Optionally clear PlatformCanvas instances.

skia/ext/bitmap_platform_device_android.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "skia/ext/bitmap_platform_device_android.h"
 
 namespace skia {
 
 BitmapPlatformDevice* BitmapPlatformDevice::Create(int width, int height,
                                                    bool is_opaque) {
   SkBitmap bitmap;
   bitmap.setConfig(SkBitmap::kARGB_8888_Config, width, height);
   if (bitmap.allocPixels()) {
     bitmap.setIsOpaque(is_opaque);
     // Follow the logic in SkCanvas::createDevice(), initialize the bitmap if it
     // is not opaque.
     if (!is_opaque)
       bitmap.eraseARGB(0, 0, 0, 0);
     return new BitmapPlatformDevice(bitmap);
   }
   return NULL;
 }
 
+BitmapPlatformDevice* BitmapPlatformDevice::CreateAndClear(int width,
+                                                           int height,
+                                                           bool is_opaque) {
+  BitmapPlatformDevice* device = Create(width, height, is_opaque);
+  if (!is_opaque)
+    device->accessBitmap(true).eraseARGB(0, 0, 0, 0);
+  return device;
+}
+
 BitmapPlatformDevice* BitmapPlatformDevice::Create(int width, int height,
                                                    bool is_opaque,
                                                    uint8_t* data) {
   SkBitmap bitmap;
   bitmap.setConfig(SkBitmap::kARGB_8888_Config, width, height);
   if (data) {
     bitmap.setPixels(data);
   } else {

[msw, 2012/03/16 07:13:22]

nit: this could now be "else if (!bitmap...)" and you can drop the braces.

[Jeff Timanus, 2012/03/16 15:52:42]

Done.

     if (!bitmap.allocPixels())
       return NULL;
-    // Follow the logic in SkCanvas::createDevice(), initialize the bitmap if it
-    // is not opaque.
-    if (!is_opaque)
-      bitmap.eraseARGB(0, 0, 0, 0);
   }
   bitmap.setIsOpaque(is_opaque);
   return new BitmapPlatformDevice(bitmap);
 }
 
 BitmapPlatformDevice::BitmapPlatformDevice(const SkBitmap& bitmap)
     : SkDevice(bitmap) {
   SetPlatformDevice(this, this);
 }
 
@@ skipping 13 matching lines @@
   return accessBitmap(true).getPixels();
 }
 
 void BitmapPlatformDevice::DrawToNativeContext(
     PlatformSurface surface, int x, int y, const PlatformRect* src_rect) {
   // Should never be called on Android.
   SkASSERT(false);
 }
 
 }  // namespace skia