handle degenerate call to blitAntiRect

Bug: skia:8043
Change-Id: Ief3653a748a1e82bd5ca9df3dd7743797e0160e8
Reviewed-on: https://skia-review.googlesource.com/132086
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>

2 files changed, 13 insertions, 8 deletions

diff --git a/src/core/SkAAClip.cpp b/src/core/SkAAClip.cpp
index b22b8ebebb..78c73931fe 100644
--- a/src/core/SkAAClip.cpp
+++ b/src/core/SkAAClip.cpp
@@ -1065,13 +1065,16 @@ public:
             this->addRun(x + width, y, rightAlpha, 1);
         }
 
-        // we assume the rect must be all we'll see for these scanlines
-        // so we ensure our row goes all the way to our right
-        this->flushRowH(fCurrRow);
+        // if we never called addRun, we might not have a fCurrRow yet
+        if (fCurrRow) {
+            // we assume the rect must be all we'll see for these scanlines
+            // so we ensure our row goes all the way to our right
+            this->flushRowH(fCurrRow);
 
-        y -= fBounds.fTop;
-        SkASSERT(y == fCurrRow->fY);
-        fCurrRow->fY = y + height - 1;
+            y -= fBounds.fTop;
+            SkASSERT(y == fCurrRow->fY);
+            fCurrRow->fY = y + height - 1;
+        }
     }
 
     bool finish(SkAAClip* target) {
diff --git a/src/core/SkBlitter.cpp b/src/core/SkBlitter.cpp
index 5cf8147019..9c72302876 100644
--- a/src/core/SkBlitter.cpp
+++ b/src/core/SkBlitter.cpp
@@ -1205,8 +1205,10 @@ void SkRectClipCheckBlitter::blitAntiRect(int x, int y, int width, int height,
                                      SkAlpha leftAlpha, SkAlpha rightAlpha) {
     bool skipLeft = !leftAlpha;
     bool skipRight = !rightAlpha;
-    SkASSERT(fClipRect.contains(SkIRect::MakeXYWH(x + skipLeft, y,
-            width + 2 - skipRight - skipLeft, height)));
+#ifdef SK_DEBUG
+    SkIRect r = SkIRect::MakeXYWH(x + skipLeft, y, width + 2 - skipRight - skipLeft, height);
+    SkASSERT(r.isEmpty() || fClipRect.contains(r));
+#endif
     fBlitter->blitAntiRect(x, y, width, height, leftAlpha, rightAlpha);
 }