core/libs/jpeg-6b/wrppm.c

   1 /*
   2  * wrppm.c
   3  *
   4  * Copyright (C) 1991-1996, 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 routines to write output images in PPM/PGM format.
   9  * The extended 2-byte-per-sample raw PPM/PGM formats are supported.
  10  * The PBMPLUS library is NOT required to compile this software
  11  * (but it is highly useful as a set of PPM image manipulation programs).
  12  *
  13  * These routines may need modification for non-Unix environments or
  14  * specialized applications.  As they stand, they assume output to
  15  * an ordinary stdio stream.
  16  */
  17
  18 #include "cdjpeg.h"             /* Common decls for cjpeg/djpeg applications */
  19
  20 #ifdef PPM_SUPPORTED
  21
  22
  23 /*
  24  * For 12-bit JPEG data, we either downscale the values to 8 bits
  25  * (to write standard byte-per-sample PPM/PGM files), or output
  26  * nonstandard word-per-sample PPM/PGM files.  Downscaling is done
  27  * if PPM_NORAWWORD is defined (this can be done in the Makefile
  28  * or in jconfig.h).
  29  * (When the core library supports data precision reduction, a cleaner
  30  * implementation will be to ask for that instead.)
  31  */
  32
  33 #if BITS_IN_JSAMPLE == 8
  34 #define PUTPPMSAMPLE(ptr,v)  *ptr++ = (char) (v)
  35 #define BYTESPERSAMPLE 1
  36 #define PPM_MAXVAL 255
  37 #else
  38 #ifdef PPM_NORAWWORD
  39 #define PUTPPMSAMPLE(ptr,v)  *ptr++ = (char) ((v) >> (BITS_IN_JSAMPLE-8))
  40 #define BYTESPERSAMPLE 1
  41 #define PPM_MAXVAL 255
  42 #else
  43 /* The word-per-sample format always puts the LSB first. */
  44 #define PUTPPMSAMPLE(ptr,v)                     \
  45         { register int val_ = v;                \
  46           *ptr++ = (char) (val_ & 0xFF);        \
  47           *ptr++ = (char) ((val_ >> 8) & 0xFF); \
  48         }
  49 #define BYTESPERSAMPLE 2
  50 #define PPM_MAXVAL ((1<<BITS_IN_JSAMPLE)-1)
  51 #endif
  52 #endif
  53
  54
  55 /*
  56  * When JSAMPLE is the same size as char, we can just fwrite() the
  57  * decompressed data to the PPM or PGM file.  On PCs, in order to make this
  58  * work the output buffer must be allocated in near data space, because we are
  59  * assuming small-data memory model wherein fwrite() can't reach far memory.
  60  * If you need to process very wide images on a PC, you might have to compile
  61  * in large-memory model, or else replace fwrite() with a putc() loop ---
  62  * which will be much slower.
  63  */
  64
  65
  66 /* Private version of data destination object */
  67
  68 typedef struct {
  69   struct djpeg_dest_struct pub; /* public fields */
  70
  71   /* Usually these two pointers point to the same place: */
  72   char *iobuffer;               /* fwrite's I/O buffer */
  73   JSAMPROW pixrow;              /* decompressor output buffer */
  74   size_t buffer_width;          /* width of I/O buffer */
  75   JDIMENSION samples_per_row;   /* JSAMPLEs per output row */
  76 } ppm_dest_struct;
  77
  78 typedef ppm_dest_struct * ppm_dest_ptr;
  79
  80
  81 /*
  82  * Write some pixel data.
  83  * In this module rows_supplied will always be 1.
  84  *
  85  * put_pixel_rows handles the "normal" 8-bit case where the decompressor
  86  * output buffer is physically the same as the fwrite buffer.
  87  */
  88
  89 METHODDEF(void)
  90 put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
  91                 JDIMENSION rows_supplied)
  92 {
  93   ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
  94
  95   (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
  96 }
  97
  98
  99 /*
 100  * This code is used when we have to copy the data and apply a pixel
 101  * format translation.  Typically this only happens in 12-bit mode.
 102  */
 103
 104 METHODDEF(void)
 105 copy_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
 106                  JDIMENSION rows_supplied)
 107 {
 108   ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
 109   register char * bufferptr;
 110   register JSAMPROW ptr;
 111   register JDIMENSION col;
 112
 113   ptr = dest->pub.buffer[0];
 114   bufferptr = dest->iobuffer;
 115   for (col = dest->samples_per_row; col > 0; col--) {
 116     PUTPPMSAMPLE(bufferptr, GETJSAMPLE(*ptr++));
 117   }
 118   (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
 119 }
 120
 121
 122 /*
 123  * Write some pixel data when color quantization is in effect.
 124  * We have to demap the color index values to straight data.
 125  */
 126
 127 METHODDEF(void)
 128 put_demapped_rgb (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
 129                   JDIMENSION rows_supplied)
 130 {
 131   ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
 132   register char * bufferptr;
 133   register int pixval;
 134   register JSAMPROW ptr;
 135   register JSAMPROW color_map0 = cinfo->colormap[0];
 136   register JSAMPROW color_map1 = cinfo->colormap[1];
 137   register JSAMPROW color_map2 = cinfo->colormap[2];
 138   register JDIMENSION col;
 139
 140   ptr = dest->pub.buffer[0];
 141   bufferptr = dest->iobuffer;
 142   for (col = cinfo->output_width; col > 0; col--) {
 143     pixval = GETJSAMPLE(*ptr++);
 144     PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map0[pixval]));
 145     PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map1[pixval]));
 146     PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map2[pixval]));
 147   }
 148   (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
 149 }
 150
 151
 152 METHODDEF(void)
 153 put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
 154                    JDIMENSION rows_supplied)
 155 {
 156   ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
 157   register char * bufferptr;
 158   register JSAMPROW ptr;
 159   register JSAMPROW color_map = cinfo->colormap[0];
 160   register JDIMENSION col;
 161
 162   ptr = dest->pub.buffer[0];
 163   bufferptr = dest->iobuffer;
 164   for (col = cinfo->output_width; col > 0; col--) {
 165     PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map[GETJSAMPLE(*ptr++)]));
 166   }
 167   (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
 168 }
 169
 170
 171 /*
 172  * Startup: write the file header.
 173  */
 174
 175 METHODDEF(void)
 176 start_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
 177 {
 178   ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
 179
 180   /* Emit file header */
 181   switch (cinfo->out_color_space) {
 182   case JCS_GRAYSCALE:
 183     /* emit header for raw PGM format */
 184     fprintf(dest->pub.output_file, "P5\n%ld %ld\n%d\n",
 185             (long) cinfo->output_width, (long) cinfo->output_height,
 186             PPM_MAXVAL);
 187     break;
 188   case JCS_RGB:
 189     /* emit header for raw PPM format */
 190     fprintf(dest->pub.output_file, "P6\n%ld %ld\n%d\n",
 191             (long) cinfo->output_width, (long) cinfo->output_height,
 192             PPM_MAXVAL);
 193     break;
 194   default:
 195     ERREXIT(cinfo, JERR_PPM_COLORSPACE);
 196   }
 197 }
 198
 199
 200 /*
 201  * Finish up at the end of the file.
 202  */
 203
 204 METHODDEF(void)
 205 finish_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
 206 {
 207   /* Make sure we wrote the output file OK */
 208   fflush(dinfo->output_file);
 209   if (ferror(dinfo->output_file))
 210     ERREXIT(cinfo, JERR_FILE_WRITE);
 211 }
 212
 213
 214 /*
 215  * The module selection routine for PPM format output.
 216  */
 217
 218 GLOBAL(djpeg_dest_ptr)
 219 jinit_write_ppm (j_decompress_ptr cinfo)
 220 {
 221   ppm_dest_ptr dest;
 222
 223   /* Create module interface object, fill in method pointers */
 224   dest = (ppm_dest_ptr)
 225       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 226                                   SIZEOF(ppm_dest_struct));
 227   dest->pub.start_output = start_output_ppm;
 228   dest->pub.finish_output = finish_output_ppm;
 229
 230   /* Calculate output image dimensions so we can allocate space */
 231   jpeg_calc_output_dimensions(cinfo);
 232
 233   /* Create physical I/O buffer.  Note we make this near on a PC. */
 234   dest->samples_per_row = cinfo->output_width * cinfo->out_color_components;
 235   dest->buffer_width = dest->samples_per_row * (BYTESPERSAMPLE * SIZEOF(char));
 236   dest->iobuffer = (char *) (*cinfo->mem->alloc_small)
 237     ((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width);
 238
 239   if (cinfo->quantize_colors || BITS_IN_JSAMPLE != 8 ||
 240       SIZEOF(JSAMPLE) != SIZEOF(char)) {
 241     /* When quantizing, we need an output buffer for colormap indexes
 242      * that's separate from the physical I/O buffer.  We also need a
 243      * separate buffer if pixel format translation must take place.
 244      */
 245     dest->pub.buffer = (*cinfo->mem->alloc_sarray)
 246       ((j_common_ptr) cinfo, JPOOL_IMAGE,
 247        cinfo->output_width * cinfo->output_components, (JDIMENSION) 1);
 248     dest->pub.buffer_height = 1;
 249     if (! cinfo->quantize_colors)
 250       dest->pub.put_pixel_rows = copy_pixel_rows;
 251     else if (cinfo->out_color_space == JCS_GRAYSCALE)
 252       dest->pub.put_pixel_rows = put_demapped_gray;
 253     else
 254       dest->pub.put_pixel_rows = put_demapped_rgb;
 255   } else {
 256     /* We will fwrite() directly from decompressor output buffer. */
 257     /* Synthesize a JSAMPARRAY pointer structure */
 258     /* Cast here implies near->far pointer conversion on PCs */
 259     dest->pixrow = (JSAMPROW) dest->iobuffer;
 260     dest->pub.buffer = & dest->pixrow;
 261     dest->pub.buffer_height = 1;
 262     dest->pub.put_pixel_rows = put_pixel_rows;
 263   }
 264
 265   return (djpeg_dest_ptr) dest;
 266 }
 267
 268 #endif /* PPM_SUPPORTED */