Always clear dest in SkBitmap::copyTo's draw path

src/core/SkBitmap.cpp

 
 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "SkBitmap.h"
@@ skipping 1101 matching lines @@
         for (int y = 0; y < src->height(); ++y) {
             SkPMColor16* SK_RESTRICT dstRow = (SkPMColor16*) tmpDst.getAddr16(0, y);
             SkPMColor* SK_RESTRICT srcRow = (SkPMColor*) src->getAddr32(0, y);
             DITHER_4444_SCAN(y);
             for (int x = 0; x < src->width(); ++x) {
                 dstRow[x] = SkDitherARGB32To4444(srcRow[x],
                                                  DITHER_VALUE(x));
             }
         }
     } else {
-        // if the src has alpha, we have to clear the dst first
-        if (!src->isOpaque()) {
-            tmpDst.eraseColor(SK_ColorTRANSPARENT);
-        }
+        // Always clear the dest in case one of the blitters accesses it
+        tmpDst.eraseColor(SK_ColorTRANSPARENT);

[reed1, 2013/10/10 15:16:38]

// TODO: switch the allocation of tmpDst to call sk_calloc_throw

[robertphillips, 2013/10/10 15:48:34]

Done.

 
         SkCanvas canvas(tmpDst);
         SkPaint  paint;
 
         paint.setDither(true);
         canvas.drawBitmap(*src, 0, 0, &paint);
     }
 
     tmpDst.setIsOpaque(src->isOpaque());
 
@@ skipping 558 matching lines @@
         if (NULL != uri) {
             str->appendf(" uri:\"%s\"", uri);
         } else {
             str->appendf(" pixelref:%p", pr);
         }
     }
 
     str->append(")");
 }
 #endif