Prevent picture recording from over optimizing the culling of clips.

src/core/SkPictureRecord.cpp

Index: src/core/SkPictureRecord.cpp
diff --git a/src/core/SkPictureRecord.cpp b/src/core/SkPictureRecord.cpp
index 915736373d0aba5df1ac3116a09607984a006811..192c81eb71f87457185b433de2d23fabd1e250a8 100644
--- a/src/core/SkPictureRecord.cpp
+++ b/src/core/SkPictureRecord.cpp
@@ -24,6 +24,7 @@ enum {
 // A lot of basic types get stored as a uint32_t: bools, ints, paint indices, etc.
 static int const kUInt32Size = 4;
 
+static const uint32_t kSaveSize = 2 * kUInt32Size;
 static const uint32_t kSaveLayerNoBoundsSize = 4 * kUInt32Size;
 static const uint32_t kSaveLayerWithBoundsSize = 4 * kUInt32Size + sizeof(SkRect);
 
@@ -149,6 +150,8 @@ int SkPictureRecord::save(SaveFlags flags) {
 
     // op + flags
     uint32_t size = 2 * kUInt32Size;
+    SkASSERT(kSaveSize == size);
+
     uint32_t initialOffset = this->addDraw(SAVE, &size);
     addInt(flags);
 
@@ -469,6 +472,7 @@ static bool collapse_save_clip_restore(SkWriter32* writer, int32_t offset,
     while (offset > 0) {
         offset = *writer->peek32(offset);
     }

[robertphillips, 2013/08/13 13:45:55]

What is this?

+    kSaveLayerNoBoundsSize;
 
     // now offset points to a save
     offset = -offset;
@@ -479,6 +483,16 @@ static bool collapse_save_clip_restore(SkWriter32* writer, int32_t offset,
         return false;
     }
     SkASSERT(SAVE == op);
+    SkASSERT(kSaveSize == opSize);
+
+    // get the save flag (last 4-bytes of the space allocated for the opSize)
+    SkCanvas::SaveFlags saveFlag = (SkCanvas::SaveFlags) *writer->peek32(offset+4);
+    if (SkCanvas::kMatrixClip_SaveFlag != (SkCanvas::kMatrixClip_SaveFlag & saveFlag)) {
+        // This function's optimization is only correct for kMatrixClip style saves.
+        // TODO: set checkMatrix & checkClip booleans here and then check for the
+        // offending operations in the following loop.
+        return false;
+    }
 
     // Walk forward until we get back to either a draw-verb (abort) or we hit
     // our restore (success).