Fix clip expansion in SkPictureRecord::recordRestoreOffsetPlaceholder()

src/core/SkPictureRecord.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "SkPictureRecord.h"
 #include "SkTSearch.h"
 #include "SkPixelRef.h"
@@ skipping 697 matching lines @@
 void SkPictureRecord::endRecording() {
     SkASSERT(kNoInitialSave != fInitialSaveCount);
     this->restoreToCount(fInitialSaveCount);
 }
 
 void SkPictureRecord::recordRestoreOffsetPlaceholder(SkRegion::Op op) {
     if (fRestoreOffsetStack.isEmpty()) {
         return;
     }
 
+    // The RestoreOffset field is initially filled with a placeholder
+    // value that points to the offset of the previous RestoreOffset
+    // in the current stack level, thus forming a linked list so that
+    // the restore offsets can be filled in when the corresponding
+    // restore command is recorded.
+    int32_t prevOffset = fRestoreOffsetStack.top();
+
     if (regionOpExpands(op)) {
         // Run back through any previous clip ops, and mark their offset to
         // be 0, disabling their ability to trigger a jump-to-restore, otherwise
         // they could hide this clips ability to expand the clip (i.e. go from
         // empty to non-empty).
         fillRestoreOffsetPlaceholdersForCurrentStackLevel(0);
+

[robertphillips, 2013/08/27 15:08:56]

Reset the pointer back to the previous clip so that ...

+        // Avoid linking to the previous RestoreOffset - otherwise a
+        // subsequent restore() will simply overwrite the offsets we just
+        // cleared.
+        prevOffset = 0;
     }
 
     size_t offset = fWriter.size();
-    // The RestoreOffset field is initially filled with a placeholder
-    // value that points to the offset of the previous RestoreOffset
-    // in the current stack level, thus forming a linked list so that
-    // the restore offsets can be filled in when the corresponding
-    // restore command is recorded.
-    addInt(fRestoreOffsetStack.top());
+    addInt(prevOffset);
     fRestoreOffsetStack.top() = offset;
 }
 
 bool SkPictureRecord::clipRect(const SkRect& rect, SkRegion::Op op, bool doAA) {
     // id + rect + clip params
     uint32_t size = 1 * kUInt32Size + sizeof(rect) + 1 * kUInt32Size;
     // recordRestoreOffsetPlaceholder doesn't always write an offset
     if (!fRestoreOffsetStack.isEmpty()) {
         // + restore offset
         size += kUInt32Size;
@@ skipping 740 matching lines @@
 void SkPictureRecord::validateRegions() const {
     int count = fRegions.count();
     SkASSERT((unsigned) count < 0x1000);
     for (int index = 0; index < count; index++) {
         const SkFlatData* region = fRegions[index];
         SkASSERT(region);
 //        region->validate();
     }
 }
 #endif