about summary refs log tree commit diff
path: root/lib/libppmcolor.c
blob: d6f00218fd619cff83418e9d980c05d9ffd9bb96 (plain) (blame)
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
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
/*
** Copyright (C) 1989 by Jef Poskanzer.
**
** Permission to use, copy, modify, and distribute this software and its
** documentation for any purpose and without fee is hereby granted, provided
** that the above copyright notice appear in all copies and that both that
** copyright notice and this permission notice appear in supporting
** documentation.  This software is provided "as is" without express or
** implied warranty.
*/

#include <stdbool.h>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>

#include "netpbm/pm_c_util.h"
#include "netpbm/mallocvar.h"
#include "netpbm/nstring.h"
#include "ppm.h"
#include "colorname.h"
#include "pam.h"


pixel
ppm_parsecolor2(const char * const colorname,
                pixval       const maxval,
                int          const closeOk) {

    tuple const color = pnm_parsecolor2(colorname, maxval, closeOk);

    pixel retval;

    PPM_PUTR(retval, color[PAM_RED_PLANE]);
    PPM_PUTG(retval, color[PAM_GRN_PLANE]);
    PPM_PUTB(retval, color[PAM_BLU_PLANE]);

    free(color);

    return retval;
}



pixel
ppm_parsecolor(const char * const colorname,
               pixval       const maxval) {

    return ppm_parsecolor2(colorname, maxval, true);
}



char *
ppm_colorname(const pixel * const colorP,
              pixval        const maxval,
              int           const hexok)   {

    int r, g, b;
    FILE * fileP;
    static char colorname[200];
        /* Null string means no suitable name so far */

    if (maxval == 255) {
        r = PPM_GETR(*colorP);
        g = PPM_GETG(*colorP);
        b = PPM_GETB(*colorP);
    } else {
        r = (int) PPM_GETR(*colorP) * 255 / (int) maxval;
        g = (int) PPM_GETG(*colorP) * 255 / (int) maxval;
        b = (int) PPM_GETB(*colorP) * 255 / (int) maxval;
    }

    fileP = pm_openColornameFile(NULL, !hexok);

    if (!fileP)
        STRSCPY(colorname, "");
    else {
        int bestDiff;
        bool eof;

        for (bestDiff = 32767, eof = false;
             !eof && bestDiff > 0; ) {
            struct colorfile_entry const ce = pm_colorget(fileP);
            if (ce.colorname)  {
                int const thisDiff =
                    abs(r - (int)ce.r) +
                    abs(g - (int)ce.g) +
                    abs(b - (int)ce.b);

                if (thisDiff < bestDiff) {
                    bestDiff = thisDiff;
                    STRSCPY(colorname, ce.colorname);
                }
            } else
                eof = true;
        }
        fclose(fileP);

        if (bestDiff == 32767) {
            /* Color file contain no entries, so we can't even pick a close
               one
            */
            STRSCPY(colorname, "");
        } else if (bestDiff > 0 && hexok) {
            /* We didn't find an exact match and user is willing to accept
               hex, so we don't have to use an approximate match.
            */
            STRSCPY(colorname, "");
        }
    }

    if (streq(colorname, "")) {
        if (hexok) {
            /* Color lookup failed, but caller is willing to take an X11-style
               hex specifier, so return that.
            */
            sprintf(colorname, "#%02x%02x%02x", r, g, b);
        } else {
            pm_error("Couldn't find any name colors at all");
        }
    }

    return colorname;
}



#define MAXCOLORNAMES 1000u

static const char **
allocColorNames() {

    const char ** colornames;

    MALLOCARRAY(colornames, MAXCOLORNAMES);

    if (colornames) {
        unsigned int i;
        for (i = 0; i < MAXCOLORNAMES; ++i)
            colornames[i] = NULL;
    }
    return colornames;
}



static colorhash_table
allocColorHash(void) {

    colorhash_table cht;
    jmp_buf jmpbuf;
    jmp_buf * origJmpbufP;

    if (setjmp(jmpbuf) != 0)
        cht = NULL;
    else {
        pm_setjmpbufsave(&jmpbuf, &origJmpbufP);
        cht = ppm_alloccolorhash();
    }
    pm_setjmpbuf(origJmpbufP);

    return cht;
}



static void
processColorfileEntry(struct colorfile_entry const ce,
                      colorhash_table        const cht,
                      const char **          const colornames,
                      pixel *                const colors,
                      unsigned int *         const colornameIndexP,
                      const char **          const errorP) {

    if (*colornameIndexP >= MAXCOLORNAMES)
        pm_asprintf(errorP, "Too many colors in colorname dictionary.  "
                    "Max allowed is %u", MAXCOLORNAMES);
    else {
        pixel color;

        PPM_ASSIGN(color, ce.r, ce.g, ce.b);

        if (ppm_lookupcolor(cht, &color) >= 0) {
            /* The color is already in the hash, which means we saw it
               earlier in the file.  We prefer the first name that the
               file gives for each color, so we just ignore the
               current entry.
            */
            *errorP = NULL;
        } else {
            ppm_addtocolorhash(cht, &color, *colornameIndexP);
            colornames[*colornameIndexP] = pm_strdup(ce.colorname);
            colors[*colornameIndexP] = color;
            if (colornames[*colornameIndexP] == pm_strsol)
                pm_asprintf(errorP, "Unable to allocate space for color name");
            else {
                *errorP = NULL;
                ++(*colornameIndexP);
            }
        }
    }
}



static void
openColornameFile(const char *  const fileName,
                  bool          const mustOpen,
                  FILE **       const filePP,
                  const char ** const errorP) {

    jmp_buf jmpbuf;
    jmp_buf * origJmpbufP;

    if (setjmp(jmpbuf) != 0) {
        pm_asprintf(errorP, "Failed to open color name file");
    } else {
        pm_setjmpbufsave(&jmpbuf, &origJmpbufP);

        *filePP = pm_openColornameFile(fileName, mustOpen);

        *errorP = NULL;  /* Would have longjmped if there were a problem */
    }
    pm_setjmpbuf(origJmpbufP);
}



static void
readOpenColorFile(FILE *          const colorFileP,
                  unsigned int *  const nColorsP,
                  const char **   const colornames,
                  pixel *         const colors,
                  colorhash_table const cht,
                  const char **   const errorP) {
/*----------------------------------------------------------------------------
   Read the color dictionary file *colorFileP and add the colors in it
   to colornames[], colors[], and 'cht'.

   colornames[] and colors[] must be allocated with MAXCOLORNAMES entries
   at entry.

   We may add colors to 'cht' even if we fail.
-----------------------------------------------------------------------------*/
    unsigned int nColorsDone;
    bool done;

    nColorsDone = 0;
    done = false;
    *errorP = NULL;

    while (!done && !*errorP) {
        struct colorfile_entry const ce = pm_colorget(colorFileP);

        if (!ce.colorname)
            done = true;
        else
            processColorfileEntry(ce, cht, colornames, colors,
                                  &nColorsDone, errorP);
    }
    *nColorsP = nColorsDone;

    if (*errorP) {
        unsigned int colorIndex;

        for (colorIndex = 0; colorIndex < nColorsDone; ++colorIndex)
            pm_strfree(colornames[colorIndex]);
    }
}



static void
readColorFile(const char *    const fileName,
              bool            const mustOpen,
              unsigned int *  const nColorsP,
              const char **   const colornames,
              pixel *         const colors,
              colorhash_table const cht,
              const char **   const errorP) {
/*----------------------------------------------------------------------------
   Read the color dictionary file named 'fileName' and add the colors in it
   to colornames[], colors[], and 'cht'.  Return as *nColorsP the number
   of colors in it.

   If the file is not openable (e.g. no file by that name exists), abort the
   program if 'mustOpen' is true; otherwise, return values indicating a
   dictionary with no colors.

   colornames[] and colors[] must be allocated with MAXCOLORNAMES entries
   at entry.

   We may add colors to 'cht' even if we fail.
-----------------------------------------------------------------------------*/
    FILE * colorFileP;

    openColornameFile(fileName, mustOpen, &colorFileP, errorP);
    if (!*errorP) {
        if (colorFileP == NULL) {
            /* Couldn't open it, but Caller says treat same as
               empty file
            */
            *nColorsP = 0;
            *errorP = NULL;
        } else {
            readOpenColorFile(colorFileP, nColorsP, colornames, colors, cht,
                              errorP);

            fclose(colorFileP);
        }
    }
}



static void
readcolordict(const char *      const fileName,
              bool              const mustOpen,
              unsigned int *    const nColorsP,
              const char ***    const colorNamesP,
              pixel **          const colorsP,
              colorhash_table * const chtP,
              const char **     const errorP) {
/*----------------------------------------------------------------------------
  Same as 'ppm_readcolordict' except that a) if we fail, we return a message
  as *errorP instead of issuing a message; and b) we always return all three
  return values.
-----------------------------------------------------------------------------*/
    const char ** colorNames;
        /* List of all the color names in the dictionary */

    colorNames = allocColorNames();

    if (colorNames == NULL)
        pm_asprintf(errorP, "Unable to allocate space for colorname table.");
    else {
        pixel * colors;
            /* colors[i] is the color that goes with name colorNames[i] */

        MALLOCARRAY(colors, MAXCOLORNAMES);

        if (colors == NULL)
            pm_asprintf(errorP, "Unable to allocate space for color table.");
        else {
            colorhash_table cht;
                /* Hash table mapping colorNames[] to colors[] */

            cht = allocColorHash();

            if (cht == NULL)
                pm_asprintf(errorP, "Unable to allocate space for color hash");
            else {
                readColorFile(fileName, mustOpen,
                              nColorsP, colorNames, colors, cht,
                              errorP);

                if (*errorP)
                    ppm_freecolorhash(cht);
                else
                    *chtP = cht;
            }
            if (*errorP)
                free(colors);
            else
                *colorsP = colors;
        }
        if (*errorP)
            free(colorNames);
        else
            *colorNamesP = colorNames;
    }
}



void
ppm_readcolordict(const char *      const fileName,
                  int               const mustOpen,
                  unsigned int *    const nColorsP,
                  const char ***    const colorNamesP,
                  pixel **          const colorsP,
                  colorhash_table * const chtP) {
/*----------------------------------------------------------------------------
   Read the color dictionary from the file named 'fileName'.  If we can't open
   the file (e.g. because it does not exist), and 'mustOpen' is false, return
   an empty dictionary (it contains no colors).  But if 'mustOpen' is true,
   abort the program instead of returning an empty dictionary.

   Return as *nColorsP the number of colors in the dictionary.

   Return as *colorNamesP the names of those colors.  *colorNamesP is a
   malloced array that Caller must free with ppm_freecolorNames().
   The first *nColorsP entries are valid; *chtP contains indices into this
   array.

   Return as *colorsP the colors.  *colorsP is a malloced array of size
   MAXCOLORS with the first elements filled in and the rest undefined.

   Return as *chtP a color hash table mapping each color in the dictionary
   to the index into *colorNamesP for the name of the color.

   Each of 'nColorsP, 'colorNamesP', and 'colorsP' may be null, in which case
   we do not return the corresponding information (or allocate memory for it).
-----------------------------------------------------------------------------*/
    colorhash_table cht;
    const char ** colorNames;
    pixel * colors;
    unsigned int nColors;
    const char * error;

    readcolordict(fileName, mustOpen, &nColors, &colorNames, &colors, &cht,
                  &error);

    if (error) {
        pm_errormsg("%s", error);
        pm_strfree(error);
        pm_longjmp();
    } else {
        if (chtP)
            *chtP = cht;
        else
            ppm_freecolorhash(cht);
        if (colorNamesP)
            *colorNamesP = colorNames;
        else
            ppm_freecolornames(colorNames);
        if (colorsP)
            *colorsP = colors;
        else
            ppm_freerow(colors);
        if (nColorsP)
            *nColorsP = nColors;
    }
}



void
ppm_readcolornamefile(const char *      const fileName,
                      int               const mustOpen,
                      colorhash_table * const chtP,
                      const char ***    const colorNamesP) {

    ppm_readcolordict(fileName, mustOpen, NULL, colorNamesP, NULL, chtP);
}



void
ppm_freecolornames(const char ** const colorNames) {

    unsigned int i;

    for (i = 0; i < MAXCOLORNAMES; ++i)
        if (colorNames[i])
            free((char *)colorNames[i]);

    free(colorNames);
}



static unsigned int
nonnegative(unsigned int const arg) {

    if ((int)(arg) < 0)
        return 0;
    else
        return arg;
}



pixel
ppm_color_from_ycbcr(unsigned int const y,
                     int          const cb,
                     int          const cr) {
/*----------------------------------------------------------------------------
   Return the color that has luminance 'y', blue chrominance 'cb', and
   red chrominance 'cr'.

   The 3 input values can be on any scale (as long as it's the same
   scale for all 3) and the maxval of the returned pixel value is the
   same as that for the input values.

   Rounding may cause an output value to be greater than the maxval.
-----------------------------------------------------------------------------*/
    pixel retval;

    PPM_ASSIGN(retval,
               y + 1.4022 * cr,
               nonnegative(y - 0.7145 * cr - 0.3456 * cb),
               y + 1.7710 * cb
        );

    return retval;
}



pixel
ppm_color_from_hsv(struct hsv const hsv,
                   pixval     const maxval) {

    pixel retval;
    double R, G, B;

    if (hsv.s == 0) {
        R = hsv.v;
        G = hsv.v;
        B = hsv.v;
    } else {
        unsigned int const sectorSize = 60;
            /* Color wheel is divided into six 60 degree sectors. */
        unsigned int const sector = (hsv.h/sectorSize);
            /* The sector in which our color resides.  Value is in 0..5 */
        double const f = (hsv.h - sector*sectorSize)/60;
            /* The fraction of the way the color is from one side of
               our sector to the other side, going clockwise.  Value is
               in [0, 1).
            */
        double const m = (hsv.v * (1 - hsv.s));
        double const n = (hsv.v * (1 - (hsv.s * f)));
        double const k = (hsv.v * (1 - (hsv.s * (1 - f))));

        switch (sector) {
        case 0:
            R = hsv.v;
            G = k;
            B = m;
            break;
        case 1:
            R = n;
            G = hsv.v;
            B = m;
            break;
        case 2:
            R = m;
            G = hsv.v;
            B = k;
            break;
        case 3:
            R = m;
            G = n;
            B = hsv.v;
            break;
        case 4:
            R = k;
            G = m;
            B = hsv.v;
            break;
        case 5:
            R = hsv.v;
            G = m;
            B = n;
            break;
        default:
            pm_error("Invalid H value passed to color_from_HSV: %f", hsv.h);
        }
    }
    PPM_ASSIGN(retval,
               ppm_unnormalize(R, maxval),
               ppm_unnormalize(G, maxval),
               ppm_unnormalize(B, maxval));

    return retval;
}



struct hsv
ppm_hsv_from_color(pixel  const color,
                   pixval const maxval) {

    double const epsilon = 1e-5;

    double const R = (double)PPM_GETR(color) / maxval;
    double const G = (double)PPM_GETG(color) / maxval;
    double const B = (double)PPM_GETB(color) / maxval;

    enum hueSector {SECTOR_RED, SECTOR_GRN, SECTOR_BLU};
    enum hueSector hueSector;

    struct hsv retval;
    double range;

    if (R >= G) {
        if (R >= B) {
            hueSector = SECTOR_RED;
            retval.v = R;
        } else {
            hueSector = SECTOR_BLU;
            retval.v = B;
        }
    } else {
        if (G >= B) {
            hueSector = SECTOR_GRN;
            retval.v = G;
        } else {
            hueSector = SECTOR_BLU;
            retval.v = B;
        }
    }

    range = retval.v - MIN(R, MIN(G, B));

    if (retval.v < epsilon)
        retval.s = 0.0;
    else
        retval.s = range/retval.v;

    if (range < epsilon)
        /* It's gray, so hue really has no meaning.  We arbitrarily pick 0 */
        retval.h = 0.0;
    else {
        double const cr = (retval.v - R) / range;
        double const cg = (retval.v - G) / range;
        double const cb = (retval.v - B) / range;

        double angle;  /* hue angle, in range -30 - +330 */

        switch(hueSector) {
        case SECTOR_RED: angle =   0.0 + 60.0 * (cb - cg); break;
        case SECTOR_GRN: angle = 120.0 + 60.0 * (cr - cb); break;
        case SECTOR_BLU: angle = 240.0 + 60.0 * (cg - cr); break;
        }
        retval.h = angle >= 0.0 ? angle : 360 + angle;
    }

    return retval;
}