jmorecfg.h 12 KB

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  1. /*
  2. * jmorecfg.h
  3. *
  4. * Copyright (C) 1991-1995, Thomas G. Lane.
  5. * This file is part of the Independent JPEG Group's software.
  6. * For conditions of distribution and use, see the accompanying README file.
  7. *
  8. * This file contains additional configuration options that customize the
  9. * JPEG software for special applications or support machine-dependent
  10. * optimizations. Most users will not need to touch this file.
  11. */
  12. /*
  13. * Define BITS_IN_JSAMPLE as either
  14. * 8 for 8-bit sample values (the usual setting)
  15. * 12 for 12-bit sample values
  16. * Only 8 and 12 are legal data precisions for lossy JPEG according to the
  17. * JPEG standard, and the IJG code does not support anything else!
  18. * We do not support run-time selection of data precision, sorry.
  19. */
  20. #define BITS_IN_JSAMPLE 8 /* use 8 or 12 */
  21. /*
  22. * Maximum number of components (color channels) allowed in JPEG image.
  23. * To meet the letter of the JPEG spec, set this to 255. However, darn
  24. * few applications need more than 4 channels (maybe 5 for CMYK + alpha
  25. * mask). We recommend 10 as a reasonable compromise; use 4 if you are
  26. * really short on memory. (Each allowed component costs a hundred or so
  27. * bytes of storage, whether actually used in an image or not.)
  28. */
  29. #define MAX_COMPONENTS 10 /* maximum number of image components */
  30. /*
  31. * Basic data types.
  32. * You may need to change these if you have a machine with unusual data
  33. * type sizes; for example, "char" not 8 bits, "short" not 16 bits,
  34. * or "long" not 32 bits. We don't care whether "int" is 16 or 32 bits,
  35. * but it had better be at least 16.
  36. */
  37. /* Representation of a single sample (pixel element value).
  38. * We frequently allocate large arrays of these, so it's important to keep
  39. * them small. But if you have memory to burn and access to char or short
  40. * arrays is very slow on your hardware, you might want to change these.
  41. */
  42. #if BITS_IN_JSAMPLE == 8
  43. /* JSAMPLE should be the smallest type that will hold the values 0..255.
  44. * You can use a signed char by having GETJSAMPLE mask it with 0xFF.
  45. */
  46. #ifdef HAVE_UNSIGNED_CHAR
  47. typedef unsigned char JSAMPLE;
  48. #define GETJSAMPLE(value) ((int) (value))
  49. #else /* not HAVE_UNSIGNED_CHAR */
  50. typedef char JSAMPLE;
  51. #ifdef CHAR_IS_UNSIGNED
  52. #define GETJSAMPLE(value) ((int) (value))
  53. #else
  54. #define GETJSAMPLE(value) ((int) (value) & 0xFF)
  55. #endif /* CHAR_IS_UNSIGNED */
  56. #endif /* HAVE_UNSIGNED_CHAR */
  57. #define MAXJSAMPLE 255
  58. #define CENTERJSAMPLE 128
  59. #endif /* BITS_IN_JSAMPLE == 8 */
  60. #if BITS_IN_JSAMPLE == 12
  61. /* JSAMPLE should be the smallest type that will hold the values 0..4095.
  62. * On nearly all machines "short" will do nicely.
  63. */
  64. typedef short JSAMPLE;
  65. #define GETJSAMPLE(value) ((int) (value))
  66. #define MAXJSAMPLE 4095
  67. #define CENTERJSAMPLE 2048
  68. #endif /* BITS_IN_JSAMPLE == 12 */
  69. /* Representation of a DCT frequency coefficient.
  70. * This should be a signed value of at least 16 bits; "short" is usually OK.
  71. * Again, we allocate large arrays of these, but you can change to int
  72. * if you have memory to burn and "short" is really slow.
  73. */
  74. typedef short JCOEF;
  75. /* Compressed datastreams are represented as arrays of JOCTET.
  76. * These must be EXACTLY 8 bits wide, at least once they are written to
  77. * external storage. Note that when using the stdio data source/destination
  78. * managers, this is also the data type passed to fread/fwrite.
  79. */
  80. #ifdef HAVE_UNSIGNED_CHAR
  81. typedef unsigned char JOCTET;
  82. #define GETJOCTET(value) (value)
  83. #else /* not HAVE_UNSIGNED_CHAR */
  84. typedef char JOCTET;
  85. #ifdef CHAR_IS_UNSIGNED
  86. #define GETJOCTET(value) (value)
  87. #else
  88. #define GETJOCTET(value) ((value) & 0xFF)
  89. #endif /* CHAR_IS_UNSIGNED */
  90. #endif /* HAVE_UNSIGNED_CHAR */
  91. /* These typedefs are used for various table entries and so forth.
  92. * They must be at least as wide as specified; but making them too big
  93. * won't cost a huge amount of memory, so we don't provide special
  94. * extraction code like we did for JSAMPLE. (In other words, these
  95. * typedefs live at a different point on the speed/space tradeoff curve.)
  96. */
  97. /* UINT8 must hold at least the values 0..255. */
  98. #ifdef HAVE_UNSIGNED_CHAR
  99. typedef unsigned char UINT8;
  100. #else /* not HAVE_UNSIGNED_CHAR */
  101. #ifdef CHAR_IS_UNSIGNED
  102. typedef char UINT8;
  103. #else /* not CHAR_IS_UNSIGNED */
  104. typedef short UINT8;
  105. #endif /* CHAR_IS_UNSIGNED */
  106. #endif /* HAVE_UNSIGNED_CHAR */
  107. /* UINT16 must hold at least the values 0..65535. */
  108. #ifdef HAVE_UNSIGNED_SHORT
  109. typedef unsigned short UINT16;
  110. #else /* not HAVE_UNSIGNED_SHORT */
  111. typedef unsigned int UINT16;
  112. #endif /* HAVE_UNSIGNED_SHORT */
  113. /* INT16 must hold at least the values -32768..32767. */
  114. #ifndef XMD_H /* X11/xmd.h correctly defines INT16 */
  115. typedef short INT16;
  116. #endif
  117. /* INT32 must hold at least signed 32-bit values. */
  118. //#ifndef XMD_H /* X11/xmd.h correctly defines INT32 */
  119. //typedef long INT32;
  120. //#endif
  121. /* Datatype used for image dimensions. The JPEG standard only supports
  122. * images up to 64K*64K due to 16-bit fields in SOF markers. Therefore
  123. * "unsigned int" is sufficient on all machines. However, if you need to
  124. * handle larger images and you don't mind deviating from the spec, you
  125. * can change this datatype.
  126. */
  127. typedef unsigned int JDIMENSION;
  128. #define JPEG_MAX_DIMENSION 65500L /* a tad under 64K to prevent overflows */
  129. /* These defines are used in all function definitions and extern declarations.
  130. * You could modify them if you need to change function linkage conventions.
  131. * Another application is to make all functions global for use with debuggers
  132. * or code profilers that require it.
  133. */
  134. #define METHODDEF static /* a function called through method pointers */
  135. #define LOCAL static /* a function used only in its module */
  136. #define GLOBAL /* a function referenced thru EXTERNs */
  137. #define EXTERN extern /* a reference to a GLOBAL function */
  138. /* Here is the pseudo-keyword for declaring pointers that must be "far"
  139. * on 80x86 machines. Most of the specialized coding for 80x86 is handled
  140. * by just saying "FAR *" where such a pointer is needed. In a few places
  141. * explicit coding is needed; see uses of the NEED_FAR_POINTERS symbol.
  142. */
  143. #ifdef NEED_FAR_POINTERS
  144. #undef FAR
  145. #define FAR far
  146. #else
  147. #undef FAR
  148. #define FAR
  149. #endif
  150. /*
  151. * On a few systems, type boolean and/or its values FALSE, TRUE may appear
  152. * in standard header files. Or you may have conflicts with application-
  153. * specific header files that you want to include together with these files.
  154. * Defining HAVE_BOOLEAN before including jpeglib.h should make it work.
  155. */
  156. //#ifndef HAVE_BOOLEAN
  157. //typedef int boolean;
  158. //#endif
  159. #ifndef FALSE /* in case these macros already exist */
  160. #define FALSE 0 /* values of boolean */
  161. #endif
  162. #ifndef TRUE
  163. #define TRUE 1
  164. #endif
  165. /*
  166. * The remaining options affect code selection within the JPEG library,
  167. * but they don't need to be visible to most applications using the library.
  168. * To minimize application namespace pollution, the symbols won't be
  169. * defined unless JPEG_INTERNALS or JPEG_INTERNAL_OPTIONS has been defined.
  170. */
  171. #ifdef JPEG_INTERNALS
  172. #define JPEG_INTERNAL_OPTIONS
  173. #endif
  174. #ifdef JPEG_INTERNAL_OPTIONS
  175. /*
  176. * These defines indicate whether to include various optional functions.
  177. * Undefining some of these symbols will produce a smaller but less capable
  178. * library. Note that you can leave certain source files out of the
  179. * compilation/linking process if you've #undef'd the corresponding symbols.
  180. * (You may HAVE to do that if your compiler doesn't like null source files.)
  181. */
  182. /* Arithmetic coding is unsupported for legal reasons. Complaints to IBM. */
  183. /* Capability options common to encoder and decoder: */
  184. #undef DCT_ISLOW_SUPPORTED /* slow but accurate integer algorithm */
  185. #undef DCT_IFAST_SUPPORTED /* faster, less accurate integer method */
  186. #define DCT_FLOAT_SUPPORTED /* floating-point: accurate, fast on fast HW */
  187. /* Encoder capability options: */
  188. #undef C_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
  189. #define C_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
  190. #define C_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
  191. #define ENTROPY_OPT_SUPPORTED /* Optimization of entropy coding parms? */
  192. /* Note: if you selected 12-bit data precision, it is dangerous to turn off
  193. * ENTROPY_OPT_SUPPORTED. The standard Huffman tables are only good for 8-bit
  194. * precision, so jchuff.c normally uses entropy optimization to compute
  195. * usable tables for higher precision. If you don't want to do optimization,
  196. * you'll have to supply different default Huffman tables.
  197. * The exact same statements apply for progressive JPEG: the default tables
  198. * don't work for progressive mode. (This may get fixed, however.)
  199. */
  200. #define INPUT_SMOOTHING_SUPPORTED /* Input image smoothing option? */
  201. /* Decoder capability options: */
  202. #undef D_ARITH_CODING_SUPPORTED /* Arithmetic coding back end? */
  203. #undef D_MULTISCAN_FILES_SUPPORTED /* Multiple-scan JPEG files? */
  204. #undef D_PROGRESSIVE_SUPPORTED /* Progressive JPEG? (Requires MULTISCAN)*/
  205. #undef BLOCK_SMOOTHING_SUPPORTED /* Block smoothing? (Progressive only) */
  206. #undef IDCT_SCALING_SUPPORTED /* Output rescaling via IDCT? */
  207. #undef UPSAMPLE_SCALING_SUPPORTED /* Output rescaling at upsample stage? */
  208. #undef UPSAMPLE_MERGING_SUPPORTED /* Fast path for sloppy upsampling? */
  209. #undef QUANT_1PASS_SUPPORTED /* 1-pass color quantization? */
  210. #undef QUANT_2PASS_SUPPORTED /* 2-pass color quantization? */
  211. /* more capability options later, no doubt */
  212. /*
  213. * Ordering of RGB data in scanlines passed to or from the application.
  214. * If your application wants to deal with data in the order B,G,R, just
  215. * change these macros. You can also deal with formats such as R,G,B,X
  216. * (one extra byte per pixel) by changing RGB_PIXELSIZE. Note that changing
  217. * the offsets will also change the order in which colormap data is organized.
  218. * RESTRICTIONS:
  219. * 1. The sample applications cjpeg,djpeg do NOT support modified RGB formats.
  220. * 2. These macros only affect RGB<=>YCbCr color conversion, so they are not
  221. * useful if you are using JPEG color spaces other than YCbCr or grayscale.
  222. * 3. The color quantizer modules will not behave desirably if RGB_PIXELSIZE
  223. * is not 3 (they don't understand about dummy color components!). So you
  224. * can't use color quantization if you change that value.
  225. */
  226. #define RGB_RED 0 /* Offset of Red in an RGB scanline element */
  227. #define RGB_GREEN 1 /* Offset of Green */
  228. #define RGB_BLUE 2 /* Offset of Blue */
  229. #define RGB_PIXELSIZE 4 /* JSAMPLEs per RGB scanline element */
  230. /* Definitions for speed-related optimizations. */
  231. /* If your compiler supports inline functions, define INLINE
  232. * as the inline keyword; otherwise define it as empty.
  233. */
  234. #ifndef INLINE
  235. #ifdef __GNUC__ /* for instance, GNU C knows about inline */
  236. #define INLINE __inline__
  237. #endif
  238. #ifndef INLINE
  239. #define INLINE /* default is to define it as empty */
  240. #endif
  241. #endif
  242. /* On some machines (notably 68000 series) "int" is 32 bits, but multiplying
  243. * two 16-bit shorts is faster than multiplying two ints. Define MULTIPLIER
  244. * as short on such a machine. MULTIPLIER must be at least 16 bits wide.
  245. */
  246. #ifndef MULTIPLIER
  247. #define MULTIPLIER int /* type for fastest integer multiply */
  248. #endif
  249. /* FAST_FLOAT should be either float or double, whichever is done faster
  250. * by your compiler. (Note that this type is only used in the floating point
  251. * DCT routines, so it only matters if you've defined DCT_FLOAT_SUPPORTED.)
  252. * Typically, float is faster in ANSI C compilers, while double is faster in
  253. * pre-ANSI compilers (because they insist on converting to double anyway).
  254. * The code below therefore chooses float if we have ANSI-style prototypes.
  255. */
  256. #ifndef FAST_FLOAT
  257. #ifdef HAVE_PROTOTYPES
  258. #define FAST_FLOAT float
  259. #else
  260. #define FAST_FLOAT double
  261. #endif
  262. #endif
  263. #endif /* JPEG_INTERNAL_OPTIONS */