When the CTM has perspective the back-project method in quickRejectY goes haywire.
R=reed@google.com
Author: robertphillips@google.com
Review URL: https://codereview.chromium.org/166873004
git-svn-id: http://skia.googlecode.com/svn/trunk@13460 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/include/core/SkCanvas.h b/include/core/SkCanvas.h
index ef2f0b9..4cd7adb 100644
--- a/include/core/SkCanvas.h
+++ b/include/core/SkCanvas.h
@@ -488,6 +488,20 @@
*/
bool quickRejectY(SkScalar top, SkScalar bottom) const {
SkASSERT(top <= bottom);
+
+#ifndef SK_WILL_NEVER_DRAW_PERSPECTIVE_TEXT
+ // TODO: add a hasPerspective method similar to getLocalClipBounds. This
+ // would cache the SkMatrix::hasPerspective result. Alternatively, have
+ // the MC stack just set a hasPerspective boolean as it is updated.
+ if (this->getTotalMatrix().hasPerspective()) {
+ // TODO: consider implementing some half-plane test between the
+ // two Y planes and the device-bounds (i.e., project the top and
+ // bottom Y planes and then determine if the clip bounds is completely
+ // outside either one).
+ return false;
+ }
+#endif
+
const SkRect& clipR = this->getLocalClipBounds();
// In the case where the clip is empty and we are provided with a
// negative top and positive bottom parameter then this test will return