1// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef UI_GFX_CODEC_JPEG_CODEC_H_
6#define UI_GFX_CODEC_JPEG_CODEC_H_
7
8#include <stddef.h>
9#include <vector>
10
11#include "ui/gfx/gfx_export.h"
12
13class SkBitmap;
14
15namespace gfx {
16
17// Interface for encoding/decoding JPEG data. This is a wrapper around libjpeg,
18// which has an inconvenient interface for callers. This is only used for UI
19// elements, WebKit has its own more complicated JPEG decoder which handles,
20// among other things, partially downloaded data.
21class GFX_EXPORT JPEGCodec {
22 public:
23  enum ColorFormat {
24    // 3 bytes per pixel (packed), in RGB order regardless of endianness.
25    // This is the native JPEG format.
26    FORMAT_RGB,
27
28    // 4 bytes per pixel, in RGBA order in mem regardless of endianness.
29    FORMAT_RGBA,
30
31    // 4 bytes per pixel, in BGRA order in mem regardless of endianness.
32    // This is the default Windows DIB order.
33    FORMAT_BGRA,
34
35    // 4 bytes per pixel, it can be either RGBA or BGRA. It depends on the bit
36    // order in kARGB_8888_Config skia bitmap.
37    FORMAT_SkBitmap
38  };
39
40  enum LibraryVariant {
41    SYSTEM_LIBJPEG = 0,
42    LIBJPEG_TURBO,
43    IJG_LIBJPEG,
44  };
45
46  // This method helps identify at run time which library chromium is using.
47  static LibraryVariant JpegLibraryVariant();
48
49  // Encodes the given raw 'input' data, with each pixel being represented as
50  // given in 'format'. The encoded JPEG data will be written into the supplied
51  // vector and true will be returned on success. On failure (false), the
52  // contents of the output buffer are undefined.
53  //
54  // w, h: dimensions of the image
55  // row_byte_width: the width in bytes of each row. This may be greater than
56  //   w * bytes_per_pixel if there is extra padding at the end of each row
57  //   (often, each row is padded to the next machine word).
58  // quality: an integer in the range 0-100, where 100 is the highest quality.
59  static bool Encode(const unsigned char* input, ColorFormat format,
60                     int w, int h, int row_byte_width,
61                     int quality, std::vector<unsigned char>* output);
62
63  // Decodes the JPEG data contained in input of length input_size. The
64  // decoded data will be placed in *output with the dimensions in *w and *h
65  // on success (returns true). This data will be written in the'format'
66  // format. On failure, the values of these output variables is undefined.
67  static bool Decode(const unsigned char* input, size_t input_size,
68                     ColorFormat format, std::vector<unsigned char>* output,
69                     int* w, int* h);
70
71  // Decodes the JPEG data contained in input of length input_size. If
72  // successful, a SkBitmap is created and returned. It is up to the caller
73  // to delete the returned bitmap.
74  static SkBitmap* Decode(const unsigned char* input, size_t input_size);
75};
76
77}  // namespace gfx
78
79#endif  // UI_GFX_CODEC_JPEG_CODEC_H_
80