store SkAlphaType inside SkBitmap, on road to support unpremul

src/image/SkSurface_Gpu.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkSurface_Base.h"
 #include "SkImagePriv.h"
 #include "SkCanvas.h"
@@ skipping 20 matching lines @@
     typedef SkSurface_Base INHERITED;
 };
 
 SK_DEFINE_INST_COUNT(SkSurface_Gpu)
 
 ///////////////////////////////////////////////////////////////////////////////
 
 SkSurface_Gpu::SkSurface_Gpu(GrContext* ctx, const SkImage::Info& info,
                              int sampleCount)
         : INHERITED(info.fWidth, info.fHeight) {
-    bool isOpaque;
-    SkBitmap::Config config = SkImageInfoToBitmapConfig(info, &isOpaque);
+    SkBitmap::Config config = SkImageInfoToBitmapConfig(info);
 
     fDevice = SkNEW_ARGS(SkGpuDevice, (ctx, config, info.fWidth, info.fHeight, sampleCount));
 
-    if (!isOpaque) {
+    if (!SkAlphaTypeIsOpaque(info.fAlphaType)) {
         fDevice->clear(0x0);

[scroggo, 2013/10/18 21:52:41]

Not needed for this CL, obviously, but is this a candidate for calloc?

[reed1, 2013/10/21 12:24:25]

The clear() turns into a GPU command, and does not write memory (at least from
calloc's perspective). However, it is worth asking brian if we can skip this by
somehow allocating the rendertarget/texture to be automatically zero'd...

[bsalomon, 2013/10/21 13:18:04]

Not that I know of. On some OSes newly created textures are zeroed, but we can't
assume it generally.

     }
 }
 
 SkSurface_Gpu::SkSurface_Gpu(GrContext* ctx, GrRenderTarget* renderTarget)
         : INHERITED(renderTarget->width(), renderTarget->height()) {
     fDevice = SkNEW_ARGS(SkGpuDevice, (ctx, renderTarget));
 
     if (kRGB_565_GrPixelConfig != renderTarget->config()) {
         fDevice->clear(0x0);
     }
@@ skipping 54 matching lines @@
     }
 
     return SkNEW_ARGS(SkSurface_Gpu, (ctx, target));
 }
 
 SkSurface* SkSurface::NewRenderTarget(GrContext* ctx, const SkImage::Info& info, int sampleCount) {
     if (NULL == ctx) {
         return NULL;
     }
 
-    bool isOpaque;
-    SkBitmap::Config config = SkImageInfoToBitmapConfig(info, &isOpaque);
+    SkBitmap::Config config = SkImageInfoToBitmapConfig(info);
 
     GrTextureDesc desc;
     desc.fFlags = kRenderTarget_GrTextureFlagBit | kCheckAllocation_GrTextureFlagBit;
     desc.fWidth = info.fWidth;
     desc.fHeight = info.fHeight;
     desc.fConfig = SkBitmapConfig2GrPixelConfig(config);
     desc.fSampleCnt = sampleCount;
 
     SkAutoTUnref<GrTexture> tex(ctx->createUncachedTexture(desc, NULL, 0));
     if (NULL == tex) {
         return NULL;
     }
 
     return SkNEW_ARGS(SkSurface_Gpu, (ctx, tex->asRenderTarget()));
 }
+