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      1 /* Copyright (C) 2011 The Android Open Source Project
      2 **
      3 ** This software is licensed under the terms of the GNU General Public
      4 ** License version 2, as published by the Free Software Foundation, and
      5 ** may be copied, distributed, and modified under those terms.
      6 **
      7 ** This program is distributed in the hope that it will be useful,
      8 ** but WITHOUT ANY WARRANTY; without even the implied warranty of
      9 ** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     10 ** GNU General Public License for more details.
     11 */
     12 #ifndef _ANDROID_UTILS_JPEG_COMPRESS_H
     13 #define _ANDROID_UTILS_JPEG_COMPRESS_H
     14 
     15 #include "android/utils/compiler.h"
     16 
     17 ANDROID_BEGIN_HEADER
     18 
     19 /*
     20  * Contains declaration of utility routines that compress an RGB bitmap into
     21  * a JPEG image.
     22  *
     23  * NOTE: This code uses a jpeglib library located in distrib/jpeg-6b. It's a
     24  * 3-rd party library that uses its own type definitions that are different from
     25  * the ones that are use elsewhere in the emulator code. For instance, in the
     26  * emulator built for Windows, sizeof(bool) = 1, while in the jpeglib sizeof(bool) = 4.
     27  * So, to simplify dealing with these issues, all the code that uses jpeglib should
     28  * be compiled separately, and should include only headers that are used to compile
     29  * jpeglib.
     30  */
     31 
     32 
     33 /* Declares descriptor for a JPEG compression. */
     34 typedef struct AJPEGDesc AJPEGDesc;
     35 
     36 /* Creates a descriptor that will be used for compression.
     37  * Param:
     38  *  header_size - Number of bytes to allocate for a custom header that should
     39  *      preceed the actual JPEG buffer. This is useful when sending JPEG
     40  *      somewhere else along with some extra data about the compressed image.
     41  *  cunk_size - Number of bytes to increment the compressed buffer with each time
     42  *      compressor requests more memory.
     43  * Return:
     44  *  Initialized compression descriptor.
     45  */
     46 extern AJPEGDesc* jpeg_compressor_create(int header_size, int chunk_size);
     47 
     48 /* Destroys compressor descriptor.
     49  * Param:
     50  *  dsc - Compressin descriptor, obtained with jpeg_compressor_create.
     51  */
     52 extern void jpeg_compressor_destroy(AJPEGDesc* dsc);
     53 
     54 /* Returns compressed data size.
     55  * Param:
     56  *  dsc - Compression descriptor, obtained with jpeg_compressor_create.
     57  * Return:
     58  *  Compressed data size.
     59  */
     60 extern int jpeg_compressor_get_jpeg_size(const AJPEGDesc* dsc);
     61 
     62 /* Returns compressed buffer.
     63  * Param:
     64  *  dsc - Compression descriptor, obtained with jpeg_compressor_create.
     65  * Return:
     66  *  Compressed buffer. NOTE: if 'header_size' parameter passed to the jpeg_compressor_create
     67  *  for this descriptor was not zero, this routine returns a pointer to the custom
     68  *  header. Compressed data follows immediately after that header.
     69  */
     70 extern void* jpeg_compressor_get_buffer(const AJPEGDesc* dsc);
     71 
     72 /* Returns size of the custom header placed before the compressed data.
     73  * Param:
     74  *  dsc - Compression descriptor, obtained with jpeg_compressor_create.
     75  * Return:
     76  *  Size of the custom header placed before the compressed data.
     77  */
     78 extern int jpeg_compressor_get_header_size(const AJPEGDesc* dsc);
     79 
     80 /* Compresses a framebuffer region into JPEG image.
     81  * Param:
     82  *  dsc - Compression descriptor, obtained with jpeg_compressor_create.
     83  *  x, y, w, h - Coordinates and sizes of framebuffer region to compress.
     84  *  num_lines - Number of lines in the framebuffer (true height).
     85  *  bpp - Number of bytes per pixel in the framebuffer.
     86  *  bpl - Number of bytes per line in the framebuffer.
     87  *  fb - Beginning of the framebuffer.
     88  *  jpeg_quality JPEG compression quality. A number from 1 to 100. Note that
     89  *      value 10 provides pretty decent image for the purpose of multi-touch
     90  *      emulation.
     91  *  ydir - Indicates direction in which lines are arranged in the framebuffer. If
     92  *      this value is negative, lines are arranged in bottom-up format (i.e. the
     93  *      bottom line is at the beginning of the buffer).
     94  */
     95 extern void jpeg_compressor_compress_fb(AJPEGDesc* dsc,
     96                                         int x, int y, int w, int h,
     97                                         int num_lines,
     98                                         int bpp, int bpl,
     99                                         const uint8_t* fb,
    100                                         int jpeg_quality,
    101                                         int ydir);
    102 
    103 ANDROID_END_HEADER
    104 
    105 #endif  /* _ANDROID_UTILS_JPEG_COMPRESS_H */
    106