Propagate the decoder frame premul info to SkBitmap

third_party/WebKit/Source/platform/image-decoders/gif/GIFImageDecoderTest.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 498 matching lines @@
     EXPECT_EQ(cAnimationLoopOnce, decoder->repetitionCount()); // Default value before decode.
 
     for (size_t i = 0; i < decoder->frameCount(); ++i) {
         ImageFrame* frame = decoder->frameBufferAtIndex(i);
         EXPECT_EQ(ImageFrame::FrameComplete, frame->getStatus());
     }
 
     EXPECT_EQ(expectedRepetitionCount, decoder->repetitionCount()); // Expected value after decode.
 }
 
+TEST(GIFImageDecoderTest, bitmapAlphaType)
+{
+    RefPtr<SharedBuffer> fullData = readFile(decodersTestingDir, "radient.gif");
+    ASSERT_TRUE(fullData.get());
+
+    // Empirically chosen

[Noel Gordon, 2016/03/21 22:37:16]

// Empirically chosen truncation size:

[f(malita), 2016/03/21 22:46:24]

Done.

+    //   a) large enough to produce a partial frame &&
+    //   b) small enough to not fully decode the frame
+    static size_t kTruncateSize = 800;

[Noel Gordon, 2016/03/21 22:37:16]

static -> const ?

[f(malita), 2016/03/21 22:46:24]

doh, done.

+    ASSERT_TRUE(kTruncateSize < fullData->size());
+    RefPtr<SharedBuffer> partialData = SharedBuffer::create(fullData->data(), kTruncateSize);
+
+    OwnPtr<ImageDecoder> premulDecoder = adoptPtr(new GIFImageDecoder(
+        ImageDecoder::AlphaPremultiplied,
+        ImageDecoder::GammaAndColorProfileApplied,
+        ImageDecoder::noDecodedImageByteLimit));
+    OwnPtr<ImageDecoder> unpremulDecoder = adoptPtr(new GIFImageDecoder(
+        ImageDecoder::AlphaNotPremultiplied,
+        ImageDecoder::GammaAndColorProfileApplied,
+        ImageDecoder::noDecodedImageByteLimit));
+
+    // Partial frame => alpha type reflects the requested format.

[Noel Gordon, 2016/03/21 22:37:16]

"Partial frame => alpha" -> "Partially decoded frame => the frame alpha type is
unknown and should reflect ..."

[f(malita), 2016/03/21 22:46:24]

Done.

+    premulDecoder->setData(partialData.get(), false);
+    ASSERT_TRUE(premulDecoder->frameCount());
+    unpremulDecoder->setData(partialData.get(), false);
+    ASSERT_TRUE(unpremulDecoder->frameCount());
+    ImageFrame* premulFrame = premulDecoder->frameBufferAtIndex(0);
+    EXPECT_TRUE(premulFrame && premulFrame->getStatus() != ImageFrame::FrameComplete);
+    EXPECT_EQ(premulFrame->bitmap().alphaType(), kPremul_SkAlphaType);
+    ImageFrame* unpremulFrame = unpremulDecoder->frameBufferAtIndex(0);
+    EXPECT_TRUE(unpremulFrame && unpremulFrame->getStatus() != ImageFrame::FrameComplete);
+    EXPECT_EQ(unpremulFrame->bitmap().alphaType(), kUnpremul_SkAlphaType);
+
+    // Full frame => alpha type is known to be opaque

[Noel Gordon, 2016/03/21 22:37:16]

"Full frame =>" -> "Fully decoded frame => the frame alpha type is known
(opaque)."

[f(malita), 2016/03/21 22:46:24]

Done.

+    premulDecoder->setData(fullData.get(), false);

[Noel Gordon, 2016/03/21 22:37:16]

false -> true

[f(malita), 2016/03/21 22:46:24]

Done.

+    ASSERT_TRUE(premulDecoder->frameCount());
+    unpremulDecoder->setData(fullData.get(), false);

[Noel Gordon, 2016/03/21 22:37:16]

false -> true

[f(malita), 2016/03/21 22:46:24]

Done.

+    ASSERT_TRUE(unpremulDecoder->frameCount());
+    premulFrame = premulDecoder->frameBufferAtIndex(0);
+    EXPECT_TRUE(premulFrame && premulFrame->getStatus() == ImageFrame::FrameComplete);
+    EXPECT_EQ(premulFrame->bitmap().alphaType(), kOpaque_SkAlphaType);
+    unpremulFrame = unpremulDecoder->frameBufferAtIndex(0);
+    EXPECT_TRUE(unpremulFrame && unpremulFrame->getStatus() == ImageFrame::FrameComplete);
+    EXPECT_EQ(unpremulFrame->bitmap().alphaType(), kOpaque_SkAlphaType);
+}
+
 } // namespace blink