Stop deriving SPCanvasItem from GtkObject

(bzr r11469.1.1)

42 files changed, 291 insertions, 246 deletions

diff --git a/src/common-context.cpp b/src/common-context.cpp
index 467d19f72..9ced41a26 100644
--- a/src/common-context.cpp
+++ b/src/common-context.cpp
@@ -8,6 +8,7 @@
 #include "message-context.h"
 #include "streq.h"
 #include "preferences.h"
+#include "display/sp-canvas-item.h"
 
 #define MIN_PRESSURE      0.0
 #define MAX_PRESSURE      1.0
@@ -116,7 +117,7 @@ static void sp_common_context_dispose(GObject *object)
     }
 
     while (ctx->segments) {
-        gtk_object_destroy(GTK_OBJECT(ctx->segments->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(ctx->segments->data));
         ctx->segments = g_slist_remove(ctx->segments, ctx->segments->data);
     }
 
@@ -134,7 +135,7 @@ static void sp_common_context_dispose(GObject *object)
     }
 
     if (ctx->currentshape) {
-        gtk_object_destroy(GTK_OBJECT(ctx->currentshape));
+        sp_canvas_item_destroy(ctx->currentshape);
         ctx->currentshape = 0;
     }
 
diff --git a/src/desktop-events.cpp b/src/desktop-events.cpp
index 57a07fee3..1e6837ed2 100644
--- a/src/desktop-events.cpp
+++ b/src/desktop-events.cpp
@@ -200,7 +200,7 @@ static gint sp_dt_ruler_event(GtkWidget *widget, GdkEvent *event, SPDesktopWidge
                     sp_dt_ruler_snap_new_guide(desktop, guide, event_dt, normal);
                 }
 
-                gtk_object_destroy(GTK_OBJECT(guide));
+                sp_canvas_item_destroy(guide);
                 guide = NULL;
                 if ((horiz ? wy : wx) >= 0) {
                     Inkscape::XML::Document *xml_doc = desktop->doc()->getReprDoc();
diff --git a/src/display/canvas-arena.cpp b/src/display/canvas-arena.cpp
index 9aa119be9..f0fd63ef4 100644
--- a/src/display/canvas-arena.cpp
+++ b/src/display/canvas-arena.cpp
@@ -32,7 +32,7 @@ enum {
 
 static void sp_canvas_arena_class_init(SPCanvasArenaClass *klass);
 static void sp_canvas_arena_init(SPCanvasArena *group);
-static void sp_canvas_arena_destroy(GtkObject *object);
+static void sp_canvas_arena_destroy(SPCanvasItem *object);
 
 static void sp_canvas_arena_item_deleted(SPCanvasArena *arena, Inkscape::DrawingItem *item);
 static void sp_canvas_arena_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
@@ -93,24 +93,19 @@ sp_canvas_arena_get_type (void)
 static void
 sp_canvas_arena_class_init (SPCanvasArenaClass *klass)
 {
-    GtkObjectClass *object_class;
-    SPCanvasItemClass *item_class;
-
-    object_class = (GtkObjectClass *) klass;
-    item_class = (SPCanvasItemClass *) klass;
+    SPCanvasItemClass *item_class = (SPCanvasItemClass *) klass;
 
     parent_class = (SPCanvasItemClass*)g_type_class_peek_parent (klass);
 
     signals[ARENA_EVENT] = g_signal_new ("arena_event",
-                                           G_TYPE_FROM_CLASS(object_class),
+                                           G_TYPE_FROM_CLASS(item_class),
                                            G_SIGNAL_RUN_LAST,
                                            ((glong)((guint8*)&(klass->arena_event) - (guint8*)klass)),
 					   NULL, NULL,
                                            sp_marshal_INT__POINTER_POINTER,
                                            G_TYPE_INT, 2, G_TYPE_POINTER, G_TYPE_POINTER);
 
-    object_class->destroy = sp_canvas_arena_destroy;
-
+    item_class->destroy = sp_canvas_arena_destroy;
     item_class->update = sp_canvas_arena_update;
     item_class->render = sp_canvas_arena_render;
     item_class->point = sp_canvas_arena_point;
@@ -147,16 +142,15 @@ sp_canvas_arena_init (SPCanvasArena *arena)
     arena->active = NULL;
 }
 
-static void
-sp_canvas_arena_destroy (GtkObject *object)
+static void sp_canvas_arena_destroy(SPCanvasItem *object)
 {
-    SPCanvasArena *arena = SP_CANVAS_ARENA (object);
+    SPCanvasArena *arena = SP_CANVAS_ARENA(object);
 
     delete arena->observer;
     arena->drawing.~Drawing();
 
-    if (GTK_OBJECT_CLASS (parent_class)->destroy)
-        (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+    if (SP_CANVAS_ITEM_CLASS(parent_class)->destroy)
+        (* SP_CANVAS_ITEM_CLASS(parent_class)->destroy) (object);
 }
 
 static void
diff --git a/src/display/canvas-bpath.cpp b/src/display/canvas-bpath.cpp
index 11bccf2a6..ee9e14f10 100644
--- a/src/display/canvas-bpath.cpp
+++ b/src/display/canvas-bpath.cpp
@@ -29,7 +29,7 @@
 
 static void sp_canvas_bpath_class_init (SPCanvasBPathClass *klass);
 static void sp_canvas_bpath_init (SPCanvasBPath *path);
-static void sp_canvas_bpath_destroy (GtkObject *object);
+static void sp_canvas_bpath_destroy(SPCanvasItem *object);
 
 static void sp_canvas_bpath_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static void sp_canvas_bpath_render (SPCanvasItem *item, SPCanvasBuf *buf);
@@ -57,19 +57,13 @@ sp_canvas_bpath_get_type (void)
     return type;
 }
 
-static void
-sp_canvas_bpath_class_init (SPCanvasBPathClass *klass)
+static void sp_canvas_bpath_class_init(SPCanvasBPathClass *klass)
 {
-    GtkObjectClass *object_class;
-    SPCanvasItemClass *item_class;
-
-    object_class = GTK_OBJECT_CLASS (klass);
-    item_class = (SPCanvasItemClass *) klass;
+    SPCanvasItemClass *item_class = (SPCanvasItemClass *) klass;
 
     parent_class = (SPCanvasItemClass*)g_type_class_peek_parent (klass);
 
-    object_class->destroy = sp_canvas_bpath_destroy;
-
+    item_class->destroy = sp_canvas_bpath_destroy;
     item_class->update = sp_canvas_bpath_update;
     item_class->render = sp_canvas_bpath_render;
     item_class->point = sp_canvas_bpath_point;
@@ -88,8 +82,7 @@ sp_canvas_bpath_init (SPCanvasBPath * bpath)
     bpath->stroke_miterlimit = 11.0;
 }
 
-static void
-sp_canvas_bpath_destroy (GtkObject *object)
+static void sp_canvas_bpath_destroy(SPCanvasItem *object)
 {
     SPCanvasBPath *cbp = SP_CANVAS_BPATH (object);
 
@@ -97,8 +90,8 @@ sp_canvas_bpath_destroy (GtkObject *object)
         cbp->curve = cbp->curve->unref();
     }
 
-    if (GTK_OBJECT_CLASS (parent_class)->destroy)
-        (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+    if (SP_CANVAS_ITEM_CLASS(parent_class)->destroy)
+        (* SP_CANVAS_ITEM_CLASS(parent_class)->destroy) (object);
 }
 
 static void sp_canvas_bpath_update(SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags)
diff --git a/src/display/canvas-grid.cpp b/src/display/canvas-grid.cpp
index 92a1b0fb8..2ba748022 100644
--- a/src/display/canvas-grid.cpp
+++ b/src/display/canvas-grid.cpp
@@ -57,8 +57,7 @@ static gchar const *const grid_svgname[] = {
 // Grid CanvasItem
 static void grid_canvasitem_class_init (GridCanvasItemClass *klass);
 static void grid_canvasitem_init (GridCanvasItem *grid);
-static void grid_canvasitem_destroy (GtkObject *object);
-
+static void grid_canvasitem_destroy(SPCanvasItem *object);
 static void grid_canvasitem_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static void grid_canvasitem_render (SPCanvasItem *item, SPCanvasBuf *buf);
 
@@ -86,19 +85,13 @@ grid_canvasitem_get_type (void)
     return grid_canvasitem_type;
 }
 
-static void
-grid_canvasitem_class_init (GridCanvasItemClass *klass)
+static void grid_canvasitem_class_init(GridCanvasItemClass *klass)
 {
-    GtkObjectClass *object_class;
-    SPCanvasItemClass *item_class;
-
-    object_class = (GtkObjectClass *) klass;
-    item_class = (SPCanvasItemClass *) klass;
+    SPCanvasItemClass *item_class = (SPCanvasItemClass *) klass;
 
     parent_class = (SPCanvasItemClass*)g_type_class_peek_parent (klass);
 
-    object_class->destroy = grid_canvasitem_destroy;
-
+    item_class->destroy = grid_canvasitem_destroy;
     item_class->update = grid_canvasitem_update;
     item_class->render = grid_canvasitem_render;
 }
@@ -109,14 +102,13 @@ grid_canvasitem_init (GridCanvasItem *griditem)
     griditem->grid = NULL;
 }
 
-static void
-grid_canvasitem_destroy (GtkObject *object)
+static void grid_canvasitem_destroy(SPCanvasItem *object)
 {
     g_return_if_fail (object != NULL);
     g_return_if_fail (INKSCAPE_IS_GRID_CANVASITEM (object));
 
-    if (GTK_OBJECT_CLASS (parent_class)->destroy)
-        (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+    if (SP_CANVAS_ITEM_CLASS(parent_class)->destroy)
+        (* SP_CANVAS_ITEM_CLASS(parent_class)->destroy) (object);
 }
 
 /**
@@ -184,7 +176,7 @@ CanvasGrid::~CanvasGrid()
     }
 
     while (canvasitems) {
-        gtk_object_destroy(GTK_OBJECT(canvasitems->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(canvasitems->data));
         canvasitems = g_slist_remove(canvasitems, canvasitems->data);
     }
 }
diff --git a/src/display/canvas-temporary-item.cpp b/src/display/canvas-temporary-item.cpp
index abe5f2f1b..551ea1536 100644
--- a/src/display/canvas-temporary-item.cpp
+++ b/src/display/canvas-temporary-item.cpp
@@ -17,6 +17,7 @@
 #include "display/canvas-temporary-item.h"
 
 #include <gtk/gtk.h>
+#include "display/sp-canvas-item.h"
 
 namespace Inkscape {
 namespace Display {
@@ -48,7 +49,7 @@ TemporaryItem::~TemporaryItem()
 
     if (canvasitem) {
         // destroying the item automatically hides it
-        gtk_object_destroy (GTK_OBJECT (canvasitem));
+        sp_canvas_item_destroy(canvasitem);
         canvasitem = NULL;
     }
 }
diff --git a/src/display/canvas-text.cpp b/src/display/canvas-text.cpp
index c7ca4ab16..ddc946d5d 100644
--- a/src/display/canvas-text.cpp
+++ b/src/display/canvas-text.cpp
@@ -28,7 +28,7 @@
 
 static void sp_canvastext_class_init (SPCanvasTextClass *klass);
 static void sp_canvastext_init (SPCanvasText *canvastext);
-static void sp_canvastext_destroy (GtkObject *object);
+static void sp_canvastext_destroy(SPCanvasItem *object);
 
 static void sp_canvastext_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static void sp_canvastext_render (SPCanvasItem *item, SPCanvasBuf *buf);
@@ -56,16 +56,13 @@ sp_canvastext_get_type (void)
     return type;
 }
 
-static void
-sp_canvastext_class_init (SPCanvasTextClass *klass)
+static void sp_canvastext_class_init(SPCanvasTextClass *klass)
 {
-    GtkObjectClass *object_class = (GtkObjectClass *) klass;
     SPCanvasItemClass *item_class = (SPCanvasItemClass *) klass;
 
     parent_class_ct = (SPCanvasItemClass*)g_type_class_peek_parent (klass);
 
-    object_class->destroy = sp_canvastext_destroy;
-
+    item_class->destroy = sp_canvastext_destroy;
     item_class->update = sp_canvastext_update;
     item_class->render = sp_canvastext_render;
 }
@@ -93,8 +90,7 @@ sp_canvastext_init (SPCanvasText *canvastext)
     canvastext->border = 3; // must be a constant, and not proportional to any width, height, or fontsize to allow alignment with other text boxes
 }
 
-static void
-sp_canvastext_destroy (GtkObject *object)
+static void sp_canvastext_destroy(SPCanvasItem *object)
 {
     g_return_if_fail (object != NULL);
     g_return_if_fail (SP_IS_CANVASTEXT (object));
@@ -105,8 +101,8 @@ sp_canvastext_destroy (GtkObject *object)
     canvastext->text = NULL;
     canvastext->item = NULL;
 
-    if (GTK_OBJECT_CLASS (parent_class_ct)->destroy)
-        (* GTK_OBJECT_CLASS (parent_class_ct)->destroy) (object);
+    if (SP_CANVAS_ITEM_CLASS(parent_class_ct)->destroy)
+        (* SP_CANVAS_ITEM_CLASS(parent_class_ct)->destroy) (object);
 }
 
 static void
diff --git a/src/display/gnome-canvas-acetate.cpp b/src/display/gnome-canvas-acetate.cpp
index 0891836b5..2cd0f296d 100644
--- a/src/display/gnome-canvas-acetate.cpp
+++ b/src/display/gnome-canvas-acetate.cpp
@@ -17,7 +17,7 @@
 
 static void sp_canvas_acetate_class_init (SPCanvasAcetateClass *klass);
 static void sp_canvas_acetate_init (SPCanvasAcetate *acetate);
-static void sp_canvas_acetate_destroy (GtkObject *object);
+static void sp_canvas_acetate_destroy(SPCanvasItem *object);
 
 static void sp_canvas_acetate_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static double sp_canvas_acetate_point (SPCanvasItem *item, Geom::Point p, SPCanvasItem **actual_item);
@@ -45,16 +45,11 @@ GType sp_canvas_acetate_get_type (void)
 
 static void sp_canvas_acetate_class_init (SPCanvasAcetateClass *klass)
 {
-	GtkObjectClass *object_class;
-	SPCanvasItemClass *item_class;
-
-	object_class = (GtkObjectClass *) klass;
-	item_class = (SPCanvasItemClass *) klass;
+	SPCanvasItemClass *item_class = (SPCanvasItemClass *) klass;
 
 	parent_class = (SPCanvasItemClass*)g_type_class_peek_parent (klass);
 
-	object_class->destroy = sp_canvas_acetate_destroy;
-
+	item_class->destroy = sp_canvas_acetate_destroy;
 	item_class->update = sp_canvas_acetate_update;
 	item_class->point = sp_canvas_acetate_point;
 }
@@ -64,13 +59,13 @@ static void sp_canvas_acetate_init (SPCanvasAcetate */*acetate*/)
     /* Nothing here */
 }
 
-static void sp_canvas_acetate_destroy (GtkObject *object)
+static void sp_canvas_acetate_destroy(SPCanvasItem *object)
 {
 	g_return_if_fail (object != NULL);
 	g_return_if_fail (GNOME_IS_CANVAS_ACETATE (object));
 
-	if (GTK_OBJECT_CLASS (parent_class)->destroy)
-		(* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+	if (SP_CANVAS_ITEM_CLASS(parent_class)->destroy)
+		(* SP_CANVAS_ITEM_CLASS(parent_class)->destroy) (object);
 }
 
 static void sp_canvas_acetate_update( SPCanvasItem *item, Geom::Affine const &/*affine*/, unsigned int /*flags*/ )
diff --git a/src/display/guideline.cpp b/src/display/guideline.cpp
index 652f4e2d7..d3385978a 100644
--- a/src/display/guideline.cpp
+++ b/src/display/guideline.cpp
@@ -31,7 +31,7 @@ using Inkscape::ControlManager;
 
 static void sp_guideline_class_init(SPGuideLineClass *c);
 static void sp_guideline_init(SPGuideLine *guideline);
-static void sp_guideline_destroy(GtkObject *object);
+static void sp_guideline_destroy(SPCanvasItem *object);
 
 static void sp_guideline_update(SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static void sp_guideline_render(SPCanvasItem *item, SPCanvasBuf *buf);
@@ -68,10 +68,8 @@ static void sp_guideline_class_init(SPGuideLineClass *c)
 {
     parent_class = (SPCanvasItemClass*) g_type_class_peek_parent(c);
 
-    GtkObjectClass *object_class = (GtkObjectClass *) c;
-    object_class->destroy = sp_guideline_destroy;
-
     SPCanvasItemClass *item_class = (SPCanvasItemClass *) c;
+    item_class->destroy = sp_guideline_destroy;
     item_class->update = sp_guideline_update;
     item_class->render = sp_guideline_render;
     item_class->point = sp_guideline_point;
@@ -90,7 +88,7 @@ static void sp_guideline_init(SPGuideLine *gl)
     gl->label = NULL;
 }
 
-static void sp_guideline_destroy(GtkObject *object)
+static void sp_guideline_destroy(SPCanvasItem *object)
 {
     g_return_if_fail (object != NULL);
     g_return_if_fail (SP_IS_GUIDELINE (object));
@@ -98,13 +96,13 @@ static void sp_guideline_destroy(GtkObject *object)
     //g_return_if_fail (SP_IS_CTRLPOINT(SP_GUIDELINE(object)->origin));
     
     if (SP_GUIDELINE(object)->origin != NULL && SP_IS_CTRLPOINT(SP_GUIDELINE(object)->origin)) {
-        gtk_object_destroy(GTK_OBJECT(SP_GUIDELINE(object)->origin));
+        sp_canvas_item_destroy(SP_GUIDELINE(object)->origin);
     } else {
         // FIXME: This branch shouldn't be reached (although it seems to be harmless).
         //g_error("Why can it be that gl->origin is not a valid SPCtrlPoint?\n");
     }
 
-    GTK_OBJECT_CLASS(parent_class)->destroy(object);
+    SP_CANVAS_ITEM_CLASS(parent_class)->destroy(object);
 }
 
 static void sp_guideline_render(SPCanvasItem *item, SPCanvasBuf *buf)
@@ -290,7 +288,7 @@ void sp_guideline_set_sensitive(SPGuideLine *gl, int sensitive)
 void sp_guideline_delete(SPGuideLine *gl)
 {
     //gtk_object_destroy(GTK_OBJECT(gl->origin));
-    gtk_object_destroy(GTK_OBJECT(gl));
+    sp_canvas_item_destroy(SP_CANVAS_ITEM(gl));
 }
 
 static void
diff --git a/src/display/sodipodi-ctrl.cpp b/src/display/sodipodi-ctrl.cpp
index 725ead0d6..e21bdff15 100644
--- a/src/display/sodipodi-ctrl.cpp
+++ b/src/display/sodipodi-ctrl.cpp
@@ -28,7 +28,7 @@ enum {
 
 static void sp_ctrl_class_init (SPCtrlClass *klass);
 static void sp_ctrl_init (SPCtrl *ctrl);
-static void sp_ctrl_destroy (GtkObject *object);
+static void sp_ctrl_destroy(SPCanvasItem *object);
 static void sp_ctrl_set_property (GObject *object, guint prop_id, const GValue *value, GParamSpec *pspec);
 static void sp_ctrl_get_property (GObject *object, guint prop_id, GValue *value, GParamSpec *pspec);
 static void sp_ctrl_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
@@ -63,19 +63,13 @@ sp_ctrl_get_type (void)
 static void
 sp_ctrl_class_init (SPCtrlClass *klass)
 {
-    GtkObjectClass *object_class;
-    SPCanvasItemClass *item_class;
-    GObjectClass *g_object_class;
-
-    object_class = (GtkObjectClass *) klass;
-    item_class = (SPCanvasItemClass *) klass;
-    g_object_class = (GObjectClass *) klass;
+    SPCanvasItemClass *item_class = (SPCanvasItemClass *) klass;
+    GObjectClass *g_object_class = (GObjectClass *) klass;
 
     parent_class = (SPCanvasItemClass *)g_type_class_peek_parent (klass);
 
     g_object_class->set_property = sp_ctrl_set_property;
     g_object_class->get_property = sp_ctrl_get_property;
-    object_class->destroy = sp_ctrl_destroy;
 
     g_object_class_install_property (g_object_class,
             ARG_SHAPE, g_param_spec_int ("shape", "shape", "Shape", 0, G_MAXINT, SP_CTRL_SHAPE_SQUARE, (GParamFlags) G_PARAM_READWRITE));
@@ -96,6 +90,7 @@ sp_ctrl_class_init (SPCtrlClass *klass)
     g_object_class_install_property (g_object_class,
             ARG_STROKE_COLOR, g_param_spec_int ("stroke_color", "stroke_color", "Stroke Color", G_MININT, G_MAXINT, 0x000000ff, (GParamFlags) G_PARAM_READWRITE));
 
+    item_class->destroy = sp_ctrl_destroy;
     item_class->update = sp_ctrl_update;
     item_class->render = sp_ctrl_render;
     item_class->point = sp_ctrl_point;
@@ -268,23 +263,20 @@ sp_ctrl_init (SPCtrl *ctrl)
     ctrl->_point = Geom::Point(0,0);
 }
 
-static void
-sp_ctrl_destroy (GtkObject *object)
+static void sp_ctrl_destroy(SPCanvasItem *object)
 {
-    SPCtrl *ctrl;
-
     g_return_if_fail (object != NULL);
     g_return_if_fail (SP_IS_CTRL (object));
 
-    ctrl = SP_CTRL (object);
+    SPCtrl *ctrl = SP_CTRL (object);
 
     if (ctrl->cache) {
         delete[] ctrl->cache;
         ctrl->cache = NULL;
     }
 
-    if (GTK_OBJECT_CLASS (parent_class)->destroy)
-        (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+    if (SP_CANVAS_ITEM_CLASS(parent_class)->destroy)
+        (* SP_CANVAS_ITEM_CLASS(parent_class)->destroy) (object);
 }
 
 static void
diff --git a/src/display/sodipodi-ctrlrect.cpp b/src/display/sodipodi-ctrlrect.cpp
index 3b50d0b5d..b0c997a92 100644
--- a/src/display/sodipodi-ctrlrect.cpp
+++ b/src/display/sodipodi-ctrlrect.cpp
@@ -28,7 +28,7 @@
 
 static void sp_ctrlrect_class_init(SPCtrlRectClass *c);
 static void sp_ctrlrect_init(CtrlRect *ctrlrect);
-static void sp_ctrlrect_destroy(GtkObject *object);
+static void sp_ctrlrect_destroy(SPCanvasItem *object);
 
 static void sp_ctrlrect_update(SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static void sp_ctrlrect_render(SPCanvasItem *item, SPCanvasBuf *buf);
@@ -61,13 +61,11 @@ GType sp_ctrlrect_get_type()
 
 static void sp_ctrlrect_class_init(SPCtrlRectClass *c)
 {
-    GtkObjectClass *object_class = (GtkObjectClass *) c;
     SPCanvasItemClass *item_class = (SPCanvasItemClass *) c;
 
     parent_class = (SPCanvasItemClass*) g_type_class_peek_parent(c);
 
-    object_class->destroy = sp_ctrlrect_destroy;
-
+    item_class->destroy = sp_ctrlrect_destroy;
     item_class->update = sp_ctrlrect_update;
     item_class->render = sp_ctrlrect_render;
 }
@@ -77,10 +75,10 @@ static void sp_ctrlrect_init(CtrlRect *cr)
     cr->init();
 }
 
-static void sp_ctrlrect_destroy(GtkObject *object)
+static void sp_ctrlrect_destroy(SPCanvasItem *object)
 {
-    if (GTK_OBJECT_CLASS(parent_class)->destroy) {
-        (* GTK_OBJECT_CLASS(parent_class)->destroy)(object);
+    if (SP_CANVAS_ITEM_CLASS(parent_class)->destroy) {
+        (* SP_CANVAS_ITEM_CLASS(parent_class)->destroy)(object);
     }
 }
 
diff --git a/src/display/sp-canvas-item.h b/src/display/sp-canvas-item.h
index ecbbd2758..f34ec453c 100644
--- a/src/display/sp-canvas-item.h
+++ b/src/display/sp-canvas-item.h
@@ -39,14 +39,17 @@ typedef struct _SPCanvasItemClass SPCanvasItemClass;
 
 #define SP_TYPE_CANVAS_ITEM (SPCanvasItem::getType())
 #define SP_CANVAS_ITEM(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj), SP_TYPE_CANVAS_ITEM, SPCanvasItem))
+#define SP_CANVAS_ITEM_CLASS(klass)      (G_TYPE_CHECK_CLASS_CAST ((klass), SP_TYPE_CANVAS_ITEM, SPCanvasItemClass))
 #define SP_IS_CANVAS_ITEM(obj) (G_TYPE_CHECK_INSTANCE_TYPE((obj), SP_TYPE_CANVAS_ITEM))
 #define SP_CANVAS_ITEM_GET_CLASS(o) (G_TYPE_INSTANCE_GET_CLASS((o), SP_TYPE_CANVAS_ITEM, SPCanvasItemClass))
 
+
 /**
  * An SPCanvasItem refers to a SPCanvas and to its parent item; it has
  * four coordinates, a bounding rectangle, and a transformation matrix.
  */
-struct SPCanvasItem : public GtkObject {
+struct SPCanvasItem {
+    GInitiallyUnowned parent_instance;
     static GType getType();
 
     SPCanvas *canvas;
@@ -66,12 +69,16 @@ struct SPCanvasItem : public GtkObject {
     gboolean visible;
     gboolean need_update;
     gboolean need_affine;
+ 
+    bool in_destruction;
 };
 
 /**
  * The vtable of an SPCanvasItem.
  */
-struct _SPCanvasItemClass : public GtkObjectClass {
+struct _SPCanvasItemClass {
+    GInitiallyUnownedClass parent_class;
+
     void (* update) (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 
     void (* render) (SPCanvasItem *item, SPCanvasBuf *buf);
@@ -79,6 +86,16 @@ struct _SPCanvasItemClass : public GtkObjectClass {
 
     int (* event) (SPCanvasItem *item, GdkEvent *event);
     void (* viewbox_changed) (SPCanvasItem *item, Geom::IntRect const &new_area);
+
+    /* Default signal handler for the ::destroy signal, which is
+     *  invoked to request that references to the widget be dropped.
+     *  If an object class overrides destroy() in order to perform class
+     *  specific destruction then it must still invoke its superclass'
+     *  implementation of the method after it is finished with its
+     *  own cleanup. (See gtk_widget_real_destroy() for an example of
+     *  how to do this).
+     */
+    void (*destroy)  (SPCanvasItem *object);
 };
 
 /**
@@ -96,6 +113,7 @@ void sp_canvas_item_lower(SPCanvasItem *item, int positions);
 bool sp_canvas_item_is_visible(SPCanvasItem *item);
 void sp_canvas_item_show(SPCanvasItem *item);
 void sp_canvas_item_hide(SPCanvasItem *item);
+void sp_canvas_item_destroy(SPCanvasItem *item);
 int sp_canvas_item_grab(SPCanvasItem *item, unsigned int event_mask, GdkCursor *cursor, guint32 etime);
 void sp_canvas_item_ungrab(SPCanvasItem *item, guint32 etime);
 
diff --git a/src/display/sp-canvas.cpp b/src/display/sp-canvas.cpp
index eff3b7ac2..2d8bb55ad 100644
--- a/src/display/sp-canvas.cpp
+++ b/src/display/sp-canvas.cpp
@@ -90,7 +90,7 @@ struct SPCanvasGroup {
      * Callback that destroys all items in group and calls group's virtual
      * destroy() function.
      */
-    static void destroy(GtkObject *object);
+    static void destroy(SPCanvasItem *object);
 
     /**
      * Update handler for canvas groups.
@@ -159,6 +159,14 @@ enum {
 
 void trackLatency(GdkEvent const *event);
 
+enum {
+  DESTROY,
+  LAST_SIGNAL
+};
+
+void sp_canvas_item_base_class_init(SPCanvasItemClass *klass);
+void sp_canvas_item_base_class_finalize(SPCanvasItemClass *klass);
+
 /**
  * Initializes the SPCanvasItem vtable and the "event" signal.
  */
@@ -167,12 +175,17 @@ void sp_canvas_item_class_init(SPCanvasItemClass *klass);
 /**
  * Callback for initialization of SPCanvasItem.
  */
-void sp_canvas_item_init(SPCanvasItem *item);
+void sp_canvas_item_init(SPCanvasItem *item, SPCanvasItemClass *klass);
 
 /**
  * Callback that removes item from all referers and destroys it.
  */
-void sp_canvas_item_dispose(GObject *object);
+void sp_canvas_item_dispose(GObject           *object);
+void sp_canvas_item_finalize(GObject          *object);
+void sp_canvas_item_real_destroy(SPCanvasItem *object);
+
+static gpointer    parent_class = NULL;
+static guint       object_signals[LAST_SIGNAL] = { 0 };
 
 /**
  * Sets up the newly created SPCanvasItem.
@@ -228,7 +241,7 @@ public:
     /**
      * Destroy handler for SPCanvas.
      */
-    static void destroy(GtkObject *object);
+    static void dispose(GObject *object);
 
     /**
      * The canvas widget's realize callback.
@@ -370,29 +383,43 @@ GtkWidgetClass *SPCanvasImpl::parentClass = 0;
 
 GType SPCanvasItem::getType()
 {
-    static GType type = 0;
-    if (!type) {
-        static GTypeInfo const info = {
+    static GType object_type = 0;
+
+    if (!object_type) {
+        static GTypeInfo const object_info = {
             sizeof(SPCanvasItemClass),
-            NULL, NULL,
+	    reinterpret_cast<GBaseInitFunc>(sp_canvas_item_base_class_init),
+	    reinterpret_cast<GBaseFinalizeFunc>(sp_canvas_item_base_class_finalize),
             reinterpret_cast<GClassInitFunc>(sp_canvas_item_class_init),
-            NULL, NULL,
+            NULL, // class_finalize
+	    NULL, // class_data
             sizeof(SPCanvasItem),
-            0,
+            16, // n_preallocs
             reinterpret_cast<GInstanceInitFunc>(sp_canvas_item_init),
-            NULL
+            NULL // value_table
         };
-        type = g_type_register_static(GTK_TYPE_OBJECT, "SPCanvasItem", &info, GTypeFlags(0));
+
+        object_type = g_type_register_static(G_TYPE_INITIALLY_UNOWNED, 
+                                             "SPCanvasItem", &object_info, GTypeFlags(0));
     }
 
-    return type;
+    return object_type;
 }
 
 namespace {
 
+void sp_canvas_item_base_class_init(SPCanvasItemClass *klass)
+{
+}
+
+void sp_canvas_item_base_class_finalize(SPCanvasItemClass *klass)
+{
+}
+
 void sp_canvas_item_class_init(SPCanvasItemClass *klass)
 {
-    GObjectClass *object_class = (GObjectClass *) klass;
+    GObjectClass *gobject_class = (GObjectClass *) klass;
+    parent_class = g_type_class_ref (G_TYPE_OBJECT);
 
     item_signals[ITEM_EVENT] = g_signal_new ("event",
                                              G_TYPE_FROM_CLASS (klass),
@@ -403,10 +430,21 @@ void sp_canvas_item_class_init(SPCanvasItemClass *klass)
                                              G_TYPE_BOOLEAN, 1,
                                              GDK_TYPE_EVENT);
 
-    object_class->dispose = sp_canvas_item_dispose;
+    gobject_class->dispose = sp_canvas_item_dispose;
+    gobject_class->finalize = sp_canvas_item_finalize;
+    klass->destroy = sp_canvas_item_real_destroy;
+  
+    object_signals[DESTROY] =
+      g_signal_new ("destroy",
+                    G_TYPE_FROM_CLASS (gobject_class),
+                    (GSignalFlags)(G_SIGNAL_RUN_CLEANUP | G_SIGNAL_NO_RECURSE | G_SIGNAL_NO_HOOKS),
+		    G_STRUCT_OFFSET (SPCanvasItemClass, destroy),
+		    NULL, NULL,
+		    g_cclosure_marshal_VOID__VOID,
+		    G_TYPE_NONE, 0);
 }
 
-void sp_canvas_item_init(SPCanvasItem *item)
+void sp_canvas_item_init(SPCanvasItem *item, SPCanvasItemClass *klass)
 {
     item->xform = Geom::Affine(Geom::identity());
     item->ctrlType = Inkscape::CTRL_TYPE_UNKNOWN;
@@ -416,6 +454,7 @@ void sp_canvas_item_init(SPCanvasItem *item)
     // that should be initially invisible; examples of such items: node handles, the CtrlRect
     // used for rubberbanding, path outline, etc.
     item->visible = TRUE;
+    item->in_destruction = false;
 }
 
 } // namespace
@@ -473,49 +512,86 @@ static void redraw_if_visible(SPCanvasItem *item)
     }
 }
 
-namespace {
+void sp_canvas_item_destroy(SPCanvasItem *item)
+{
+  g_return_if_fail(SP_IS_CANVAS_ITEM(item));
+  
+  if (!item->in_destruction)
+    g_object_run_dispose(G_OBJECT(item));
+}
 
+namespace {
 void sp_canvas_item_dispose(GObject *object)
 {
     SPCanvasItem *item = SP_CANVAS_ITEM (object);
 
-    // Hack: if this is a ctrlrect, move it to 0,0;
-    // this redraws only the stroke of the rect to be deleted,
-    // avoiding redraw of the entire area
-    if (SP_IS_CTRLRECT(item)) {
-        SP_CTRLRECT(object)->setRectangle(Geom::Rect(Geom::Point(0,0),Geom::Point(0,0)));
-        SP_CTRLRECT(object)->update(item->xform, 0);
-    } else {
-        redraw_if_visible (item);
-    }
-    item->visible = FALSE;
-
-    if (item == item->canvas->current_item) {
-        item->canvas->current_item = NULL;
-        item->canvas->need_repick = TRUE;
-    }
-
-    if (item == item->canvas->new_current_item) {
-        item->canvas->new_current_item = NULL;
-        item->canvas->need_repick = TRUE;
-    }
-
-    if (item == item->canvas->grabbed_item) {
-        item->canvas->grabbed_item = NULL;
-        gdk_pointer_ungrab (GDK_CURRENT_TIME);
-    }
-
-    if (item == item->canvas->focused_item) {
-        item->canvas->focused_item = NULL;
-    }
-
-    if (item->parent) {
-        SP_CANVAS_GROUP(item->parent)->remove(item);
+    /* guard against reinvocations during
+     * destruction with the in_destruction flag.
+     */
+    if (!item->in_destruction)
+    {
+      item->in_destruction=true;
+
+      // Hack: if this is a ctrlrect, move it to 0,0;
+      // this redraws only the stroke of the rect to be deleted,
+      // avoiding redraw of the entire area
+      if (SP_IS_CTRLRECT(item)) {
+          SP_CTRLRECT(object)->setRectangle(Geom::Rect(Geom::Point(0,0),Geom::Point(0,0)));
+          SP_CTRLRECT(object)->update(item->xform, 0);
+      } else {
+          redraw_if_visible (item);
+      }
+      item->visible = FALSE;
+  
+      if (item == item->canvas->current_item) {
+          item->canvas->current_item = NULL;
+          item->canvas->need_repick = TRUE;
+      }
+  
+      if (item == item->canvas->new_current_item) {
+          item->canvas->new_current_item = NULL;
+          item->canvas->need_repick = TRUE;
+      }
+
+      if (item == item->canvas->grabbed_item) {
+          item->canvas->grabbed_item = NULL;
+          gdk_pointer_ungrab (GDK_CURRENT_TIME);
+      }
+
+      if (item == item->canvas->focused_item) {
+          item->canvas->focused_item = NULL;
+      }
+ 
+      if (item->parent) {
+          SP_CANVAS_GROUP(item->parent)->remove(item);
+      }
+      
+      g_signal_emit (object, object_signals[DESTROY], 0);
+      item->in_destruction = false;
+    }
+
+    G_OBJECT_CLASS(parent_class)->dispose(object);
+}
+
+void sp_canvas_item_real_destroy(SPCanvasItem *object)
+{
+  g_signal_handlers_destroy(object);
+}
+	
+void sp_canvas_item_finalize(GObject *gobject)
+{
+  SPCanvasItem *object = SP_CANVAS_ITEM(gobject);
+
+  if (g_object_is_floating (object))
+    {
+      g_warning ("A floating object was finalized. This means that someone\n"
+		 "called g_object_unref() on an object that had only a floating\n"
+		 "reference; the initial floating reference is not owned by anyone\n"
+		 "and must be removed with g_object_ref_sink().");
     }
-
-    G_OBJECT_CLASS(g_type_class_peek(g_type_parent(SPCanvasItem::getType())))->dispose(object);
+  
+  G_OBJECT_CLASS (parent_class)->finalize (gobject);
 }
-
 } // namespace
 
 /**
@@ -931,13 +1007,11 @@ GType SPCanvasGroup::getType(void)
 
 void SPCanvasGroup::classInit(SPCanvasGroupClass *klass)
 {
-    GtkObjectClass *object_class = reinterpret_cast<GtkObjectClass *>(klass);
     SPCanvasItemClass *item_class = reinterpret_cast<SPCanvasItemClass *>(klass);
 
     parentClass = reinterpret_cast<SPCanvasItemClass*>(g_type_class_peek_parent(klass));
 
-    object_class->destroy = SPCanvasGroup::destroy;
-
+    item_class->destroy = SPCanvasGroup::destroy;
     item_class->update = SPCanvasGroup::update;
     item_class->render = SPCanvasGroup::render;
     item_class->point = SPCanvasGroup::point;
@@ -949,7 +1023,7 @@ void SPCanvasGroup::init(SPCanvasGroup * /*group*/)
     // Nothing here
 }
 
-void SPCanvasGroup::destroy(GtkObject *object)
+void SPCanvasGroup::destroy(SPCanvasItem *object)
 {
     g_return_if_fail(object != NULL);
     g_return_if_fail(SP_IS_CANVAS_GROUP(object));
@@ -961,11 +1035,11 @@ void SPCanvasGroup::destroy(GtkObject *object)
         SPCanvasItem *child = reinterpret_cast<SPCanvasItem *>(list->data);
         list = list->next;
 
-        gtk_object_destroy(GTK_OBJECT(child));
+        sp_canvas_item_destroy(child);
     }
 
-    if (GTK_OBJECT_CLASS(parentClass)->destroy) {
-        (* GTK_OBJECT_CLASS(parentClass)->destroy)(object);
+    if (SP_CANVAS_ITEM_CLASS(parentClass)->destroy) {
+        (* SP_CANVAS_ITEM_CLASS(parentClass)->destroy)(object);
     }
 }
 
@@ -1141,12 +1215,12 @@ GType SPCanvas::getType(void)
 
 void SPCanvasImpl::classInit(SPCanvasClass *klass)
 {
-    GtkObjectClass *object_class = (GtkObjectClass *) klass;
+    GObjectClass *object_class = (GObjectClass *) klass;
     GtkWidgetClass *widget_class = (GtkWidgetClass *) klass;
 
     parentClass = reinterpret_cast<GtkWidgetClass *>(g_type_class_peek_parent(klass));
 
-    object_class->destroy = SPCanvasImpl::destroy;
+    object_class->dispose = SPCanvasImpl::dispose;
 
     widget_class->realize = SPCanvasImpl::realize;
     widget_class->unrealize = SPCanvasImpl::unrealize;
@@ -1235,7 +1309,7 @@ void SPCanvasImpl::shutdown_transients(SPCanvas *canvas)
     remove_idle(canvas);
 }
 
-void SPCanvasImpl::destroy(GtkObject *object)
+void SPCanvasImpl::dispose(GObject *object)
 {
     SPCanvas *canvas = SP_CANVAS(object);
 
@@ -1248,8 +1322,8 @@ void SPCanvasImpl::destroy(GtkObject *object)
 #if defined(HAVE_LIBLCMS1) || defined(HAVE_LIBLCMS2)
     canvas->cms_key.~ustring();
 #endif
-    if (GTK_OBJECT_CLASS(parentClass)->destroy) {
-        (* GTK_OBJECT_CLASS(parentClass)->destroy)(object);
+    if (G_OBJECT_CLASS(parentClass)->dispose) {
+        (* G_OBJECT_CLASS(parentClass)->dispose)(object);
     }
 }
 
diff --git a/src/display/sp-ctrlcurve.cpp b/src/display/sp-ctrlcurve.cpp
index 5ef4c4d3f..d9b687f2e 100644
--- a/src/display/sp-ctrlcurve.cpp
+++ b/src/display/sp-ctrlcurve.cpp
@@ -25,7 +25,7 @@ namespace {
 
 static void sp_ctrlcurve_class_init(SPCtrlCurveClass *klass, gpointer data);
 static void sp_ctrlcurve_init(SPCtrlCurve *ctrlcurve, gpointer g_class);
-static void sp_ctrlcurve_destroy(GtkObject *object);
+static void sp_ctrlcurve_destroy(SPCanvasItem *object);
 
 static void sp_ctrlcurve_update(SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static void sp_ctrlcurve_render(SPCanvasItem *item, SPCanvasBuf *buf);
@@ -74,7 +74,7 @@ sp_ctrlcurve_init(SPCtrlCurve *ctrlcurve, gpointer /*g_class*/)
 }
 
 static void
-sp_ctrlcurve_destroy(GtkObject *object)
+sp_ctrlcurve_destroy(SPCanvasItem *object)
 {
     g_return_if_fail (object != NULL);
     g_return_if_fail (SP_IS_CTRLCURVE (object));
@@ -83,8 +83,8 @@ sp_ctrlcurve_destroy(GtkObject *object)
 
     ctrlcurve->item=NULL;
 
-    if (GTK_OBJECT_CLASS (parent_class)->destroy)
-        (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+    if (SP_CANVAS_ITEM_CLASS (parent_class)->destroy)
+        (* SP_CANVAS_ITEM_CLASS (parent_class)->destroy) (object);
 }
 
 static void
diff --git a/src/display/sp-ctrlline.cpp b/src/display/sp-ctrlline.cpp
index b7ad262b8..aef284c1a 100644
--- a/src/display/sp-ctrlline.cpp
+++ b/src/display/sp-ctrlline.cpp
@@ -32,7 +32,7 @@ namespace {
 
 void sp_ctrlline_class_init(SPCtrlLineClass *klass, gpointer data);
 void sp_ctrlline_init(SPCtrlLine *ctrlline, gpointer g_class);
-void sp_ctrlline_destroy(GtkObject *object);
+void sp_ctrlline_destroy(SPCanvasItem *object);
 
 void sp_ctrlline_update(SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 void sp_ctrlline_render(SPCanvasItem *item, SPCanvasBuf *buf);
@@ -79,7 +79,7 @@ void sp_ctrlline_init(SPCtrlLine *ctrlline, gpointer /*g_class*/)
     ctrlline->item=NULL;
 }
 
-void sp_ctrlline_destroy(GtkObject *object)
+void sp_ctrlline_destroy(SPCanvasItem *object)
 {
     g_return_if_fail(object != NULL);
     g_return_if_fail(SP_IS_CTRLLINE(object));
@@ -88,8 +88,8 @@ void sp_ctrlline_destroy(GtkObject *object)
 
     ctrlline->item = NULL;
 
-    if (GTK_OBJECT_CLASS (parent_class)->destroy) {
-        (* GTK_OBJECT_CLASS (parent_class)->destroy)(object);
+    if(SP_CANVAS_ITEM_CLASS (parent_class)->destroy) {
+        (* SP_CANVAS_ITEM_CLASS (parent_class)->destroy)(object);
     }
 }
 
diff --git a/src/display/sp-ctrlpoint.cpp b/src/display/sp-ctrlpoint.cpp
index 3c8e2bc5d..d07e9385b 100644
--- a/src/display/sp-ctrlpoint.cpp
+++ b/src/display/sp-ctrlpoint.cpp
@@ -23,7 +23,7 @@
 
 static void sp_ctrlpoint_class_init (SPCtrlPointClass *klass);
 static void sp_ctrlpoint_init (SPCtrlPoint *ctrlpoint);
-static void sp_ctrlpoint_destroy (GtkObject *object);
+static void sp_ctrlpoint_destroy(SPCanvasItem *object);
 
 static void sp_ctrlpoint_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static void sp_ctrlpoint_render (SPCanvasItem *item, SPCanvasBuf *buf);
@@ -50,16 +50,13 @@ sp_ctrlpoint_get_type (void)
     return type;
 }
 
-static void
-sp_ctrlpoint_class_init (SPCtrlPointClass *klass)
+static void sp_ctrlpoint_class_init(SPCtrlPointClass *klass)
 {
-    GtkObjectClass *object_class = (GtkObjectClass *) klass;
     SPCanvasItemClass *item_class = (SPCanvasItemClass *) klass;
 
     parent_class = (SPCanvasItemClass*)g_type_class_peek_parent (klass);
 
-    object_class->destroy = sp_ctrlpoint_destroy;
-
+    item_class->destroy = sp_ctrlpoint_destroy;
     item_class->update = sp_ctrlpoint_update;
     item_class->render = sp_ctrlpoint_render;
 }
@@ -73,8 +70,7 @@ sp_ctrlpoint_init (SPCtrlPoint *ctrlpoint)
     ctrlpoint->radius = 2;
 }
 
-static void
-sp_ctrlpoint_destroy (GtkObject *object)
+static void sp_ctrlpoint_destroy(SPCanvasItem *object)
 {
     g_return_if_fail (object != NULL);
     g_return_if_fail (SP_IS_CTRLPOINT (object));
@@ -83,8 +79,8 @@ sp_ctrlpoint_destroy (GtkObject *object)
 
     ctrlpoint->item=NULL;
 
-    if (GTK_OBJECT_CLASS (parent_class)->destroy)
-        (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+    if (SP_CANVAS_ITEM_CLASS(parent_class)->destroy)
+        (* SP_CANVAS_ITEM_CLASS(parent_class)->destroy) (object);
 }
 
 static void
diff --git a/src/display/sp-ctrlquadr.cpp b/src/display/sp-ctrlquadr.cpp
index 723075f74..ae15d620a 100644
--- a/src/display/sp-ctrlquadr.cpp
+++ b/src/display/sp-ctrlquadr.cpp
@@ -31,7 +31,7 @@ struct SPCtrlQuadrClass : public SPCanvasItemClass{};
 
 static void sp_ctrlquadr_class_init (SPCtrlQuadrClass *klass);
 static void sp_ctrlquadr_init (SPCtrlQuadr *ctrlquadr);
-static void sp_ctrlquadr_destroy (GtkObject *object);
+static void sp_ctrlquadr_destroy(SPCanvasItem *object);
 
 static void sp_ctrlquadr_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
 static void sp_ctrlquadr_render (SPCanvasItem *item, SPCanvasBuf *buf);
@@ -61,13 +61,11 @@ sp_ctrlquadr_get_type (void)
 static void
 sp_ctrlquadr_class_init (SPCtrlQuadrClass *klass)
 {
-    GtkObjectClass *object_class = (GtkObjectClass *) klass;
     SPCanvasItemClass *item_class = (SPCanvasItemClass *) klass;
 
     parent_class = (SPCanvasItemClass*)g_type_class_peek_parent (klass);
 
-    object_class->destroy = sp_ctrlquadr_destroy;
-
+    item_class->destroy = sp_ctrlquadr_destroy;
     item_class->update = sp_ctrlquadr_update;
     item_class->render = sp_ctrlquadr_render;
 }
@@ -82,14 +80,13 @@ sp_ctrlquadr_init (SPCtrlQuadr *ctrlquadr)
     ctrlquadr->p4 = Geom::Point(0, 0);
 }
 
-static void
-sp_ctrlquadr_destroy (GtkObject *object)
+static void sp_ctrlquadr_destroy(SPCanvasItem *object)
 {
     g_return_if_fail (object != NULL);
     g_return_if_fail (SP_IS_CTRLQUADR (object));
 
-    if (GTK_OBJECT_CLASS (parent_class)->destroy)
-        (* GTK_OBJECT_CLASS (parent_class)->destroy) (object);
+    if (SP_CANVAS_ITEM_CLASS(parent_class)->destroy)
+        (* SP_CANVAS_ITEM_CLASS(parent_class)->destroy) (object);
 }
 
 static void
diff --git a/src/draw-anchor.cpp b/src/draw-anchor.cpp
index 591129d0b..2133d5de6 100644
--- a/src/draw-anchor.cpp
+++ b/src/draw-anchor.cpp
@@ -65,7 +65,7 @@ SPDrawAnchor *sp_draw_anchor_destroy(SPDrawAnchor *anchor)
         anchor->curve->unref();
     }
     if (anchor->ctrl) {
-        gtk_object_destroy(GTK_OBJECT(anchor->ctrl));
+        sp_canvas_item_destroy(anchor->ctrl);
     }
     g_free(anchor);
     return NULL;
diff --git a/src/draw-context.cpp b/src/draw-context.cpp
index cf47fed29..fb7a60703 100644
--- a/src/draw-context.cpp
+++ b/src/draw-context.cpp
@@ -537,7 +537,7 @@ void spdc_concat_colors_and_flush(SPDrawContext *dc, gboolean forceclosed)
     // Green
     dc->green_curve = new SPCurve();
     while (dc->green_bpaths) {
-        gtk_object_destroy(GTK_OBJECT(dc->green_bpaths->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(dc->green_bpaths->data));
         dc->green_bpaths = g_slist_remove(dc->green_bpaths, dc->green_bpaths->data);
     }
 
@@ -732,7 +732,7 @@ static void spdc_free_colors(SPDrawContext *dc)
 {
     // Red
     if (dc->red_bpath) {
-        gtk_object_destroy(GTK_OBJECT(dc->red_bpath));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(dc->red_bpath));
         dc->red_bpath = NULL;
     }
     if (dc->red_curve) {
@@ -741,7 +741,7 @@ static void spdc_free_colors(SPDrawContext *dc)
 
     // Blue
     if (dc->blue_bpath) {
-        gtk_object_destroy(GTK_OBJECT(dc->blue_bpath));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(dc->blue_bpath));
         dc->blue_bpath = NULL;
     }
     if (dc->blue_curve) {
@@ -750,7 +750,7 @@ static void spdc_free_colors(SPDrawContext *dc)
 
     // Green
     while (dc->green_bpaths) {
-        gtk_object_destroy(GTK_OBJECT(dc->green_bpaths->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(dc->green_bpaths->data));
         dc->green_bpaths = g_slist_remove(dc->green_bpaths, dc->green_bpaths->data);
     }
     if (dc->green_curve) {
diff --git a/src/dropper-context.cpp b/src/dropper-context.cpp
index be0379813..312a96171 100644
--- a/src/dropper-context.cpp
+++ b/src/dropper-context.cpp
@@ -143,7 +143,7 @@ static void sp_dropper_context_finish(SPEventContext *ec)
     }
 
     if (dc->area) {
-        gtk_object_destroy(GTK_OBJECT(dc->area));
+        sp_canvas_item_destroy(dc->area);
         dc->area = NULL;
     }
 }
diff --git a/src/dyna-draw-context.cpp b/src/dyna-draw-context.cpp
index 9e204cc14..ddd37af91 100644
--- a/src/dyna-draw-context.cpp
+++ b/src/dyna-draw-context.cpp
@@ -181,7 +181,7 @@ sp_dyna_draw_context_dispose(GObject *object)
     SPDynaDrawContext *ddc = SP_DYNA_DRAW_CONTEXT(object);
 
     if (ddc->hatch_area) {
-        gtk_object_destroy(GTK_OBJECT(ddc->hatch_area));
+        sp_canvas_item_destroy(ddc->hatch_area);
         ddc->hatch_area = NULL;
     }
 
@@ -519,7 +519,7 @@ calligraphic_cancel(SPDynaDrawContext *dc)
     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), 0);
             /* Remove all temporary line segments */
             while (dc->segments) {
-                gtk_object_destroy(GTK_OBJECT(dc->segments->data));
+                sp_canvas_item_destroy(SP_CANVAS_ITEM(dc->segments->data));
                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
             }
             /* reset accumulated curve */
@@ -836,7 +836,7 @@ sp_dyna_draw_context_root_handler(SPEventContext *event_context,
 
             /* Remove all temporary line segments */
             while (dc->segments) {
-                gtk_object_destroy(GTK_OBJECT(dc->segments->data));
+                sp_canvas_item_destroy(SP_CANVAS_ITEM(dc->segments->data));
                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
             }
 
diff --git a/src/eraser-context.cpp b/src/eraser-context.cpp
index 07e28ec20..b88329028 100644
--- a/src/eraser-context.cpp
+++ b/src/eraser-context.cpp
@@ -462,7 +462,7 @@ eraser_cancel(SPEraserContext *dc)
     sp_canvas_item_ungrab(SP_CANVAS_ITEM(desktop->acetate), 0);
             /* Remove all temporary line segments */
             while (dc->segments) {
-                gtk_object_destroy(GTK_OBJECT(dc->segments->data));
+                sp_canvas_item_destroy(SP_CANVAS_ITEM(dc->segments->data));
                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
             }
             /* reset accumulated curve */
@@ -569,7 +569,7 @@ sp_eraser_context_root_handler(SPEventContext *event_context,
 
             /* Remove all temporary line segments */
             while (dc->segments) {
-                gtk_object_destroy(GTK_OBJECT(dc->segments->data));
+                sp_canvas_item_destroy(SP_CANVAS_ITEM(dc->segments->data));
                 dc->segments = g_slist_remove(dc->segments, dc->segments->data);
             }
 
diff --git a/src/gradient-drag.cpp b/src/gradient-drag.cpp
index dbd9da517..a77eb5e2a 100644
--- a/src/gradient-drag.cpp
+++ b/src/gradient-drag.cpp
@@ -696,7 +696,7 @@ GrDrag::~GrDrag()
     this->selected = NULL;
 
     for (GSList *l = this->lines; l != NULL; l = l->next) {
-        gtk_object_destroy( GTK_OBJECT (l->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(l->data));
     }
     g_slist_free (this->lines);
     this->lines = NULL;
@@ -2130,7 +2130,7 @@ void GrDrag::updateLines()
 {
     // delete old lines
     for (GSList const *i = this->lines; i != NULL; i = i->next) {
-        gtk_object_destroy( GTK_OBJECT(i->data) );
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(i->data));
     }
     g_slist_free(this->lines);
     this->lines = NULL;
diff --git a/src/ink-comboboxentry-action.cpp b/src/ink-comboboxentry-action.cpp
index 6b5266709..ad9f775c4 100644
--- a/src/ink-comboboxentry-action.cpp
+++ b/src/ink-comboboxentry-action.cpp
@@ -569,7 +569,7 @@ void ink_comboboxentry_action_popup_disable( Ink_ComboBoxEntry_Action* action )
   action->popup = false;
 
   if( action->entry_completion ) {
-    gtk_object_destroy( GTK_OBJECT( action->entry_completion ) );
+    gtk_widget_destroy(GTK_WIDGET(action->entry_completion));
     action->entry_completion = 0;
   }
 }
diff --git a/src/knot.cpp b/src/knot.cpp
index 27a4c83d9..e6fd5c044 100644
--- a/src/knot.cpp
+++ b/src/knot.cpp
@@ -239,7 +239,7 @@ static void sp_knot_dispose(GObject *object)
         }
 
     if (knot->item) {
-        gtk_object_destroy (GTK_OBJECT (knot->item));
+        sp_canvas_item_destroy(knot->item);
         knot->item = NULL;
     }
 
diff --git a/src/lpe-tool-context.cpp b/src/lpe-tool-context.cpp
index c4d38c400..60588abf3 100644
--- a/src/lpe-tool-context.cpp
+++ b/src/lpe-tool-context.cpp
@@ -124,7 +124,7 @@ sp_lpetool_context_dispose(GObject *object)
     delete lc->shape_editor;
 
     if (lc->canvas_bbox) {
-        gtk_object_destroy(GTK_OBJECT(lc->canvas_bbox));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(lc->canvas_bbox));
         lc->canvas_bbox = NULL;
     }
 
@@ -412,7 +412,7 @@ void
 lpetool_context_reset_limiting_bbox(SPLPEToolContext *lc)
 {
     if (lc->canvas_bbox) {
-        gtk_object_destroy(GTK_OBJECT(lc->canvas_bbox));
+        sp_canvas_item_destroy(lc->canvas_bbox);
         lc->canvas_bbox = NULL;
     }
 
@@ -497,7 +497,7 @@ lpetool_delete_measuring_items(SPLPEToolContext *lc)
 {
     std::map<SPPath *, SPCanvasItem*>::iterator i;
     for (i = lc->measuring_items->begin(); i != lc->measuring_items->end(); ++i) {
-        gtk_object_destroy(GTK_OBJECT(i->second));
+        sp_canvas_item_destroy(i->second);
     }
     lc->measuring_items->clear();
 }
diff --git a/src/pen-context.cpp b/src/pen-context.cpp
index b97fc5527..a8aedb649 100644
--- a/src/pen-context.cpp
+++ b/src/pen-context.cpp
@@ -169,19 +169,19 @@ static void sp_pen_context_dispose(GObject *object)
     SPPenContext *pc = SP_PEN_CONTEXT(object);
 
     if (pc->c0) {
-        gtk_object_destroy(GTK_OBJECT(pc->c0));
+        sp_canvas_item_destroy(pc->c0);
         pc->c0 = NULL;
     }
     if (pc->c1) {
-        gtk_object_destroy(GTK_OBJECT(pc->c1));
+        sp_canvas_item_destroy(pc->c1);
         pc->c1 = NULL;
     }
     if (pc->cl0) {
-        gtk_object_destroy(GTK_OBJECT(pc->cl0));
+        sp_canvas_item_destroy(pc->cl0);
         pc->cl0 = NULL;
     }
     if (pc->cl1) {
-        gtk_object_destroy(GTK_OBJECT(pc->cl1));
+        sp_canvas_item_destroy(pc->cl1);
         pc->cl1 = NULL;
     }
 
@@ -871,7 +871,7 @@ void pen_redraw_all (SPPenContext *const pc)
     if (pc->green_bpaths) {
         // remove old piecewise green canvasitems
         while (pc->green_bpaths) {
-            gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
+            sp_canvas_item_destroy(SP_CANVAS_ITEM(pc->green_bpaths->data));
             pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
         }
         // one canvas bpath for all of green_curve
@@ -1135,7 +1135,7 @@ static gint pen_handle_key_press(SPPenContext *const pc, GdkEvent *event)
                 // Destroy topmost green bpath
                 if (pc->green_bpaths) {
                     if (pc->green_bpaths->data)
-                        gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
+                        sp_canvas_item_destroy(SP_CANVAS_ITEM(pc->green_bpaths->data));
                     pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
                 }
                 // Get last segment
@@ -1182,7 +1182,7 @@ static void spdc_reset_colors(SPPenContext *pc)
     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->blue_bpath), NULL);
     // Green
     while (pc->green_bpaths) {
-        gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(pc->green_bpaths->data));
         pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
     }
     pc->green_curve->reset();
diff --git a/src/pencil-context.cpp b/src/pencil-context.cpp
index c93feb4d4..866231e96 100644
--- a/src/pencil-context.cpp
+++ b/src/pencil-context.cpp
@@ -553,7 +553,7 @@ pencil_cancel (SPPencilContext *const pc)
     pc->red_curve->reset();
     sp_canvas_bpath_set_bpath(SP_CANVAS_BPATH(pc->red_bpath), NULL);
     while (pc->green_bpaths) {
-        gtk_object_destroy(GTK_OBJECT(pc->green_bpaths->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(pc->green_bpaths->data));
         pc->green_bpaths = g_slist_remove(pc->green_bpaths, pc->green_bpaths->data);
     }
     pc->green_curve->reset();
diff --git a/src/rubberband.cpp b/src/rubberband.cpp
index 89ac04ee6..08492837a 100644
--- a/src/rubberband.cpp
+++ b/src/rubberband.cpp
@@ -32,14 +32,14 @@ Inkscape::Rubberband::Rubberband(SPDesktop *dt)
 void Inkscape::Rubberband::delete_canvas_items()
 {
     if (_rect) {
-        GtkObject *temp = _rect;
+        SPCanvasItem *temp = _rect;
         _rect = NULL;
-        gtk_object_destroy(temp);
+        sp_canvas_item_destroy(temp);
     }
     if (_touchpath) {
-        GtkObject *temp = _touchpath;
+        SPCanvasItem *temp = _touchpath;
         _touchpath = NULL;
-        gtk_object_destroy(temp);
+        sp_canvas_item_destroy(temp);
     }
 }
 
diff --git a/src/selcue.cpp b/src/selcue.cpp
index 9a2d105ae..4c35307f7 100644
--- a/src/selcue.cpp
+++ b/src/selcue.cpp
@@ -47,12 +47,12 @@ Inkscape::SelCue::~SelCue()
     _sel_modified_connection.disconnect();
 
     for (std::vector<SPCanvasItem*>::iterator i = _item_bboxes.begin(); i != _item_bboxes.end(); ++i) {
-        gtk_object_destroy(*i);
+        sp_canvas_item_destroy(*i);
     }
     _item_bboxes.clear();
 
     for (std::vector<SPCanvasItem*>::iterator i = _text_baselines.begin(); i != _text_baselines.end(); ++i) {
-        gtk_object_destroy(*i);
+        sp_canvas_item_destroy(*i);
     }
     _text_baselines.clear();
 }
@@ -104,7 +104,7 @@ void Inkscape::SelCue::_updateItemBboxes()
 void Inkscape::SelCue::_newItemBboxes()
 {
     for (std::vector<SPCanvasItem*>::iterator i = _item_bboxes.begin(); i != _item_bboxes.end(); ++i) {
-        gtk_object_destroy(*i);
+        sp_canvas_item_destroy(*i);
     }
     _item_bboxes.clear();
 
@@ -167,7 +167,7 @@ void Inkscape::SelCue::_newItemBboxes()
 void Inkscape::SelCue::_newTextBaselines()
 {
     for (std::vector<SPCanvasItem*>::iterator i = _text_baselines.begin(); i != _text_baselines.end(); ++i) {
-        gtk_object_destroy(*i);
+        sp_canvas_item_destroy(*i);
     }
     _text_baselines.clear();
 
diff --git a/src/seltrans.cpp b/src/seltrans.cpp
index 4b0ef284b..88a4a536d 100644
--- a/src/seltrans.cpp
+++ b/src/seltrans.cpp
@@ -196,16 +196,16 @@ Inkscape::SelTrans::~SelTrans()
     }
 
     if (_norm) {
-        gtk_object_destroy(GTK_OBJECT(_norm));
+        sp_canvas_item_destroy(_norm);
         _norm = NULL;
     }
     if (_grip) {
-        gtk_object_destroy(GTK_OBJECT(_grip));
+        sp_canvas_item_destroy(_grip);
         _grip = NULL;
     }
     for (int i = 0; i < 4; i++) {
         if (_l[i]) {
-            gtk_object_destroy(_l[i]);
+            sp_canvas_item_destroy(_l[i]);
             _l[i] = NULL;
         }
     }
diff --git a/src/spray-context.cpp b/src/spray-context.cpp
index a575affc4..7ac04db58 100644
--- a/src/spray-context.cpp
+++ b/src/spray-context.cpp
@@ -200,7 +200,7 @@ static void sp_spray_context_dispose(GObject *object)
     tc->style_set_connection.~connection();
 
     if (tc->dilate_area) {
-        gtk_object_destroy(GTK_OBJECT(tc->dilate_area));
+        sp_canvas_item_destroy(tc->dilate_area);
         tc->dilate_area = NULL;
     }
 
diff --git a/src/text-context.cpp b/src/text-context.cpp
index ae5dac88c..e8d03eb71 100644
--- a/src/text-context.cpp
+++ b/src/text-context.cpp
@@ -302,24 +302,24 @@ static void sp_text_context_finish(SPEventContext *ec)
     }
 
     if (tc->cursor) {
-        gtk_object_destroy(tc->cursor);
+        sp_canvas_item_destroy(tc->cursor);
         tc->cursor = NULL;
     }
 
     if (tc->indicator) {
-        gtk_object_destroy(GTK_OBJECT(tc->indicator));
+        sp_canvas_item_destroy(tc->indicator);
         tc->indicator = NULL;
     }
 
     if (tc->frame) {
-        gtk_object_destroy(GTK_OBJECT(tc->frame));
+        sp_canvas_item_destroy(tc->frame);
         tc->frame = NULL;
     }
 
     for (std::vector<SPCanvasItem*>::iterator it = tc->text_selection_quads.begin() ;
          it != tc->text_selection_quads.end() ; ++it) {
         sp_canvas_item_hide(*it);
-        gtk_object_destroy(*it);
+        sp_canvas_item_destroy(*it);
     }
     tc->text_selection_quads.clear();
 }
@@ -1674,7 +1674,7 @@ static void sp_text_context_update_text_selection(SPTextContext *tc)
 
     for (std::vector<SPCanvasItem*>::iterator it = tc->text_selection_quads.begin() ; it != tc->text_selection_quads.end() ; it++) {
         sp_canvas_item_hide(*it);
-        gtk_object_destroy(*it);
+        sp_canvas_item_destroy(*it);
     }
     tc->text_selection_quads.clear();
 
diff --git a/src/tweak-context.cpp b/src/tweak-context.cpp
index f6bbd6992..c06e0280a 100644
--- a/src/tweak-context.cpp
+++ b/src/tweak-context.cpp
@@ -169,7 +169,7 @@ sp_tweak_context_dispose(GObject *object)
     tc->style_set_connection.~connection();
 
     if (tc->dilate_area) {
-        gtk_object_destroy(GTK_OBJECT(tc->dilate_area));
+        sp_canvas_item_destroy(tc->dilate_area);
         tc->dilate_area = NULL;
     }
 
diff --git a/src/ui/dialog/spellcheck.cpp b/src/ui/dialog/spellcheck.cpp
index 85320618b..0da28061e 100644
--- a/src/ui/dialog/spellcheck.cpp
+++ b/src/ui/dialog/spellcheck.cpp
@@ -220,7 +220,7 @@ void SpellCheck::clearRects()
 {
     for (GSList *it = _rects; it; it = it->next) {
         sp_canvas_item_hide((SPCanvasItem*) it->data);
-        gtk_object_destroy((SPCanvasItem*) it->data);
+        sp_canvas_item_destroy((SPCanvasItem*) it->data);
     }
     g_slist_free(_rects);
     _rects = NULL;
@@ -729,7 +729,7 @@ SpellCheck::deleteLastRect ()
 {
     if (_rects) {
         sp_canvas_item_hide(SP_CANVAS_ITEM(_rects->data));
-        gtk_object_destroy(GTK_OBJECT(_rects->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(_rects->data));
         _rects = _rects->next; // pop latest-prepended rect
     }
 }
diff --git a/src/ui/tool/control-point.cpp b/src/ui/tool/control-point.cpp
index c3e7ccbe6..e1ee71d53 100644
--- a/src/ui/tool/control-point.cpp
+++ b/src/ui/tool/control-point.cpp
@@ -115,7 +115,7 @@ ControlPoint::~ControlPoint()
 
     g_signal_handler_disconnect(G_OBJECT(_canvas_item), _event_handler_connection);
     //sp_canvas_item_hide(_canvas_item);
-    gtk_object_destroy(_canvas_item);
+    sp_canvas_item_destroy(_canvas_item);
 }
 
 void ControlPoint::_commonInit()
diff --git a/src/ui/tool/node-tool.cpp b/src/ui/tool/node-tool.cpp
index 76b309ad6..8dfee6e65 100644
--- a/src/ui/tool/node-tool.cpp
+++ b/src/ui/tool/node-tool.cpp
@@ -158,7 +158,7 @@ SPCanvasGroup *create_control_group(SPDesktop *d)
 
 void destroy_group(SPCanvasGroup *g)
 {
-    gtk_object_destroy(GTK_OBJECT(g));
+    sp_canvas_item_destroy(SP_CANVAS_ITEM(g));
 }
 
 void ink_node_tool_class_init(InkNodeToolClass *klass)
diff --git a/src/ui/tool/node.cpp b/src/ui/tool/node.cpp
index 8098cbee2..136309a8e 100644
--- a/src/ui/tool/node.cpp
+++ b/src/ui/tool/node.cpp
@@ -120,7 +120,7 @@ Handle::Handle(NodeSharedData const &data, Geom::Point const &initial_pos, Node
 Handle::~Handle()
 {
     //sp_canvas_item_hide(_handle_line);
-    gtk_object_destroy(_handle_line);
+    sp_canvas_item_destroy(_handle_line);
 }
 
 void Handle::setVisible(bool v)
diff --git a/src/ui/tool/path-manipulator.cpp b/src/ui/tool/path-manipulator.cpp
index e292a9347..35eb23f42 100644
--- a/src/ui/tool/path-manipulator.cpp
+++ b/src/ui/tool/path-manipulator.cpp
@@ -152,7 +152,7 @@ PathManipulator::~PathManipulator()
 {
     delete _dragpoint;
     delete _observer;
-    gtk_object_destroy(_outline);
+    sp_canvas_item_destroy(_outline);
     _spcurve->unref();
     clear();
 }
diff --git a/src/ui/tool/selector.cpp b/src/ui/tool/selector.cpp
index 5122d3c0f..4a414e4ea 100644
--- a/src/ui/tool/selector.cpp
+++ b/src/ui/tool/selector.cpp
@@ -47,7 +47,7 @@ public:
     }
 
     ~SelectorPoint() {
-        gtk_object_destroy(_rubber);
+        sp_canvas_item_destroy(_rubber);
     }
 
     SPDesktop *desktop() { return _desktop; }
diff --git a/src/ui/widget/ruler.cpp b/src/ui/widget/ruler.cpp
index 189f20093..b97ef4312 100644
--- a/src/ui/widget/ruler.cpp
+++ b/src/ui/widget/ruler.cpp
@@ -177,7 +177,7 @@ Ruler::on_button_release_event(GdkEventButton *evb)
         Gdk::Window::pointer_ungrab(evb->time);
 #endif
 
-        gtk_object_destroy(GTK_OBJECT(_guide));
+        sp_canvas_item_destroy(_guide);
         _guide = 0;
         _dragging = false;
 
diff --git a/src/vanishing-point.cpp b/src/vanishing-point.cpp
index 20758d37c..f342f2c69 100644
--- a/src/vanishing-point.cpp
+++ b/src/vanishing-point.cpp
@@ -523,7 +523,7 @@ VPDrag::~VPDrag()
     this->draggers = NULL;
 
     for (GSList const *i = this->lines; i != NULL; i = i->next) {
-        gtk_object_destroy( GTK_OBJECT (i->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(i->data));
     }
     g_slist_free (this->lines);
     this->lines = NULL;
@@ -597,7 +597,7 @@ VPDrag::updateLines ()
 {
     // delete old lines
     for (GSList const *i = this->lines; i != NULL; i = i->next) {
-        gtk_object_destroy( GTK_OBJECT (i->data));
+        sp_canvas_item_destroy(SP_CANVAS_ITEM(i->data));
     }
     g_slist_free (this->lines);
     this->lines = NULL;