Save a bitmap copy when advancing to dependent GIF and WebP animation frames

third_party/WebKit/Source/platform/graphics/gpu/WebGLImageConversion.cpp

 // Copyright 2014 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 "platform/graphics/gpu/WebGLImageConversion.h"
 
 #include "platform/CheckedInt.h"
 #include "platform/graphics/ImageObserver.h"
 #include "platform/graphics/cpu/arm/WebGLImageConversionNEON.h"
 #include "platform/graphics/cpu/x86/WebGLImageConversionSSE.h"
@@ skipping 1906 matching lines @@
             unpack<SrcFormat>(srcRowStart, reinterpret_cast<IntermType*>(m_unpackedIntermediateSrcData.get()), m_width);
             pack<DstFormat, alphaOp>(reinterpret_cast<IntermType*>(m_unpackedIntermediateSrcData.get()), dstRowStart, m_width);
             srcRowStart += srcStrideInElements;
             dstRowStart += dstStrideInElements;
         }
     }
     m_success = true;
     return;
 }
 
-bool frameIsValid(const SkBitmap& frameBitmap)
-{
-    return !frameBitmap.isNull()
-        && !frameBitmap.empty()
-        && frameBitmap.isImmutable()
-        && frameBitmap.colorType() == kN32_SkColorType;
-}
-
 } // anonymous namespace
 
 WebGLImageConversion::PixelStoreParams::PixelStoreParams()
     : alignment(4)
     , rowLength(0)
     , imageHeight(0)
     , skipPixels(0)
     , skipRows(0)
     , skipImages(0)
 {
@@ skipping 198 matching lines @@
         // Attempt to get raw unpremultiplied image data.
         std::unique_ptr<ImageDecoder> decoder(ImageDecoder::create(
             ImageDecoder::determineImageType(*(m_image->data())), ImageDecoder::AlphaNotPremultiplied,
             ignoreGammaAndColorProfile ? ImageDecoder::GammaAndColorProfileIgnored : ImageDecoder::GammaAndColorProfileApplied));
         if (!decoder)
             return;
         decoder->setData(m_image->data(), true);
         if (!decoder->frameCount())
             return;
         ImageFrame* frame = decoder->frameBufferAtIndex(0);
+
+        // TODO(fmalita): Partial frames are not supported currently: only fully
+        // decoded frames make it through.  We could potentially relax this and
+        // allow ImageFrame::finalizePixelsAndGetImage to make a copy.

[Peter Kasting, 2016/08/30 06:59:40]

Isn't it already allowed to make a copy?  Does this comment mean something like
"We could potentially relax this if we decided it was OK for the conversion from
bitmap to image to make a copy in this case."?

[aleksandar.stojiljkovic, 2016/09/21 20:56:57]

By early return if "frame->getStatus() != ImageFrame::FrameComplete" we ensure
that there is no copy done by finalizePixelsAndGetImage. This means that if
don't want to prevent copy by finalizePixelsAndGetImage, we can relax the check
to e.g.:
if (!frame)
    return;

         if (!frame || frame->getStatus() != ImageFrame::FrameComplete)
             return;
         hasAlpha = frame->hasAlpha();
         SkBitmap bitmap = frame->bitmap();
-        if (!frameIsValid(bitmap))
-            return;
 
-        // TODO(fmalita): Partial frames are not supported currently: frameIsValid ensures that
-        // only immutable/fully decoded frames make it through.  We could potentially relax this
-        // and allow SkImage::NewFromBitmap to make a copy.
-        ASSERT(bitmap.isImmutable());
-        skiaImage = fromSkSp(SkImage::MakeFromBitmap(bitmap));
+        DCHECK_EQ(bitmap.colorType(), kN32_SkColorType);

[Peter Kasting, 2016/08/30 06:59:40]

Same comment as in ImageBitmap.cpp.

[aleksandar.stojiljkovic, 2016/09/21 20:56:57]

Done.

+        skiaImage = frame->finalizePixelsAndGetImage();
         info = bitmap.info();
 
         if (hasAlpha && premultiplyAlpha)
             m_alphaOp = AlphaDoPremultiply;
     } else if (!premultiplyAlpha && hasAlpha) {
         // 1. For texImage2D with HTMLVideoElment input, assume no PremultiplyAlpha had been applied and the alpha value for each pixel is 0xFF
         // which is true at present and may be changed in the future and needs adjustment accordingly.
         // 2. For texImage2D with HTMLCanvasElement input in which Alpha is already Premultiplied in this port,
         // do AlphaDoUnmultiply if UNPACK_PREMULTIPLY_ALPHA_WEBGL is set to false.
         if (m_imageHtmlDomSource != HtmlDomVideo)
@@ skipping 230 matching lines @@
     }
 
     FormatConverter converter(width, height, sourceData, destinationData, srcStride, dstStride);
     converter.convert(sourceDataFormat, dstDataFormat, alphaOp);
     if (!converter.Success())
         return false;
     return true;
 }
 
 } // namespace blink