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// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#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__
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