tests/ImageDecodingTest.cpp

/*
 * 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 "Test.h"
#include "TestClassDef.h"
#include "SkBitmap.h"
#include "SkCanvas.h"
#include "SkColor.h"
#include "SkColorPriv.h"
#include "SkData.h"
#include "SkDecodingImageGenerator.h"
#include "SkForceLinking.h"
#include "SkGradientShader.h"
#include "SkImageDecoder.h"
#include "SkImageEncoder.h"
#include "SkOSFile.h"
#include "SkPoint.h"
#include "SkShader.h"
#include "SkStream.h"
#include "SkString.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_unpremul(skiatest::Reporter* reporter) {
    // This test cannot run if there is no resource path.
    SkString resourcePath = skiatest::Test::GetResourcePath();
    if (resourcePath.isEmpty()) {
        SkDebugf("Could not run unpremul test because resourcePath not specified.");
        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");
    }
}

#ifdef SK_DEBUG
// Create a stream containing a bitmap encoded to Type type.
static SkMemoryStream* create_image_stream(SkImageEncoder::Type type) {
    SkBitmap bm;
    const int size = 50;
    bm.setConfig(SkBitmap::kARGB_8888_Config, size, size);
    bm.allocPixels();
    SkCanvas canvas(bm);
    SkPoint points[2] = {
        { SkIntToScalar(0), SkIntToScalar(0) },
        { SkIntToScalar(size), SkIntToScalar(size) }
    };
    SkColor colors[2] = { SK_ColorWHITE, SK_ColorBLUE };
    SkShader* shader = SkGradientShader::CreateLinear(points, colors, NULL,
                                                      SK_ARRAY_COUNT(colors),
                                                      SkShader::kClamp_TileMode);
    SkPaint paint;
    paint.setShader(shader)->unref();
    canvas.drawPaint(paint);
    // Now encode it to a stream.
    SkAutoTUnref<SkData> data(SkImageEncoder::EncodeData(bm, type, 100));
    if (NULL == data.get()) {
        return NULL;
    }
    return SkNEW_ARGS(SkMemoryStream, (data.get()));
}

// For every format that supports tile based decoding, ensure that
// calling decodeSubset will not fail if the caller has unreffed the
// stream provided in buildTileIndex.
// Only runs in debug mode since we are testing for a crash.
static void test_stream_life() {
    const SkImageEncoder::Type gTypes[] = {
#ifdef SK_BUILD_FOR_ANDROID
        SkImageEncoder::kJPEG_Type,
        SkImageEncoder::kPNG_Type,
#endif
        SkImageEncoder::kWEBP_Type,
    };
    for (size_t i = 0; i < SK_ARRAY_COUNT(gTypes); ++i) {
        //SkDebugf("encoding to %i\n", i);
        SkAutoTUnref<SkMemoryStream> stream(create_image_stream(gTypes[i]));
        if (NULL == stream.get()) {
            SkDebugf("no stream\n");
            continue;
        }
        SkAutoTDelete<SkImageDecoder> decoder(SkImageDecoder::Factory(stream));
        if (NULL == decoder.get()) {
            SkDebugf("no decoder\n");
            continue;
        }
        int width, height;
        if (!decoder->buildTileIndex(stream.get(), &width, &height)) {
            SkDebugf("could not build a tile index\n");
            continue;
        }
        // Now unref the stream to make sure it survives
        stream.reset(NULL);
        SkBitmap bm;
        decoder->decodeSubset(&bm, SkIRect::MakeWH(width, height),
                              SkBitmap::kARGB_8888_Config);
    }
}

// Test inside SkScaledBitmapSampler.cpp
extern void test_row_proc_choice();

#endif // SK_DEBUG

DEF_TEST(ImageDecoding, reporter) {
    test_unpremul(reporter);
#ifdef SK_DEBUG
    test_stream_life();
    test_row_proc_choice();
#endif
}

////////////////////////////////////////////////////////////////////////////////

DEF_TEST(WebP, reporter) {
    const unsigned char encodedWebP[] = {
        0x52, 0x49, 0x46, 0x46, 0x2c, 0x01, 0x00, 0x00, 0x57, 0x45, 0x42, 0x50,
        0x56, 0x50, 0x38, 0x4c, 0x20, 0x01, 0x00, 0x00, 0x2f, 0x07, 0xc0, 0x01,
        0x00, 0xff, 0x01, 0x45, 0x03, 0x00, 0xe2, 0xd5, 0xae, 0x60, 0x2b, 0xad,
        0xd9, 0x68, 0x76, 0xb6, 0x8d, 0x6a, 0x1d, 0xc0, 0xe6, 0x19, 0xd6, 0x16,
        0xb7, 0xb4, 0xef, 0xcf, 0xc3, 0x15, 0x6c, 0xb3, 0xbd, 0x77, 0x0d, 0x85,
        0x6d, 0x1b, 0xa9, 0xb1, 0x2b, 0xdc, 0x3d, 0x83, 0xdb, 0x00, 0x00, 0xc8,
        0x26, 0xe5, 0x01, 0x99, 0x8a, 0xd5, 0xdd, 0xfc, 0x82, 0xcd, 0xcd, 0x9a,
        0x8c, 0x13, 0xcc, 0x1b, 0xba, 0xf5, 0x05, 0xdb, 0xee, 0x6a, 0xdb, 0x38,
        0x60, 0xfe, 0x43, 0x2c, 0xd4, 0x6a, 0x99, 0x4d, 0xc6, 0xc0, 0xd3, 0x28,
        0x1b, 0xc1, 0xb1, 0x17, 0x4e, 0x43, 0x0e, 0x3d, 0x27, 0xe9, 0xe4, 0x84,
        0x4f, 0x24, 0x62, 0x69, 0x85, 0x43, 0x8d, 0xc2, 0x04, 0x00, 0x07, 0x59,
        0x60, 0xfd, 0x8b, 0x4d, 0x60, 0x32, 0x72, 0xcf, 0x88, 0x0c, 0x2f, 0x2f,
        0xad, 0x62, 0xbd, 0x27, 0x09, 0x16, 0x70, 0x78, 0x6c, 0xd9, 0x82, 0xef,
        0x1a, 0xa2, 0xcc, 0xf0, 0xf1, 0x6f, 0xd8, 0x78, 0x2e, 0x39, 0xa1, 0xcf,
        0x14, 0x4b, 0x89, 0xb4, 0x1b, 0x48, 0x15, 0x7c, 0x48, 0x6f, 0x8c, 0x20,
        0xb7, 0x00, 0xcf, 0xfc, 0xdb, 0xd0, 0xe9, 0xe7, 0x42, 0x09, 0xa4, 0x03,
        0x40, 0xac, 0xda, 0x40, 0x01, 0x00, 0x5f, 0xa1, 0x3d, 0x64, 0xe1, 0xf4,
        0x03, 0x45, 0x29, 0xe0, 0xe2, 0x4a, 0xc3, 0xa2, 0xe8, 0xe0, 0x25, 0x12,
        0x74, 0xc6, 0xe8, 0xfb, 0x93, 0x4f, 0x9f, 0x5e, 0xc0, 0xa6, 0x91, 0x1b,
        0xa4, 0x24, 0x82, 0xc3, 0x61, 0x07, 0x4c, 0x49, 0x4f, 0x53, 0xae, 0x5f,
        0x5d, 0x39, 0x36, 0xc0, 0x5b, 0x57, 0x54, 0x60, 0x10, 0x00, 0x00, 0xd1,
        0x68, 0xb6, 0x6d, 0xdb, 0x36, 0x22, 0xfa, 0x1f, 0x35, 0x75, 0x22, 0xec,
        0x31, 0xbc, 0x5d, 0x8f, 0x87, 0x53, 0xa2, 0x05, 0x8c, 0x2f, 0xcd, 0xa8,
        0xa7, 0xf3, 0xa3, 0xbd, 0x83, 0x8b, 0x2a, 0xc8, 0x58, 0xf5, 0xac, 0x80,
        0xe3, 0xfe, 0x66, 0xa4, 0x7c, 0x1b, 0x6c, 0xd1, 0xa9, 0xd8, 0x14, 0xd0,
        0xc5, 0xb5, 0x39, 0x71, 0x97, 0x19, 0x19, 0x1b
    };
    const SkColor thePixels[]  = {
        0xffbba570, 0xff395f5d, 0xffe25c39, 0xff197666,
        0xff3cba27, 0xffdefcb0, 0xffc13874, 0xfffa0093,
        0xffbda60e, 0xffc01db6, 0xff2bd688, 0xff9362d4,
        0xffc641b2, 0xffa5cede, 0xff606eba, 0xff8f4bf3,
        0xff3bf742, 0xff8f02a8, 0xff5509df, 0xffc7027e,
        0xff24aa8a, 0xff886c96, 0xff625481, 0xff403689,
        0xffc52152, 0xff78ccd6, 0xffdcb4ab, 0xff09d27d,
        0xffca00f3, 0xff605d47, 0xff446fb2, 0xff576e46,
        0xff273df9, 0xffb41a83, 0xfff812c3, 0xffccab67,
        0xff034218, 0xff7db9a7, 0xff821048, 0xfffe4ab4,
        0xff6fac98, 0xff941d27, 0xff5fe411, 0xfffbb283,
        0xffd86e99, 0xff169162, 0xff71128c, 0xff39cab4,
        0xffa7fe63, 0xff4c956b, 0xffbc22e0, 0xffb272e4,
        0xff129f4a, 0xffe34513, 0xff3d3742, 0xffbd190a,
        0xffb07222, 0xff2e23f8, 0xfff089d9, 0xffb35738,
        0xffa86022, 0xff3340fe, 0xff95fe71, 0xff6a71df
    };
    SkAutoDataUnref encoded(SkData::NewWithCopy(encodedWebP,
                                                sizeof(encodedWebP)));
    SkBitmap bm;
    bool success = SkDecodingImageGenerator::Install(encoded, &bm, NULL);
    REPORTER_ASSERT(reporter, success);
    if (!success) {
        return;
    }
    SkAutoLockPixels alp(bm);
    bool rightSize = SK_ARRAY_COUNT(thePixels) == bm.width() * bm.height();
    REPORTER_ASSERT(reporter, rightSize);
    if (rightSize) {
        bool error = false;
        const SkColor* correctPixel = thePixels;
        for (int y = 0; y < bm.height(); ++y) {
            for (int x = 0; x < bm.width(); ++x) {
                error |= (*correctPixel != bm.getColor(x, y));
                ++correctPixel;
            }
        }
        REPORTER_ASSERT(reporter, !error);
    }
}