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/*
* Copyright 2013 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkBitmap.h"
#include "SkColorPriv.h"
#include "SkForceLinking.h"
#include "SkImageDecoder.h"
#include "SkOSFile.h"
#include "SkStream.h"
#include "SkString.h"
#include "Test.h"
__SK_FORCE_IMAGE_DECODER_LINKING;
/**
* Interprets c as an unpremultiplied color, and returns the
* premultiplied equivalent.
*/
static SkPMColor premultiply_unpmcolor(SkPMColor c) {
U8CPU a = SkGetPackedA32(c);
U8CPU r = SkGetPackedR32(c);
U8CPU g = SkGetPackedG32(c);
U8CPU b = SkGetPackedB32(c);
return SkPreMultiplyARGB(a, r, g, b);
}
/**
* Return true if this stream format should be skipped, due
* to do being an opaque format or not a valid format.
*/
static bool skip_image_format(SkImageDecoder::Format format) {
switch (format) {
case SkImageDecoder::kPNG_Format:
case SkImageDecoder::kWEBP_Format:
return false;
// Skip unknown since it will not be decoded anyway.
case SkImageDecoder::kUnknown_Format:
// Technically ICO and BMP supports alpha channels, but our image
// decoders do not, so skip them as well.
case SkImageDecoder::kICO_Format:
case SkImageDecoder::kBMP_Format:
// The rest of these are opaque.
case SkImageDecoder::kWBMP_Format:
case SkImageDecoder::kGIF_Format:
case SkImageDecoder::kJPEG_Format:
return true;
}
SkASSERT(false);
return true;
}
/**
* Test decoding an image in premultiplied mode and unpremultiplied mode and compare
* them.
*/
static void compare_unpremul(skiatest::Reporter* reporter, const SkString& filename) {
// Decode a resource:
SkBitmap bm8888;
SkBitmap bm8888Unpremul;
SkFILEStream stream(filename.c_str());
SkImageDecoder::Format format = SkImageDecoder::GetStreamFormat(&stream);
if (skip_image_format(format)) {
return;
}
SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(&stream));
if (NULL == decoder.get()) {
SkDebugf("couldn't decode %s\n", filename.c_str());
return;
}
bool success = decoder->decode(&stream, &bm8888, SkBitmap::kARGB_8888_Config,
SkImageDecoder::kDecodePixels_Mode);
if (!success) {
return;
}
success = stream.rewind();
REPORTER_ASSERT(reporter, success);
if (!success) {
return;
}
decoder->setRequireUnpremultipliedColors(true);
success = decoder->decode(&stream, &bm8888Unpremul, SkBitmap::kARGB_8888_Config,
SkImageDecoder::kDecodePixels_Mode);
if (!success) {
return;
}
bool dimensionsMatch = bm8888.width() == bm8888Unpremul.width()
&& bm8888.height() == bm8888Unpremul.height();
REPORTER_ASSERT(reporter, dimensionsMatch);
if (!dimensionsMatch) {
return;
}
// Only do the comparison if the two bitmaps are both 8888.
if (bm8888.config() != SkBitmap::kARGB_8888_Config
|| bm8888Unpremul.config() != SkBitmap::kARGB_8888_Config) {
return;
}
// Now compare the two bitmaps.
for (int i = 0; i < bm8888.width(); ++i) {
for (int j = 0; j < bm8888.height(); ++j) {
// "c0" is the color of the premultiplied bitmap at (i, j).
const SkPMColor c0 = *bm8888.getAddr32(i, j);
// "c1" is the result of premultiplying the color of the unpremultiplied
// bitmap at (i, j).
const SkPMColor c1 = premultiply_unpmcolor(*bm8888Unpremul.getAddr32(i, j));
// Compute the difference for each component.
int da = SkAbs32(SkGetPackedA32(c0) - SkGetPackedA32(c1));
int dr = SkAbs32(SkGetPackedR32(c0) - SkGetPackedR32(c1));
int dg = SkAbs32(SkGetPackedG32(c0) - SkGetPackedG32(c1));
int db = SkAbs32(SkGetPackedB32(c0) - SkGetPackedB32(c1));
// Alpha component must be exactly the same.
REPORTER_ASSERT(reporter, 0 == da);
// Color components may not match exactly due to rounding error.
REPORTER_ASSERT(reporter, dr <= 1);
REPORTER_ASSERT(reporter, dg <= 1);
REPORTER_ASSERT(reporter, db <= 1);
}
}
}
static void test_imageDecodingTests(skiatest::Reporter* reporter) {
// This test cannot run if there is no resource path.
SkString resourcePath = skiatest::Test::GetResourcePath();
if (resourcePath.isEmpty()) {
return;
}
SkOSFile::Iter iter(resourcePath.c_str());
SkString basename;
if (iter.next(&basename)) {
do {
SkString filename = SkOSPath::SkPathJoin(resourcePath.c_str(), basename.c_str());
//SkDebugf("about to decode \"%s\"\n", filename.c_str());
compare_unpremul(reporter, filename);
} while (iter.next(&basename));
} else {
SkDebugf("Failed to find any files :(\n");
}
}
#include "TestClassDef.h"
DEFINE_TESTCLASS("ImageDecoding", ImageDecodingTestClass,
test_imageDecodingTests)
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