Add sanity checks against singular transforms in the drawing tree.

Fixes LP #825767.

Fixed bugs:
  - https://launchpad.net/bugs/825767

(bzr r10347.1.33)

5 files changed, 15 insertions, 38 deletions

diff --git a/src/display/drawing-item.cpp b/src/display/drawing-item.cpp
index f28894c14..1195bc56c 100644
--- a/src/display/drawing-item.cpp
+++ b/src/display/drawing-item.cpp
@@ -66,8 +66,7 @@ DrawingItem::DrawingItem(Drawing &drawing)
     , _propagate(0)
 //    , _renders_opacity(0)
     , _pick_children(0)
-{
-}
+{}
 
 DrawingItem::~DrawingItem()
 {
@@ -120,7 +119,7 @@ DrawingItem *
 DrawingItem::parent() const
 {
     // initially I wanted to return NULL if we are a clip or mask child,
-    // but the previous behavior was just to return the parent
+    // but the previous behavior was just to return the parent regardless of child type
     return _parent;
 }
 
@@ -442,6 +441,7 @@ DrawingItem::render(DrawingContext &ct, Geom::IntRect const &area, unsigned flag
 
     // If we are invisible, return immediately
     if (!_visible) return;
+    if (_ctm.isSingular(NR_EPSILON)) return;
 
     // TODO convert outline rendering to a separate virtual function
     if (outline) {
diff --git a/src/display/drawing-item.h b/src/display/drawing-item.h
index 6d142c061..abc69be02 100644
--- a/src/display/drawing-item.h
+++ b/src/display/drawing-item.h
@@ -112,7 +112,7 @@ public:
 
 protected:
     enum ChildType {
-        CHILD_ORPHAN = 0, // no parent
+        CHILD_ORPHAN = 0, // no parent - implies _parent == NULL
         CHILD_NORMAL = 1, // contained in _children of parent
         CHILD_CLIP = 2, // referenced by _clip member of parent
         CHILD_MASK = 3, // referenced by _mask member of parent
diff --git a/src/display/drawing-text.cpp b/src/display/drawing-text.cpp
index 21588cc4f..5e6396df1 100644
--- a/src/display/drawing-text.cpp
+++ b/src/display/drawing-text.cpp
@@ -23,7 +23,6 @@ namespace Inkscape {
 
 DrawingGlyphs::DrawingGlyphs(Drawing &drawing)
     : DrawingItem(drawing)
-    , _glyph_transform(NULL)
     , _font(NULL)
     , _glyph(0)
 {}
@@ -34,7 +33,6 @@ DrawingGlyphs::~DrawingGlyphs()
         _font->Unref();
         _font = NULL;
     }
-    delete _glyph_transform;
 }
 
 void
@@ -42,12 +40,7 @@ DrawingGlyphs::setGlyph(font_instance *font, int glyph, Geom::Affine const &tran
 {
     _markForRendering();
 
-    if (trans.isIdentity()) {
-        delete _glyph_transform; // delete NULL; is safe
-        _glyph_transform = NULL;
-    } else {
-        _glyph_transform = new Geom::Affine(trans);
-    }
+    setTransform(trans);
 
     if (font) font->Ref();
     if (_font) _font->Unref();
@@ -70,12 +63,7 @@ DrawingGlyphs::_updateItem(Geom::IntRect const &area, UpdateContext const &ctx,
         return STATE_ALL;
     }
 
-    Geom::OptRect b;
-    Geom::Affine t = _glyph_transform ? *_glyph_transform * ctx.ctm : ctx.ctm;
-    _x = t[4];
-    _y = t[5];
-
-    b = bounds_exact_transformed(*_font->PathVector(_glyph), t);
+    Geom::OptRect b = bounds_exact_transformed(*_font->PathVector(_glyph), ctx.ctm);
     if (b && ggroup->_nrstyle.stroke.type != NRStyle::PAINT_NONE) {
         float width, scale;
         scale = ctx.ctm.descrim();
@@ -165,21 +153,19 @@ void
 DrawingText::_renderItem(DrawingContext &ct, Geom::IntRect const &area, unsigned flags)
 {
     if (_drawing.outline()) {
-        DrawingContext::Save save(ct);
         guint32 rgba = _drawing.outlinecolor;
+        Inkscape::DrawingContext::Save save(ct);
         ct.setSource(rgba);
         ct.setTolerance(1.25); // low quality, but good enough for outline mode
-        ct.newPath();
-        ct.transform(_ctm);
 
         for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
             DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&*i);
             if (!g) throw InvalidItemException();
 
             Inkscape::DrawingContext::Save save(ct);
-            if (g->_glyph_transform) {
-                ct.transform(*g->_glyph_transform);
-            }
+            // skip glpyhs with singular transforms
+            if (g->_ctm.isSingular()) continue;
+            ct.transform(g->_ctm);
             ct.path(*g->_font->PathVector(g->_glyph));
             ct.fill();
         }
@@ -189,9 +175,6 @@ DrawingText::_renderItem(DrawingContext &ct, Geom::IntRect const &area, unsigned
     // NOTE: this is very similar to drawing-shape.cpp; the only difference is in path feeding
     bool has_stroke, has_fill;
 
-    Inkscape::DrawingContext::Save save(ct);
-    ct.transform(_ctm);
-
     has_fill   = _nrstyle.prepareFill(ct, _paintbox);
     has_stroke = _nrstyle.prepareStroke(ct, _paintbox);
 
@@ -201,9 +184,8 @@ DrawingText::_renderItem(DrawingContext &ct, Geom::IntRect const &area, unsigned
             if (!g) throw InvalidItemException();
 
             Inkscape::DrawingContext::Save save(ct);
-            if (g->_glyph_transform) {
-                ct.transform(*g->_glyph_transform);
-            }
+            if (g->_ctm.isSingular()) continue;
+            ct.transform(g->_ctm);
             ct.path(*g->_font->PathVector(g->_glyph));
         }
 
@@ -232,16 +214,13 @@ DrawingText::_clipItem(DrawingContext &ct, Geom::IntRect const &area)
             ct.setFillRule(CAIRO_FILL_RULE_WINDING);
         }
     }
-    ct.transform(_ctm);
 
     for (ChildrenList::iterator i = _children.begin(); i != _children.end(); ++i) {
         DrawingGlyphs *g = dynamic_cast<DrawingGlyphs *>(&*i);
         if (!g) throw InvalidItemException();
 
         Inkscape::DrawingContext::Save save(ct);
-        if (g->_glyph_transform) {
-            ct.transform(*g->_glyph_transform);
-        }
+        ct.transform(g->_ctm);
         ct.path(*g->_font->PathVector(g->_glyph));
     }
     ct.fill();
diff --git a/src/display/drawing-text.h b/src/display/drawing-text.h
index faa33057c..07962365c 100644
--- a/src/display/drawing-text.h
+++ b/src/display/drawing-text.h
@@ -34,10 +34,8 @@ protected:
                                  unsigned flags, unsigned reset);
     virtual DrawingItem *_pickItem(Geom::Point const &p, double delta, unsigned flags);
 
-    Geom::Affine *_glyph_transform;
     font_instance *_font;
     int _glyph;
-    float _x, _y;
 
     friend class DrawingText;
 };
diff --git a/src/display/nr-filter-gaussian.cpp b/src/display/nr-filter-gaussian.cpp
index 988a8479e..19cf51772 100644
--- a/src/display/nr-filter-gaussian.cpp
+++ b/src/display/nr-filter-gaussian.cpp
@@ -511,7 +511,7 @@ gaussian_pass_IIR(Geom::Dim2 d, double deviation, cairo_surface_t *src, cairo_su
             w, h, b, M, tmpdata, num_threads);
         break;
     default:
-        assert(false);
+        g_warning("gaussian_pass_IIR: unsupported image format");
     };
 }
 
@@ -544,7 +544,7 @@ gaussian_pass_FIR(Geom::Dim2 d, double deviation, cairo_surface_t *src, cairo_su
             w, h, &kernel[0], scr_len, num_threads);
         break;
     default:
-        assert(false);
+        g_warning("gaussian_pass_FIR: unsupported image format");
     };
 }