third_party/WebKit/Source/platform/image-encoders/WEBPImageEncoder.cpp

/*
 * Copyright (c) 2011, 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
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
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 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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#include "platform/image-encoders/WEBPImageEncoder.h"

#include "platform/geometry/IntSize.h"
#include "platform/graphics/ImageBuffer.h"
#include "webp/encode.h"

namespace blink {

static int writeOutput(const uint8_t* data, size_t size, const WebPPicture* const picture)
{
    static_cast<Vector<unsigned char>*>(picture->custom_ptr)->append(data, size);
    return 1;
}

static bool encodePixels(const IntSize& imageSize, const unsigned char* pixels, int quality, Vector<unsigned char>* output)
{
    if (imageSize.width() <= 0 || imageSize.width() > WEBP_MAX_DIMENSION)
        return false;
    if (imageSize.height() <= 0 || imageSize.height() > WEBP_MAX_DIMENSION)
        return false;

    WebPConfig config;
    if (!WebPConfigInit(&config))
        return false;
    WebPPicture picture;
    if (!WebPPictureInit(&picture))
        return false;

    picture.width = imageSize.width();
    picture.height = imageSize.height();

    bool useLosslessEncoding = (quality >= 100);
    if (useLosslessEncoding)
        picture.use_argb = 1;
    if (!WebPPictureImportRGBA(&picture, pixels, picture.width * 4))
        return false;

    picture.custom_ptr = output;
    picture.writer = &writeOutput;

    if (useLosslessEncoding) {
        config.lossless = 1;
        config.quality = 75;
        config.method = 0;
    } else {
        config.quality = quality;
        config.method = 3;
    }

    bool success = WebPEncode(&config, &picture);
    WebPPictureFree(&picture);
    return success;
}

bool WEBPImageEncoder::encode(const ImageDataBuffer& imageData, int quality, Vector<unsigned char>* output)
{
    if (!imageData.pixels())
        return false;

    return encodePixels(imageData.size(), imageData.pixels(), quality, output);
}

} // namespace blink