object-snapper.cpp

 * fix snapping to clip/mask with parent transform
 * replace matrix_to_desktop call

sp-item.h
sp-item.cpp
 * improve snapping to clip/mask with parent transform
 * remove matrix_to_desktop/matrix_from_desktop
 * use desktop->doc2dt() with sp_item_i2d_affine(...)

desktop.h
desktop.cpp
 * new method: dt2doc()

selection-chemistry.cpp
 * remove awkward matrix_to_desktop(matrix_from_desktop(...)) calls

(bzr r7016)

6 files changed, 20 insertions, 46 deletions

diff --git a/src/desktop.cpp b/src/desktop.cpp
index cd39e77ae..85c53be6f 100644
--- a/src/desktop.cpp
+++ b/src/desktop.cpp
@@ -1806,6 +1806,12 @@ Geom::Matrix SPDesktop::doc2dt() const
     return _doc2dt;
 }
 
+Geom::Matrix SPDesktop::dt2doc() const
+{
+    // doc2dt is its own inverse
+    return _doc2dt;
+}
+
 Geom::Point SPDesktop::doc2dt(Geom::Point const &p) const
 {
     return p * _doc2dt;
@@ -1813,7 +1819,7 @@ Geom::Point SPDesktop::doc2dt(Geom::Point const &p) const
 
 Geom::Point SPDesktop::dt2doc(Geom::Point const &p) const
 {
-    return p * _doc2dt.inverse();
+    return p * dt2doc();
 }
 
 
diff --git a/src/desktop.h b/src/desktop.h
index ce82f4ea6..b55d9da01 100644
--- a/src/desktop.h
+++ b/src/desktop.h
@@ -310,6 +310,7 @@ struct SPDesktop : public Inkscape::UI::View::View
     Geom::Point w2d(Geom::Point const &p) const;
     Geom::Point d2w(Geom::Point const &p) const;
     Geom::Matrix doc2dt() const;
+    Geom::Matrix dt2doc() const;
     Geom::Point doc2dt(Geom::Point const &p) const;
     Geom::Point dt2doc(Geom::Point const &p) const;
 
diff --git a/src/object-snapper.cpp b/src/object-snapper.cpp
index 922c35bcb..cf10ab5e2 100644
--- a/src/object-snapper.cpp
+++ b/src/object-snapper.cpp
@@ -112,25 +112,19 @@ void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
 
             if (it == NULL || i == it->end()) {
                 SPItem *item = SP_ITEM(o);
-                Geom::Matrix transform = Geom::identity();
                 if (item) {
                     SPObject *obj = NULL;
-                    if (clip_or_mask) { // If the current item is a clipping path or a mask
-                        // then store the transformation of the clipped path or mask itself
-                        // but also take into account the additional affine of the object
-                        // being clipped / masked
-                        transform = to_2geom(item->transform) * additional_affine;
-                    } else { // cannot clip or mask more than once
+                    if (!clip_or_mask) { // cannot clip or mask more than once
                         // The current item is not a clipping path or a mask, but might
                         // still be the subject of clipping or masking itself ; if so, then
                         // we should also consider that path or mask for snapping to
                         obj = SP_OBJECT(item->clip_ref->getObject());
                         if (obj) {
-                            _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
+                            _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
                         }
                         obj = SP_OBJECT(item->mask_ref->getObject());
                         if (obj) {
-                            _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, item->transform);
+                            _findCandidates(obj, it, false, bbox_to_snap, snap_dim, true, sp_item_i2doc_affine(item));
                         }
                     }
                 }
@@ -144,7 +138,7 @@ void Inkscape::ObjectSnapper::_findCandidates(SPObject* parent,
                         // insert an additional transformation in document coordinates (code copied from sp_item_i2d_affine)
                         sp_item_invoke_bbox(item,
                             bbox_of_item,
-                            sp_item_i2doc_affine(item) * matrix_to_desktop(additional_affine, item),
+                            sp_item_i2doc_affine(item) * additional_affine * _snapmanager->getDesktop()->doc2dt(),
                             true);
                     } else {
                         sp_item_invoke_bbox(item, bbox_of_item, sp_item_i2d_affine(item), true);
diff --git a/src/selection-chemistry.cpp b/src/selection-chemistry.cpp
index b6a194d9a..92f751e85 100644
--- a/src/selection-chemistry.cpp
+++ b/src/selection-chemistry.cpp
@@ -1216,9 +1216,9 @@ void sp_selection_apply_affine(Inkscape::Selection *selection, Geom::Matrix cons
             sp_object_read_attr (SP_OBJECT (item), "transform");
 
             // calculate the matrix we need to apply to the clone to cancel its induced transform from its original
-            Geom::Matrix parent_transform = sp_item_i2doc_affine(SP_ITEM(SP_OBJECT_PARENT (item)));
-            Geom::Matrix t = parent_transform * matrix_to_desktop (matrix_from_desktop (affine, item), item) * parent_transform.inverse();
-            Geom::Matrix t_inv =parent_transform * matrix_to_desktop (matrix_from_desktop (affine.inverse(), item), item) * parent_transform.inverse();
+            Geom::Matrix parent2dt = sp_item_i2d_affine(SP_ITEM(SP_OBJECT_PARENT (item)));
+            Geom::Matrix t = parent2dt * affine * parent2dt.inverse();
+            Geom::Matrix t_inv = t.inverse();
             Geom::Matrix result = t_inv * item->transform * t;
 
             if ((prefs_parallel || prefs_unmoved) && affine.isTranslation()) {
diff --git a/src/sp-item.cpp b/src/sp-item.cpp
index 519ed2a45..fb13b1770 100644
--- a/src/sp-item.cpp
+++ b/src/sp-item.cpp
@@ -33,6 +33,7 @@
 #include "document.h"
 #include "uri.h"
 #include "inkscape.h"
+#include "desktop.h"
 #include "desktop-handles.h"
 
 #include "style.h"
@@ -978,6 +979,7 @@ void sp_item_snappoints(SPItem const *item, SnapPointsIter p, Inkscape::SnapPref
     clips_and_masks.push_back(SP_OBJECT(item->clip_ref->getObject()));
     clips_and_masks.push_back(SP_OBJECT(item->mask_ref->getObject()));
 
+    SPDesktop *desktop = inkscape_active_desktop();
     for (std::list<SPObject const *>::const_iterator o = clips_and_masks.begin(); o != clips_and_masks.end(); o++) {
         if (*o) {
             // obj is a group object, the children are the actual clippers
@@ -990,7 +992,7 @@ void sp_item_snappoints(SPItem const *item, SnapPointsIter p, Inkscape::SnapPref
                     for (std::vector<Geom::Point>::const_iterator p_orig = p_clip_or_mask.begin(); p_orig != p_clip_or_mask.end(); p_orig++) {
                         // All snappoints are in desktop coordinates, but the item's transformation is
                         // in document coordinates. Hence the awkward construction below
-                        *p = (*p_orig) * matrix_to_desktop (matrix_from_desktop (item->transform, item), item);
+                        *p = desktop->dt2doc(*p_orig) * sp_item_i2d_affine(item);
                     }
                 }
             }
@@ -1551,34 +1553,8 @@ Geom::Matrix sp_item_i2d_affine(SPItem const *item)
     g_assert(item != NULL);
     g_assert(SP_IS_ITEM(item));
 
-    Geom::Matrix const ret( sp_item_i2doc_affine(item)
-                          * Geom::Scale(1, -1)
-                          * Geom::Translate(0, sp_document_height(SP_OBJECT_DOCUMENT(item))) );
-    return ret;
-}
-
-/**
- * Converts a matrix \a m into the desktop coords of the \a item.
- * Will become a noop when we eliminate the coordinate flipping.
- */
-Geom::Matrix matrix_to_desktop(Geom::Matrix const m, SPItem const *item)
-{
-    Geom::Matrix const ret(m
-                         * Geom::Translate(0, -sp_document_height(SP_OBJECT_DOCUMENT(item)))
-                         * Geom::Scale(1, -1));
-    return ret;
-}
-
-/**
- * Converts a matrix \a m from the desktop coords of the \a item.
- * Will become a noop when we eliminate the coordinate flipping.
- */
-Geom::Matrix matrix_from_desktop(Geom::Matrix const m, SPItem const *item)
-{
-    Geom::Matrix const ret(Geom::Scale(1, -1)
-                         * Geom::Translate(0, sp_document_height(SP_OBJECT_DOCUMENT(item)))
-                         * m);
-    return ret;
+    SPDesktop *desktop = inkscape_active_desktop();
+    return sp_item_i2doc_affine(item) * desktop->doc2dt();
 }
 
 void sp_item_set_i2d_affine(SPItem *item, Geom::Matrix const &i2dt)
diff --git a/src/sp-item.h b/src/sp-item.h
index 03fec93e6..f1ec6f434 100644
--- a/src/sp-item.h
+++ b/src/sp-item.h
@@ -258,9 +258,6 @@ Geom::Matrix i2i_affine(SPObject const *src, SPObject const *dest);
 
 Geom::Matrix sp_item_i2doc_affine(SPItem const *item);
 
-Geom::Matrix matrix_to_desktop (Geom::Matrix m, SPItem const *item);
-Geom::Matrix matrix_from_desktop (Geom::Matrix m, SPItem const *item);
-
 /* fixme: - these are evil, but OK */
 
 /* Fill *TRANSFORM with the item-to-desktop transform.  See doc/coordinates.txt