Added some consts.

(bzr r12729)

49 files changed, 196 insertions, 183 deletions

diff --git a/src/box3d.cpp b/src/box3d.cpp
index ff99fccba..32442746d 100644
--- a/src/box3d.cpp
+++ b/src/box3d.cpp
@@ -1325,53 +1325,50 @@ SPGroup *box3d_convert_to_group(SPBox3D *box)
     return SP_GROUP(doc->getObjectByRepr(grepr));
 }
 
-const char *SPBox3D::displayName() {
+const char *SPBox3D::displayName() const {
     return _("3D Box");
 }
 
-gchar *SPBox3D::description() {
+gchar *SPBox3D::description() const {
     // We could put more details about the 3d box here
     return g_strdup("");
 }
 
 static inline void
-box3d_push_back_corner_pair(SPBox3D *box, std::list<std::pair<Geom::Point, Geom::Point> > &pts, int c1, int c2) {
+box3d_push_back_corner_pair(SPBox3D const *box, std::list<std::pair<Geom::Point, Geom::Point> > &pts, int c1, int c2) {
     pts.push_back(std::make_pair(box3d_get_corner_screen(box, c1, false),
                                  box3d_get_corner_screen(box, c2, false)));
 }
 
-void SPBox3D::convert_to_guides() {
-	SPBox3D* item = this;
-    SPBox3D *box = item;
-
+void SPBox3D::convert_to_guides() const {
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 
     if (!prefs->getBool("/tools/shapes/3dbox/convertguides", true)) {
-        box->convert_to_guides();
+        this->convert_to_guides();
         return;
     }
 
     std::list<std::pair<Geom::Point, Geom::Point> > pts;
 
     /* perspective lines in X direction */
-    box3d_push_back_corner_pair(box, pts, 0, 1);
-    box3d_push_back_corner_pair(box, pts, 2, 3);
-    box3d_push_back_corner_pair(box, pts, 4, 5);
-    box3d_push_back_corner_pair(box, pts, 6, 7);
+    box3d_push_back_corner_pair(this, pts, 0, 1);
+    box3d_push_back_corner_pair(this, pts, 2, 3);
+    box3d_push_back_corner_pair(this, pts, 4, 5);
+    box3d_push_back_corner_pair(this, pts, 6, 7);
 
     /* perspective lines in Y direction */
-    box3d_push_back_corner_pair(box, pts, 0, 2);
-    box3d_push_back_corner_pair(box, pts, 1, 3);
-    box3d_push_back_corner_pair(box, pts, 4, 6);
-    box3d_push_back_corner_pair(box, pts, 5, 7);
+    box3d_push_back_corner_pair(this, pts, 0, 2);
+    box3d_push_back_corner_pair(this, pts, 1, 3);
+    box3d_push_back_corner_pair(this, pts, 4, 6);
+    box3d_push_back_corner_pair(this, pts, 5, 7);
 
     /* perspective lines in Z direction */
-    box3d_push_back_corner_pair(box, pts, 0, 4);
-    box3d_push_back_corner_pair(box, pts, 1, 5);
-    box3d_push_back_corner_pair(box, pts, 2, 6);
-    box3d_push_back_corner_pair(box, pts, 3, 7);
+    box3d_push_back_corner_pair(this, pts, 0, 4);
+    box3d_push_back_corner_pair(this, pts, 1, 5);
+    box3d_push_back_corner_pair(this, pts, 2, 6);
+    box3d_push_back_corner_pair(this, pts, 3, 7);
 
-    sp_guide_pt_pairs_to_guides(item->document, pts);
+    sp_guide_pt_pairs_to_guides(this->document, pts);
 }
 
 /*
diff --git a/src/box3d.h b/src/box3d.h
index 1dec1e792..4107d2452 100644
--- a/src/box3d.h
+++ b/src/box3d.h
@@ -60,9 +60,9 @@ public:
 
         virtual const char* display_name();
 	virtual Geom::Affine set_transform(Geom::Affine const &transform);
-    virtual void convert_to_guides();
-    virtual const char* displayName();
-    virtual gchar *description();
+    virtual void convert_to_guides() const;
+    virtual const char* displayName() const;
+    virtual gchar *description() const;
 };
 
 void box3d_position_set (SPBox3D *box);
diff --git a/src/marker.cpp b/src/marker.cpp
index 50e7c970f..b38138f8c 100644
--- a/src/marker.cpp
+++ b/src/marker.cpp
@@ -503,7 +503,7 @@ void SPMarker::hide(unsigned int key) {
 	SPGroup::hide(key);
 }
 
-Geom::OptRect SPMarker::bbox(Geom::Affine const &transform, SPItem::BBoxType type) {
+Geom::OptRect SPMarker::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
 	return Geom::OptRect();
 }
 
diff --git a/src/marker.h b/src/marker.h
index aae4e020f..831b298ac 100644
--- a/src/marker.h
+++ b/src/marker.h
@@ -77,7 +77,7 @@ public:
 	virtual Inkscape::DrawingItem* show(Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
 	virtual void hide(unsigned int key);
 
-	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type);
+	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type) const;
 	virtual void print(SPPrintContext *ctx);
 };
 
diff --git a/src/selection-describer.cpp b/src/selection-describer.cpp
index 5dddb0832..4fd920bf8 100644
--- a/src/selection-describer.cpp
+++ b/src/selection-describer.cpp
@@ -62,7 +62,7 @@ static int count_filtered (GSList *items)
     int count=0;
     for (GSList *i = items; i != NULL; i = i->next) {
         SPItem *item = SP_ITEM(i->data);
-        count += item->ifilt();
+        count += item->isFiltered();
     }
     return count;
 }
diff --git a/src/sp-anchor.cpp b/src/sp-anchor.cpp
index a6a41bef3..7b558bf08 100644
--- a/src/sp-anchor.cpp
+++ b/src/sp-anchor.cpp
@@ -115,11 +115,11 @@ Inkscape::XML::Node* SPAnchor::write(Inkscape::XML::Document *xml_doc, Inkscape:
     return repr;
 }
 
-const char* SPAnchor::displayName() {
+const char* SPAnchor::displayName() const {
     return _("Link");
 }
 
-gchar* SPAnchor::description() {
+gchar* SPAnchor::description() const {
     if (this->href) {
         char *quoted_href = xml_quote_strdup(this->href);
         char *ret = g_strdup_printf(_("to %s"), quoted_href);
diff --git a/src/sp-anchor.h b/src/sp-anchor.h
index 39f6d0b7a..778640032 100644
--- a/src/sp-anchor.h
+++ b/src/sp-anchor.h
@@ -30,8 +30,8 @@ public:
 	virtual void set(unsigned int key, gchar const* value);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
 
-    virtual const char* displayName();
-	virtual gchar* description();
+    virtual const char* displayName() const;
+	virtual gchar* description() const;
 	virtual gint event(SPEvent *event);
 };
 
diff --git a/src/sp-ellipse.cpp b/src/sp-ellipse.cpp
index 8a0a8f233..4cf96e432 100644
--- a/src/sp-ellipse.cpp
+++ b/src/sp-ellipse.cpp
@@ -362,7 +362,7 @@ Inkscape::XML::Node *SPGenericEllipse::write(Inkscape::XML::Document *xml_doc, I
     return repr;
 }
 
-const char *SPGenericEllipse::displayName()
+const char *SPGenericEllipse::displayName() const
 {
 
     switch ( type ) {
@@ -560,9 +560,11 @@ Geom::Affine SPGenericEllipse::set_transform(Geom::Affine const &xform)
     return ret;
 }
 
-void SPGenericEllipse::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs)
+void SPGenericEllipse::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const
 {
-    this->normalize();
+	// CPPIFY: is this call necessary?
+	const_cast<SPGenericEllipse*>(this)->normalize();
+
     Geom::Affine const i2dt = this->i2dt_affine();
 
     // Snap to the 4 quadrant points of the ellipse, but only if the arc
diff --git a/src/sp-ellipse.h b/src/sp-ellipse.h
index 94bddde98..cb988b8bb 100644
--- a/src/sp-ellipse.h
+++ b/src/sp-ellipse.h
@@ -57,12 +57,12 @@ public:
     virtual void update(SPCtx *ctx, unsigned int flags);
 
     virtual Inkscape::XML::Node *write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
-    virtual const char *displayName();
+    virtual const char *displayName() const;
 
     virtual void set_shape();
     virtual Geom::Affine set_transform(Geom::Affine const &xform);
 
-    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
+    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
 
     virtual void modified(unsigned int flags);
 
diff --git a/src/sp-flowregion.cpp b/src/sp-flowregion.cpp
index 13ab7bc64..709e9e464 100644
--- a/src/sp-flowregion.cpp
+++ b/src/sp-flowregion.cpp
@@ -188,7 +188,7 @@ Inkscape::XML::Node *SPFlowregion::write(Inkscape::XML::Document *xml_doc, Inksc
     return repr;
 }
 
-const char* SPFlowregion::displayName() {
+const char* SPFlowregion::displayName() const {
 	// TRANSLATORS: "Flow region" is an area where text is allowed to flow
 	return _("Flow Region");
 }
@@ -335,7 +335,7 @@ Inkscape::XML::Node *SPFlowregionExclude::write(Inkscape::XML::Document *xml_doc
     return repr;
 }
 
-const char* SPFlowregionExclude::displayName() {
+const char* SPFlowregionExclude::displayName() const {
 	/* TRANSLATORS: A region "cut out of" a flow region; text is not allowed to flow inside the
 	 * flow excluded region.  flowRegionExclude in SVG 1.2: see
 	 * http://www.w3.org/TR/2004/WD-SVG12-20041027/flow.html#flowRegion-elem and
diff --git a/src/sp-flowregion.h b/src/sp-flowregion.h
index 111a32c6c..721eb0432 100644
--- a/src/sp-flowregion.h
+++ b/src/sp-flowregion.h
@@ -31,7 +31,7 @@ public:
 	virtual void update(SPCtx *ctx, unsigned int flags);
 	virtual void modified(guint flags);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
-	virtual const char* displayName();
+	virtual const char* displayName() const;
 };
 
 class SPFlowregionExclude : public SPItem {
@@ -48,7 +48,7 @@ public:
 	virtual void update(SPCtx *ctx, unsigned int flags);
 	virtual void modified(guint flags);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
-	virtual const char* displayName();
+	virtual const char* displayName() const;
 };
 
 #endif
diff --git a/src/sp-flowtext.cpp b/src/sp-flowtext.cpp
index 49360f9d9..0331df312 100644
--- a/src/sp-flowtext.cpp
+++ b/src/sp-flowtext.cpp
@@ -260,7 +260,7 @@ Inkscape::XML::Node* SPFlowtext::write(Inkscape::XML::Document* doc, Inkscape::X
     return repr;
 }
 
-Geom::OptRect SPFlowtext::bbox(Geom::Affine const &transform, SPItem::BBoxType type) {
+Geom::OptRect SPFlowtext::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
     Geom::OptRect bbox = this->layout.bounds(transform);
 
     // Add stroke width
@@ -284,7 +284,7 @@ void SPFlowtext::print(SPPrintContext *ctx) {
     this->layout.print(ctx, pbox, dbox, bbox, ctm);
 }
 
-const char* SPFlowtext::displayName() {
+const char* SPFlowtext::displayName() const {
     if (SP_FLOWTEXT(this)->has_internal_frame()) {
         return _("Flowed Text");
     } else {
@@ -292,7 +292,7 @@ const char* SPFlowtext::displayName() {
     }
 }
 
-gchar* SPFlowtext::description() {
+gchar* SPFlowtext::description() const {
     Inkscape::Text::Layout const &layout = SP_FLOWTEXT(this)->layout;
     int const nChars = layout.iteratorToCharIndex(layout.end());
     char const *trunc = (layout.inputTruncated()) ? _(" [truncated]") : "";
@@ -300,7 +300,7 @@ gchar* SPFlowtext::description() {
     return g_strdup_printf(ngettext(_("(%d character%s)"), _("(%d characters%s)"), nChars), nChars, trunc);
 }
 
-void SPFlowtext::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+void SPFlowtext::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
     if (snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_TEXT_BASELINE)) {
         // Choose a point on the baseline for snapping from or to, with the horizontal position
         // of this point depending on the text alignment (left vs. right)
diff --git a/src/sp-flowtext.h b/src/sp-flowtext.h
index f56cba3cd..a5b7db22e 100644
--- a/src/sp-flowtext.h
+++ b/src/sp-flowtext.h
@@ -71,13 +71,13 @@ public:
 
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document* doc, Inkscape::XML::Node* repr, guint flags);
 
-	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type);
+	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type) const;
 	virtual void print(SPPrintContext *ctx);
-        virtual const char* displayName();
-	virtual gchar* description();
+        virtual const char* displayName() const;
+	virtual gchar* description() const;
 	virtual Inkscape::DrawingItem* show(Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
 	virtual void hide(unsigned int key);
-    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
+    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
 };
 
 SPItem *create_flowtext_with_internal_frame (SPDesktop *desktop, Geom::Point p1, Geom::Point p2);
diff --git a/src/sp-image.cpp b/src/sp-image.cpp
index 86668d9ed..1032b6d93 100644
--- a/src/sp-image.cpp
+++ b/src/sp-image.cpp
@@ -555,7 +555,7 @@ Inkscape::XML::Node *SPImage::write(Inkscape::XML::Document *xml_doc, Inkscape::
     return repr;
 }
 
-Geom::OptRect SPImage::bbox(Geom::Affine const &transform, SPItem::BBoxType type) {
+Geom::OptRect SPImage::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
     Geom::OptRect bbox;
 
     if ((this->width.computed > 0.0) && (this->height.computed > 0.0)) {
@@ -612,11 +612,11 @@ void SPImage::print(SPPrintContext *ctx) {
     }
 }
 
-const char* SPImage::displayName() {
+const char* SPImage::displayName() const {
     return _("Image");
 }
 
-gchar* SPImage::description() {
+gchar* SPImage::description() const {
     char *href_desc;
 
     if (this->href) {
@@ -748,7 +748,7 @@ static void sp_image_update_canvas_image(SPImage *image)
     }
 }
 
-void SPImage::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+void SPImage::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
     /* An image doesn't have any nodes to snap, but still we want to be able snap one image
     to another. Therefore we will create some snappoints at the corner, similar to a rect. If
     the image is rotated, then the snappoints will rotate with it. Again, just like a rect.
diff --git a/src/sp-image.h b/src/sp-image.h
index b5834c988..3b7208487 100644
--- a/src/sp-image.h
+++ b/src/sp-image.h
@@ -62,12 +62,12 @@ public:
     virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
     virtual void modified(unsigned int flags);
 
-    virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type);
+    virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type) const;
     virtual void print(SPPrintContext *ctx);
-    virtual const char* displayName();
-    virtual gchar* description();
+    virtual const char* displayName() const;
+    virtual gchar* description() const;
     virtual Inkscape::DrawingItem* show(Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
-    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
+    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
     virtual Geom::Affine set_transform(Geom::Affine const &transform);
 };
 
diff --git a/src/sp-item-group.cpp b/src/sp-item-group.cpp
index ae974200f..2cfe97db8 100644
--- a/src/sp-item-group.cpp
+++ b/src/sp-item-group.cpp
@@ -291,11 +291,12 @@ Inkscape::XML::Node* SPGroup::write(Inkscape::XML::Document *xml_doc, Inkscape::
     return repr;
 }
 
-Geom::OptRect SPGroup::bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype)
+Geom::OptRect SPGroup::bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype) const
 {
     Geom::OptRect bbox;
 
-    GSList *l = this->childList(false, SPObject::ActionBBox);
+    // CPPIFY: replace this const_cast later
+    GSList *l = const_cast<SPGroup*>(this)->childList(false, SPObject::ActionBBox);
 
     while (l) {
         SPObject *o = SP_OBJECT (l->data);
@@ -326,11 +327,11 @@ void SPGroup::print(SPPrintContext *ctx) {
     }
 }
 
-const char *SPGroup::displayName() {
+const char *SPGroup::displayName() const {
     return _("Group");
 }
 
-gchar *SPGroup::description() {
+gchar *SPGroup::description() const {
     gint len = this->getItemCount();
     return g_strdup_printf(
         ngettext(_("of <b>%d</b> object"), _("of <b>%d</b> objects"), len), len);
@@ -385,7 +386,7 @@ void SPGroup::hide (unsigned int key) {
 }
 
 
-void SPGroup::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+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)) {
@@ -720,9 +721,9 @@ void SPGroup::scaleChildItemsRec(Geom::Scale const &sc, Geom::Point const &p)
     }
 }
 
-gint SPGroup::getItemCount() {
+gint SPGroup::getItemCount() const {
     gint len = 0;
-    for (SPObject *o = this->firstChild() ; o ; o = o->getNext() ) {
+    for (SPObject const *o = this->firstChild() ; o ; o = o->getNext() ) {
         if (SP_IS_ITEM(o)) {
             len++;
         }
diff --git a/src/sp-item-group.h b/src/sp-item-group.h
index 3954a5d21..deb80a641 100644
--- a/src/sp-item-group.h
+++ b/src/sp-item-group.h
@@ -54,7 +54,7 @@ public:
     void translateChildItems(Geom::Translate const &tr);
     void scaleChildItemsRec(Geom::Scale const &sc, Geom::Point const &p);
 
-    gint getItemCount();
+    gint getItemCount() const;
     void _showChildren (Inkscape::Drawing &drawing, Inkscape::DrawingItem *ai, unsigned int key, unsigned int flags);
 
 private:
@@ -74,14 +74,14 @@ public:
 
     virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
 
-    virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype);
+    virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype) const;
     virtual void print(SPPrintContext *ctx);
-    virtual const char* displayName();
-    virtual gchar *description();
+    virtual const char* displayName() const;
+    virtual gchar *description() const;
     virtual Inkscape::DrawingItem *show (Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
     virtual void hide (unsigned int key);
 
-    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
+    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
 
     virtual void update_patheffect(bool write);
 };
diff --git a/src/sp-item.cpp b/src/sp-item.cpp
index e8338046b..d32fbdef6 100644
--- a/src/sp-item.cpp
+++ b/src/sp-item.cpp
@@ -255,7 +255,7 @@ SPItem::unsetCenter() {
     transform_center_y = 0;
 }
 
-bool SPItem::isCenterSet() {
+bool SPItem::isCenterSet() const {
     return (transform_center_x != 0 || transform_center_y != 0);
 }
 
@@ -688,7 +688,7 @@ Inkscape::XML::Node* SPItem::write(Inkscape::XML::Document *xml_doc, Inkscape::X
 }
 
 // CPPIFY: make pure virtual
-Geom::OptRect SPItem::bbox(Geom::Affine const &transform, SPItem::BBoxType type) {
+Geom::OptRect SPItem::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
 	//throw;
 	return Geom::OptRect();
 }
@@ -848,18 +848,17 @@ Geom::OptRect SPItem::desktopBounds(BBoxType type) const
     }
 }
 
-unsigned SPItem::pos_in_parent()
-{
+unsigned int SPItem::pos_in_parent() const {
     g_assert(parent != NULL);
     g_assert(SP_IS_OBJECT(parent));
 
-    SPObject *object = this;
+    unsigned int pos = 0;
 
-    unsigned pos=0;
     for ( SPObject *iter = parent->firstChild() ; iter ; iter = iter->next) {
-        if ( iter == object ) {
+        if (iter == this) {
             return pos;
         }
+
         if (SP_IS_ITEM(iter)) {
             pos++;
         }
@@ -870,7 +869,7 @@ unsigned SPItem::pos_in_parent()
 }
 
 // CPPIFY: make pure virtual, see below!
-void SPItem::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+void SPItem::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
 	//throw;
 }
     /* This will only be called if the derived class doesn't override this.
@@ -937,11 +936,11 @@ void SPItem::invoke_print(SPPrintContext *ctx)
     }
 }
 
-const char* SPItem::displayName() {
+const char* SPItem::displayName() const {
     return _("Object");
 }
 
-gchar* SPItem::description() {
+gchar* SPItem::description() const {
     return g_strdup("");
 }
 
@@ -950,8 +949,7 @@ gchar* SPItem::description() {
  *
  * Must be freed by caller.
  */
-gchar *SPItem::detailedDescription()
-{
+gchar *SPItem::detailedDescription() const {
         gchar* s = g_strdup_printf("<b>%s</b> %s",
                     this->displayName(), this->description());
 
@@ -985,17 +983,11 @@ gchar *SPItem::detailedDescription()
 }
 
 /**
- * Returns 1 if the item is filtered, 0 otherwise.  Used with groups/lists to determine how many, or if any, are filtered
+ * Returns true if the item is filtered, false otherwise.  Used with groups/lists to determine how many, or if any, are filtered
  *
  */
-int SPItem::ifilt()
-{
-    int retval=0;
-    if ( style && style->filter.href && style->filter.href->getObject() ) {
-		retval=1;
-	}
-
-    return retval;
+bool SPItem::isFiltered() const {
+	return (style && style->filter.href && style->filter.href->getObject());
 }
 
 /**
@@ -1443,8 +1435,8 @@ void SPItem::set_item_transform(Geom::Affine const &transform_matrix)
     }
 }
 
-//void SPItem::convert_to_guides() {
-//	// CPPIFY: If not overridden, call SPItem::convert_to_guides(), see below!
+//void SPItem::convert_to_guides() const {
+//	// CPPIFY: If not overridden, call SPItem::convert_to_guides() const, see below!
 //	this->convert_to_guides();
 //}
 
@@ -1607,7 +1599,7 @@ SPItem *sp_item_first_item_child(SPObject *obj)
     return child;
 }
 
-void SPItem::convert_to_guides() {
+void SPItem::convert_to_guides() const {
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
     int prefs_bbox = prefs->getInt("/tools/bounding_box", 0);
 
diff --git a/src/sp-item.h b/src/sp-item.h
index ce5400e66..d605c99b9 100644
--- a/src/sp-item.h
+++ b/src/sp-item.h
@@ -157,7 +157,7 @@ public:
 
     void setCenter(Geom::Point const &object_centre);
     void unsetCenter();
-    bool isCenterSet();
+    bool isCenterSet() const;
     Geom::Point getCenter() const;
 
     bool isVisibleAndUnlocked() const;
@@ -187,9 +187,12 @@ public:
     Geom::OptRect desktopPreferredBounds() const;
     Geom::OptRect desktopBounds(BBoxType type) const;
 
-    unsigned pos_in_parent();
-    gchar *detailedDescription();
-    int ifilt();
+    unsigned int pos_in_parent() const;
+
+    gchar *detailedDescription() const;
+
+    bool isFiltered() const;
+
     void invoke_print(SPPrintContext *ctx);
     static unsigned int display_key_new(unsigned int numkeys);
     Inkscape::DrawingItem *invoke_show(Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
@@ -204,7 +207,6 @@ public:
     void adjust_livepatheffect(Geom::Affine const &postmul, bool set = false);
     void doWriteTransform(Inkscape::XML::Node *repr, Geom::Affine const &transform, Geom::Affine const *adv = NULL, bool compensate = true);
     void set_item_transform(Geom::Affine const &transform_matrix);
-    void convert_item_to_guides();
     gint emitEvent (SPEvent &event);
     Inkscape::DrawingItem *get_arenaitem(unsigned int key);
 
@@ -212,7 +214,6 @@ public:
     Geom::Affine i2dt_affine() const;
     void set_i2d_affine(Geom::Affine const &transform);
     Geom::Affine dt2i_affine() const;
-    //void convert_to_guides();
 
 private:
     enum EvaluatedStatus
@@ -234,15 +235,17 @@ public:
 	virtual void update(SPCtx *ctx, guint flags);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
 
-	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type);
+	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type) const;
 	virtual void print(SPPrintContext *ctx);
-    virtual const char* displayName();
-	virtual gchar* description();
+    virtual const char* displayName() const;
+	virtual gchar* description() const;
 	virtual Inkscape::DrawingItem* show(Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
 	virtual void hide(unsigned int key);
-    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
+    virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
     virtual Geom::Affine set_transform(Geom::Affine const &transform);
-    virtual void convert_to_guides();
+
+    virtual void convert_to_guides() const;
+
     virtual gint event(SPEvent *event);
 };
 
diff --git a/src/sp-line.cpp b/src/sp-line.cpp
index 6b7df84f6..8af95b4ce 100644
--- a/src/sp-line.cpp
+++ b/src/sp-line.cpp
@@ -122,11 +122,11 @@ Inkscape::XML::Node* SPLine::write(Inkscape::XML::Document *xml_doc, Inkscape::X
     return repr;
 }
 
-const char* SPLine::displayName() {
+const char* SPLine::displayName() const {
 	return _("Line");
 }
 
-void SPLine::convert_to_guides() {
+void SPLine::convert_to_guides() const {
     Geom::Point points[2];
     Geom::Affine const i2dt(this->i2dt_affine());
 
diff --git a/src/sp-line.h b/src/sp-line.h
index f76c3449b..c1932d3ee 100644
--- a/src/sp-line.h
+++ b/src/sp-line.h
@@ -34,9 +34,9 @@ public:
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
 	virtual void set(unsigned int key, gchar const* value);
 
-	virtual const char* displayName();
+	virtual const char* displayName() const;
 	virtual Geom::Affine set_transform(Geom::Affine const &transform);
-	virtual void convert_to_guides();
+	virtual void convert_to_guides() const;
 	virtual void update(SPCtx* ctx, guint flags);
 
 	virtual void set_shape();
diff --git a/src/sp-offset.cpp b/src/sp-offset.cpp
index f0b152d0e..c5a3557a7 100644
--- a/src/sp-offset.cpp
+++ b/src/sp-offset.cpp
@@ -339,7 +339,7 @@ void SPOffset::update(SPCtx *ctx, guint flags) {
     SPShape::update(ctx, flags);
 }
 
-const char* SPOffset::displayName() {
+const char* SPOffset::displayName() const {
     if ( this->sourceHref ) {
         return _("Linked Offset");
     } else {
@@ -347,7 +347,7 @@ const char* SPOffset::displayName() {
     }
 }
 
-gchar* SPOffset::description() {
+gchar* SPOffset::description() const {
     // TRANSLATORS COMMENT: %s is either "outset" or "inset" depending on sign
     return g_strdup_printf(_("%s by %f pt"), (this->rad >= 0) ?
             _("outset") : _("inset"), fabs (this->rad));
@@ -692,7 +692,7 @@ void SPOffset::set_shape() {
     }
 }
 
-void SPOffset::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+void SPOffset::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
     SPShape::snappoints(p, snapprefs);
 }
 
diff --git a/src/sp-offset.h b/src/sp-offset.h
index b93a6846b..259a69b78 100644
--- a/src/sp-offset.h
+++ b/src/sp-offset.h
@@ -81,9 +81,9 @@ public:
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
 	virtual void release();
 
-	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
-        virtual const char* displayName();
-	virtual gchar* description();
+	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
+        virtual const char* displayName() const;
+	virtual gchar* description() const;
 
 	virtual void set_shape();
 };
diff --git a/src/sp-path.cpp b/src/sp-path.cpp
index b225f0735..563c5b326 100644
--- a/src/sp-path.cpp
+++ b/src/sp-path.cpp
@@ -66,11 +66,11 @@ gint SPPath::nodesInPath() const
     return _curve ? _curve->nodes_in_path() : 0;
 }
 
-const char* SPPath::displayName() {
+const char* SPPath::displayName() const {
     return _("Path");
 }
 
-gchar* SPPath::description() {
+gchar* SPPath::description() const {
     int count = this->nodesInPath();
     char *lpe_desc = g_strdup("");
     
@@ -100,7 +100,7 @@ gchar* SPPath::description() {
     return ret;
 }
 
-void SPPath::convert_to_guides() {
+void SPPath::convert_to_guides() const {
     if (!this->_curve) {
         return;
     }
diff --git a/src/sp-path.h b/src/sp-path.h
index 77c64a2cc..5f8a91d98 100644
--- a/src/sp-path.h
+++ b/src/sp-path.h
@@ -54,10 +54,10 @@ public:
 	virtual void set(unsigned int key, gchar const* value);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
 
-        virtual const char* displayName();
-	virtual gchar* description();
+        virtual const char* displayName() const;
+	virtual gchar* description() const;
 	virtual Geom::Affine set_transform(Geom::Affine const &transform);
-    virtual void convert_to_guides();
+    virtual void convert_to_guides() const;
 
     virtual void update_patheffect(bool write);
 };
diff --git a/src/sp-polygon.cpp b/src/sp-polygon.cpp
index a5ddd653a..10d097e70 100644
--- a/src/sp-polygon.cpp
+++ b/src/sp-polygon.cpp
@@ -178,7 +178,7 @@ void SPPolygon::set(unsigned int key, const gchar* value) {
     }
 }
 
-gchar* SPPolygon::description() {
+gchar* SPPolygon::description() const {
 	return g_strdup(_("<b>Polygon</b>"));
 }
 
diff --git a/src/sp-polygon.h b/src/sp-polygon.h
index f9c93ac8f..41ab245bd 100644
--- a/src/sp-polygon.h
+++ b/src/sp-polygon.h
@@ -27,7 +27,7 @@ public:
 	virtual void build(SPDocument *document, Inkscape::XML::Node *repr);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
 	virtual void set(unsigned int key, gchar const* value);
-	virtual gchar* description();
+	virtual gchar* description() const;
 };
 
 // made 'public' so that SPCurve can set it as friend:
diff --git a/src/sp-polyline.cpp b/src/sp-polyline.cpp
index 1de5492cd..c80190097 100644
--- a/src/sp-polyline.cpp
+++ b/src/sp-polyline.cpp
@@ -127,7 +127,7 @@ Inkscape::XML::Node* SPPolyLine::write(Inkscape::XML::Document *xml_doc, Inkscap
     return repr;
 }
 
-gchar* SPPolyLine::description() {
+gchar* SPPolyLine::description() const {
 	return g_strdup(_("<b>Polyline</b>"));
 }
 
diff --git a/src/sp-polyline.h b/src/sp-polyline.h
index f8b7e9b49..e24ea95c7 100644
--- a/src/sp-polyline.h
+++ b/src/sp-polyline.h
@@ -15,7 +15,7 @@ public:
 	virtual void set(unsigned int key, gchar const* value);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
 
-	virtual gchar* description();
+	virtual gchar* description() const;
 };
 
 #endif // SEEN_SP_POLYLINE_H
diff --git a/src/sp-rect.cpp b/src/sp-rect.cpp
index b327f0b83..af3e2bfb4 100644
--- a/src/sp-rect.cpp
+++ b/src/sp-rect.cpp
@@ -159,7 +159,7 @@ Inkscape::XML::Node * SPRect::write(Inkscape::XML::Document *xml_doc, Inkscape::
     return repr;
 }
 
-const char* SPRect::displayName() {
+const char* SPRect::displayName() const {
     return _("Rectangle");
 }
 
@@ -484,7 +484,7 @@ gdouble SPRect::getVisibleHeight() const {
         this->transform);
 }
 
-void SPRect::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+void SPRect::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
     /* This method overrides sp_shape_snappoints, which is the default for any shape. The default method
     returns all eight points along the path of a rounded rectangle, but not the real corners. Snapping
     the startpoint and endpoint of each rounded corner is not very useful and really confusing. Instead
@@ -518,7 +518,7 @@ void SPRect::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::
     }
 }
 
-void SPRect::convert_to_guides() {
+void SPRect::convert_to_guides() const {
     Inkscape::Preferences *prefs = Inkscape::Preferences::get();
 
     if (!prefs->getBool("/tools/shapes/rect/convertguides", true)) {
diff --git a/src/sp-rect.h b/src/sp-rect.h
index 3219a3ace..aa3f88e42 100644
--- a/src/sp-rect.h
+++ b/src/sp-rect.h
@@ -55,13 +55,13 @@ public:
 	virtual void update(SPCtx* ctx, unsigned int flags);
 
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
-        virtual const char* displayName();
+        virtual const char* displayName() const;
 
 	virtual void set_shape();
 	virtual Geom::Affine set_transform(Geom::Affine const& xform);
 
-	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
-	virtual void convert_to_guides();
+	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
+	virtual void convert_to_guides() const;
 
 	SVGLength x;
 	SVGLength y;
diff --git a/src/sp-shape.cpp b/src/sp-shape.cpp
index 913e208aa..3cc7ea1ce 100644
--- a/src/sp-shape.cpp
+++ b/src/sp-shape.cpp
@@ -389,7 +389,7 @@ void SPShape::modified(unsigned int flags) {
     }
 }
 
-Geom::OptRect SPShape::bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype) {
+Geom::OptRect SPShape::bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype) const {
     Geom::OptRect bbox;
 
     if (!this->_curve) {
@@ -796,8 +796,7 @@ int SPShape::hasMarkers() const
 * \param type Marker type (e.g. SP_MARKER_LOC_START)
 * \return Number of markers that the shape has of this type.
 */
-int SPShape::numberOfMarkers(int type)
-{
+int SPShape::numberOfMarkers(int type) const {
     Geom::PathVector const & pathv = this->_curve->get_pathvector();
 
     if (pathv.size() == 0) {
@@ -1025,7 +1024,7 @@ void SPShape::setCurveInsync(SPCurve *new_curve, unsigned int owner)
     }
 }
 
-void SPShape::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+void SPShape::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
     if (this->_curve == NULL) {
         return;
     }
diff --git a/src/sp-shape.h b/src/sp-shape.h
index bc51f3d45..f260c1ee6 100644
--- a/src/sp-shape.h
+++ b/src/sp-shape.h
@@ -44,7 +44,7 @@ public:
     void setCurveInsync (SPCurve *curve, unsigned int owner);
     void setCurveBeforeLPE (SPCurve *curve);
     int hasMarkers () const;
-    int numberOfMarkers (int type);
+    int numberOfMarkers (int type) const;
 
 public: // temporarily public, until SPPath is properly classed, etc.
     SPCurve *_curve_before_lpe;
@@ -63,13 +63,13 @@ public:
 	virtual void set(unsigned int key, gchar const* value);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document *xml_doc, Inkscape::XML::Node *repr, guint flags);
 
-	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype);
+	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype) const;
 	virtual void print(SPPrintContext* ctx);
 
 	virtual Inkscape::DrawingItem* show(Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
 	virtual void hide(unsigned int key);
 
-	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
+	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
 
 	virtual void set_shape();
 };
diff --git a/src/sp-spiral.cpp b/src/sp-spiral.cpp
index 56aca507f..ffb875f2a 100644
--- a/src/sp-spiral.cpp
+++ b/src/sp-spiral.cpp
@@ -226,11 +226,11 @@ void SPSpiral::update_patheffect(bool write) {
     this->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
-const char* SPSpiral::displayName() {
+const char* SPSpiral::displayName() const {
     return _("Spiral");
 }
 
-gchar* SPSpiral::description() {
+gchar* SPSpiral::description() const {
     // TRANSLATORS: since turn count isn't an integer, please adjust the
     // string as needed to deal with an localized plural forms.
     return g_strdup_printf (_("with %3f turns"), this->revo);
@@ -413,7 +413,7 @@ void SPSpiral::setPosition(gdouble cx, gdouble cy, gdouble exp, gdouble revo, gd
     this->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
-void SPSpiral::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+void SPSpiral::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
     // We will determine the spiral's midpoint ourselves, instead of trusting on the base class
     // Therefore snapping to object midpoints is temporarily disabled
     Inkscape::SnapPreferences local_snapprefs = *snapprefs;
diff --git a/src/sp-spiral.h b/src/sp-spiral.h
index 4e067981b..64b95d951 100644
--- a/src/sp-spiral.h
+++ b/src/sp-spiral.h
@@ -66,9 +66,9 @@ public:
 	virtual void update(SPCtx *ctx, guint flags);
 	virtual void set(unsigned int key, gchar const* value);
 
-	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
-    virtual const char* displayName();
-	virtual gchar* description();
+	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
+    virtual const char* displayName() const;
+	virtual gchar* description() const;
 
 	virtual void set_shape();
 	virtual void update_patheffect(bool write);
diff --git a/src/sp-star.cpp b/src/sp-star.cpp
index e634eccac..da10eeaa3 100644
--- a/src/sp-star.cpp
+++ b/src/sp-star.cpp
@@ -251,13 +251,13 @@ void SPStar::update_patheffect(bool write) {
     this->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
-const char* SPStar::displayName() {
+const char* SPStar::displayName() const {
     if (this->flatsided == false)
         return _("Star");
     return _("Polygon");
 }
 
-gchar* SPStar::description() {
+gchar* SPStar::description() const {
     // while there will never be less than 3 vertices, we still need to
     // make calls to ngettext because the pluralization may be different
     // for various numbers >=3.  The singular form is used as the index.
@@ -498,7 +498,7 @@ sp_star_position_set (SPStar *star, gint sides, Geom::Point center, gdouble r1,
     star->requestDisplayUpdate(SP_OBJECT_MODIFIED_FLAG);
 }
 
-void SPStar::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+void SPStar::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
     // We will determine the star's midpoint ourselves, instead of trusting on the base class
     // Therefore snapping to object midpoints is temporarily disabled
     Inkscape::SnapPreferences local_snapprefs = *snapprefs;
diff --git a/src/sp-star.h b/src/sp-star.h
index 799880c42..0070ce685 100644
--- a/src/sp-star.h
+++ b/src/sp-star.h
@@ -50,9 +50,9 @@ public:
 	virtual void set(unsigned int key, gchar const* value);
 	virtual void update(SPCtx* ctx, guint flags);
 
-    virtual const char* displayName();
-	virtual gchar* description();
-	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
+    virtual const char* displayName() const;
+	virtual gchar* description() const;
+	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
 
 	virtual void update_patheffect(bool write);
 	virtual void set_shape();
diff --git a/src/sp-switch.cpp b/src/sp-switch.cpp
index fa97cde91..911357660 100644
--- a/src/sp-switch.cpp
+++ b/src/sp-switch.cpp
@@ -71,11 +71,11 @@ GSList *SPSwitch::_childList(bool add_ref, SPObject::Action action) {
     return g_slist_prepend (NULL, child);
 }
 
-const char *SPSwitch::displayName() {
+const char *SPSwitch::displayName() const {
     return _("Conditional Group");
 }
 
-gchar *SPSwitch::description() {
+gchar *SPSwitch::description() const {
     gint len = this->getItemCount();
     return g_strdup_printf(
         ngettext(_("of <b>%d</b> object"), _("of <b>%d</b> objects"), len), len);
diff --git a/src/sp-switch.h b/src/sp-switch.h
index e6dc6f01f..3ccc9e3b7 100644
--- a/src/sp-switch.h
+++ b/src/sp-switch.h
@@ -41,8 +41,8 @@ public:
     virtual void child_added(Inkscape::XML::Node* child, Inkscape::XML::Node* ref);
     virtual void remove_child(Inkscape::XML::Node *child);
     virtual void order_changed(Inkscape::XML::Node *child, Inkscape::XML::Node *old_ref, Inkscape::XML::Node *new_ref);
-    virtual const char* displayName();
-    virtual gchar *description();
+    virtual const char* displayName() const;
+    virtual gchar *description() const;
 };
 
 #endif
diff --git a/src/sp-symbol.cpp b/src/sp-symbol.cpp
index b2346ac91..8ffc2ab2c 100644
--- a/src/sp-symbol.cpp
+++ b/src/sp-symbol.cpp
@@ -363,7 +363,7 @@ void SPSymbol::hide(unsigned int key) {
 }
 
 
-Geom::OptRect SPSymbol::bbox(Geom::Affine const &transform, SPItem::BBoxType type) {
+Geom::OptRect SPSymbol::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
     Geom::OptRect bbox;
 
     // We don't need a bounding box for Symbols dialog when selecting
diff --git a/src/sp-symbol.h b/src/sp-symbol.h
index 952ba00df..7a43ed658 100644
--- a/src/sp-symbol.h
+++ b/src/sp-symbol.h
@@ -54,7 +54,7 @@ public:
 
 	virtual Inkscape::DrawingItem* show(Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
 	virtual void print(SPPrintContext *ctx);
-	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type);
+	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type) const;
 	virtual void hide (unsigned int key);
 };
 
diff --git a/src/sp-text.cpp b/src/sp-text.cpp
index de5e63fe6..11d0e1a6c 100644
--- a/src/sp-text.cpp
+++ b/src/sp-text.cpp
@@ -293,7 +293,7 @@ Inkscape::XML::Node *SPText::write(Inkscape::XML::Document *xml_doc, Inkscape::X
     return repr;
 }
 
-Geom::OptRect SPText::bbox(Geom::Affine const &transform, SPItem::BBoxType type) {
+Geom::OptRect SPText::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
     Geom::OptRect bbox = SP_TEXT(this)->layout.bounds(transform);
 
     // FIXME this code is incorrect
@@ -326,11 +326,11 @@ void SPText::hide(unsigned int key) {
     }
 }
 
-const char* SPText::displayName() {
+const char* SPText::displayName() const {
     return _("Text");
 }
 
-gchar* SPText::description() {
+gchar* SPText::description() const {
     SPStyle *style = this->style;
 
     font_instance *tf = font_factory::Default()->FaceFromStyle(style);
@@ -364,7 +364,7 @@ gchar* SPText::description() {
     return ret;
 }
 
-void SPText::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
+void SPText::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
     if (snapprefs->isTargetSnappable(Inkscape::SNAPTARGET_TEXT_BASELINE)) {
         // Choose a point on the baseline for snapping from or to, with the horizontal position
         // of this point depending on the text alignment (left vs. right)
diff --git a/src/sp-text.h b/src/sp-text.h
index a7149159a..f7cf5a3aa 100644
--- a/src/sp-text.h
+++ b/src/sp-text.h
@@ -82,13 +82,13 @@ public:
 	virtual void modified(unsigned int flags);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document* doc, Inkscape::XML::Node* repr, guint flags);
 
-	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type);
+	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type) const;
 	virtual void print(SPPrintContext *ctx);
-        virtual const char* displayName();
-	virtual gchar* description();
+        virtual const char* displayName() const;
+	virtual gchar* description() const;
 	virtual Inkscape::DrawingItem* show(Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
 	virtual void hide(unsigned int key);
-	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
+	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
 	virtual Geom::Affine set_transform(Geom::Affine const &transform);
 };
 
diff --git a/src/sp-tref.cpp b/src/sp-tref.cpp
index 1c0481547..edbb9faa7 100644
--- a/src/sp-tref.cpp
+++ b/src/sp-tref.cpp
@@ -206,7 +206,7 @@ Inkscape::XML::Node* SPTRef::write(Inkscape::XML::Document *xml_doc, Inkscape::X
     return repr;
 }
 
-Geom::OptRect SPTRef::bbox(Geom::Affine const &transform, SPItem::BBoxType type) {
+Geom::OptRect SPTRef::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
     Geom::OptRect bbox;
     // find out the ancestor text which holds our layout
     SPObject const *parent_text = this;
@@ -233,14 +233,14 @@ Geom::OptRect SPTRef::bbox(Geom::Affine const &transform, SPItem::BBoxType type)
     return bbox;
 }
 
-const char* SPTRef::displayName() {
+const char* SPTRef::displayName() const {
     return _("Cloned Character Data");
 }
 
-gchar* SPTRef::description() {
-    SPObject *referred = this->getObjectReferredTo();
+gchar* SPTRef::description() const {
+    SPObject const *referred = this->getObjectReferredTo();
 
-    if (this->getObjectReferredTo()) {
+    if (referred) {
 	char *child_desc;
 
 	if (SP_IS_ITEM(referred)) {
@@ -313,6 +313,19 @@ SPObject * SPTRef::getObjectReferredTo(void)
     return referredObject;
 }
 
+/**
+ * Return the object referred to via the URI reference
+ */
+SPObject const *SPTRef::getObjectReferredTo() const {
+    SPObject *referredObject = NULL;
+
+    if (uriOriginalRef) {
+        referredObject = uriOriginalRef->getObject();
+    }
+
+    return referredObject;
+}
+
 
 /**
  * Returns true when the given tref is allowed to refer to a particular object
diff --git a/src/sp-tref.h b/src/sp-tref.h
index 6d43d679d..f5aed9ba6 100644
--- a/src/sp-tref.h
+++ b/src/sp-tref.h
@@ -49,6 +49,7 @@ public:
     sigc::connection _changed_connection;
     
     SPObject * getObjectReferredTo();
+    SPObject const *getObjectReferredTo() const;
 
 	virtual void build(SPDocument* doc, Inkscape::XML::Node* repr);
 	virtual void release();
@@ -57,9 +58,9 @@ public:
 	virtual void modified(unsigned int flags);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document* doc, Inkscape::XML::Node* repr, guint flags);
 
-	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type);
-        virtual const char* displayName();
-	virtual gchar* description();
+	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type) const;
+        virtual const char* displayName() const;
+	virtual gchar* description() const;
 };
 
 void sp_tref_update_text(SPTRef *tref);
diff --git a/src/sp-tspan.cpp b/src/sp-tspan.cpp
index 20d404130..8c4105777 100644
--- a/src/sp-tspan.cpp
+++ b/src/sp-tspan.cpp
@@ -138,7 +138,7 @@ void SPTSpan::modified(unsigned int flags) {
     }
 }
 
-Geom::OptRect SPTSpan::bbox(Geom::Affine const &transform, SPItem::BBoxType type) {
+Geom::OptRect SPTSpan::bbox(Geom::Affine const &transform, SPItem::BBoxType type) const {
     Geom::OptRect bbox;
     // find out the ancestor text which holds our layout
     SPObject const *parent_text = this;
@@ -216,7 +216,7 @@ Inkscape::XML::Node* SPTSpan::write(Inkscape::XML::Document *xml_doc, Inkscape::
     return repr;
 }
 
-const char* SPTSpan::displayName() {
+const char* SPTSpan::displayName() const {
     return _("Text Span");
 }
 
diff --git a/src/sp-tspan.h b/src/sp-tspan.h
index a7ae563bb..4c23b2eba 100644
--- a/src/sp-tspan.h
+++ b/src/sp-tspan.h
@@ -33,8 +33,8 @@ public:
 	virtual void modified(unsigned int flags);
 	virtual Inkscape::XML::Node* write(Inkscape::XML::Document* doc, Inkscape::XML::Node* repr, guint flags);
 
-	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type);
-        virtual const char* displayName();
+	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType type) const;
+        virtual const char* displayName() const;
 };
 
 #endif /* !INKSCAPE_SP_TSPAN_H */
diff --git a/src/sp-use.cpp b/src/sp-use.cpp
index ec367d786..b2a51b8d9 100644
--- a/src/sp-use.cpp
+++ b/src/sp-use.cpp
@@ -178,7 +178,7 @@ Inkscape::XML::Node* SPUse::write(Inkscape::XML::Document *xml_doc, Inkscape::XM
     return repr;
 }
 
-Geom::OptRect SPUse::bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype) {
+Geom::OptRect SPUse::bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype) const {
     Geom::OptRect bbox;
 
     if (this->child) {
@@ -208,7 +208,7 @@ void SPUse::print(SPPrintContext* ctx) {
     }
 }
 
-const char* SPUse::displayName() {
+const char* SPUse::displayName() const {
     if (this->child && SP_IS_SYMBOL( this->child )) {
         return _("Symbol");
     }
@@ -216,7 +216,7 @@ const char* SPUse::displayName() {
     return _("Clone");
 }
 
-gchar* SPUse::description() {
+gchar* SPUse::description() const {
     if (this->child) {
         if( SP_IS_SYMBOL( this->child ) ) {
             return g_strdup_printf(_("called %s"), this->child->title());
@@ -295,6 +295,10 @@ SPItem *SPUse::root() {
     return orig;
 }
 
+SPItem const *SPUse::root() const {
+	return const_cast<SPUse*>(this)->root();
+}
+
 /**
  * Returns the effective transform that goes from the ultimate original to given SPUse, both ends
  * included.
@@ -652,8 +656,8 @@ SPItem *SPUse::get_original() {
     return ref;
 }
 
-void SPUse::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) {
-    SPItem *root = this->root();
+void SPUse::snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const {
+    SPItem const *root = this->root();
 
     if (!root) {
         return;
diff --git a/src/sp-use.h b/src/sp-use.h
index 6a83c384f..31a52c1a1 100644
--- a/src/sp-use.h
+++ b/src/sp-use.h
@@ -56,15 +56,16 @@ public:
 	virtual void update(SPCtx* ctx, unsigned int flags);
 	virtual void modified(unsigned int flags);
 
-	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype);
-    virtual const char* displayName();
-	virtual gchar* description();
+	virtual Geom::OptRect bbox(Geom::Affine const &transform, SPItem::BBoxType bboxtype) const;
+    virtual const char* displayName() const;
+	virtual gchar* description() const;
 	virtual void print(SPPrintContext *ctx);
 	virtual Inkscape::DrawingItem* show(Inkscape::Drawing &drawing, unsigned int key, unsigned int flags);
 	virtual void hide(unsigned int key);
-	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs);
+	virtual void snappoints(std::vector<Inkscape::SnapCandidatePoint> &p, Inkscape::SnapPreferences const *snapprefs) const;
 
 	SPItem *root();
+	SPItem const *root() const;
 
 	SPItem *unlink();
 	SPItem *get_original();