Moving GraphicsContext and dependencies from core to platform.

Source/core/platform/image-encoders/skia/PNGImageEncoder.cpp

-/*
- * Copyright (c) 2010, 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.
- *     * Neither the name of Google Inc. nor the names of its
- * 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,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "config.h"
-#include "core/platform/image-encoders/skia/PNGImageEncoder.h"
-
-#include "SkBitmap.h"
-#include "SkColorPriv.h"
-#include "SkUnPreMultiply.h"
-#include "core/platform/graphics/ImageBuffer.h"
-#include "platform/geometry/IntSize.h"
-extern "C" {
-#include "png.h"
-}
-
-namespace WebCore {
-
-static void writeOutput(png_structp png, png_bytep data, png_size_t size)
-{
-    static_cast<Vector<unsigned char>*>(png_get_io_ptr(png))->append(data, size);
-}
-
-static void preMultipliedBGRAtoRGBA(const void* pixels, int pixelCount, unsigned char* output)
-{
-    static const SkUnPreMultiply::Scale* scale = SkUnPreMultiply::GetScaleTable();
-    const SkPMColor* input = static_cast<const SkPMColor*>(pixels);
-
-    for (; pixelCount-- > 0; ++input) {
-        const unsigned alpha = SkGetPackedA32(*input);
-        if ((alpha != 0) && (alpha != 255)) {
-            *output++ = SkUnPreMultiply::ApplyScale(scale[alpha], SkGetPackedR32(*input));
-            *output++ = SkUnPreMultiply::ApplyScale(scale[alpha], SkGetPackedG32(*input));
-            *output++ = SkUnPreMultiply::ApplyScale(scale[alpha], SkGetPackedB32(*input));
-            *output++ = alpha;
-        } else {
-            *output++ = SkGetPackedR32(*input);
-            *output++ = SkGetPackedG32(*input);
-            *output++ = SkGetPackedB32(*input);
-            *output++ = alpha;
-        }
-    }
-}
-
-static bool encodePixels(IntSize imageSize, unsigned char* inputPixels, bool premultiplied, Vector<unsigned char>* output)
-{
-    imageSize.clampNegativeToZero();
-    Vector<unsigned char> row;
-
-    png_struct* png = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0);
-    png_info* info = png_create_info_struct(png);
-    if (!png || !info || setjmp(png_jmpbuf(png))) {
-        png_destroy_write_struct(png ? &png : 0, info ? &info : 0);
-        return false;
-    }
-
-    // Optimize compression for speed.
-    // The parameters are the same as what libpng uses by default for RGB and RGBA images, except:
-    // - the zlib compression level is 3 instead of 6, to avoid the lazy Ziv-Lempel match searching;
-    // - the delta filter is 1 ("sub") instead of 5 ("all"), to reduce the filter computations.
-    // The zlib memory level (8) and strategy (Z_FILTERED) will be set inside libpng.
-    //
-    // Avoid the zlib strategies Z_HUFFMAN_ONLY or Z_RLE.
-    // Although they are the fastest for poorly-compressible images (e.g. photographs),
-    // they are very slow for highly-compressible images (e.g. text, drawings or business graphics).
-    png_set_compression_level(png, 3);
-    png_set_filter(png, PNG_FILTER_TYPE_BASE, PNG_FILTER_SUB);
-
-    png_set_write_fn(png, output, writeOutput, 0);
-    png_set_IHDR(png, info, imageSize.width(), imageSize.height(),
-                 8, PNG_COLOR_TYPE_RGB_ALPHA, 0, 0, 0);
-    png_write_info(png, info);
-
-    unsigned char* pixels = inputPixels;
-    row.resize(imageSize.width() * sizeof(SkPMColor));
-    const size_t pixelRowStride = imageSize.width() * 4;
-    for (int y = 0; y < imageSize.height(); ++y) {
-        if (premultiplied) {
-            preMultipliedBGRAtoRGBA(pixels, imageSize.width(), row.data());
-            png_write_row(png, row.data());
-        } else
-            png_write_row(png, pixels);
-        pixels += pixelRowStride;
-    }
-
-    png_write_end(png, info);
-    png_destroy_write_struct(&png, &info);
-    return true;
-}
-
-bool PNGImageEncoder::encode(const SkBitmap& bitmap, Vector<unsigned char>* output)
-{
-    SkAutoLockPixels bitmapLock(bitmap);
-
-    if (bitmap.config() != SkBitmap::kARGB_8888_Config || !bitmap.getPixels())
-        return false; // Only support 32 bit/pixel skia bitmaps.
-
-    return encodePixels(IntSize(bitmap.width(), bitmap.height()), static_cast<unsigned char*>(bitmap.getPixels()), true, output);
-}
-
-bool PNGImageEncoder::encode(const ImageDataBuffer& imageData, Vector<unsigned char>* output)
-{
-    return encodePixels(imageData.size(), imageData.data(), false, output);
-}
-
-} // namespace WebCore