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Diffstat (limited to 'base/gfx/png_encoder.h')
-rw-r--r-- | base/gfx/png_encoder.h | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/base/gfx/png_encoder.h b/base/gfx/png_encoder.h new file mode 100644 index 0000000..3129775 --- /dev/null +++ b/base/gfx/png_encoder.h @@ -0,0 +1,83 @@ +// Copyright 2008, 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. + +#ifndef BASE_GFX_PNG_ENCODER_H__ +#define BASE_GFX_PNG_ENCODER_H__ + +#include <vector> + +#include "base/basictypes.h" + +// Interface for encoding PNG data. This is a wrapper around libpng, +// which has an inconvenient interface for callers. This is currently designed +// for use in tests only (where we control the files), so the handling isn't as +// robust as would be required for a browser (see Decode() for more). WebKit +// has its own more complicated PNG decoder which handles, among other things, +// partially downloaded data. +class PNGEncoder { + public: + enum ColorFormat { + // 3 bytes per pixel (packed), in RGB order regardless of endianness. + // This is the native JPEG format. + FORMAT_RGB, + + // 4 bytes per pixel, in RGBA order in memory regardless of endianness. + FORMAT_RGBA, + + // 4 bytes per pixel, in BGRA order in memory regardless of endianness. + // This is the default Windows DIB order. + FORMAT_BGRA + }; + + // Encodes the given raw 'input' data, with each pixel being represented as + // given in 'format'. The encoded PNG data will be written into the supplied + // vector and true will be returned on success. On failure (false), the + // contents of the output buffer are undefined. + // + // When writing alpha values, the input colors are assumed to be post + // multiplied. + // + // w, h: dimensions of the image + // row_byte_width: the width in bytes of each row. This may be greater than + // w * bytes_per_pixel if there is extra padding at the end of each row + // (often, each row is padded to the next machine word). + // discard_transparency: when true, and when the input data format includes + // alpha values, these alpha values will be discarded and only RGB will be + // written to the resulting file. Otherwise, alpha values in the input + // will be preserved. + static bool Encode(const unsigned char* input, ColorFormat format, + int w, int h, int row_byte_width, + bool discard_transparency, + std::vector<unsigned char>* output); + + private: + DISALLOW_EVIL_CONSTRUCTORS(PNGEncoder); +}; + +#endif // BASE_GFX_PNG_ENCODER_H__ |