1 /*
2 * wrppm.c
3 *
4 * Copyright (C) 1991-1994, 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
put_pixel_rows(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo,JDIMENSION rows_supplied)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
copy_pixel_rows(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo,JDIMENSION rows_supplied)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
put_demapped_rgb(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo,JDIMENSION rows_supplied)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
put_demapped_gray(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo,JDIMENSION rows_supplied)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
start_output_ppm(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo)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
finish_output_ppm(j_decompress_ptr cinfo,djpeg_dest_ptr dinfo)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
jinit_write_ppm(j_decompress_ptr cinfo)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 */
269