don't draw unpremul alpha (yet)

src/core/SkSpriteBlitter_RGB16.cpp

 
 /*
  * Copyright 2006 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 "SkSpriteBlitter.h"
@@ skipping 303 matching lines @@
     if (paint.getMaskFilter() != NULL) { // may add cases for this
         return NULL;
     }
     if (paint.getXfermode() != NULL) { // may add cases for this
         return NULL;
     }
     if (paint.getColorFilter() != NULL) { // may add cases for this
         return NULL;
     }
 
+    const SkAlphaType at = source.alphaType();
+
     SkSpriteBlitter* blitter = NULL;
     unsigned alpha = paint.getAlpha();
 
     switch (source.colorType()) {
         case kN32_SkColorType: {
+            if (kPremul_SkAlphaType != at && kOpaque_SkAlphaType != at) {
+                break;
+            }
             blitter = allocator->createT<Sprite_D16_S32_BlitRowProc>(source);
             break;
         }
         case kARGB_4444_SkColorType:
+            if (kPremul_SkAlphaType != at && kOpaque_SkAlphaType != at) {
+                break;
+            }
             if (255 == alpha) {
                 blitter = allocator->createT<Sprite_D16_S4444_Opaque>(source);
             } else {
                 blitter = allocator->createT<Sprite_D16_S4444_Blend>(source, alpha >> 4);
             }
             break;
         case kRGB_565_SkColorType:
             if (255 == alpha) {
                 blitter = allocator->createT<Sprite_D16_S16_Opaque>(source);
             } else {
                 blitter = allocator->createT<Sprite_D16_S16_Blend>(source, alpha);
             }
             break;
         case kIndex_8_SkColorType:
+            if (kPremul_SkAlphaType != at && kOpaque_SkAlphaType != at) {
+                break;
+            }
             if (paint.isDither()) {
                 // we don't support dither yet in these special cases
                 break;
             }
             if (source.isOpaque()) {
                 if (255 == alpha) {
                     blitter = allocator->createT<Sprite_D16_SIndex8_Opaque>(source);
                 } else {
                     blitter = allocator->createT<Sprite_D16_SIndex8_Blend>(source, alpha);
                 }
             } else {
                 if (255 == alpha) {
                     blitter = allocator->createT<Sprite_D16_SIndex8A_Opaque>(source);
                 } else {
                     blitter = allocator->createT<Sprite_D16_SIndex8A_Blend>(source, alpha);
                 }
             }
             break;
         default:
             break;
     }
     return blitter;
 }