Fix for saveLayer() with filters vs. the BBox Hierarchy.

src/core/SkBBoxRecord.cpp

Index: src/core/SkBBoxRecord.cpp
diff --git a/src/core/SkBBoxRecord.cpp b/src/core/SkBBoxRecord.cpp
index a40ea8ba0d27e531e997dfaa922488e0c19433a3..3670f9145e8bcf7581dea8d4c7f6ff98ccab3ecc 100644
--- a/src/core/SkBBoxRecord.cpp
+++ b/src/core/SkBBoxRecord.cpp
@@ -8,6 +8,13 @@
 
 #include "SkBBoxRecord.h"
 
+SkBBoxRecord::~SkBBoxRecord() {
+    while (!fSaveStack.empty()) {
+        delete fSaveStack.top();
+        fSaveStack.pop();
+    }
+}
+
 void SkBBoxRecord::drawOval(const SkRect& rect, const SkPaint& paint) {
     if (this->transformBounds(rect, &paint)) {
         INHERITED::drawOval(rect, paint);
@@ -287,6 +294,26 @@ void SkBBoxRecord::onDrawPicture(const SkPicture* picture) {
     }
 }
 
+void SkBBoxRecord::willSave() {
+    fSaveStack.push(NULL);
+    this->INHERITED::willSave();
+}
+
+SkCanvas::SaveLayerStrategy SkBBoxRecord::willSaveLayer(const SkRect* bounds,
+                                                        const SkPaint* paint,
+                                                        SaveFlags flags) {
+    // Image filters can affect the effective bounds of primitives drawn inside saveLayer().
+    // Copy the paint so we can compute the modified bounds in transformBounds().
+    fSaveStack.push(paint && paint->getImageFilter() ? new SkPaint(*paint) : NULL);
+    return this->INHERITED::willSaveLayer(bounds, paint, flags);
+}
+
+void SkBBoxRecord::willRestore() {
+    delete fSaveStack.top();
+    fSaveStack.pop();
+    this->INHERITED::willRestore();
+}
+
 bool SkBBoxRecord::transformBounds(const SkRect& bounds, const SkPaint* paint) {
     SkRect outBounds = bounds;
     outBounds.sort();
@@ -305,6 +332,14 @@ bool SkBBoxRecord::transformBounds(const SkRect& bounds, const SkPaint* paint) {
         }
     }
 

[robertphillips, 2014/07/13 18:57:29]

I don't think SkTDStack::index does what you want! If the number of elements in
your stack exceeds the amount cached in each SkTDStack::Rec object an assert
will fire (and sorrow will ensue). Just running:

render_pictures -r desk_pokemonwiki.skp --mode tile 256 256 --bbh grid 256 256

should reproduce the problem

[Stephen White, 2014/07/14 15:35:13]

Yeah; looks like SkTDStack is hopelessly broken. Switched to using SkTDArray for
now.

+    for (int i = fSaveStack.count() - 1; i >= 0; --i) {
+        const SkPaint* paint = fSaveStack.index(i);
+        if (paint && paint->canComputeFastBounds()) {
+            SkRect temp;
+            outBounds = paint->computeFastBounds(outBounds, &temp);
+        }
+    }
+
     if (!outBounds.isEmpty() && !this->quickReject(outBounds)) {
         this->getTotalMatrix().mapRect(&outBounds);
         this->handleBBox(outBounds);