],
-                                          s->key() + i,
-                                          this->numberOfMarkers (i));
+            if (_marker[i]) {
+                sp_marker_show_dimension(_marker[i],
+                                         s->key() + i,
+                                         numberOfMarkers(i));
             }
         }
 
@@ -757,17 +756,17 @@ Inkscape::DrawingItem* SPShape::show(Inkscape::Drawing &drawing, unsigned int /*
  * Sets style, path, and paintbox.  Updates marker views, including dimensions.
  */
 void SPShape::hide(unsigned int key) {
-	for (int i=0; i<SP_MARKER_LOC_QTY; i++) {
-		if (this->_marker[i]) {
-			for (SPItemView* v = this->display; v != NULL; v = v->next) {
-				if (key == v->key) {
-					sp_marker_hide ((SPMarker *) this->_marker[i], v->arenaitem->key() + i);
-				}
-			}
-		}
-	}
+    for (int i = 0; i < SP_MARKER_LOC_QTY; ++i) {
+        if (_marker[i]) {
+            for (SPItemView* v = display; v != NULL; v = v->next) {
+                if (key == v->key) {
+                    sp_marker_hide(_marker[i], v->arenaitem->key() + i);
+                }
+            }
+        }
+    }
 
-	//SPLPEItem::onHide(key);
+    //SPLPEItem::onHide(key);
 }
 
 /**
@@ -782,7 +781,7 @@ int SPShape::hasMarkers() const
 
     // Ignore markers for objects which are inside markers themselves.
     for (SPObject *parent = this->parent; parent != NULL; parent = parent->parent) {
-      if(SP_IS_MARKER(parent)) {
+      if (dynamic_cast<SPMarker *>(parent)) {
         return 0;
       }
     }
@@ -860,22 +859,20 @@ int SPShape::numberOfMarkers(int type) const {
 static void
 sp_shape_marker_release (SPObject *marker, SPShape *shape)
 {
-    SPItem *item;
-    int i;
+    SPItem *item = dynamic_cast<SPItem *>(shape);
+    g_return_if_fail(item != NULL);
 
-    item = (SPItem *) shape;
-
-    for (i = 0; i < SP_MARKER_LOC_QTY; i++) {
+    for (int i = 0; i < SP_MARKER_LOC_QTY; i++) {
         if (marker == shape->_marker[i]) {
             SPItemView *v;
             /* Hide marker */
             for (v = item->display; v != NULL; v = v->next) {
-              sp_marker_hide ((SPMarker *) (shape->_marker[i]), v->arenaitem->key() + i);
+                sp_marker_hide(shape->_marker[i], v->arenaitem->key() + i);
             }
             /* Detach marker */
             shape->_release_connect[i].disconnect();
             shape->_modified_connect[i].disconnect();
-            shape->_marker[i] = sp_object_hunref (shape->_marker[i], item);
+            shape->_marker[i] = static_cast<SPMarker *>(sp_object_hunref(shape->_marker[i], item));
         }
     }
 }
@@ -900,15 +897,16 @@ sp_shape_marker_modified (SPObject */*marker*/, guint /*flags*/, SPItem */*item*
 void
 sp_shape_set_marker (SPObject *object, unsigned int key, const gchar *value)
 {
-    SPItem *item = (SPItem *) object;
-    SPShape *shape = (SPShape *) object;
+    SPShape *shape = dynamic_cast<SPShape *>(object);
+    g_return_if_fail(shape != NULL);
 
     if (key > SP_MARKER_LOC_END) {
         return;
     }
 
     SPObject *mrk = sp_css_uri_reference_resolve(object->document, value);
-    if (mrk != shape->_marker[key]) {
+    SPMarker *marker = dynamic_cast<SPMarker *>(mrk);
+    if (marker != shape->_marker[key]) {
         if (shape->_marker[key]) {
             SPItemView *v;
 
@@ -917,18 +915,18 @@ sp_shape_set_marker (SPObject *object, unsigned int key, const gchar *value)
             shape->_modified_connect[key].disconnect();
 
             /* Hide marker */
-            for (v = item->display; v != NULL; v = v->next) {
-                sp_marker_hide ((SPMarker *) (shape->_marker[key]),
-                                v->arenaitem->key() + key);
+            for (v = shape->display; v != NULL; v = v->next) {
+                sp_marker_hide(shape->_marker[key],
+                               v->arenaitem->key() + key);
             }
 
             /* Unref marker */
-            shape->_marker[key] = sp_object_hunref (shape->_marker[key], object);
+            shape->_marker[key] = static_cast<SPMarker *>(sp_object_hunref(shape->_marker[key], object));
         }
-        if (SP_IS_MARKER (mrk)) {
-            shape->_marker[key] = sp_object_href (mrk, object);
-            shape->_release_connect[key] = mrk->connectRelease(sigc::bind<1>(sigc::ptr_fun(&sp_shape_marker_release), shape));
-            shape->_modified_connect[key] = mrk->connectModified(sigc::bind<2>(sigc::ptr_fun(&sp_shape_marker_modified), shape));
+        if (marker) {
+            shape->_marker[key] = static_cast<SPMarker *>(sp_object_href(marker, object));
+            shape->_release_connect[key] = marker->connectRelease(sigc::bind<1>(sigc::ptr_fun(&sp_shape_marker_release), shape));
+            shape->_modified_connect[key] = marker->connectModified(sigc::bind<2>(sigc::ptr_fun(&sp_shape_marker_modified), shape));
         }
     }
 }
diff --git a/src/sp-shape.h b/src/sp-shape.h
index da8e4c007..fe9d03275 100644
--- a/src/sp-shape.h
+++ b/src/sp-shape.h
@@ -28,6 +28,7 @@
 #define SP_SHAPE_WRITE_PATH (1 << 2)
 
 class SPDesktop;
+class SPMarker;
 namespace Inkscape { class DrawingItem; }
 
 /**
@@ -51,7 +52,7 @@ public: // temporarily public, until SPPath is properly classed, etc.
     SPCurve *_curve;
 
 public:
-    SPObject *_marker[SP_MARKER_LOC_QTY];
+    SPMarker *_marker[SP_MARKER_LOC_QTY];
     sigc::connection _release_connect [SP_MARKER_LOC_QTY];
     sigc::connection _modified_connect [SP_MARKER_LOC_QTY];
 
diff --git a/src/ui/clipboard.cpp b/src/ui/clipboard.cpp
index 40500cf15..931a295d8 100644
--- a/src/ui/clipboard.cpp
+++ b/src/ui/clipboard.cpp
@@ -54,6 +54,7 @@
 #include <2geom/transforms.h>
 #include "box3d.h"
 #include "gradient-drag.h"
+#include "sp-marker.h"
 #include "sp-item.h"
 #include "sp-item-transform.h" // for sp_item_scale_rel, used in _pasteSize
 #include "sp-path.h"
@@ -505,12 +506,15 @@ bool ClipboardManagerImpl::pasteSize(SPDesktop *desktop, bool separately, bool a
         // resize each object in the selection
         if (separately) {
             for (GSList *i = const_cast<GSList*>(selection->itemList()) ; i ; i = i->next) {
-                SPItem *item = SP_ITEM(i->data);
-                Geom::OptRect obj_size = item->desktopVisualBounds();
-                if ( !obj_size ) {
-                    continue;
+                SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(i->data));
+                if (item) {
+                    Geom::OptRect obj_size = item->desktopVisualBounds();
+                    if ( obj_size ) {
+                        sp_item_scale_rel(item, _getScale(desktop, min, max, *obj_size, apply_x, apply_y));
+                    }
+                } else {
+                    g_assert_not_reached();
                 }
-                sp_item_scale_rel(item, _getScale(desktop, min, max, *obj_size, apply_x, apply_y));
             }
         }
         // resize the selection as a whole
@@ -640,7 +644,12 @@ void ClipboardManagerImpl::_copySelection(Inkscape::Selection *selection)
     GSList const *items = selection->itemList();
     // copy the defs used by all items
     for (GSList *i = const_cast<GSList *>(items) ; i != NULL ; i = i->next) {
-        _copyUsedDefs(SP_ITEM (i->data));
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(i->data));
+        if (item) {
+            _copyUsedDefs(item);
+        } else {
+            g_assert_not_reached();
+        }
     }
 
     // copy the representation of the items
@@ -648,36 +657,38 @@ void ClipboardManagerImpl::_copySelection(Inkscape::Selection *selection)
     sorted_items = g_slist_sort(sorted_items, (GCompareFunc) sp_object_compare_position);
 
     for (GSList *i = sorted_items ; i ; i = i->next) {
-        if (!SP_IS_ITEM(i->data)) {
-            continue;
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(i->data));
+        if (item) {
+            Inkscape::XML::Node *obj = item->getRepr();
+            Inkscape::XML::Node *obj_copy = _copyNode(obj, _doc, _root);
+
+            // copy complete inherited style
+            SPCSSAttr *css = sp_repr_css_attr_inherited(obj, "style");
+            sp_repr_css_set(obj_copy, css, "style");
+            sp_repr_css_attr_unref(css);
+
+            // write the complete accumulated transform passed to us
+            // (we're dealing with unattached representations, so we write to their attributes
+            // instead of using sp_item_set_transform)
+            gchar *transform_str = sp_svg_transform_write(item->i2doc_affine());
+            obj_copy->setAttribute("transform", transform_str);
+            g_free(transform_str);
         }
-        Inkscape::XML::Node *obj = reinterpret_cast<SPObject *>(i->data)->getRepr();
-        Inkscape::XML::Node *obj_copy = _copyNode(obj, _doc, _root);
-
-        // copy complete inherited style
-        SPCSSAttr *css = sp_repr_css_attr_inherited(obj, "style");
-        sp_repr_css_set(obj_copy, css, "style");
-        sp_repr_css_attr_unref(css);
-
-        // write the complete accumulated transform passed to us
-        // (we're dealing with unattached representations, so we write to their attributes
-        // instead of using sp_item_set_transform)
-        gchar *transform_str = sp_svg_transform_write(SP_ITEM(i->data)->i2doc_affine());
-        obj_copy->setAttribute("transform", transform_str);
-        g_free(transform_str);
     }
 
     // copy style for Paste Style action
     if (sorted_items) {
-        if (SP_IS_ITEM(sorted_items->data)) {
-            SPCSSAttr *style = take_style_from_item((SPItem *) sorted_items->data);
+        SPObject *object = static_cast<SPObject *>(sorted_items->data);
+        SPItem *item = dynamic_cast<SPItem *>(object);
+        if (item) {
+            SPCSSAttr *style = take_style_from_item(item);
             sp_repr_css_set(_clipnode, style, "style");
             sp_repr_css_attr_unref(style);
         }
 
         // copy path effect from the first path
-        if (SP_IS_OBJECT(sorted_items->data)) {
-            gchar const *effect = reinterpret_cast<SPObject *>(sorted_items->data)->getRepr()->attribute("inkscape:path-effect");
+        if (object) {
+            gchar const *effect =object->getRepr()->attribute("inkscape:path-effect");
             if (effect) {
                 _clipnode->setAttribute("inkscape:path-effect", effect);
             }
@@ -704,35 +715,38 @@ void ClipboardManagerImpl::_copyUsedDefs(SPItem *item)
 
     if (style && (style->fill.isPaintserver())) {
         SPPaintServer *server = item->style->getFillPaintServer();
-        if ( SP_IS_LINEARGRADIENT(server) || SP_IS_RADIALGRADIENT(server) ) {
-            _copyGradient(SP_GRADIENT(server));
+        if ( dynamic_cast<SPLinearGradient *>(server) || dynamic_cast<SPRadialGradient *>(server) ) {
+            _copyGradient(dynamic_cast<SPGradient *>(server));
         }
-        if ( SP_IS_PATTERN(server) ) {
-            _copyPattern(SP_PATTERN(server));
+        SPPattern *pattern = dynamic_cast<SPPattern *>(server);
+        if ( pattern ) {
+            _copyPattern(pattern);
         }
     }
     if (style && (style->stroke.isPaintserver())) {
         SPPaintServer *server = item->style->getStrokePaintServer();
-        if ( SP_IS_LINEARGRADIENT(server) || SP_IS_RADIALGRADIENT(server) ) {
-            _copyGradient(SP_GRADIENT(server));
+        if ( dynamic_cast<SPLinearGradient *>(server) || dynamic_cast<SPRadialGradient *>(server) ) {
+            _copyGradient(dynamic_cast<SPGradient *>(server));
         }
-        if ( SP_IS_PATTERN(server) ) {
-            _copyPattern(SP_PATTERN(server));
+        SPPattern *pattern = dynamic_cast<SPPattern *>(server);
+        if ( pattern ) {
+            _copyPattern(pattern);
         }
     }
 
     // For shapes, copy all of the shape's markers
-    if (SP_IS_SHAPE(item)) {
-        SPShape *shape = SP_SHAPE (item);
+    SPShape *shape = dynamic_cast<SPShape *>(item);
+    if (shape) {
         for (int i = 0 ; i < SP_MARKER_LOC_QTY ; i++) {
             if (shape->_marker[i]) {
                 _copyNode(shape->_marker[i]->getRepr(), _doc, _defs);
             }
         }
     }
+
     // For lpe items, copy lpe stack if applicable
-    if (SP_IS_LPE_ITEM(item)) {
-        SPLPEItem *lpeitem = SP_LPE_ITEM (item);
+    SPLPEItem *lpeitem = dynamic_cast<SPLPEItem *>(item);
+    if (lpeitem) {
         if (lpeitem->hasPathEffect()) {
             for (PathEffectList::iterator it = lpeitem->path_effect_list->begin(); it != lpeitem->path_effect_list->end(); ++it)
             {
@@ -743,14 +757,24 @@ void ClipboardManagerImpl::_copyUsedDefs(SPItem *item)
             }
         }
     }
+
     // For 3D boxes, copy perspectives
-    if (SP_IS_BOX3D(item)) {
-        _copyNode(box3d_get_perspective(SP_BOX3D(item))->getRepr(), _doc, _defs);
+    {
+        SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+        if (box) {
+            _copyNode(box3d_get_perspective(box)->getRepr(), _doc, _defs);
+        }
     }
+
     // Copy text paths
-    if (SP_IS_TEXT_TEXTPATH(item)) {
-        _copyTextPath(SP_TEXTPATH(item->firstChild()));
+    {
+        SPText *text = dynamic_cast<SPText *>(item);
+        SPTextPath *textpath = (text) ? dynamic_cast<SPTextPath *>(text->firstChild()) : NULL;
+        if (textpath) {
+            _copyTextPath(textpath);
+        }
     }
+
     // Copy clipping objects
     if (item->clip_ref){
         if (item->clip_ref->getObject()) {
@@ -764,8 +788,9 @@ void ClipboardManagerImpl::_copyUsedDefs(SPItem *item)
             _copyNode(mask->getRepr(), _doc, _defs);
             // recurse into the mask for its gradients etc.
             for (SPObject *o = mask->children ; o != NULL ; o = o->next) {
-                if (SP_IS_ITEM(o)) {
-                    _copyUsedDefs(SP_ITEM(o));
+                SPItem *childItem = dynamic_cast<SPItem *>(o);
+                if (childItem) {
+                    _copyUsedDefs(childItem);
                 }
             }
         }
@@ -774,15 +799,16 @@ void ClipboardManagerImpl::_copyUsedDefs(SPItem *item)
     // Copy filters
     if (style->getFilter()) {
         SPObject *filter = style->getFilter();
-        if (SP_IS_FILTER(filter)) {
+        if (dynamic_cast<SPFilter *>(filter)) {
             _copyNode(filter->getRepr(), _doc, _defs);
         }
     }
 
     // recurse
     for (SPObject *o = item->children ; o != NULL ; o = o->next) {
-        if (SP_IS_ITEM(o)) {
-            _copyUsedDefs(SP_ITEM(o));
+        SPItem *childItem = dynamic_cast<SPItem *>(o);
+        if (childItem) {
+            _copyUsedDefs(childItem);
         }
     }
 }
@@ -817,10 +843,10 @@ void ClipboardManagerImpl::_copyPattern(SPPattern *pattern)
 
         // items in the pattern may also use gradients and other patterns, so recurse
         for ( SPObject *child = pattern->firstChild() ; child ; child = child->getNext() ) {
-            if (!SP_IS_ITEM (child)) {
-                continue;
+            SPItem *childItem = dynamic_cast<SPItem *>(child);
+            if (childItem) {
+                _copyUsedDefs(childItem);
             }
-            _copyUsedDefs(SP_ITEM(child));
         }
         if (pattern->ref){
             pattern = pattern->ref->getObject();
@@ -939,13 +965,13 @@ void ClipboardManagerImpl::_applyPathEffect(SPItem *item, gchar const *effectsta
     if ( item == NULL ) {
         return;
     }
-    if ( SP_IS_RECT(item) ) {
+    if ( dynamic_cast<SPRect *>(item) ) {
         return;
     }
 
-    if (SP_IS_LPE_ITEM(item))
+    SPLPEItem *lpeitem = dynamic_cast<SPLPEItem *>(item);
+    if (lpeitem)
     {
-        SPLPEItem *lpeitem = SP_LPE_ITEM(item);
         // for each effect in the stack, check if we need to fork it before adding it to the item
         lpeitem->forkPathEffectsIfNecessary(1);
 
diff --git a/src/ui/dialog/aboutbox.cpp b/src/ui/dialog/aboutbox.cpp
index 7212fa372..50b35ca2f 100644
--- a/src/ui/dialog/aboutbox.cpp
+++ b/src/ui/dialog/aboutbox.cpp
@@ -452,13 +452,13 @@ void AboutBox::initStrings() {
      */          
     gchar const *allTranslators =
 "3ARRANO.com <3arrano@3arrano.com>, 2005.\n"
-"Adib Taraben <theadib@gmail.com>, 2004.\n"
+"Adib Taraben <theadib@gmail.com>, 2004-2014.\n"
 "Alan Monfort <alan.monfort@free.fr>, 2009-2010.\n"
 "Alastair McKinstry <mckinstry@computer.org>, 2000.\n"
 "Aleksandar Urošević <urke@users.sourceforge.net>, 2004-2006.\n"
 "Alessio Frusciante <algol@firenze.linux.it>, 2002, 2003.\n"
 "Alexander Shopov <ash@contact.bg>, 2006.\n"
-"Alexandre Prokoudine <alexandre.prokoudine@gmail.com>, 2005, 2010-2013.\n"
+"Alexandre Prokoudine <alexandre.prokoudine@gmail.com>, 2005, 2010-2014.\n"
 "Alexey Remizov <alexey@remizov.pp.ru>, 2004.\n"
 "Ali Ghanavatian <ghanvatian.ali@gmail.com>, 2010.\n"
 "Álvaro Lopes <alvieboy@alvie.com>, 2001, 2002.\n"
@@ -503,7 +503,7 @@ void AboutBox::initStrings() {
 "Hleb Valoshka <375gnu@gmail.com>, 2008-2009.\n"
 "Hizkuntza Politikarako Sailburuordetza <hizkpol@ej-gv.es>, 2005.\n"
 "Ilia Penev <lichopicho@gmail.com>, 2006.\n"
-"Ivan Masár <helix84@centrum.sk>, 2006-2010. \n"
+"Ivan Masár <helix84@centrum.sk>, 2006-2014. \n"
 "Ivan Řihošek <irihosek@seznam.cz>, 2014.\n"
 "Iñaki Larrañaga <dooteo@euskalgnu.org>, 2006.\n"
 "Jānis Eisaks <jancs@dv.lv>, 2012-2014.\n"
@@ -537,7 +537,7 @@ void AboutBox::initStrings() {
 "Mahesh subedi <submanesh@hotmail.com>, 2006.\n"
 "Martin Srebotnjak, <miles@filmsi.net>, 2005, 2010.\n"
 "Masatake YAMATO <jet@gyve.org>, 2002.\n"
-"Masato Hashimoto <cabezon.hashimoto@gmail.com>, 2009-2012.\n"
+"Masato Hashimoto <cabezon.hashimoto@gmail.com>, 2009-2014.\n"
 "Matiphas <matiphas _a_ free _point_ fr>, 2004-2006.\n"
 "Mattias Hultgren <mattias_hultgren@tele2.se>, 2005, 2006.\n"
 "Maxim Dziumanenko <mvd@mylinux.com.ua>, 2004.\n"
@@ -553,7 +553,7 @@ void AboutBox::initStrings() {
 "Przemysław Loesch <p_loesch@poczta.onet.pl>, 2005.\n"
 "Quico Llach <quico@softcatala.org>, 2000. Traducció sodipodi.\n"
 "Raymond Ostertag <raymond@linuxgraphic.org>, 2002, 2003.\n"
-"Riku Leino <tsoots@gmail.com>, 2006.\n"
+"Riku Leino <tsoots@gmail.com>, 2006-2011.\n"
 "Rune Rønde Laursen <runerl@skjoldhoej.dk>, 2006.\n"
 "Ruud Steltenpool <svg@steltenpower.com>, 2006.\n"
 "Serdar Soytetir <sendirom@gmail.com>, 2005.\n"
@@ -569,9 +569,11 @@ void AboutBox::initStrings() {
 "Thiago Pimentel <thiago.merces@gmail.com>, 2006.\n"
 "Toshifumi Sato <sato@centrosystem.com>, 2005.\n"
 "Jon South <striker@lunar-linux.org>, 2006. \n"
-"Uwe Schöler <oss@oss-marketplace.com>, 2006-2013.\n"
+"Uwe Schöler <oss@oss-marketplace.com>, 2006-2014.\n"
 "Valek Filippov <frob@df.ru>, 2000, 2003.\n"
 "Victor Dachev <vdachev@gmail.com>, 2006.\n"
+"Victor Westmann <victor.westmann@gmail.com>, 2011, 2014.\n"
+"Ville Pätsi, 2013.\n"
 "Vincent van Adrighem <V.vanAdrighem@dirck.mine.nu>, 2003.\n"
 "Vital Khilko <dojlid@mova.org>, 2003.\n"
 "Vitaly Lipatov <lav@altlinux.ru>, 2002, 2004.\n"
@@ -584,7 +586,7 @@ void AboutBox::initStrings() {
 "Yaron Shahrabani <sh.yaron@gmail.com>, 2009.\n"
 "Yukihiro Nakai <nakai@gnome.gr.jp>, 2000, 2003.\n"
 "Yuri Beznos <zhiz0id@gmail.com>, 2006.\n"
-"Yuri Chornoivan <yurchor@ukr.net>, 2007-2013.\n"
+"Yuri Chornoivan <yurchor@ukr.net>, 2007-2014.\n"
 "Yuri Syrota <rasta@renome.rovno.ua>, 2000.\n"
 "Yves Guillou <yvesguillou@users.sourceforge.net>, 2004.\n"
 "Zdenko Podobný <zdpo@mailbox.sk>, 2003, 2004."
diff --git a/src/ui/object-edit.cpp b/src/ui/object-edit.cpp
index cc96727f8..ca550502d 100644
--- a/src/ui/object-edit.cpp
+++ b/src/ui/object-edit.cpp
@@ -6,6 +6,7 @@
  *   Mitsuru Oka
  *   Maximilian Albert <maximilian.albert@gmail.com>
  *   Abhishek Sharma
+ *   Jon A. Cruz <jon@joncruz.org>
  *
  * Licensed under GNU GPL
  */
@@ -42,11 +43,11 @@
 
 namespace {
 
-static KnotHolder *sp_lpe_knot_holder(SPItem *item, SPDesktop *desktop)
+static KnotHolder *sp_lpe_knot_holder(SPLPEItem *item, SPDesktop *desktop)
 {
     KnotHolder *knot_holder = new KnotHolder(desktop, item, NULL);
 
-    Inkscape::LivePathEffect::Effect *effect = SP_LPE_ITEM(item)->getCurrentLPE();
+    Inkscape::LivePathEffect::Effect *effect = item->getCurrentLPE();
     effect->addHandles(knot_holder, desktop, item);
 
     return knot_holder;
@@ -61,29 +62,33 @@ KnotHolder *createKnotHolder(SPItem *item, SPDesktop *desktop)
 {
     KnotHolder *knotholder = NULL;
 
-    if (SP_IS_LPE_ITEM(item) &&
-        SP_LPE_ITEM(item)->getCurrentLPE() &&
-        SP_LPE_ITEM(item)->getCurrentLPE()->isVisible() &&
-        SP_LPE_ITEM(item)->getCurrentLPE()->providesKnotholder()) {
-        knotholder = sp_lpe_knot_holder(item, desktop);
-    } else if (SP_IS_RECT(item)) {
+    SPLPEItem *lpe = dynamic_cast<SPLPEItem *>(item);
+    if (lpe &&
+        lpe->getCurrentLPE() &&
+        lpe->getCurrentLPE()->isVisible() &&
+        lpe->getCurrentLPE()->providesKnotholder()) {
+        knotholder = sp_lpe_knot_holder(lpe, desktop);
+    } else if (dynamic_cast<SPRect *>(item)) {
         knotholder = new RectKnotHolder(desktop, item, NULL);
-    } else if (SP_IS_BOX3D(item)) {
+    } else if (dynamic_cast<SPBox3D *>(item)) {
         knotholder = new Box3DKnotHolder(desktop, item, NULL);
-    } else if (SP_IS_GENERICELLIPSE(item)) {
+    } else if (dynamic_cast<SPGenericEllipse *>(item)) {
         knotholder = new ArcKnotHolder(desktop, item, NULL);
-    } else if (SP_IS_STAR(item)) {
+    } else if (dynamic_cast<SPStar *>(item)) {
         knotholder = new StarKnotHolder(desktop, item, NULL);
-    } else if (SP_IS_SPIRAL(item)) {
+    } else if (dynamic_cast<SPSpiral *>(item)) {
         knotholder = new SpiralKnotHolder(desktop, item, NULL);
-    } else if (SP_IS_OFFSET(item)) {
+    } else if (dynamic_cast<SPOffset *>(item)) {
         knotholder = new OffsetKnotHolder(desktop, item, NULL);
-    } else if (SP_IS_FLOWTEXT(item) && SP_FLOWTEXT(item)->has_internal_frame()) {
-        knotholder = new FlowtextKnotHolder(desktop, SP_FLOWTEXT(item)->get_frame(NULL), NULL);
-    } else if ((item->style->fill.isPaintserver() && SP_IS_PATTERN(item->style->getFillPaintServer())) ||
-               (item->style->stroke.isPaintserver() && SP_IS_PATTERN(item->style->getStrokePaintServer()))) {
-        knotholder = new KnotHolder(desktop, item, NULL);
-        knotholder->add_pattern_knotholder();
+    } else {
+        SPFlowtext *flowtext = dynamic_cast<SPFlowtext *>(item);
+        if (flowtext && flowtext->has_internal_frame()) {
+            knotholder = new FlowtextKnotHolder(desktop, flowtext->get_frame(NULL), NULL);
+        } else if ((item->style->fill.isPaintserver() && dynamic_cast<SPPattern *>(item->style->getFillPaintServer())) ||
+                   (item->style->stroke.isPaintserver() && dynamic_cast<SPPattern *>(item->style->getStrokePaintServer()))) {
+            knotholder = new KnotHolder(desktop, item, NULL);
+            knotholder->add_pattern_knotholder();
+        }
     }
 
     return knotholder;
@@ -130,7 +135,8 @@ public:
 Geom::Point
 RectKnotHolderEntityRX::knot_get() const
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     return Geom::Point(rect->x.computed + rect->width.computed - rect->rx.computed, rect->y.computed);
 }
@@ -138,7 +144,8 @@ RectKnotHolderEntityRX::knot_get() const
 void
 RectKnotHolderEntityRX::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, unsigned int state)
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     //In general we cannot just snap this radius to an arbitrary point, as we have only a single
     //degree of freedom. For snapping to an arbitrary point we need two DOF. If we're going to snap
@@ -157,13 +164,14 @@ RectKnotHolderEntityRX::knot_set(Geom::Point const &p, Geom::Point const &/*orig
 
     update_knot();
 
-    (static_cast<SPObject*>(rect))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    rect->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 void
 RectKnotHolderEntityRX::knot_click(unsigned int state)
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     if (state & GDK_SHIFT_MASK) {
         /* remove rounding from rectangle */
@@ -179,7 +187,8 @@ RectKnotHolderEntityRX::knot_click(unsigned int state)
 Geom::Point
 RectKnotHolderEntityRY::knot_get() const
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     return Geom::Point(rect->x.computed + rect->width.computed, rect->y.computed + rect->ry.computed);
 }
@@ -187,7 +196,8 @@ RectKnotHolderEntityRY::knot_get() const
 void
 RectKnotHolderEntityRY::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, unsigned int state)
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     //In general we cannot just snap this radius to an arbitrary point, as we have only a single
     //degree of freedom. For snapping to an arbitrary point we need two DOF. If we're going to snap
@@ -215,13 +225,14 @@ RectKnotHolderEntityRY::knot_set(Geom::Point const &p, Geom::Point const &/*orig
 
     update_knot();
 
-    (static_cast<SPObject *>(rect))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    rect->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 void
 RectKnotHolderEntityRY::knot_click(unsigned int state)
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     if (state & GDK_SHIFT_MASK) {
         /* remove rounding */
@@ -251,7 +262,8 @@ static void sp_rect_clamp_radii(SPRect *rect)
 Geom::Point
 RectKnotHolderEntityWH::knot_get() const
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     return Geom::Point(rect->x.computed + rect->width.computed, rect->y.computed + rect->height.computed);
 }
@@ -259,7 +271,8 @@ RectKnotHolderEntityWH::knot_get() const
 void
 RectKnotHolderEntityWH::set_internal(Geom::Point const &p, Geom::Point const &origin, unsigned int state)
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     Geom::Point s = p;
 
@@ -325,7 +338,7 @@ RectKnotHolderEntityWH::set_internal(Geom::Point const &p, Geom::Point const &or
 
     sp_rect_clamp_radii(rect);
 
-    (static_cast<SPObject *>(rect))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    rect->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 void
@@ -338,7 +351,8 @@ RectKnotHolderEntityWH::knot_set(Geom::Point const &p, Geom::Point const &origin
 Geom::Point
 RectKnotHolderEntityXY::knot_get() const
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     return Geom::Point(rect->x.computed, rect->y.computed);
 }
@@ -346,7 +360,8 @@ RectKnotHolderEntityXY::knot_get() const
 void
 RectKnotHolderEntityXY::knot_set(Geom::Point const &p, Geom::Point const &origin, unsigned int state)
 {
-    SPRect *rect = SP_RECT(item);
+    SPRect *rect = dynamic_cast<SPRect *>(item);
+    g_assert(rect != NULL);
 
     // opposite corner (unmoved)
     gdouble opposite_x = (rect->x.computed + rect->width.computed);
@@ -426,7 +441,7 @@ RectKnotHolderEntityXY::knot_set(Geom::Point const &p, Geom::Point const &origin
 
     update_knot();
 
-    (static_cast<SPObject *>(rect))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    rect->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 RectKnotHolder::RectKnotHolder(SPDesktop *desktop, SPItem *item, SPKnotHolderReleasedFunc relhandler) :
@@ -479,7 +494,12 @@ public:
 Geom::Point
 Box3DKnotHolderEntity::knot_get_generic(SPItem *item, unsigned int knot_id) const
 {
-    return box3d_get_corner_screen(SP_BOX3D(item), knot_id);
+    SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+    if (box) {
+        return box3d_get_corner_screen(box, knot_id);
+    } else {
+        return Geom::Point(); // TODO investigate proper fallback
+    }
 }
 
 void
@@ -488,7 +508,8 @@ Box3DKnotHolderEntity::knot_set_generic(SPItem *item, unsigned int knot_id, Geom
     Geom::Point const s = snap_knot_position(new_pos, state);
 
     g_assert(item != NULL);
-    SPBox3D *box = SP_BOX3D(item);
+    SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+    g_assert(box != NULL);
     Geom::Affine const i2dt (item->i2dt_affine ());
 
     Box3D::Axis movement;
@@ -608,7 +629,12 @@ Box3DKnotHolderEntity7::knot_get() const
 Geom::Point
 Box3DKnotHolderEntityCenter::knot_get() const
 {
-    return box3d_get_center_screen(SP_BOX3D(item));
+    SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+    if (box) {
+        return box3d_get_center_screen(box);
+    } else {
+        return Geom::Point(); // TODO investigate proper fallback
+    }
 }
 
 void
@@ -664,10 +690,11 @@ Box3DKnotHolderEntityCenter::knot_set(Geom::Point const &new_pos, Geom::Point co
 {
     Geom::Point const s = snap_knot_position(new_pos, state);
 
-    SPBox3D *box = SP_BOX3D(item);
+    SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+    g_assert(box != NULL);
     Geom::Affine const i2dt (item->i2dt_affine ());
 
-    box3d_set_center (SP_BOX3D(item), s * i2dt, origin * i2dt, !(state & GDK_SHIFT_MASK) ? Box3D::XY : Box3D::Z,
+    box3d_set_center(box, s * i2dt, origin * i2dt, !(state & GDK_SHIFT_MASK) ? Box3D::XY : Box3D::Z,
                       state & GDK_CONTROL_MASK);
 
     box3d_set_z_orders(box);
@@ -789,7 +816,8 @@ ArcKnotHolderEntityStart::knot_set(Geom::Point const &p, Geom::Point const &/*or
 {
     int snaps = Inkscape::Preferences::get()->getInt("/options/rotationsnapsperpi/value", 12);
 
-    SPGenericEllipse *arc = SP_GENERICELLIPSE(item);
+    SPGenericEllipse *arc = dynamic_cast<SPGenericEllipse *>(item);
+    g_assert(arc != NULL);
 
     arc->setClosed(sp_genericellipse_side(arc, p) == -1);
 
@@ -809,7 +837,8 @@ ArcKnotHolderEntityStart::knot_set(Geom::Point const &p, Geom::Point const &/*or
 Geom::Point
 ArcKnotHolderEntityStart::knot_get() const
 {
-    SPGenericEllipse const *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse const *ge = dynamic_cast<SPGenericEllipse const *>(item);
+    g_assert(ge != NULL);
 
     return ge->getPointAtAngle(ge->start);
 }
@@ -817,11 +846,12 @@ ArcKnotHolderEntityStart::knot_get() const
 void
 ArcKnotHolderEntityStart::knot_click(unsigned int state)
 {
-    SPGenericEllipse *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse *ge = dynamic_cast<SPGenericEllipse *>(item);
+    g_assert(ge != NULL);
 
     if (state & GDK_SHIFT_MASK) {
         ge->end = ge->start = 0;
-        (static_cast<SPObject *>(ge))->updateRepr();
+        ge->updateRepr();
     }
 }
 
@@ -830,7 +860,8 @@ ArcKnotHolderEntityEnd::knot_set(Geom::Point const &p, Geom::Point const &/*orig
 {
     int snaps = Inkscape::Preferences::get()->getInt("/options/rotationsnapsperpi/value", 12);
 
-    SPGenericEllipse *arc = SP_GENERICELLIPSE(item);
+    SPGenericEllipse *arc = dynamic_cast<SPGenericEllipse *>(item);
+    g_assert(arc != NULL);
 
     arc->setClosed(sp_genericellipse_side(arc, p) == -1);
 
@@ -850,7 +881,8 @@ ArcKnotHolderEntityEnd::knot_set(Geom::Point const &p, Geom::Point const &/*orig
 Geom::Point
 ArcKnotHolderEntityEnd::knot_get() const
 {
-    SPGenericEllipse const *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse const *ge = dynamic_cast<SPGenericEllipse const *>(item);
+    g_assert(ge != NULL);
 
     return ge->getPointAtAngle(ge->end);
 }
@@ -859,11 +891,12 @@ ArcKnotHolderEntityEnd::knot_get() const
 void
 ArcKnotHolderEntityEnd::knot_click(unsigned int state)
 {
-    SPGenericEllipse *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse *ge = dynamic_cast<SPGenericEllipse *>(item);
+    g_assert(ge != NULL);
 
     if (state & GDK_SHIFT_MASK) {
         ge->end = ge->start = 0;
-        (static_cast<SPObject *>(ge))->updateRepr();
+        ge->updateRepr();
     }
 }
 
@@ -871,7 +904,8 @@ ArcKnotHolderEntityEnd::knot_click(unsigned int state)
 void
 ArcKnotHolderEntityRX::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, unsigned int state)
 {
-    SPGenericEllipse *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse *ge = dynamic_cast<SPGenericEllipse *>(item);
+    g_assert(ge != NULL);
 
     Geom::Point const s = snap_knot_position(p, state);
 
@@ -881,13 +915,14 @@ ArcKnotHolderEntityRX::knot_set(Geom::Point const &p, Geom::Point const &/*origi
         ge->ry.computed = ge->rx.computed;
     }
 
-    (static_cast<SPObject *>(item))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    item->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 Geom::Point
 ArcKnotHolderEntityRX::knot_get() const
 {
-    SPGenericEllipse const *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse const *ge = dynamic_cast<SPGenericEllipse const *>(item);
+    g_assert(ge != NULL);
 
     return (Geom::Point(ge->cx.computed, ge->cy.computed) -  Geom::Point(ge->rx.computed, 0));
 }
@@ -895,18 +930,20 @@ ArcKnotHolderEntityRX::knot_get() const
 void
 ArcKnotHolderEntityRX::knot_click(unsigned int state)
 {
-    SPGenericEllipse *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse *ge = dynamic_cast<SPGenericEllipse *>(item);
+    g_assert(ge != NULL);
 
     if (state & GDK_CONTROL_MASK) {
         ge->ry.computed = ge->rx.computed;
-        (static_cast<SPObject *>(ge))->updateRepr();
+        ge->updateRepr();
     }
 }
 
 void
 ArcKnotHolderEntityRY::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, unsigned int state)
 {
-    SPGenericEllipse *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse *ge = dynamic_cast<SPGenericEllipse *>(item);
+    g_assert(ge != NULL);
 
     Geom::Point const s = snap_knot_position(p, state);
 
@@ -916,13 +953,14 @@ ArcKnotHolderEntityRY::knot_set(Geom::Point const &p, Geom::Point const &/*origi
         ge->rx.computed = ge->ry.computed;
     }
 
-    (static_cast<SPObject *>(item))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    item->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 Geom::Point
 ArcKnotHolderEntityRY::knot_get() const
 {
-    SPGenericEllipse const *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse const *ge = dynamic_cast<SPGenericEllipse *>(item);
+    g_assert(ge != NULL);
 
     return (Geom::Point(ge->cx.computed, ge->cy.computed) -  Geom::Point(0, ge->ry.computed));
 }
@@ -930,11 +968,12 @@ ArcKnotHolderEntityRY::knot_get() const
 void
 ArcKnotHolderEntityRY::knot_click(unsigned int state)
 {
-    SPGenericEllipse *ge = SP_GENERICELLIPSE(item);
+    SPGenericEllipse *ge = dynamic_cast<SPGenericEllipse *>(item);
+    g_assert(ge != NULL);
 
     if (state & GDK_CONTROL_MASK) {
         ge->rx.computed = ge->ry.computed;
-        (static_cast<SPObject *>(ge))->updateRepr();
+        ge->updateRepr();
     }
 }
 
@@ -991,7 +1030,8 @@ public:
 void
 StarKnotHolderEntity1::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, unsigned int state)
 {
-    SPStar *star = SP_STAR(item);
+    SPStar *star = dynamic_cast<SPStar *>(item);
+    g_assert(star != NULL);
 
     Geom::Point const s = snap_knot_position(p, state);
 
@@ -1011,13 +1051,14 @@ StarKnotHolderEntity1::knot_set(Geom::Point const &p, Geom::Point const &/*origi
         star->arg[0]  = arg1;
         star->arg[1] += darg1;
     }
-    (static_cast<SPObject *>(star))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    star->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 void
 StarKnotHolderEntity2::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, unsigned int state)
 {
-    SPStar *star = SP_STAR(item);
+    SPStar *star = dynamic_cast<SPStar *>(item);
+    g_assert(star != NULL);
 
     Geom::Point const s = snap_knot_position(p, state);
 
@@ -1039,7 +1080,7 @@ StarKnotHolderEntity2::knot_set(Geom::Point const &p, Geom::Point const &/*origi
             star->r[1]   = L2(d);
             star->arg[1] = atan2(d);
         }
-        (static_cast<SPObject *>(star))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+        star->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
     }
 }
 
@@ -1048,7 +1089,8 @@ StarKnotHolderEntity1::knot_get() const
 {
     g_assert(item != NULL);
 
-    SPStar const *star = SP_STAR(item);
+    SPStar const *star = dynamic_cast<SPStar const *>(item);
+    g_assert(star != NULL);
 
     return sp_star_get_xy(star, SP_STAR_POINT_KNOT1, 0);
 
@@ -1059,7 +1101,8 @@ StarKnotHolderEntity2::knot_get() const
 {
     g_assert(item != NULL);
 
-    SPStar const *star = SP_STAR(item);
+    SPStar const *star = dynamic_cast<SPStar const *>(item);
+    g_assert(star != NULL);
 
     return sp_star_get_xy(star, SP_STAR_POINT_KNOT2, 0);
 }
@@ -1067,17 +1110,18 @@ StarKnotHolderEntity2::knot_get() const
 static void
 sp_star_knot_click(SPItem *item, unsigned int state)
 {
-    SPStar *star = SP_STAR(item);
+    SPStar *star = dynamic_cast<SPStar *>(item);
+    g_assert(star != NULL);
 
     if (state & GDK_MOD1_MASK) {
         star->randomized = 0;
-        (static_cast<SPObject *>(star))->updateRepr();
+        star->updateRepr();
     } else if (state & GDK_SHIFT_MASK) {
         star->rounded = 0;
-        (static_cast<SPObject *>(star))->updateRepr();
+        star->updateRepr();
     } else if (state & GDK_CONTROL_MASK) {
         star->arg[1] = star->arg[0] + M_PI / star->sides;
-        (static_cast<SPObject *>(star))->updateRepr();
+        star->updateRepr();
     }
 }
 
@@ -1096,7 +1140,8 @@ StarKnotHolderEntity2::knot_click(unsigned int state)
 StarKnotHolder::StarKnotHolder(SPDesktop *desktop, SPItem *item, SPKnotHolderReleasedFunc relhandler) :
     KnotHolder(desktop, item, relhandler)
 {
-    SPStar *star = SP_STAR(item);
+    SPStar *star = dynamic_cast<SPStar *>(item);
+    g_assert(item != NULL);
 
     StarKnotHolderEntity1 *entity1 = new StarKnotHolderEntity1();
     entity1->create(desktop, item, this, Inkscape::CTRL_TYPE_SHAPER,
@@ -1144,7 +1189,8 @@ SpiralKnotHolderEntityInner::knot_set(Geom::Point const &p, Geom::Point const &o
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     int snaps = prefs->getInt("/options/rotationsnapsperpi/value", 12);
 
-    SPSpiral *spiral = SP_SPIRAL(item);
+    SPSpiral *spiral = dynamic_cast<SPSpiral *>(item);
+    g_assert(spiral != NULL);
 
     gdouble   dx = p[Geom::X] - spiral->cx;
     gdouble   dy = p[Geom::Y] - spiral->cy;
@@ -1179,7 +1225,7 @@ SpiralKnotHolderEntityInner::knot_set(Geom::Point const &p, Geom::Point const &o
         spiral->t0 = CLAMP(spiral->t0, 0.0, 0.999);
     }
 
-    (static_cast<SPObject *>(spiral))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    spiral->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 /*
@@ -1193,7 +1239,8 @@ SpiralKnotHolderEntityOuter::knot_set(Geom::Point const &p, Geom::Point const &/
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     int snaps = prefs->getInt("/options/rotationsnapsperpi/value", 12);
 
-    SPSpiral *spiral = SP_SPIRAL(item);
+    SPSpiral *spiral = dynamic_cast<SPSpiral *>(item);
+    g_assert(spiral != NULL);
 
     gdouble  dx = p[Geom::X] - spiral->cx;
     gdouble  dy = p[Geom::Y] - spiral->cy;
@@ -1258,13 +1305,14 @@ SpiralKnotHolderEntityOuter::knot_set(Geom::Point const &p, Geom::Point const &/
         spiral->t0 = CLAMP(spiral->t0, 0.0, 0.999);
     }
 
-    (static_cast<SPObject *>(spiral))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    spiral->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 Geom::Point
 SpiralKnotHolderEntityInner::knot_get() const
 {
-    SPSpiral const *spiral = SP_SPIRAL(item);
+    SPSpiral const *spiral = dynamic_cast<SPSpiral const *>(item);
+    g_assert(spiral != NULL);
 
     return spiral->getXY(spiral->t0);
 }
@@ -1272,7 +1320,8 @@ SpiralKnotHolderEntityInner::knot_get() const
 Geom::Point
 SpiralKnotHolderEntityOuter::knot_get() const
 {
-    SPSpiral const *spiral = SP_SPIRAL(item);
+    SPSpiral const *spiral = dynamic_cast<SPSpiral const *>(item);
+    g_assert(spiral != NULL);
 
     return spiral->getXY(1.0);
 }
@@ -1280,14 +1329,15 @@ SpiralKnotHolderEntityOuter::knot_get() const
 void
 SpiralKnotHolderEntityInner::knot_click(unsigned int state)
 {
-    SPSpiral *spiral = SP_SPIRAL(item);
+    SPSpiral *spiral = dynamic_cast<SPSpiral *>(item);
+    g_assert(spiral != NULL);
 
     if (state & GDK_MOD1_MASK) {
         spiral->exp = 1;
-        (static_cast<SPObject *>(spiral))->updateRepr();
+        spiral->updateRepr();
     } else if (state & GDK_SHIFT_MASK) {
         spiral->t0 = 0;
-        (static_cast<SPObject *>(spiral))->updateRepr();
+        spiral->updateRepr();
     }
 }
 
@@ -1322,20 +1372,22 @@ public:
 void
 OffsetKnotHolderEntity::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, unsigned int /*state*/)
 {
-    SPOffset *offset = SP_OFFSET(item);
+    SPOffset *offset = dynamic_cast<SPOffset *>(item);
+    g_assert(offset != NULL);
 
     offset->rad = sp_offset_distance_to_original(offset, p);
     offset->knot = p;
     offset->knotSet = true;
 
-    (static_cast<SPObject *>(offset))->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
+    offset->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
 
 Geom::Point
 OffsetKnotHolderEntity::knot_get() const
 {
-    SPOffset const *offset = SP_OFFSET(item);
+    SPOffset const *offset = dynamic_cast<SPOffset const *>(item);
+    g_assert(offset != NULL);
 
     Geom::Point np;
     sp_offset_top_point(offset,&np);
@@ -1365,7 +1417,8 @@ public:
 Geom::Point
 FlowtextKnotHolderEntity::knot_get() const
 {
-    SPRect const *rect = SP_RECT(item);
+    SPRect const *rect = dynamic_cast<SPRect const *>(item);
+    g_assert(rect != NULL);
 
     return Geom::Point(rect->x.computed + rect->width.computed, rect->y.computed + rect->height.computed);
 }
diff --git a/src/ui/tools-switch.cpp b/src/ui/tools-switch.cpp
index 048252788..47b9d2832 100644
--- a/src/ui/tools-switch.cpp
+++ b/src/ui/tools-switch.cpp
@@ -4,6 +4,7 @@
  * Authors:
  *   bulia byak <buliabyak@users.sf.net>
  *   Josh Andler <scislac@users.sf.net>
+ *   Jon A. Cruz <jon@joncruz.org>
  *
  * Copyright (C) 2003-2007 authors
  *
@@ -59,6 +60,8 @@
 
 #include "message-context.h"
 
+using Inkscape::UI::Tools::ToolBase;
+
 static char const *const tool_names[] = {
     NULL,
     "/tools/select",
@@ -130,9 +133,11 @@ int
 tools_isactive(SPDesktop *dt, unsigned num)
 {
     g_assert( num < G_N_ELEMENTS(tool_names) );
-    if (SP_IS_EVENT_CONTEXT(dt->event_context))
+    if (dynamic_cast<ToolBase *>(dt->event_context)) {
         return dt->event_context->pref_observer->observed_path == tool_names[num];
-    else return FALSE;
+    } else {
+        return FALSE;
+    }
 }
 
 int
@@ -159,27 +164,27 @@ tools_switch(SPDesktop *dt, int num)
 
 void tools_switch_by_item(SPDesktop *dt, SPItem *item, Geom::Point const p)
 {
-    if (SP_IS_RECT(item)) {
+    if (dynamic_cast<SPRect *>(item)) {
         tools_switch(dt, TOOLS_SHAPES_RECT);
-    } else if (SP_IS_BOX3D(item)) {
+    } else if (dynamic_cast<SPBox3D *>(item)) {
         tools_switch(dt, TOOLS_SHAPES_3DBOX);
-    } else if (SP_IS_GENERICELLIPSE(item)) {
+    } else if (dynamic_cast<SPGenericEllipse *>(item)) {
         tools_switch(dt, TOOLS_SHAPES_ARC);
-    } else if (SP_IS_STAR(item)) {
+    } else if (dynamic_cast<SPStar *>(item)) {
         tools_switch(dt, TOOLS_SHAPES_STAR);
-    } else if (SP_IS_SPIRAL(item)) {
+    } else if (dynamic_cast<SPSpiral *>(item)) {
         tools_switch(dt, TOOLS_SHAPES_SPIRAL);
-    } else if (SP_IS_PATH(item)) {
+    } else if (dynamic_cast<SPPath *>(item)) {
         if (Inkscape::UI::Tools::cc_item_is_connector(item)) {
             tools_switch(dt, TOOLS_CONNECTOR);
         }
         else {
             tools_switch(dt, TOOLS_NODES);
         }
-    } else if (SP_IS_TEXT(item) || SP_IS_FLOWTEXT(item))  {
+    } else if (dynamic_cast<SPText *>(item) || dynamic_cast<SPFlowtext *>(item))  {
         tools_switch(dt, TOOLS_TEXT);
-        sp_text_context_place_cursor_at (SP_TEXT_CONTEXT(dt->event_context), SP_OBJECT(item), p);
-    } else if (SP_IS_OFFSET(item))  {
+        sp_text_context_place_cursor_at (SP_TEXT_CONTEXT(dt->event_context), item, p);
+    } else if (dynamic_cast<SPOffset *>(item))  {
         tools_switch(dt, TOOLS_NODES);
     }
 }
diff --git a/src/ui/tools/select-tool.cpp b/src/ui/tools/select-tool.cpp
index 394b0b369..21459e5d0 100644
--- a/src/ui/tools/select-tool.cpp
+++ b/src/ui/tools/select-tool.cpp
@@ -264,15 +264,16 @@ sp_select_context_up_one_layer(SPDesktop *desktop)
     SPObject *const current_layer = desktop->currentLayer();
     if (current_layer) {
         SPObject *const parent = current_layer->parent;
+        SPGroup *current_group = dynamic_cast<SPGroup *>(current_layer);
         if ( parent
              && ( parent->parent
-                  || !( SP_IS_GROUP(current_layer)
-                        && ( SPGroup::LAYER
-                             == SP_GROUP(current_layer)->layerMode() ) ) ) )
+                  || !( current_group
+                        && ( SPGroup::LAYER == current_group->layerMode() ) ) ) )
         {
             desktop->setCurrentLayer(parent);
-            if (SP_IS_GROUP(current_layer) && SPGroup::LAYER != SP_GROUP(current_layer)->layerMode())
+            if (current_group && (SPGroup::LAYER != current_group->layerMode())) {
                 sp_desktop_selection(desktop)->set(current_layer);
+            }
         }
     }
 }
@@ -403,7 +404,8 @@ void SelectTool::sp_select_context_cycle_through_items(Inkscape::Selection *sele
     }
 
     Inkscape::DrawingItem *arenaitem;
-    SPItem *item = SP_ITEM(this->cycling_cur_item->data);
+    SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(cycling_cur_item->data));
+    g_assert(item != NULL);
 
     // Deactivate current item
     if (!g_list_find(this->cycling_items_selected_before, item) && selection->includes(item)) {
@@ -427,7 +429,8 @@ void SelectTool::sp_select_context_cycle_through_items(Inkscape::Selection *sele
 
     if (next) {
         this->cycling_cur_item = next;
-        item = SP_ITEM(this->cycling_cur_item->data);
+        item = dynamic_cast<SPItem *>(static_cast<SPObject *>(this->cycling_cur_item->data));
+        g_assert(item != NULL);
     }
 
     arenaitem = item->get_arenaitem(desktop->dkey);
@@ -442,8 +445,13 @@ void SelectTool::sp_select_context_cycle_through_items(Inkscape::Selection *sele
 
 void SelectTool::sp_select_context_reset_opacities() {
     for (GList *l = this->cycling_items; l != NULL; l = g_list_next(l)) {
-        Inkscape::DrawingItem *arenaitem = SP_ITEM(l->data)->get_arenaitem(this->desktop->dkey);
-        arenaitem->setOpacity(SP_SCALE24_TO_FLOAT(SP_ITEM(l->data)->style->opacity.value));
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(l->data));
+        if (item) {
+            Inkscape::DrawingItem *arenaitem = item->get_arenaitem(desktop->dkey);
+            arenaitem->setOpacity(SP_SCALE24_TO_FLOAT(item->style->opacity.value));
+        } else {
+            g_assert_not_reached();
+        }
     }
 
     g_list_free(this->cycling_items);
@@ -475,8 +483,8 @@ bool SelectTool::root_handler(GdkEvent* event) {
                 if (!selection->isEmpty()) {
                     SPItem *clicked_item = static_cast<SPItem *>(selection->itemList()->data);
 
-                    if (SP_IS_GROUP(clicked_item) && !SP_IS_BOX3D(clicked_item)) { // enter group if it's not a 3D box
-                        desktop->setCurrentLayer(reinterpret_cast<SPObject *>(clicked_item));
+                    if (dynamic_cast<SPGroup *>(clicked_item) && !dynamic_cast<SPBox3D *>(clicked_item)) { // enter group if it's not a 3D box
+                        desktop->setCurrentLayer(clicked_item);
                         sp_desktop_selection(desktop)->clear();
                         this->dragging = false;
                         sp_event_context_discard_delayed_snap_event(this);
@@ -591,8 +599,11 @@ bool SelectTool::root_handler(GdkEvent* event) {
                             item_in_group = desktop->getItemAtPoint(Geom::Point(event->button.x, event->button.y), TRUE);
                             group_at_point = desktop->getGroupAtPoint(Geom::Point(event->button.x, event->button.y));
 
-                            if (SP_IS_LAYER(selection->single())) {
-                                group_at_point = SP_GROUP(selection->single());
+                            {
+                                SPGroup *selGroup = dynamic_cast<SPGroup *>(selection->single());
+                                if (selGroup && (selGroup->layerMode() == SPGroup::LAYER)) {
+                                    group_at_point = selGroup;
+                                }
                             }
 
                             // group-at-point is meant to be topmost item if it's a group,
@@ -673,10 +684,11 @@ bool SelectTool::root_handler(GdkEvent* event) {
                                 selection->toggle(this->item);
                             } else {
                                 SPObject* single = selection->single();
+                                SPGroup *singleGroup = dynamic_cast<SPGroup *>(single);
                                 // without shift, increase state (i.e. toggle scale/rotation handles)
                                 if (selection->includes(this->item)) {
                                     _seltrans->increaseState();
-                                } else if (SP_IS_LAYER(single) && single->isAncestorOf(this->item)) {
+                                } else if (singleGroup && (singleGroup->layerMode() == SPGroup::LAYER) && single->isAncestorOf(this->item)) {
                                     _seltrans->increaseState();
                                 } else {
                                     _seltrans->resetState();
@@ -818,7 +830,7 @@ bool SelectTool::root_handler(GdkEvent* event) {
                 SPItem *item = desktop->getItemAtPoint(p, true, NULL);
 
                 // Save pointer to current cycle-item so that we can find it again later, in the freshly built list
-                SPItem *tmp_cur_item = this->cycling_cur_item ? SP_ITEM(this->cycling_cur_item->data) : NULL;
+                SPItem *tmp_cur_item = this->cycling_cur_item ? dynamic_cast<SPItem *>(static_cast<SPObject *>(this->cycling_cur_item->data)) : NULL;
                 g_list_free(this->cycling_items);
                 this->cycling_items = NULL;
                 this->cycling_cur_item = NULL;
@@ -851,11 +863,14 @@ bool SelectTool::root_handler(GdkEvent* event) {
                     Inkscape::DrawingItem *arenaitem;
 
                     for(GList *l = this->cycling_items_cmp; l != NULL; l = l->next) {
-                        arenaitem = SP_ITEM(l->data)->get_arenaitem(desktop->dkey);
-                        arenaitem->setOpacity(1.0);
-                        //if (!shift_pressed && !g_list_find(this->cycling_items_selected_before, SP_ITEM(l->data)) && selection->includes(SP_ITEM(l->data)))
-                        if (!g_list_find(this->cycling_items_selected_before, SP_ITEM(l->data)) && selection->includes(SP_ITEM(l->data))) {
-                            selection->remove(SP_ITEM(l->data));
+                        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(l->data));
+                        if (item) {
+                            arenaitem = item->get_arenaitem(desktop->dkey);
+                            arenaitem->setOpacity(1.0);
+                            //if (!shift_pressed && !g_list_find(this->cycling_items_selected_before, item) && selection->includes(item))
+                            if (!g_list_find(this->cycling_items_selected_before, item) && selection->includes(item)) {
+                                selection->remove(item);
+                            }
                         }
                     }
 
@@ -869,16 +884,19 @@ bool SelectTool::root_handler(GdkEvent* event) {
 
                     // ... and rebuild them with the new items.
                     this->cycling_items_cmp = g_list_copy(this->cycling_items);
-                    SPItem *item;
 
                     for(GList *l = this->cycling_items; l != NULL; l = l->next) {
-                        item = SP_ITEM(l->data);
-                        arenaitem = item->get_arenaitem(desktop->dkey);
-                        arenaitem->setOpacity(0.3);
-
-                        if (selection->includes(item)) {
-                            // already selected items are stored separately, too
-                            this->cycling_items_selected_before = g_list_append(this->cycling_items_selected_before, item);
+                        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(l->data));
+                        if (item) {
+                            arenaitem = item->get_arenaitem(desktop->dkey);
+                            arenaitem->setOpacity(0.3);
+
+                            if (selection->includes(item)) {
+                                // already selected items are stored separately, too
+                                this->cycling_items_selected_before = g_list_append(this->cycling_items_selected_before, item);
+                            }
+                        } else {
+                            g_assert_not_reached();
                         }
                     }
 
@@ -1134,9 +1152,9 @@ bool SelectTool::root_handler(GdkEvent* event) {
                     if (MOD__CTRL_ONLY(event)) {
                         if (selection->singleItem()) {
                             SPItem *clicked_item = selection->singleItem();
-                            
-                            if ( SP_IS_GROUP(clicked_item) || SP_IS_BOX3D(clicked_item)) { // enter group or a 3D box
-                                desktop->setCurrentLayer(reinterpret_cast<SPObject *>(clicked_item));
+                            SPGroup *clickedGroup = dynamic_cast<SPGroup *>(clicked_item);
+                            if ( (clickedGroup && (clickedGroup->layerMode() == SPGroup::LAYER)) || dynamic_cast<SPBox3D *>(clicked_item)) { // enter group or a 3D box
+                                desktop->setCurrentLayer(clicked_item);
                                 sp_desktop_selection(desktop)->clear();
                             } else {
                                 this->desktop->messageStack()->flash(Inkscape::NORMAL_MESSAGE, _("Selected object is not a group. Cannot enter."));
diff --git a/src/ui/tools/spray-tool.cpp b/src/ui/tools/spray-tool.cpp
index 933da6fb1..cdc608558 100644
--- a/src/ui/tools/spray-tool.cpp
+++ b/src/ui/tools/spray-tool.cpp
@@ -384,11 +384,14 @@ static bool sp_spray_recursive(SPDesktop *desktop,
                                gint _distrib)
 {
     bool did = false;
-    
-    if (SP_IS_BOX3D(item) ) {
-        // convert 3D boxes to ordinary groups before spraying their shapes
-        item = box3d_convert_to_group(SP_BOX3D(item));
-        selection->add(item);
+
+    {
+        SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+        if (box) {
+            // convert 3D boxes to ordinary groups before spraying their shapes
+            item = box3d_convert_to_group(box);
+            selection->add(item);
+        }
     }
 
     double _fid = g_random_double_range(0, 1);
@@ -413,7 +416,7 @@ static bool sp_spray_recursive(SPDesktop *desktop,
                 parent->appendChild(copy);
 
                 SPObject *new_obj = doc->getObjectByRepr(copy);
-                item_copied = SP_ITEM(new_obj);   // Convertion object->item
+                item_copied = dynamic_cast<SPItem *>(new_obj);   // Convertion object->item
                 Geom::Point center=item->getCenter();
                 sp_spray_scale_rel(center,desktop, item_copied, Geom::Scale(_scale,_scale));
                 sp_spray_scale_rel(center,desktop, item_copied, Geom::Scale(scale,scale));
@@ -437,7 +440,7 @@ static bool sp_spray_recursive(SPDesktop *desktop,
                 items != NULL;
                 items = items->next) {
 
-            SPItem *item1 = SP_ITEM(items->data);
+            SPItem *item1 = dynamic_cast<SPItem *>(static_cast<SPObject *>(items->data));
             if (i == 1) {
                 parent_item = item1;
             }
@@ -458,7 +461,7 @@ static bool sp_spray_recursive(SPDesktop *desktop,
                 Inkscape::XML::Node *copy = old_repr->duplicate(xml_doc);
                 parent->appendChild(copy);
                 SPObject *new_obj = doc->getObjectByRepr(copy);
-                item_copied = SP_ITEM(new_obj);
+                item_copied = dynamic_cast<SPItem *>(new_obj);
 
                 // Move around the cursor
                 Geom::Point move = (Geom::Point(cos(tilt)*cos(dp)*dr/(1-ratio)+sin(tilt)*sin(dp)*dr/(1+ratio), -sin(tilt)*cos(dp)*dr/(1-ratio)+cos(tilt)*sin(dp)*dr/(1+ratio)))+(p-a->midpoint()); 
@@ -503,7 +506,7 @@ static bool sp_spray_recursive(SPDesktop *desktop,
 
                 SPObject *clone_object = doc->getObjectByRepr(clone);
                 // Conversion object->item
-                item_copied = SP_ITEM(clone_object);
+                item_copied = dynamic_cast<SPItem *>(clone_object);
                 Geom::Point center = item->getCenter();
                 sp_spray_scale_rel(center, desktop, item_copied, Geom::Scale(_scale, _scale));
                 sp_spray_scale_rel(center, desktop, item_copied, Geom::Scale(scale, scale));
@@ -554,13 +557,16 @@ static bool sp_spray_dilate(SprayTool *tc, Geom::Point /*event_p*/, Geom::Point
         for (GSList *items = original_selection;
                 items != NULL;
                 items = items->next) {
-            sp_object_ref(SP_ITEM(items->data));
+            SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(items->data));
+            g_assert(item != NULL);
+            sp_object_ref(item);
         }
 
         for (GSList *items = original_selection;
                 items != NULL;
                 items = items->next) {
-            SPItem *item = SP_ITEM(items->data);
+            SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(items->data));
+            g_assert(item != NULL);
 
             if (is_transform_modes(tc->mode)) {
                 if (sp_spray_recursive(desktop, selection, item, p, vector, tc->mode, radius, move_force, tc->population, tc->scale, tc->scale_variation, reverse, move_mean, move_standard_deviation, tc->ratio, tc->tilt, tc->rotation_variation, tc->distrib)) {
@@ -576,7 +582,9 @@ static bool sp_spray_dilate(SprayTool *tc, Geom::Point /*event_p*/, Geom::Point
         for (GSList *items = original_selection;
                 items != NULL;
                 items = items->next) {
-            sp_object_unref(SP_ITEM(items->data));
+            SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(items->data));
+            g_assert(item != NULL);
+            sp_object_unref(item);
         }
     }
 
diff --git a/src/ui/tools/tweak-tool.cpp b/src/ui/tools/tweak-tool.cpp
index 340f64a0b..f56975de2 100644
--- a/src/ui/tools/tweak-tool.cpp
+++ b/src/ui/tools/tweak-tool.cpp
@@ -372,13 +372,16 @@ sp_tweak_dilate_recursive (Inkscape::Selection *selection, SPItem *item, Geom::P
 {
     bool did = false;
 
-    if (SP_IS_BOX3D(item) && !is_transform_mode(mode) && !is_color_mode(mode)) {
-        // convert 3D boxes to ordinary groups before tweaking their shapes
-        item = box3d_convert_to_group(SP_BOX3D(item));
-        selection->add(item);
+    {
+        SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+        if (box && !is_transform_mode(mode) && !is_color_mode(mode)) {
+            // convert 3D boxes to ordinary groups before tweaking their shapes
+            item = box3d_convert_to_group(box);
+            selection->add(item);
+        }
     }
 
-    if (SP_IS_TEXT(item) || SP_IS_FLOWTEXT(item)) {
+    if (dynamic_cast<SPText *>(item) || dynamic_cast<SPFlowtext *>(item)) {
         GSList *items = g_slist_prepend (NULL, item);
         GSList *selected = NULL;
         GSList *to_select = NULL;
@@ -387,22 +390,25 @@ sp_tweak_dilate_recursive (Inkscape::Selection *selection, SPItem *item, Geom::P
         g_slist_free (items);
         SPObject* newObj = doc->getObjectByRepr(static_cast<Inkscape::XML::Node *>(to_select->data));
         g_slist_free (to_select);
-        item = SP_ITEM(newObj);
+        item = dynamic_cast<SPItem *>(newObj);
+        g_assert(item != NULL);
         selection->add(item);
     }
 
-    if (SP_IS_GROUP(item) && !SP_IS_BOX3D(item)) {
+    if (dynamic_cast<SPGroup *>(item) && !dynamic_cast<SPBox3D *>(item)) {
         GSList *children = NULL;
         for (SPObject *child = item->firstChild() ; child; child = child->getNext() ) {
-            if (SP_IS_ITEM(child)) {
+            if (dynamic_cast<SPItem *>(static_cast<SPObject *>(child))) {
                 children = g_slist_prepend(children, child);
             }
         }
 
         for (GSList *i = children; i; i = i->next) {
-            SPItem *child = SP_ITEM(i->data);
-            if (sp_tweak_dilate_recursive (selection, SP_ITEM(child), p, vector, mode, radius, force, fidelity, reverse))
+            SPItem *child = dynamic_cast<SPItem *>(static_cast<SPObject *>(i->data));
+            g_assert(child != NULL);
+            if (sp_tweak_dilate_recursive (selection, child, p, vector, mode, radius, force, fidelity, reverse)) {
                 did = true;
+            }
         }
 
         g_slist_free(children);
@@ -509,13 +515,13 @@ sp_tweak_dilate_recursive (Inkscape::Selection *selection, SPItem *item, Geom::P
                 }
             }
 
-        } else if (SP_IS_PATH(item) || SP_IS_SHAPE(item)) {
+        } else if (dynamic_cast<SPPath *>(item) || dynamic_cast<SPShape *>(item)) {
 
             Inkscape::XML::Node *newrepr = NULL;
             gint pos = 0;
             Inkscape::XML::Node *parent = NULL;
             char const *id = NULL;
-            if (!SP_IS_PATH(item)) {
+            if (!dynamic_cast<SPPath *>(item)) {
                 newrepr = sp_selected_item_to_curved_repr(item, 0);
                 if (!newrepr) {
                     return false;
@@ -631,7 +637,8 @@ sp_tweak_dilate_recursive (Inkscape::Selection *selection, SPItem *item, Geom::P
                     if (newrepr) {
                         newrepr->setAttribute("d", str);
                     } else {
-                        if (SP_IS_LPE_ITEM(item) && SP_LPE_ITEM(item)->hasPathEffectRecursive()) {
+                        SPLPEItem *lpeitem = dynamic_cast<SPLPEItem *>(item);
+                        if (lpeitem && lpeitem->hasPathEffectRecursive()) {
                             item->getRepr()->setAttribute("inkscape:original-d", str);
                         } else {
                             item->getRepr()->setAttribute("d", str);
@@ -769,7 +776,7 @@ static void tweak_colors_in_gradient(SPItem *item, Inkscape::PaintTarget fill_or
 {
     SPGradient *gradient = getGradient(item, fill_or_stroke);
 
-    if (!gradient || !SP_IS_GRADIENT(gradient)) {
+    if (!gradient || !dynamic_cast<SPGradient *>(gradient)) {
         return;
     }
 
@@ -780,9 +787,9 @@ static void tweak_colors_in_gradient(SPItem *item, Inkscape::PaintTarget fill_or
 
     double pos = 0;
     double r = 0;
-    if (SP_IS_LINEARGRADIENT(gradient)) {
-        SPLinearGradient *lg = SP_LINEARGRADIENT(gradient);
 
+    SPLinearGradient *lg = dynamic_cast<SPLinearGradient *>(gradient);
+    if (lg) {
         Geom::Point p1(lg->x1.computed, lg->y1.computed);
         Geom::Point p2(lg->x2.computed, lg->y2.computed);
         Geom::Point pdiff(p2 - p1);
@@ -800,11 +807,13 @@ static void tweak_colors_in_gradient(SPItem *item, Inkscape::PaintTarget fill_or
         // Calculate radius in lenfth-of-gradient-line units
         r = radius / vl;
 
-    } else if (SP_IS_RADIALGRADIENT(gradient)) {
-        SPRadialGradient *rg = SP_RADIALGRADIENT(gradient);
-        Geom::Point c (rg->cx.computed, rg->cy.computed);
-        pos = Geom::L2(p - c) / rg->r.computed;
-        r = radius / rg->r.computed;
+    } else {
+        SPRadialGradient *rg = dynamic_cast<SPRadialGradient *>(gradient);
+        if (rg) {
+            Geom::Point c (rg->cx.computed, rg->cy.computed);
+            pos = Geom::L2(p - c) / rg->r.computed;
+            r = radius / rg->r.computed;
+        }
     }
 
     // Normalize pos to 0..1, taking into accound gradient spread:
@@ -836,14 +845,16 @@ static void tweak_colors_in_gradient(SPItem *item, Inkscape::PaintTarget fill_or
     double offset_h = 0;
     SPObject *child_prev = NULL;
     for (SPObject *child = vector->firstChild(); child; child = child->getNext()) {
-        if (!SP_IS_STOP(child)) {
+        SPStop *stop = dynamic_cast<SPStop *>(child);
+        if (!stop) {
             continue;
         }
-        SPStop *stop = SP_STOP (child);
 
         offset_h = stop->offset;
 
         if (child_prev) {
+            SPStop *prevStop = dynamic_cast<SPStop *>(child_prev);
+            g_assert(prevStop != NULL);
 
             if (offset_h - offset_l > r && pos_e >= offset_l && pos_e <= offset_h) {
                 // the summit falls in this interstop, and the radius is small,
@@ -853,9 +864,9 @@ static void tweak_colors_in_gradient(SPItem *item, Inkscape::PaintTarget fill_or
                 tweak_color (mode, stop->specified_color.v.c, rgb_goal,
                                   force * (pos_e - offset_l) / (offset_h - offset_l),
                                   do_h, do_s, do_l);
-                tweak_color (mode, SP_STOP(child_prev)->specified_color.v.c, rgb_goal,
-                                  force * (offset_h - pos_e) / (offset_h - offset_l),
-                                  do_h, do_s, do_l);
+                tweak_color(mode, prevStop->specified_color.v.c, rgb_goal,
+                            force * (offset_h - pos_e) / (offset_h - offset_l),
+                            do_h, do_s, do_l);
                 stop->updateRepr();
                 child_prev->updateRepr();
                 break;
@@ -863,9 +874,9 @@ static void tweak_colors_in_gradient(SPItem *item, Inkscape::PaintTarget fill_or
                 // wide brush, may affect more than 2 stops,
                 // paint each stop by the force from the profile curve
                 if (offset_l <= pos_e && offset_l > pos_e - r) {
-                    tweak_color (mode, SP_STOP(child_prev)->specified_color.v.c, rgb_goal,
-                                 force * tweak_profile (fabs (pos_e - offset_l), r),
-                                 do_h, do_s, do_l);
+                    tweak_color(mode, prevStop->specified_color.v.c, rgb_goal,
+                                force * tweak_profile (fabs (pos_e - offset_l), r),
+                                do_h, do_s, do_l);
                     child_prev->updateRepr();
                 }
 
@@ -894,10 +905,11 @@ sp_tweak_color_recursive (guint mode, SPItem *item, SPItem *item_at_point,
 {
     bool did = false;
 
-    if (SP_IS_GROUP(item)) {
+    if (dynamic_cast<SPGroup *>(item)) {
         for (SPObject *child = item->firstChild() ; child; child = child->getNext() ) {
-            if (SP_IS_ITEM(child)) {
-                if (sp_tweak_color_recursive (mode, SP_ITEM(child), item_at_point,
+            SPItem *childItem = dynamic_cast<SPItem *>(child);
+            if (childItem) {
+                if (sp_tweak_color_recursive (mode, childItem, item_at_point,
                                           fill_goal, do_fill,
                                           stroke_goal, do_stroke,
                                           opacity_goal, do_opacity,
@@ -953,11 +965,11 @@ sp_tweak_color_recursive (guint mode, SPItem *item, SPItem *item_at_point,
                     //cycle through filter primitives
                     SPObject *primitive_obj = style->getFilter()->children;
                     while (primitive_obj) {
-                        if (SP_IS_FILTER_PRIMITIVE(primitive_obj)) {
-                            SPFilterPrimitive *primitive = SP_FILTER_PRIMITIVE(primitive_obj);
+                        SPFilterPrimitive *primitive = dynamic_cast<SPFilterPrimitive *>(primitive_obj);
+                        if (primitive) {
                             //if primitive is gaussianblur
-                            if(SP_IS_GAUSSIANBLUR(primitive)) {
-                                SPGaussianBlur * spblur = SP_GAUSSIANBLUR(primitive);
+                            SPGaussianBlur * spblur = dynamic_cast<SPGaussianBlur *>(primitive);
+                            if (spblur) {
                                 float num = spblur->stdDeviation.getNumber();
                                 blur_now += num * i2dt.descrim(); // sum all blurs in the filter
                             }
@@ -1080,7 +1092,7 @@ sp_tweak_dilate (TweakTool *tc, Geom::Point event_p, Geom::Point p, Geom::Point
          items != NULL;
          items = items->next) {
 
-        SPItem *item = SP_ITEM(items->data);
+        SPItem *item = dynamic_cast<SPItem *>(static_cast<SPObject *>(items->data));
 
         if (is_color_mode (tc->mode)) {
             if (do_fill || do_stroke || do_opacity) {
diff --git a/src/vanishing-point.cpp b/src/vanishing-point.cpp
index d1c8083de..13dd03ee3 100644
--- a/src/vanishing-point.cpp
+++ b/src/vanishing-point.cpp
@@ -6,6 +6,7 @@
  *   Johan Engelen <j.b.c.engelen@ewi.utwente.nl>
  *   Maximilian Albert <Anhalter42@gmx.de>
  *   Abhishek Sharma
+ *   Jon A. Cruz <jon@joncruz.org>
  *
  * Copyright (C) 2005-2007 authors
  *
@@ -256,11 +257,10 @@ std::list<SPBox3D *>
 VanishingPoint::selectedBoxes(Inkscape::Selection *sel) {
     std::list<SPBox3D *> sel_boxes;
     for (GSList const* i = sel->itemList(); i != NULL; i = i->next) {
-        if (!SP_IS_BOX3D(i->data))
-            continue;
-        SPBox3D *box = SP_BOX3D(i->data);
-        if (this->hasBox(box)) {
-            sel_boxes.push_back (box);
+        SPItem *item = static_cast<SPItem *>(i->data);
+        SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+        if (box && this->hasBox(box)) {
+            sel_boxes.push_back(box);
         }
     }
     return sel_boxes;
@@ -396,12 +396,13 @@ VPDragger::VPsOfSelectedBoxes() {
     // FIXME: Should we take the selection from the parent VPDrag? I guess it shouldn't make a difference.
     Inkscape::Selection *sel = sp_desktop_selection(inkscape_active_desktop());
     for (GSList const* i = sel->itemList(); i != NULL; i = i->next) {
-        if (!SP_IS_BOX3D(i->data))
-            continue;
-        SPBox3D *box = SP_BOX3D(i->data);
-        vp = this->findVPWithBox(box);
-        if (vp) {
-            sel_vps.insert (vp);
+        SPItem *item = static_cast<SPItem *>(i->data);
+        SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+        if (box) {
+            vp = this->findVPWithBox(box);
+            if (vp) {
+                sel_vps.insert (vp);
+            }
         }
     }
     return sel_vps;
@@ -577,14 +578,14 @@ VPDrag::updateDraggers ()
     g_return_if_fail (this->selection != NULL);
 
     for (GSList const* i = this->selection->itemList(); i != NULL; i = i->next) {
-        SPItem *item = SP_ITEM(i->data);
-        if (!SP_IS_BOX3D (item)) continue;
-        SPBox3D *box = SP_BOX3D (item);
-
-        VanishingPoint vp;
-        for (int i = 0; i < 3; ++i) {
-            vp.set(box3d_get_perspective(box), Proj::axes[i]);
-            addDragger (vp);
+        SPItem *item = static_cast<SPItem *>(i->data);
+        SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+        if (box) {
+            VanishingPoint vp;
+            for (int i = 0; i < 3; ++i) {
+                vp.set(box3d_get_perspective(box), Proj::axes[i]);
+                addDragger (vp);
+            }
         }
     }
 }
@@ -609,12 +610,13 @@ VPDrag::updateLines ()
     g_return_if_fail (this->selection != NULL);
 
     for (GSList const* i = this->selection->itemList(); i != NULL; i = i->next) {
-        if (!SP_IS_BOX3D(i->data)) continue;
-        SPBox3D *box = SP_BOX3D (i->data);
-
-        this->drawLinesForFace (box, Proj::X);
-        this->drawLinesForFace (box, Proj::Y);
-        this->drawLinesForFace (box, Proj::Z);
+        SPItem *item = static_cast<SPItem *>(i->data);
+        SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+        if (box) {
+            this->drawLinesForFace (box, Proj::X);
+            this->drawLinesForFace (box, Proj::Y);
+            this->drawLinesForFace (box, Proj::Z);
+        }
     }
 }
 
diff --git a/src/widgets/box3d-toolbar.cpp b/src/widgets/box3d-toolbar.cpp
index 41f440ccc..02d102a11 100644
--- a/src/widgets/box3d-toolbar.cpp
+++ b/src/widgets/box3d-toolbar.cpp
@@ -183,9 +183,9 @@ static void box3d_toolbox_selection_changed(Inkscape::Selection *selection, GObj
     purge_repr_listener(tbl, tbl);
 
     SPItem *item = selection->singleItem();
-    if (item && SP_IS_BOX3D(item)) {
+    SPBox3D *box = dynamic_cast<SPBox3D *>(item);
+    if (box) {
         // FIXME: Also deal with multiple selected boxes
-        SPBox3D *box = SP_BOX3D(item);
         Persp3D *persp = box3d_get_perspective(box);
         persp_repr = persp->getRepr();
         if (persp_repr) {
diff --git a/src/widgets/stroke-style.cpp b/src/widgets/stroke-style.cpp
index cb18207f4..02dd5df6e 100644
--- a/src/widgets/stroke-style.cpp
+++ b/src/widgets/stroke-style.cpp
@@ -764,7 +764,7 @@ StrokeStyle::setJoinType (unsigned const jointype)
             break;
         default:
             // Should not happen
-            std::cerr << "StrokeStyle::setJoinType(): Invalid value" << std::endl;
+            std::cerr << "StrokeStyle::setJoinType(): Invalid value: " << jointype << std::endl;
             tb = joinMiter;
             break;
     }
@@ -790,7 +790,7 @@ StrokeStyle::setCapType (unsigned const captype)
             break;
         default:
             // Should not happen
-            std::cerr << "StrokeStyle::setCapType(): Invalid value" << std::endl;
+            std::cerr << "StrokeStyle::setCapType(): Invalid value: " << captype << std::endl;
             tb = capButt;
             break;
     }
@@ -884,13 +884,15 @@ StrokeStyle::updateLine()
         miterLimitAdj->set_value(query->stroke_miterlimit.value); // TODO: reflect averagedness?
 #endif
 
-    if (result_join != QUERY_STYLE_MULTIPLE_DIFFERENT) {
+    if (result_join != QUERY_STYLE_MULTIPLE_DIFFERENT &&
+        result_join != QUERY_STYLE_NOTHING ) {
         setJoinType(query->stroke_linejoin.value);
     } else {
         setJoinButtons(NULL);
     }
 
-    if (result_cap != QUERY_STYLE_MULTIPLE_DIFFERENT) {
+    if (result_cap != QUERY_STYLE_MULTIPLE_DIFFERENT &&
+        result_cap != QUERY_STYLE_NOTHING ) {
         setCapType (query->stroke_linecap.value);
     } else {
         setCapButtons(NULL);