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| 1 /* | |
| 2 * Copyright (c) 2010, Google Inc. All rights reserved. | |
| 3 * | |
| 4 * Redistribution and use in source and binary forms, with or without | |
| 5 * modification, are permitted provided that the following conditions are | |
| 6 * met: | |
| 7 * | |
| 8 * * Redistributions of source code must retain the above copyright | |
| 9 * notice, this list of conditions and the following disclaimer. | |
| 10 * * Redistributions in binary form must reproduce the above | |
| 11 * copyright notice, this list of conditions and the following disclaimer | |
| 12 * in the documentation and/or other materials provided with the | |
| 13 * distribution. | |
| 14 * * Neither the name of Google Inc. nor the names of its | |
| 15 * contributors may be used to endorse or promote products derived from | |
| 16 * this software without specific prior written permission. | |
| 17 * | |
| 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 29 */ | |
| 30 | |
| 31 #include "platform/image-encoders/PNGImageEncoder.h" | |
| 32 | |
| 33 #include <memory> | |
| 34 #include "platform/graphics/ImageBuffer.h" | |
| 35 #include "platform/wtf/PtrUtil.h" | |
| 36 | |
| 37 #include "zlib.h" | |
| 38 | |
| 39 namespace blink { | |
| 40 | |
| 41 PNGImageEncoderState::~PNGImageEncoderState() { | |
| 42 png_destroy_write_struct(&png_, &info_); | |
| 43 } | |
| 44 | |
| 45 static void WriteOutput(png_structp png, png_bytep data, png_size_t size) { | |
| 46 static_cast<Vector<unsigned char>*>(png_get_io_ptr(png))->Append(data, size); | |
| 47 } | |
| 48 | |
| 49 std::unique_ptr<PNGImageEncoderState> PNGImageEncoderState::Create( | |
| 50 const IntSize& image_size, | |
| 51 Vector<unsigned char>* output) { | |
| 52 if (image_size.Width() <= 0 || image_size.Height() <= 0) | |
| 53 return nullptr; | |
| 54 | |
| 55 png_struct* png = png_create_write_struct(PNG_LIBPNG_VER_STRING, 0, 0, 0); | |
| 56 png_info* info = png_create_info_struct(png); | |
| 57 if (!png || !info || setjmp(png_jmpbuf(png))) { | |
| 58 png_destroy_write_struct(png ? &png : 0, info ? &info : 0); | |
| 59 return nullptr; | |
| 60 } | |
| 61 | |
| 62 // Optimize compression for speed. | |
| 63 // The parameters are the same as what libpng uses by default for RGB and RGBA | |
| 64 // images, except: | |
| 65 // The zlib compression level is set to 3 instead of 6, to avoid the lazy | |
| 66 // Ziv-Lempel match searching. | |
| 67 png_set_compression_level(png, 3); | |
| 68 | |
| 69 // The zlib memory level is set to 8. This actually matches the default, we | |
| 70 // are just future-proofing. | |
| 71 png_set_compression_mem_level(png, 8); | |
| 72 | |
| 73 // The zlib strategy is set to Z_FILTERED, which does not match the default. | |
| 74 // Avoid the zlib strategies Z_HUFFMAN_ONLY or Z_RLE. | |
| 75 // Although they are the fastest for poorly-compressible images (e.g. | |
| 76 // photographs), they are very slow for highly-compressible images (e.g. text, | |
| 77 // drawings or business graphics) | |
| 78 png_set_compression_strategy(png, Z_FILTERED); | |
| 79 | |
| 80 // The delta filter is PNG_FILTER_SUB instead of PNG_ALL_FILTERS, to reduce | |
| 81 // the filter computations. | |
| 82 png_set_filter(png, PNG_FILTER_TYPE_BASE, PNG_FILTER_SUB); | |
| 83 | |
| 84 png_set_write_fn(png, output, WriteOutput, 0); | |
| 85 png_set_IHDR(png, info, image_size.Width(), image_size.Height(), 8, | |
| 86 PNG_COLOR_TYPE_RGB_ALPHA, 0, 0, 0); | |
| 87 png_write_info(png, info); | |
| 88 | |
| 89 return WTF::WrapUnique(new PNGImageEncoderState(png, info)); | |
| 90 } | |
| 91 | |
| 92 void PNGImageEncoder::WriteOneRowToPng(unsigned char* pixels, | |
| 93 PNGImageEncoderState* encoder_state) { | |
| 94 png_write_row(encoder_state->Png(), pixels); | |
| 95 } | |
| 96 | |
| 97 void PNGImageEncoder::FinalizePng(PNGImageEncoderState* encoder_state) { | |
| 98 png_write_end(encoder_state->Png(), encoder_state->Info()); | |
| 99 } | |
| 100 | |
| 101 static bool EncodePixels(const IntSize& image_size, | |
| 102 const unsigned char* input_pixels, | |
| 103 Vector<unsigned char>* output) { | |
| 104 std::unique_ptr<PNGImageEncoderState> encoder_state = | |
| 105 PNGImageEncoderState::Create(image_size, output); | |
| 106 if (!encoder_state.get()) | |
| 107 return false; | |
| 108 | |
| 109 unsigned char* pixels = const_cast<unsigned char*>(input_pixels); | |
| 110 const size_t pixel_row_stride = image_size.Width() * 4; | |
| 111 for (int y = 0; y < image_size.Height(); ++y) { | |
| 112 PNGImageEncoder::WriteOneRowToPng(pixels, encoder_state.get()); | |
| 113 pixels += pixel_row_stride; | |
| 114 } | |
| 115 | |
| 116 PNGImageEncoder::FinalizePng(encoder_state.get()); | |
| 117 return true; | |
| 118 } | |
| 119 | |
| 120 bool PNGImageEncoder::Encode(const ImageDataBuffer& image_data, | |
| 121 Vector<unsigned char>* output) { | |
| 122 if (!image_data.Pixels()) | |
| 123 return false; | |
| 124 | |
| 125 return EncodePixels(image_data.size(), image_data.Pixels(), output); | |
| 126 } | |
| 127 | |
| 128 } // namespace blink | |
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Chromium Code Reviews
Issue 2891373002:
Use SkPngEncoder and SkWebpEncoder in WebKit platform (Closed)
