fix slowness of getImageData() for CanvasRenderingContext2D in linux due to un-optimized format for…

src/gpu/GrContext.cpp

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrContext.h"
@@ skipping 1262 matching lines @@
     bool flipY = fGpu->readPixelsWillPayForYFlip(target, left, top,
                                                  width, height, dstConfig,
                                                  rowBytes);
     // We ignore the preferred config if it is different than our config unless it is an R/B swap.
     // In that case we'll perform an R and B swap while drawing to a scratch texture of the swapped
     // config. Then we will call readPixels on the scratch with the swapped config. The swaps during
     // the draw cancels out the fact that we call readPixels with a config that is R/B swapped from
     // dstConfig.
     GrPixelConfig readConfig = dstConfig;
     bool swapRAndB = false;
-    if (GrPixelConfigSwapRAndB(dstConfig) == fGpu->preferredReadPixelsConfig(dstConfig)) {
+    if (GrPixelConfigSwapRAndB(dstConfig) ==
+        fGpu->preferredReadPixelsConfig(dstConfig, target->config())) {
         readConfig = GrPixelConfigSwapRAndB(readConfig);
         swapRAndB = true;
     }
 
     bool unpremul = SkToBool(kUnpremul_PixelOpsFlag & flags);
 
     if (unpremul && !GrPixelConfigIs8888(dstConfig)) {
         // The unpremul flag is only allowed for these two configs.
         return false;
     }
@@ skipping 177 matching lines @@
                                         srcConfig, buffer, rowBytes, flags);
     }
 #endif
 
     // We ignore the preferred config unless it is a R/B swap of the src config. In that case
     // we will upload the original src data to a scratch texture but we will spoof it as the swapped
     // config. This scratch will then have R and B swapped. We correct for this by swapping again
     // when drawing the scratch to the dst using a conversion effect.
     bool swapRAndB = false;
     GrPixelConfig writeConfig = srcConfig;
-    if (fGpu->preferredWritePixelsConfig(srcConfig) == GrPixelConfigSwapRAndB(srcConfig)) {
+    if (GrPixelConfigSwapRAndB(srcConfig) ==
+        fGpu->preferredWritePixelsConfig(srcConfig, target->config())) {
         writeConfig = GrPixelConfigSwapRAndB(srcConfig);
         swapRAndB = true;
     }
 
     GrTextureDesc desc;
     desc.fWidth = width;
     desc.fHeight = height;
     desc.fConfig = writeConfig;
     GrAutoScratchTexture ast(this, desc);
     GrTexture* texture = ast.texture();
@@ skipping 369 matching lines @@
         return srcTexture;
     }
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 #if GR_CACHE_STATS
 void GrContext::printCacheStats() const {
     fTextureCache->printStats();
 }
 #endif