Fix cull nesting assertion.

src/core/SkCanvas.cpp

Index: src/core/SkCanvas.cpp
diff --git a/src/core/SkCanvas.cpp b/src/core/SkCanvas.cpp
index cd2065bd30daaa135d98507edd2b1f5b48c0b091..77256840fc903efb4fa82f8b8081f21858ece25f 100644
--- a/src/core/SkCanvas.cpp
+++ b/src/core/SkCanvas.cpp
@@ -1162,6 +1162,54 @@ void SkCanvas::onPopCull() {
 }
 
 /////////////////////////////////////////////////////////////////////////////
+#ifdef SK_DEBUG
+// Ensure that cull rects are properly nested in device space.

[robertphillips, 2014/03/20 12:23:56]

I think this is a bad name since it conflates validation with the actual push
operation.

[f(malita), 2014/03/20 13:30:58]

Renamed to validateAndTrack().

+void SkCanvas::validateCull(const SkRect& cull) {
+    SkRect mappedCull;
+    this->getTotalMatrix().mapRect(&mappedCull, cull);
+
+    // Take clipping into account.
+    SkIRect devClip, devCull;
+    this->getClipDeviceBounds(&devClip);
+    mappedCull.roundOut(&devCull);
+    if (!devCull.intersect(devClip))

[robertphillips, 2014/03/20 12:23:56]

{} needed

[f(malita), 2014/03/20 13:30:58]

Done.

+        devCull.setEmpty();
+
+    if (!fCullStack.isEmpty()
+        && !devCull.isEmpty()
+        && !fCullStack.top().contains(devCull)) {
+        SkDEBUGF(("Invalid cull: [%d %d %d %d] (previous cull: [%d %d %d %d])\n",
+                  devCull.x(), devCull.y(), devCull.right(), devCull.bottom(),
+                  fCullStack.top().x(), fCullStack.top().y(),
+                  fCullStack.top().right(), fCullStack.top().bottom()));
+
+#ifdef ASSERT_NESTED_CULLING

[robertphillips, 2014/03/20 12:23:56]

This assert seems odd inside this code block.

[f(malita), 2014/03/20 13:30:58]

Hmm, the intention is to provide an easy way to select error behavior. Maybe
DEBUGFAIL would not seem so strange? Done.

Or would you rather remove it completely?

+        SkASSERT(fCullStack.top().contains(devCull));
+#endif
+    }
+
+    fCullStack.push(devCull); // balanced in popCull
+}
+#endif
+
+void SkCanvas::pushCull(const SkRect& cullRect) {

[robertphillips, 2014/03/20 12:23:56]

this->

+    SkDEBUGCODE(validateCull(cullRect));
+
+    ++fCullCount;
+    this->onPushCull(cullRect);
+}
+
+void SkCanvas::popCull() {
+    SkASSERT(fCullStack.count() == fCullCount);
+
+    if (fCullCount > 0) {
+        SkDEBUGCODE(fCullStack.pop());
+        --fCullCount;
+        this->onPopCull();
+    }
+}
+
+/////////////////////////////////////////////////////////////////////////////
 
 void SkCanvas::internalDrawBitmap(const SkBitmap& bitmap,
                                 const SkMatrix& matrix, const SkPaint* paint) {