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_ 80