Bug 1123019 - In DrawTargetTiled::StrokeRect and StrokeLine, skip tiles that don't intersect the stroke. r=jrmuizel

gfx/2d/DrawTargetTiled.cpp

@@ -3,11 +3,9 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#define _USE_MATH_DEFINES
-#include <cmath>
-
 #include "DrawTargetTiled.h"
 #include "Logging.h"
+#include "PathHelpers.h"
 
 using namespace std;
 
@@ -107,8 +105,6 @@ TILED_COMMAND(Flush)
 TILED_COMMAND4(DrawFilter, FilterNode*, const Rect&, const Point&, const DrawOptions&)
 TILED_COMMAND1(ClearRect, const Rect&)
 TILED_COMMAND4(MaskSurface, const Pattern&, SourceSurface*, Point, const DrawOptions&)
-TILED_COMMAND4(StrokeRect, const Rect&, const Pattern&, const StrokeOptions&, const DrawOptions&)
-TILED_COMMAND5(StrokeLine, const Point&, const Point&, const Pattern&, const StrokeOptions&, const DrawOptions&)
 TILED_COMMAND5(FillGlyphs, ScaledFont*, const GlyphBuffer&, const Pattern&, const DrawOptions&, const GlyphRenderingOptions*)
 TILED_COMMAND3(Mask, const Pattern&, const Pattern&, const DrawOptions&)
 
@@ -232,40 +228,12 @@ DrawTargetTiled::FillRect(const Rect& aRect, const Pattern& aPattern, const Draw
   }
 }
 
-// The logic for this comes from _cairo_stroke_style_max_distance_from_path
-static Rect
-PathExtentsToMaxStrokeExtents(const StrokeOptions &aStrokeOptions,
-                              const Rect &aRect,
-                              const Matrix &aTransform)
-{
-  double styleExpansionFactor = 0.5f;
-
-  if (aStrokeOptions.mLineCap == CapStyle::SQUARE) {
-    styleExpansionFactor = M_SQRT1_2;
-  }
-
-  if (aStrokeOptions.mLineJoin == JoinStyle::MITER &&
-      styleExpansionFactor < M_SQRT2 * aStrokeOptions.mMiterLimit) {
-    styleExpansionFactor = M_SQRT2 * aStrokeOptions.mMiterLimit;
-  }
-
-  styleExpansionFactor *= aStrokeOptions.mLineWidth;
-
-  double dx = styleExpansionFactor * hypot(aTransform._11, aTransform._21);
-  double dy = styleExpansionFactor * hypot(aTransform._22, aTransform._12);
-
-  Rect result = aRect;
-  result.Inflate(dx, dy);
-  return result;
-}
-
 void
 DrawTargetTiled::Stroke(const Path* aPath, const Pattern& aPattern, const StrokeOptions& aStrokeOptions, const DrawOptions& aDrawOptions)
 {
   // Approximate the stroke extents, since Path::GetStrokeExtents can be slow
-  Rect deviceRect = PathExtentsToMaxStrokeExtents(aStrokeOptions,
+  Rect deviceRect = aPath->GetBounds(mTransform);
-                                                 aPath->GetBounds(mTransform),
+  deviceRect.Inflate(MaxStrokeExtents(aStrokeOptions, mTransform));
-                                                 mTransform);
   for (size_t i = 0; i < mTiles.size(); i++) {
     if (!mTiles[i].mClippedOut &&
         deviceRect.Intersects(Rect(mTiles[i].mTileOrigin.x,
@@ -277,6 +245,51 @@ DrawTargetTiled::Stroke(const Path* aPath, const Pattern& aPattern, const Stroke
   }
 }
 
+void
+DrawTargetTiled::StrokeRect(const Rect& aRect, const Pattern& aPattern, const StrokeOptions &aStrokeOptions, const DrawOptions& aDrawOptions)
+{
+  Rect deviceRect = mTransform.TransformBounds(aRect);
+  Margin strokeMargin = MaxStrokeExtents(aStrokeOptions, mTransform);
+  Rect outerRect = deviceRect;
+  outerRect.Inflate(strokeMargin);
+  Rect innerRect;
+  if (mTransform.IsRectilinear()) {
+    // If rects are mapped to rects, we can compute the inner rect
+    // of the stroked rect.
+    innerRect = deviceRect;
+    innerRect.Deflate(strokeMargin);
+  }
+  for (size_t i = 0; i < mTiles.size(); i++) {
+    if (mTiles[i].mClippedOut) {
+      continue;
+    }
+    Rect tileRect(mTiles[i].mTileOrigin.x,
+                  mTiles[i].mTileOrigin.y,
+                  mTiles[i].mDrawTarget->GetSize().width,
+                  mTiles[i].mDrawTarget->GetSize().height);
+    if (outerRect.Intersects(tileRect) && !innerRect.Contains(tileRect)) {
+      mTiles[i].mDrawTarget->StrokeRect(aRect, aPattern, aStrokeOptions, aDrawOptions);
+    }
+  }
+}
+
+void
+DrawTargetTiled::StrokeLine(const Point& aStart, const Point& aEnd, const Pattern& aPattern, const StrokeOptions &aStrokeOptions, const DrawOptions& aDrawOptions)
+{
+  Rect lineBounds = Rect(aStart, Size()).UnionEdges(Rect(aEnd, Size()));
+  Rect deviceRect = mTransform.TransformBounds(lineBounds);
+  deviceRect.Inflate(MaxStrokeExtents(aStrokeOptions, mTransform));
+  for (size_t i = 0; i < mTiles.size(); i++) {
+    if (!mTiles[i].mClippedOut &&
+        deviceRect.Intersects(Rect(mTiles[i].mTileOrigin.x,
+                                   mTiles[i].mTileOrigin.y,
+                                   mTiles[i].mDrawTarget->GetSize().width,
+                                   mTiles[i].mDrawTarget->GetSize().height))) {
+      mTiles[i].mDrawTarget->StrokeLine(aStart, aEnd, aPattern, aStrokeOptions, aDrawOptions);
+    }
+  }
+}
+
 void
 DrawTargetTiled::Fill(const Path* aPath, const Pattern& aPattern, const DrawOptions& aDrawOptions)
 {

gfx/2d/PathHelpers.cpp

@@ -3,6 +3,9 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#define _USE_MATH_DEFINES
+#include <cmath>
+
 #include "PathHelpers.h"
 
 namespace mozilla {
@@ -238,6 +241,29 @@ StrokeSnappedEdgesOfRect(const Rect& aRect, DrawTarget& aDrawTarget,
   aDrawTarget.StrokeLine(p1, p2, aColor, aStrokeOptions);
 }
 
+// The logic for this comes from _cairo_stroke_style_max_distance_from_path
+Margin
+MaxStrokeExtents(const StrokeOptions& aStrokeOptions,
+                 const Matrix& aTransform)
+{
+  double styleExpansionFactor = 0.5f;
+
+  if (aStrokeOptions.mLineCap == CapStyle::SQUARE) {
+    styleExpansionFactor = M_SQRT1_2;
+  }
+
+  if (aStrokeOptions.mLineJoin == JoinStyle::MITER &&
+      styleExpansionFactor < M_SQRT2 * aStrokeOptions.mMiterLimit) {
+    styleExpansionFactor = M_SQRT2 * aStrokeOptions.mMiterLimit;
+  }
+
+  styleExpansionFactor *= aStrokeOptions.mLineWidth;
+
+  double dx = styleExpansionFactor * hypot(aTransform._11, aTransform._21);
+  double dy = styleExpansionFactor * hypot(aTransform._22, aTransform._12);
+  return Margin(dy, dx, dy, dx);
+}
+
 } // namespace gfx
 } // namespace mozilla
 

gfx/2d/PathHelpers.h

@@ -283,6 +283,16 @@ GFX2D_API void StrokeSnappedEdgesOfRect(const Rect& aRect,
                                         const ColorPattern& aColor,
                                         const StrokeOptions& aStrokeOptions);
 
+/**
+ * Return the margin, in device space, by which a stroke can extend beyond the
+ * rendered shape.
+ * @param  aStrokeOptions The stroke options that the stroke is drawn with.
+ * @param  aTransform     The user space to device space transform.
+ * @return                The stroke margin.
+ */
+GFX2D_API Margin MaxStrokeExtents(const StrokeOptions& aStrokeOptions,
+                                  const Matrix& aTransform);
+
 extern UserDataKey sDisablePixelSnapping;
 
 /**

gfx/2d/moz.build

@@ -109,6 +109,7 @@ UNIFIED_SOURCES += [
     'DrawTargetCapture.cpp',
     'DrawTargetDual.cpp',
     'DrawTargetRecording.cpp',
+    'DrawTargetTiled.cpp',
     'Factory.cpp',
     'FilterNodeSoftware.cpp',
     'FilterProcessing.cpp',
@@ -117,7 +118,6 @@ UNIFIED_SOURCES += [
     'Matrix.cpp',
     'Path.cpp',
     'PathCairo.cpp',
-    'PathHelpers.cpp',
     'PathRecording.cpp',
     'RecordedEvent.cpp',
     'Scale.cpp',
@@ -128,7 +128,7 @@ UNIFIED_SOURCES += [
 ]
 
 SOURCES += [
-    'DrawTargetTiled.cpp',
+    'PathHelpers.cpp', # Uses _USE_MATH_DEFINES
 ]
 
 if CONFIG['MOZ_WIDGET_TOOLKIT'] == 'cocoa':