// Copyright (c) 2011 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 UI_GFX_CODEC_JPEG_CODEC_H_
#define UI_GFX_CODEC_JPEG_CODEC_H_
#include <stddef.h>
#include <vector>
#include "ui/gfx/gfx_export.h"
class SkBitmap;
namespace gfx {
// Interface for encoding/decoding JPEG data. This is a wrapper around libjpeg,
// which has an inconvenient interface for callers. This is only used for UI
// elements, WebKit has its own more complicated JPEG decoder which handles,
// among other things, partially downloaded data.
class GFX_EXPORT JPEGCodec {
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 mem regardless of endianness.
FORMAT_RGBA,
// 4 bytes per pixel, in BGRA order in mem regardless of endianness.
// This is the default Windows DIB order.
FORMAT_BGRA,
// 4 bytes per pixel, it can be either RGBA or BGRA. It depends on the bit
// order in kARGB_8888_Config skia bitmap.
FORMAT_SkBitmap
};
enum LibraryVariant {
SYSTEM_LIBJPEG = 0,
LIBJPEG_TURBO,
IJG_LIBJPEG,
};
// This method helps identify at run time which library chromium is using.
static LibraryVariant JpegLibraryVariant();
// Encodes the given raw 'input' data, with each pixel being represented as
// given in 'format'. The encoded JPEG 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.
//
// 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).
// quality: an integer in the range 0-100, where 100 is the highest quality.
static bool Encode(const unsigned char* input, ColorFormat format,
int w, int h, int row_byte_width,
int quality, std::vector<unsigned char>* output);
// Decodes the JPEG data contained in input of length input_size. The
// decoded data will be placed in *output with the dimensions in *w and *h
// on success (returns true). This data will be written in the'format'
// format. On failure, the values of these output variables is undefined.
static bool Decode(const unsigned char* input, size_t input_size,
ColorFormat format, std::vector<unsigned char>* output,
int* w, int* h);
// Decodes the JPEG data contained in input of length input_size. If
// successful, a SkBitmap is created and returned. It is up to the caller
// to delete the returned bitmap.
static SkBitmap* Decode(const unsigned char* input, size_t input_size);
};
} // namespace gfx
#endif // UI_GFX_CODEC_JPEG_CODEC_H_