File: tga.c

package info (click to toggle)
xmorph 1%3A20150712-2
  • links: PTS, VCS
  • area: main
  • in suites: bookworm
  • size: 5,404 kB
  • sloc: ansic: 24,887; sh: 7,755; cpp: 1,231; makefile: 524; sed: 16
file content (853 lines) | stat: -rw-r--r-- 21,741 bytes parent folder | download | duplicates (11)
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
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
/* tga.c: Targa TrueVision image file handling routines
//
// Written and Copyright (C) 1994-1999 by Michael J. Gourlay
//
// Provided as is.  No warrantees, express or implied.
*/

#include <stdio.h>
#include <stdlib.h>
#include <memory.h>

#include "my_malloc.h"
#include "tga.h"




/* Global Targa colormap */
static unsigned char tga_cmap_r[16384];
static unsigned char tga_cmap_g[16384];
static unsigned char tga_cmap_b[16384];
static unsigned char tga_cmap_a[16384];




RgbaImageT tga_cmap = {
  0, 0, 0, 0, 0, 0,
  tga_cmap_r, tga_cmap_g, tga_cmap_b, tga_cmap_a,
};




#define CURR_ROW(irow) ((tgaP->origin_bit)?(irow):(imgP->nrows-(irow)-1))




#define ROW_INC \
{ \
  row_count++; \
  if(tgaP->interleave==TGA_IL_Four) { ilace_row += 4 ; } \
  else if(tgaP->interleave==TGA_IL_Two) { ilace_row += 2 ; } \
  else  { ilace_row ++ ; } \
  if(ilace_row > imgP->nrows) ilace_row = ++ top_row; \
  c_row = CURR_ROW(ilace_row); \
}




/* get_byte : get from fio a byte
*/
#define GET_BYTE(byte, fio) \
{\
  int rv;\
  (byte)=(unsigned char)(rv=getc(fio));\
  if(rv==EOF) {\
    fprintf(stderr, "get_byte: EOF/read error\n");\
    return EOF ;\
  }\
}




/* NAME
//   put_le_word : put into fio a 2-byte little-endian unsigned integer
*/
int
put_le_word(short le_int, FILE *fio)
{
  unsigned char b1, b2;

  b1 = le_int & 0xff;

  b2 = (le_int >> 8) & 0xff;

  /* least significant byte comes first */
  if(putc(b1, fio)==EOF) return EOF ;

  /* most significant byte comes last */
  if(putc(b2, fio)==EOF) return EOF ;

  return 0 ;
}




/* NAME
//   get_le_word : get from fio a 2-byte little-endian unsigned integer
*/
long
get_le_word(FILE * fio)
{
  unsigned char b1, b2;

  /* least significant byte comes first */
  GET_BYTE(b1, fio);

  /* most significant byte comes last */
  GET_BYTE(b2, fio);

  return (b1 + b2*256);
}




/* NAME
//   get_block : get from fio an block of n bytes, and store it in buf
//
//
// RETURN VALUES
//   return EOF if there is a read error, or 0 otherwise
//
//
// NOTES
//   get_block is nothing but fread with error reporting.
//   Calls to get_block should probably just be replaced
//   with fread.
*/
short
get_block(FILE * fio, char *buf, long n)
{
  int rv;

  if(feof(fio)) return EOF ;
  rv=fread(buf, 1, (size_t)n, fio);
  if(rv!=n) {
    if(rv) {
      fprintf(stderr, "get_block: EOF/read error reading byte %i/%li\n", rv, n);
    }
    return EOF ;
  }

  return 0 ;
}




/* NAME
//   tgaPixelRead: read a Targa pixel from fio into imgP
//
//
// ARGUMENTS
//   npixels: the number of literal pixels to read.
//   size: the size of the pixel in the file, in bits.
//   mapped: tells whether bits are gray, coded RGB, or cmap index.
//
//
// NOTES
//   This code is optimized for speed, not readability or compactness
//   so the redundancy is intentional.
*/
static int
tgaPixelRead(FILE *fio, RgbaImageT *imgP, int npixels, int size, int mapped)
{
  int   pcount;

  switch(size) {
    case 8:
      if(get_block(fio, (char*)imgP->ri, npixels)) {
        fprintf(stderr, "tgaPixelRead: read error\n");
        return -1 ;
      }
      if(mapped) {
        for(pcount=0; pcount < npixels; pcount++) {
          /* cmap indices are stored in ri, so do lookups with r last  */
          imgP->bi[pcount] = tga_cmap.bi[imgP->ri[pcount]];
          imgP->gi[pcount] = tga_cmap.gi[imgP->ri[pcount]];
          imgP->ri[pcount] = tga_cmap.ri[imgP->ri[pcount]];
        }
      } else {
        memcpy(imgP->gi, imgP->ri, npixels);
        memcpy(imgP->bi, imgP->ri, npixels);
      }
      memset(imgP->ai, RGBA_IMAGE_OPAQUE, npixels);
      break;

    case 16: case 15:
      {
        int ip, jp;
        int pixel;

        for(pcount=0; pcount < npixels; pcount++) {
          GET_BYTE(ip, fio);
          GET_BYTE(jp, fio);
          if(mapped) {
            pixel = ((unsigned int) jp << 8) + ip;
            imgP->ri[pcount] = tga_cmap.ri[pixel];
            imgP->gi[pcount] = tga_cmap.gi[pixel];
            imgP->bi[pcount] = tga_cmap.bi[pixel];
          } else {
            /* Unpack color bits (5 each for red, green, blue */
            imgP->ri[pcount] = (jp & 0x7c) >> 2;
            imgP->gi[pcount] = ((jp & 0x03) << 3) + ((ip & 0xe0) >> 5);
            imgP->bi[pcount] = ip & 0x1f;
          }
          imgP->ai[pcount] = RGBA_IMAGE_OPAQUE;
        }
      }
      break;

    case 32: case 24:
      {
        for(pcount=0; pcount < npixels; pcount++) {
          GET_BYTE(imgP->bi[pcount], fio);
          GET_BYTE(imgP->gi[pcount], fio);
          GET_BYTE(imgP->ri[pcount], fio);
          if(size == 32) {
            GET_BYTE(imgP->ai[pcount], fio);
          } else {
            imgP->ai[pcount] = RGBA_IMAGE_OPAQUE;
          }
        }
      }
      break;

    default:
      fprintf(stderr, "tgaPixelRead: unknown pixel size %i\n", size);
      return -1 ;

      /*NOTREACHED*/
      break;

  }
  return 0 ;
}




/* NAME
//   tgaRead: Load a Targa image file from fio into imgP
*/
int
tgaRead(tga_hdr_t *tgaP, RgbaImageT *imgP, FILE *fio)
{
  int        col;
  int        rle_count;      /* run-length of data */
  int        c_row;          /* current row index being loaded */
  int        rl_encoded;     /* boolean flag */
  int        row_count;      /* total count of rows loaded */
  int        ilace_row;      /* interlaced row counter */
  int        top_row;        /* where to start over for interlaced images */
  RgbaImageT timg;

  if(tgaP->img_type == TGA_RLE_Map || tgaP->img_type == TGA_RLE_RGB ||
     tgaP->img_type == TGA_RLE_Mono)
  {
    rl_encoded = 1;
  } else {
    rl_encoded = 0;
  }

  row_count = ilace_row = top_row = 0;
  c_row = CURR_ROW(ilace_row);

  if(rl_encoded) {
    int           nbytes;
    int           rle_compressed; /* whether run is encoded or literal */
    int           blir;           /* bytes left in row */
    unsigned char ibyte;
    unsigned char tri;
    unsigned char tgi;
    unsigned char tbi;
    unsigned char tai;

    /* Load the temporary image with info from imgP */
    timg = *imgP;

    while(row_count < imgP->nrows) {

      for(col=0 ; col < imgP->ncols; ) {

        /* Read in the RLE count */
        GET_BYTE(ibyte, fio);
        if(ibyte & 0x80) {
          /* run-length encoded pixel */
          rle_count = ibyte - 127;
          rle_compressed = 1;
          /* Read the repeated byte */
          timg.ri = &tri; timg.gi = &tgi; timg.bi = &tbi; timg.ai = &tai;
          if(tgaPixelRead(fio, &timg, 1, tgaP->pixel_size, tgaP->mapped))
          {
            fprintf(stderr,"tgaRead: read error in rle row %i\n", c_row);
            return EOF ;
          }

        } else {
          /* stream of unencoded pixels */
          rle_count = ibyte + 1;
          rle_compressed = 0;
        }

        blir = imgP->ncols - col;

        /* Put run data into image memory */
        while(rle_count) {
          if(rle_count <= blir) {
            /* finish the RLE block */
            nbytes = rle_count;
          } else {
            /* finish the row */
            nbytes = blir;
          }
          if(row_count >= imgP->nrows) {
            fprintf(stderr, "tgaRead: overread image.\n");
            col = imgP->ncols;
            break;
          }
          if(rle_compressed) {
            memset(&imgP->ri[c_row*imgP->ncols+col], timg.ri[0], nbytes);
            memset(&imgP->gi[c_row*imgP->ncols+col], timg.gi[0], nbytes);
            memset(&imgP->bi[c_row*imgP->ncols+col], timg.bi[0], nbytes);
            memset(&imgP->ai[c_row*imgP->ncols+col], timg.ai[0], nbytes);
          } else {
            timg.ri = &(imgP->ri[c_row*imgP->ncols+col]);
            timg.gi = &(imgP->gi[c_row*imgP->ncols+col]);
            timg.bi = &(imgP->bi[c_row*imgP->ncols+col]);
            timg.ai = &(imgP->ai[c_row*imgP->ncols+col]);
            if(tgaPixelRead(fio, &timg,nbytes,tgaP->pixel_size, tgaP->mapped))
            {
              fprintf(stderr, "tgaRead: read err 3 in row %i\n", c_row);
              return EOF ;
            }
          }
          if(rle_count <= blir) {
            /* just emptied the RLE block */
            col += rle_count;
            rle_count = 0;
          } else {
            /* just emptied a row */
            rle_count -= blir;
            col = 0;
            blir = imgP->ncols;
            ROW_INC;
          }
        }
      } /* for col */

      ROW_INC;
    } /* while row_count */

  } else {
    /* Not run-length encoded */
    /* load pixel data one row at a time */
    while(row_count < imgP->nrows) {
      timg.ri = &(imgP->ri[c_row*imgP->ncols]);
      timg.gi = &(imgP->gi[c_row*imgP->ncols]);
      timg.bi = &(imgP->bi[c_row*imgP->ncols]);
      timg.ai = &(imgP->ai[c_row*imgP->ncols]);
      if(tgaPixelRead(fio, &timg,imgP->ncols, tgaP->pixel_size, tgaP->mapped))
      {
        fprintf(stderr, "tgaRead: read error in row %i\n", c_row);
        return EOF ;
      }
      ROW_INC;
    }
  }

  return 0 ;
}




/* NAME
//   tgaHeaderRead: load a Targa image header from fio into tgaP and imgP
//
//
// DESCRIPTION
//   Since Targa files (aka tga files) have no magic number
//   it is not a simple matter to determine whether a file is a valid
//   Targa image.  Therefore, there are several consistency checks in
//   this header reading routine to try to determine whether the file
//   is a valid targa file.
//
//   In the case that the file is not a Targa file, then you could
//   lseek to the beginning of the file and try to read it as another
//   type of image.
//
//   Since there is no way to be certain of whether the error is because
//   this is not a Targa at all, or if it is because the file is simply
//   a corrupt or unsupported Targa, no error messages are reported
//   by this routine.  Instead, a different value is returned for
//   every different kind of reason why this routine rejected the
//   header.  The caller routine is responsible for handling this return
//   value appropriately.
//
//
// RETURN VALUES
//   If this routine returns nonzero, then either the file is not a
//   valid targa file, or we don't support this type.
//
*/
int
tgaHeaderRead(tga_hdr_t *tgaP, RgbaImageT *imgP, FILE *fio)
{
  unsigned char flags;

  GET_BYTE(tgaP->id_len, fio);
  GET_BYTE(tgaP->cmap_type, fio);
  GET_BYTE(tgaP->img_type, fio);

  /* Verify that this is among the supported Targa types */
  switch(tgaP->img_type) {
    case TGA_RLE_Map:
    case TGA_RLE_RGB:
    case TGA_RLE_Mono:
      imgP->compressed = 1;
      break;

    case TGA_Map:
    case TGA_RGB:
    case TGA_Mono:
      break;

    default:
      /* This is not a Targa I can deal with */
      /* (or it is not a Targa at all) */
      return 1 ;

      /*NOTREACHED*/
      break;
  }

  imgP->type = TARGA_MAGIC;

  /* Load rest of Targa header */
  tgaP->cmap_index = get_le_word(fio);
  tgaP->cmap_len = get_le_word(fio);
  GET_BYTE(tgaP->cmap_size, fio);
  tgaP->x_off = get_le_word(fio);
  tgaP->y_off = get_le_word(fio);
  imgP->ncols = get_le_word(fio);
  imgP->nrows = get_le_word(fio);
  GET_BYTE(tgaP->pixel_size, fio);

  GET_BYTE(flags, fio);
  tgaP->att_bits = flags & 0xf;
  tgaP->reserved = (flags & 0x10) >> 4;
  tgaP->origin_bit = (flags & 0x20) >> 5;
  tgaP->interleave = (flags & 0xc0) >> 6;

  /* Load the ID field */
  if(tgaP->id_len) {
    char *id_field;
    id_field=MY_CALLOC(tgaP->id_len, char);

    if(get_block(fio, id_field, tgaP->id_len)) {
      fprintf(stderr, "tgaHeaderRead: read error in id field\n");
      return EOF ;
    }
    FREE(id_field);
  }

  /* Verify the validity of the colormap or pixel size */
  if(tgaP->img_type == TGA_Map || tgaP->img_type == TGA_RLE_Map
     || tgaP->img_type == TGA_CompMap || tgaP->img_type == TGA_CompMap4 )
  {
    if(tgaP->cmap_type != 1) {
      /* There was no valid colormap, but one was required */
      return 2 ;
    }

    imgP->color_mapped = tgaP->mapped = 1;

    switch(tgaP->cmap_size) {
      case 8:
      case 24: case 32:
      case 15: case 16:
        break;

      default:
        /* invalid colormap entry size */
        return 3 ;
        /*NOTREACHED*/
        break;
    }
    imgP->pixel_size = tgaP->cmap_size;

    if(tgaP->pixel_size!=8 && tgaP->pixel_size!=15 && tgaP->pixel_size!=16)
    {
      return 7 ;
    }
  } else {

    tgaP->mapped = 0;

    switch(tgaP->pixel_size) {
      case 8:
      case 15: case 16:
      case 24: case 32:
        break;

      default:
        /* invalid pixel size */
        return 4 ;
        /*NOTREACHED*/
        break;
    }
    imgP->pixel_size = tgaP->pixel_size;
  }

  if(tgaP->cmap_type) {
    if(tgaP->cmap_index + tgaP->cmap_len > 16384) {
      /* colormap is invalid length */
      return 5 ;
    }

#ifdef CMAP256
    if(tgaP->cmap_index + tgaP->cmap_len > 256) {
      /* colormap will not fit */
      return 6 ;
    }
#endif

    tga_cmap.ri = &tga_cmap_r[tgaP->cmap_index];
    tga_cmap.gi = &tga_cmap_g[tgaP->cmap_index];
    tga_cmap.bi = &tga_cmap_b[tgaP->cmap_index];
    tga_cmap.ai = &tga_cmap_a[tgaP->cmap_index];
    tgaPixelRead(fio, &tga_cmap, tgaP->cmap_len, tgaP->cmap_size, 0);
  }
  return 0 ;
}




/* ---------------------------------------------------------------------- */

#define RPIX(row, col) (imgP->ri[(row) * imgP->ncols + (col)])
#define GPIX(row, col) (imgP->gi[(row) * imgP->ncols + (col)])
#define BPIX(row, col) (imgP->bi[(row) * imgP->ncols + (col)])
#define APIX(row, col) (imgP->ai[(row) * imgP->ncols + (col)])




/* tgaPixelWrite: save Targa pixels to fio from imgP
//
//
// ARGUMENTS
//   fio: pointer to the output image file opened for binary output.
//
//   imgP: used for the image arrays (and imgP->ncols used to index)
//
//   npixels: number of consecutive pixels to write.
//
//   mpsize: size of the pixels in memory, not the size of the
//     pixels being written.
//     -- For mpsize 8, use only the red channel.
//     -- For mpsize 15|16, use the red and green channels.
//          Use red as the MSB and green as the LSB.
//
//   mapped: tells whether pixel values are gray/coded RGB, or cmap index
//     if mpsize==8|15|16 then mapped implies that a lookup ought to be
//     done, and the mapped pixel should be written.
//
//
// [There are two kinds of map: 24/32 bit pixel and 15 bit pixel.
//   "mpsize" refers to the size of the stored image, not the written
//   image.  To date, mapped saves are not supported, so this issue is moot.]
*/
static int
tgaPixelWrite(FILE *fio, RgbaImageT *imgP, int col, int row, int npixels, int mpsize, int mapped)
{
  register int pcount;

  switch(mpsize) {
    case 8:
      if(mapped) {
        fprintf(stderr, "tgaPixelWrite: I only do non-mapped 8\n");
        return EOF ;
      }
      {
        for(pcount=col; pcount < col+npixels; pcount++) {
          if(putc(RPIX(row, pcount), fio)==EOF) return EOF ;
        }
      }

    case 15: case 16:
      if(mapped) {
        fprintf(stderr, "tgaPixelWrite: I only do non-mapped 15/16\n");
        return EOF ;
      }
      {
        for(pcount=col; pcount < col+npixels; pcount++) {
          if(putc(GPIX(row, pcount), fio)==EOF) return EOF ;
          if(putc(RPIX(row, pcount), fio)==EOF) return EOF ;
        }
      }
      break;

    case 32: case 24:
      if(mapped) {
        fprintf(stderr, "tgaPixelWrite: 24/32 can't be mapped\n");
      }
      {
        for(pcount=col; pcount < col+npixels; pcount++) {
          if(putc(BPIX(row, pcount), fio)==EOF) return EOF ;
          if(putc(GPIX(row, pcount), fio)==EOF) return EOF ;
          if(putc(RPIX(row, pcount), fio)==EOF) return EOF ;
          if(mpsize == 32) {
            if(putc(APIX(row, pcount), fio)==EOF) return EOF ;
          }
        }
      }
      break;

    default:
      fprintf(stderr, "tgaPixelWrite: bad pixel size %i\n", mpsize);
      return EOF ;
      /*NOTREACHED*/
      break;
  }
  return 0 ;
}




/* NAME
//   tgaRunLength: find RLE run length for Targa image file
//
//
// DESCRIPTION
//   tgaRunLength: find RLE run length at current col, row of img
//   depth is the number of bits per pixel
//
//   For depth 8 Use only red channel.
//   For depth 15|16 Use red as the MSB and green as the LSB.
//
//   Only runs along rows;  Will not read into next row.
//
//
// RETURN VALUES
//   If pixel repeat 2 or 3 times, return negative of number of repeats
//   otherwise Return positive number of distinct pixels until a 2|3+
//
//   If error, return 0.
//
//   A return value of 0 is indistinguishible from a start-at-end-of-row
//   occurance, so the caller must check for end-of-row before calling
//   this routine;
*/
int
tgaRunLength(RgbaImageT *imgP, int col, int row, int depth)
{
  int xi, ri;
  int run_length;

  switch(depth) {
    case 8: case 15: case 16: case 24: case 32:
      break;

    default:
      fprintf(stderr, "tgaRunLength: invalid depth %i\n", depth);
      return 0 ;
  }

  /* Check for a run of (at least 2 or 3, at most 128) identical pixels */
  /* Don't look at the first pixel;  It's obviously equal to itself. */
  for(ri=col+1; ri<imgP->ncols && ri-col<128; ri++) {
    if(RPIX(row, ri) != RPIX(row, col)) break;
    if(depth>8) {
      if(GPIX(row, ri) != GPIX(row, col)) break;
      if(depth>16) {
        if(BPIX(row, ri) != BPIX(row, col)) break;
        if(depth==32) {
          if(APIX(row, ri) != APIX(row, col)) break;
        }
      }
    }
  } run_length=ri-col;

  switch(depth) {
    case 8:
      if(run_length>=3) return -run_length ;
      break;

    case 15: case 16: case 24: case 32:
      if(run_length>=2) return -run_length ;
      break;
  }

  /* If we've reached this far, we've into a run of distinct pixels. */
  /* Look for runs of (at most 128) distinct pixels. */
  for(xi=col+1; xi<imgP->ncols && xi-col<128; xi+=run_length) {

    for(ri=xi+1; ri<imgP->ncols && ri-xi<3; ri++) {
      if(RPIX(row, ri) != RPIX(row, xi)) break;
      if(depth>8) {
        if(GPIX(row, ri) != GPIX(row, xi)) break;
        if(depth>16) {
          if(BPIX(row, ri) != BPIX(row, xi)) break;
          if(depth==32) {
            if(APIX(row, ri) != APIX(row, xi)) break;
          }
        }
      }
    } run_length=ri-xi;

    switch(depth) {
      case 8:
        if(run_length>=3) return (xi-col);
        break;

      case 15: case 16: case 24: case 32:
        if(run_length>=2) return (xi-col);
        break;
    }
  }
  return (xi-col);
}




/* NAME
//   tgaWrite: Save a Targa image file
//
//
// DESCRIPTION
//   Save a Targa image file into fio from imgP
*/
int
tgaWrite(tga_hdr_t *tgaP, RgbaImageT *imgP, FILE *fio)
{
  int   c_row;          /* current row index being saved */
  int   rl_encoded;     /* boolean flag */
  int   row_count;      /* total count of rows saved */
  int   ilace_row;      /* interlaced row counter */
  int   top_row;        /* where to start over for interlaced images */

  if(tgaP->img_type == TGA_RLE_Map || tgaP->img_type == TGA_RLE_RGB ||
     tgaP->img_type == TGA_RLE_Mono)
  {
    rl_encoded = 1;
  } else {
    rl_encoded = 0;
  }

  row_count = ilace_row = top_row = 0;
  c_row = CURR_ROW(ilace_row);
  if(rl_encoded) {
    int rle_count;  /* run-length of data */
    int col;        /* current column */

    while(row_count < imgP->nrows) {
      for(col=0; col < imgP->ncols; ) {
        rle_count = tgaRunLength(imgP, col, c_row, tgaP->pixel_size);
        if(rle_count < 0) {
          /* Write the repeat count (negative) */
          putc(127 - rle_count, fio);

          /* Write out the pixels */
          if(tgaPixelWrite(fio, imgP, col, c_row, 1, tgaP->pixel_size,
             tgaP->mapped))
          {
            fprintf(stderr, "tgaWrite: write error in row %i\n", c_row);
            return EOF ;
          }

          /* Advance the column counter */
          col += -rle_count;

        } else if(rle_count > 0) {
          /* Write the distinct count (positive) */
          putc(rle_count - 1, fio);

          /* Write out the pixels */
          if(tgaPixelWrite(fio, imgP, col, c_row, rle_count,
               tgaP->pixel_size, tgaP->mapped))
          {
            fprintf(stderr, "tgaWrite: write error in row %i\n", c_row);
            return EOF ;
          }

          /* Advance the column counter */
          col += rle_count;

        } else {
          fprintf(stderr, "tgaWrite: bad RLE count %i\n", rle_count);
        }
      }
      ROW_INC;
    }
  } else {
    /* Not run-length encoded */
    /* save pixel data one row at a time */
    while(row_count < imgP->nrows) {
      if(tgaPixelWrite(fio, imgP, 0, c_row, imgP->ncols, tgaP->pixel_size,
         tgaP->mapped))
      {
        fprintf(stderr, "tgaWrite: write error in row %i\n", c_row);
        return EOF ;
      }
      ROW_INC;
    }
  }
  return 0 ;
}




/* NAME
//   tgaHeaderWrite: save a Targa image header into fio from tgaP and imgP
*/
int
tgaHeaderWrite(tga_hdr_t *tgaP, RgbaImageT *imgP, FILE *fio)
{
  unsigned char flags;

  tgaP->id_len = 0;
  putc(tgaP->id_len, fio);
  putc(tgaP->cmap_type, fio);
  putc(tgaP->img_type, fio);

  /* Save rest of Targa header */
  put_le_word(tgaP->cmap_index, fio);
  put_le_word(tgaP->cmap_len, fio);
  putc(tgaP->cmap_size, fio);
  put_le_word(tgaP->x_off, fio);
  put_le_word(tgaP->y_off, fio);
  put_le_word(imgP->ncols, fio);
  put_le_word(imgP->nrows, fio);
  putc(tgaP->pixel_size, fio);

  flags  = tgaP->att_bits    & 0xf;
  flags |= (tgaP->reserved   & 0x1) << 4;
  flags |= (tgaP->origin_bit & 0x1) << 5;
  flags |= (tgaP->interleave & 0x3) << 6;
  putc(flags, fio);

  if(tgaP->cmap_type) {
    tgaP->mapped = 1;

    /* Save the colormap for the Targa file */
    tgaPixelWrite(fio, &tga_cmap, 0, 0, tgaP->cmap_len, tgaP->cmap_size, 0);

  } else {
    tgaP->mapped = 0;
  }

  return 0 ;
}