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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 | |
13 class SkBitmap; | |
14 | |
15 namespace 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. | |
21 class 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_ | |
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