Modify SkPngCodec to recognize 565 images from the sBIT chunk

tests/CodecTest.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Resources.h"
 #include "SkAndroidCodec.h"
 #include "SkBitmap.h"
 #include "SkCodec.h"
 #include "SkCodecImageGenerator.h"
 #include "SkData.h"
+#include "SkImageEncoder.h"
 #include "SkFrontBufferedStream.h"
 #include "SkMD5.h"
 #include "SkRandom.h"
 #include "SkStream.h"
 #include "SkStreamPriv.h"
 #include "SkPngChunkReader.h"
 #include "Test.h"
 
 #include "png.h"
 
@@ skipping 1011 matching lines @@
     // Perform a sampled decode.
     SkAndroidCodec::AndroidOptions opts;
     opts.fSampleSize = 12;
     codec->getAndroidPixels(codec->getInfo().makeWH(width / 12, height / 12), pixelStorage.get(),
                             rowBytes, &opts);
 
     // Rewind the codec and perform a full image decode.
     SkCodec::Result result = codec->getPixels(codec->getInfo(), pixelStorage.get(), rowBytes);
     REPORTER_ASSERT(r, SkCodec::kSuccess == result);
 }
+
+DEF_TEST(Codec_Png565, r) {
+    // Create an arbitrary 565 bitmap.
+    const char* path = "mandrill_512_q075.jpg";
+    SkAutoTDelete<SkStream> stream(resource(path));
+    SkAutoTDelete<SkCodec> codec(SkCodec::NewFromStream(stream.release()));
+    SkImageInfo info565 = codec->getInfo().makeColorType(kRGB_565_SkColorType);
+    SkBitmap bm1;
+    bm1.allocPixels(info565);
+    SkCodec::Result result = codec->getPixels(info565, bm1.getPixels(), bm1.rowBytes());
+    REPORTER_ASSERT(r, SkCodec::kSuccess == result);
+
+    // Encode the image to png.
+    sk_sp<SkData> data =
+            sk_sp<SkData>(SkImageEncoder::EncodeData(bm1, SkImageEncoder::kPNG_Type, 100));
+
+    // Prepare to decode.  The codec should recognize that the PNG is 565.
+    codec.reset(SkCodec::NewFromData(data.get()));
+    REPORTER_ASSERT(r, kRGB_565_SkColorType == codec->getInfo().colorType());
+    REPORTER_ASSERT(r, kOpaque_SkAlphaType == codec->getInfo().alphaType());
+
+    SkBitmap bm2;
+    bm2.allocPixels(codec->getInfo());
+    result = codec->getPixels(codec->getInfo(), bm2.getPixels(), bm2.rowBytes());
+    REPORTER_ASSERT(r, SkCodec::kSuccess == result);
+
+    SkMD5::Digest d1, d2;
+    md5(bm1, &d1);
+    md5(bm2, &d2);
+    REPORTER_ASSERT(r, d1 == d2);
+}