summaryrefslogtreecommitdiff
path: root/gs/jpeg/wrppm.c
blob: 6c6d908817c9c3dd253f3432ec1a5a8d7251923c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
/*
 * wrppm.c
 *
 * Copyright (C) 1991-1996, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains routines to write output images in PPM/PGM format.
 * The extended 2-byte-per-sample raw PPM/PGM formats are supported.
 * The PBMPLUS library is NOT required to compile this software
 * (but it is highly useful as a set of PPM image manipulation programs).
 *
 * These routines may need modification for non-Unix environments or
 * specialized applications.  As they stand, they assume output to
 * an ordinary stdio stream.
 */

#include "cdjpeg.h"		/* Common decls for cjpeg/djpeg applications */

#ifdef PPM_SUPPORTED


/*
 * For 12-bit JPEG data, we either downscale the values to 8 bits
 * (to write standard byte-per-sample PPM/PGM files), or output
 * nonstandard word-per-sample PPM/PGM files.  Downscaling is done
 * if PPM_NORAWWORD is defined (this can be done in the Makefile
 * or in jconfig.h).
 * (When the core library supports data precision reduction, a cleaner
 * implementation will be to ask for that instead.)
 */

#if BITS_IN_JSAMPLE == 8
#define PUTPPMSAMPLE(ptr,v)  *ptr++ = (char) (v)
#define BYTESPERSAMPLE 1
#define PPM_MAXVAL 255
#else
#ifdef PPM_NORAWWORD
#define PUTPPMSAMPLE(ptr,v)  *ptr++ = (char) ((v) >> (BITS_IN_JSAMPLE-8))
#define BYTESPERSAMPLE 1
#define PPM_MAXVAL 255
#else
/* The word-per-sample format always puts the LSB first. */
#define PUTPPMSAMPLE(ptr,v)			\
	{ register int val_ = v;		\
	  *ptr++ = (char) (val_ & 0xFF);	\
	  *ptr++ = (char) ((val_ >> 8) & 0xFF);	\
	}
#define BYTESPERSAMPLE 2
#define PPM_MAXVAL ((1<<BITS_IN_JSAMPLE)-1)
#endif
#endif


/*
 * When JSAMPLE is the same size as char, we can just fwrite() the
 * decompressed data to the PPM or PGM file.  On PCs, in order to make this
 * work the output buffer must be allocated in near data space, because we are
 * assuming small-data memory model wherein fwrite() can't reach far memory.
 * If you need to process very wide images on a PC, you might have to compile
 * in large-memory model, or else replace fwrite() with a putc() loop ---
 * which will be much slower.
 */


/* Private version of data destination object */

typedef struct {
  struct djpeg_dest_struct pub;	/* public fields */

  /* Usually these two pointers point to the same place: */
  char *iobuffer;		/* fwrite's I/O buffer */
  JSAMPROW pixrow;		/* decompressor output buffer */
  size_t buffer_width;		/* width of I/O buffer */
  JDIMENSION samples_per_row;	/* JSAMPLEs per output row */
} ppm_dest_struct;

typedef ppm_dest_struct * ppm_dest_ptr;


/*
 * Write some pixel data.
 * In this module rows_supplied will always be 1.
 *
 * put_pixel_rows handles the "normal" 8-bit case where the decompressor
 * output buffer is physically the same as the fwrite buffer.
 */

METHODDEF(void)
put_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
		JDIMENSION rows_supplied)
{
  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;

  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}


/*
 * This code is used when we have to copy the data and apply a pixel
 * format translation.  Typically this only happens in 12-bit mode.
 */

METHODDEF(void)
copy_pixel_rows (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
		 JDIMENSION rows_supplied)
{
  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
  register char * bufferptr;
  register JSAMPROW ptr;
  register JDIMENSION col;

  ptr = dest->pub.buffer[0];
  bufferptr = dest->iobuffer;
  for (col = dest->samples_per_row; col > 0; col--) {
    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(*ptr++));
  }
  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}


/*
 * Write some pixel data when color quantization is in effect.
 * We have to demap the color index values to straight data.
 */

METHODDEF(void)
put_demapped_rgb (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
		  JDIMENSION rows_supplied)
{
  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
  register char * bufferptr;
  register int pixval;
  register JSAMPROW ptr;
  register JSAMPROW color_map0 = cinfo->colormap[0];
  register JSAMPROW color_map1 = cinfo->colormap[1];
  register JSAMPROW color_map2 = cinfo->colormap[2];
  register JDIMENSION col;

  ptr = dest->pub.buffer[0];
  bufferptr = dest->iobuffer;
  for (col = cinfo->output_width; col > 0; col--) {
    pixval = GETJSAMPLE(*ptr++);
    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map0[pixval]));
    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map1[pixval]));
    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map2[pixval]));
  }
  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}


METHODDEF(void)
put_demapped_gray (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo,
		   JDIMENSION rows_supplied)
{
  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;
  register char * bufferptr;
  register JSAMPROW ptr;
  register JSAMPROW color_map = cinfo->colormap[0];
  register JDIMENSION col;

  ptr = dest->pub.buffer[0];
  bufferptr = dest->iobuffer;
  for (col = cinfo->output_width; col > 0; col--) {
    PUTPPMSAMPLE(bufferptr, GETJSAMPLE(color_map[GETJSAMPLE(*ptr++)]));
  }
  (void) JFWRITE(dest->pub.output_file, dest->iobuffer, dest->buffer_width);
}


/*
 * Startup: write the file header.
 */

METHODDEF(void)
start_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{
  ppm_dest_ptr dest = (ppm_dest_ptr) dinfo;

  /* Emit file header */
  switch (cinfo->out_color_space) {
  case JCS_GRAYSCALE:
    /* emit header for raw PGM format */
    fprintf(dest->pub.output_file, "P5\n%ld %ld\n%d\n",
	    (long) cinfo->output_width, (long) cinfo->output_height,
	    PPM_MAXVAL);
    break;
  case JCS_RGB:
    /* emit header for raw PPM format */
    fprintf(dest->pub.output_file, "P6\n%ld %ld\n%d\n",
	    (long) cinfo->output_width, (long) cinfo->output_height,
	    PPM_MAXVAL);
    break;
  default:
    ERREXIT(cinfo, JERR_PPM_COLORSPACE);
  }
}


/*
 * Finish up at the end of the file.
 */

METHODDEF(void)
finish_output_ppm (j_decompress_ptr cinfo, djpeg_dest_ptr dinfo)
{
  /* Make sure we wrote the output file OK */
  fflush(dinfo->output_file);
  if (ferror(dinfo->output_file))
    ERREXIT(cinfo, JERR_FILE_WRITE);
}


/*
 * The module selection routine for PPM format output.
 */

GLOBAL(djpeg_dest_ptr)
jinit_write_ppm (j_decompress_ptr cinfo)
{
  ppm_dest_ptr dest;

  /* Create module interface object, fill in method pointers */
  dest = (ppm_dest_ptr)
      (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				  SIZEOF(ppm_dest_struct));
  dest->pub.start_output = start_output_ppm;
  dest->pub.finish_output = finish_output_ppm;

  /* Calculate output image dimensions so we can allocate space */
  jpeg_calc_output_dimensions(cinfo);

  /* Create physical I/O buffer.  Note we make this near on a PC. */
  dest->samples_per_row = cinfo->output_width * cinfo->out_color_components;
  dest->buffer_width = dest->samples_per_row * (BYTESPERSAMPLE * SIZEOF(char));
  dest->iobuffer = (char *) (*cinfo->mem->alloc_small)
    ((j_common_ptr) cinfo, JPOOL_IMAGE, dest->buffer_width);

  if (cinfo->quantize_colors || BITS_IN_JSAMPLE != 8 ||
      SIZEOF(JSAMPLE) != SIZEOF(char)) {
    /* When quantizing, we need an output buffer for colormap indexes
     * that's separate from the physical I/O buffer.  We also need a
     * separate buffer if pixel format translation must take place.
     */
    dest->pub.buffer = (*cinfo->mem->alloc_sarray)
      ((j_common_ptr) cinfo, JPOOL_IMAGE,
       cinfo->output_width * cinfo->output_components, (JDIMENSION) 1);
    dest->pub.buffer_height = 1;
    if (! cinfo->quantize_colors)
      dest->pub.put_pixel_rows = copy_pixel_rows;
    else if (cinfo->out_color_space == JCS_GRAYSCALE)
      dest->pub.put_pixel_rows = put_demapped_gray;
    else
      dest->pub.put_pixel_rows = put_demapped_rgb;
  } else {
    /* We will fwrite() directly from decompressor output buffer. */
    /* Synthesize a JSAMPARRAY pointer structure */
    /* Cast here implies near->far pointer conversion on PCs */
    dest->pixrow = (JSAMPROW) dest->iobuffer;
    dest->pub.buffer = & dest->pixrow;
    dest->pub.buffer_height = 1;
    dest->pub.put_pixel_rows = put_pixel_rows;
  }

  return (djpeg_dest_ptr) dest;
}

#endif /* PPM_SUPPORTED */