Avoid 'flashing' between front and rear face during initial dragging process of 3D boxes

(bzr r3552)

3 files changed, 31 insertions, 8 deletions

diff --git a/src/box3d-context.cpp b/src/box3d-context.cpp
index 3b45abdb2..8ef5f5960 100644
--- a/src/box3d-context.cpp
+++ b/src/box3d-context.cpp
@@ -362,8 +362,11 @@ static gint sp_3dbox_context_root_handler(SPEventContext *event_context, GdkEven
 
             if (event->motion.state & GDK_SHIFT_MASK && !bc->extruded) {
                 /* once shift is pressed, set bc->extruded (no need to create further faces;
-                   all of them are already created in sp_3dbox_init) */
+                   all of them are already created in sp_3dbox_init); since we made the rear face
+                   invisible in the beginning to avoid "flashing", we must set its correct style now */
                 bc->extruded = true;
+                g_assert (bc->item);
+                SP_3DBOX (bc->item)->faces[5]->set_style (NULL, true);
             }
 
             if (!bc->extruded) {
@@ -585,6 +588,8 @@ static void sp_3dbox_drag(SP3DBoxContext &bc, guint state)
         for (int i = 0; i < 6; ++i) {
             SP_3DBOX(bc.item)->faces[i]->hook_path_to_3dbox();
         }
+        // make rear face invisible in the beginning to avoid "flashing"
+        SP_3DBOX (bc.item)->faces[5]->set_style (NULL, false);
 
         bc.item->updateRepr();
         sp_3dbox_set_z_orders (SP_3DBOX (bc.item));
diff --git a/src/box3d-face.cpp b/src/box3d-face.cpp
index 9a6ca2ef2..de52031da 100644
--- a/src/box3d-face.cpp
+++ b/src/box3d-face.cpp
@@ -177,16 +177,36 @@ void Box3DFace::hook_path_to_3dbox(SPPath * existing_path)
         return;
     }
 
-    SPDesktop *desktop = inkscape_active_desktop();
+    /* create new path for face */
     Inkscape::XML::Document *xml_doc = sp_document_repr_doc(SP_OBJECT_DOCUMENT(SP_OBJECT(parent_box3d)));
 
-    /* apply style */
-    bool use_current = prefs_get_int_attribute("tools.shapes.3dbox", "usecurrent", 0);
     Inkscape::XML::Node *repr_face = xml_doc->createElement("svg:path");
     repr_face->setAttribute("inkscape:box3dface", this->axes_string());
+    this->path = SP_PATH(SP_OBJECT(parent_box3d)->appendChildRepr(repr_face));
+    Inkscape::GC::release(repr_face);
+
+    /* set the correct style */
+    this->set_style (repr_face);
+}
+
+void Box3DFace::set_style(Inkscape::XML::Node *repr_face, bool extruded)
+{
+    if (repr_face == NULL) {
+        repr_face = SP_OBJECT_REPR (this->path);
+    }
 
-    gchar *descr = g_strconcat ("desktop.", axes_string(), NULL);
+    if (!extruded && !strcmp (axes_string (), "XYrear")) {
+        // to avoid "flashing" during the initial dragging process, we make the rear face invisible in this case
+        repr_face->setAttribute("style", "fill:none");
+        return;
+    }
+
+    gchar *descr = g_strconcat ("desktop.", axes_string (), NULL);
     const gchar * cur_style = prefs_get_string_attribute(descr, "style");
+    g_free (descr);    
+    
+    SPDesktop *desktop = inkscape_active_desktop();
+    bool use_current = prefs_get_int_attribute("tools.shapes.3dbox", "usecurrent", 0);
     if (use_current && cur_style !=NULL) {
         /* use last used style */
         repr_face->setAttribute("style", cur_style);
@@ -196,9 +216,6 @@ void Box3DFace::hook_path_to_3dbox(SPPath * existing_path)
         g_string_printf (pstring, "tools.shapes.3dbox.%s", axes_string());
         sp_desktop_apply_style_tool (desktop, repr_face, pstring->str, false);
     }
-    g_free (descr);
-    this->path = SP_PATH(SP_OBJECT(parent_box3d)->appendChildRepr(repr_face));
-    Inkscape::GC::release(repr_face);
 }
 
 /**
diff --git a/src/box3d-face.h b/src/box3d-face.h
index d3d83e702..091a8108b 100644
--- a/src/box3d-face.h
+++ b/src/box3d-face.h
@@ -43,6 +43,7 @@ public:
     //void set_face (NR::Point const A, NR::Point const C, Box3D::Axis const dir1, Box3D::Axis const dir2);
     
     void hook_path_to_3dbox(SPPath * existing_path = NULL);
+    void set_style(Inkscape::XML::Node *repr_face = NULL, bool extruded = true);
     void set_path_repr();
     void set_curve();
     inline void lower_to_bottom() { SP_ITEM (path)->lowerToBottom(); }