Recompute box corners relative to new perspective when merging persps (to prevent boxes from jumping randomly)

(bzr r4311)

3 files changed, 16 insertions, 10 deletions

diff --git a/src/box3d.cpp b/src/box3d.cpp
index 0f9f8defe..3397cd6b0 100644
--- a/src/box3d.cpp
+++ b/src/box3d.cpp
@@ -1428,7 +1428,19 @@ box3d_get_perspective(SPBox3D const *box) {
 }
 
 void
-box3d_switch_perspectives(SPBox3D *box, Persp3D *old_persp, Persp3D *new_persp) {
+box3d_switch_perspectives(SPBox3D *box, Persp3D *old_persp, Persp3D *new_persp, bool recompute_corners) {
+    if (recompute_corners) {
+        box->orig_corner0.normalize();
+        box->orig_corner7.normalize();
+        double z0 = box->orig_corner0[Proj::Z];
+        double z7 = box->orig_corner7[Proj::Z];
+        NR::Point corner0_screen = box3d_get_corner_screen(box, 0);
+        NR::Point corner7_screen = box3d_get_corner_screen(box, 7);
+
+        box->orig_corner0 = new_persp->tmat.preimage(corner0_screen, z0, Proj::Z);
+        box->orig_corner7 = new_persp->tmat.preimage(corner7_screen, z7, Proj::Z);
+    }
+
     persp3d_remove_box (old_persp, box);
     persp3d_add_box (new_persp, box);
 
diff --git a/src/box3d.h b/src/box3d.h
index d6243d5e0..d80cf038b 100644
--- a/src/box3d.h
+++ b/src/box3d.h
@@ -79,7 +79,7 @@ void box3d_remove_from_selection(SPBox3D *box);
 void box3d_mark_transformed(SPBox3D *box);
 
 Persp3D *box3d_get_perspective(SPBox3D const *box);
-void box3d_switch_perspectives(SPBox3D *box, Persp3D *old_persp, Persp3D *new_persp);
+void box3d_switch_perspectives(SPBox3D *box, Persp3D *old_persp, Persp3D *new_persp, bool recompute_corners = false);
 
 #endif /* __SP_BOX3D_H__ */
 
diff --git a/src/persp3d.cpp b/src/persp3d.cpp
index 05a699446..1029516f7 100644
--- a/src/persp3d.cpp
+++ b/src/persp3d.cpp
@@ -529,16 +529,10 @@ persp3d_absorb(Persp3D *persp1, Persp3D *persp2) {
     //       otherwise the loop below gets confused when perspectives are reattached.
     std::list<SPBox3D *> boxes_of_persp2 = persp3d_list_of_boxes(persp2);
 
-    Inkscape::XML::Node *persp_repr = SP_OBJECT_REPR(persp1);
-    const gchar *persp_id = persp_repr->attribute("id");
-    gchar *href = g_strdup_printf("#%s", persp_id);
-
     for (std::list<SPBox3D *>::iterator i = boxes_of_persp2.begin(); i != boxes_of_persp2.end(); ++i) {
-        SP_OBJECT_REPR(*i)->setAttribute("inkscape:perspectiveID", href);
+        box3d_switch_perspectives((*i), persp2, persp1, true);
+        SP_OBJECT(*i)->updateRepr(SP_OBJECT_WRITE_EXT); // so that undo/redo can do its job properly
     }
-    g_free(href);
-
-    persp1->boxes.insert(persp1->boxes.begin(), persp2->boxes.begin(), persp2->boxes.end());
 }
 
 static void