forked from nothings/stb
-
Notifications
You must be signed in to change notification settings - Fork 1
/
Copy pathstb_image_write.h
1559 lines (1370 loc) · 62.5 KB
/
stb_image_write.h
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
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* stb_image_write - v1.08 - public domain - http://nothings.org/stb/stb_image_write.h
writes out PNG/BMP/TGA/JPEG/HDR images to C stdio - Sean Barrett 2010-2015
no warranty implied; use at your own risk
Before #including,
#define STB_IMAGE_WRITE_IMPLEMENTATION
in the file that you want to have the implementation.
Will probably not work correctly with strict-aliasing optimizations.
If using a modern Microsoft Compiler, non-safe versions of CRT calls may cause
compilation warnings or even errors. To avoid this, also before #including,
#define STBI_MSC_SECURE_CRT
ABOUT:
This header file is a library for writing images to C stdio. It could be
adapted to write to memory or a general streaming interface; let me know.
The PNG output is not optimal; it is 20-50% larger than the file
written by a decent optimizing implementation; though providing a custom
zlib compress function (see STBIW_ZLIB_COMPRESS) can mitigate that.
This library is designed for source code compactness and simplicity,
not optimal image file size or run-time performance.
BUILDING:
You can #define STBIW_ASSERT(x) before the #include to avoid using assert.h.
You can #define STBIW_MALLOC(), STBIW_REALLOC(), and STBIW_FREE() to replace
malloc,realloc,free.
You can #define STBIW_MEMMOVE() to replace memmove()
You can #define STBIW_ZLIB_COMPRESS to use a custom zlib-style compress function
for PNG compression (instead of the builtin one), it must have the following signature:
unsigned char * my_compress(unsigned char *data, int data_len, int *out_len, int quality);
The returned data will be freed with STBIW_FREE() (free() by default),
so it must be heap allocated with STBIW_MALLOC() (malloc() by default),
USAGE:
There are five functions, one for each image file format:
int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
int stbi_write_jpg(char const *filename, int w, int h, int comp, const float *data, int quality);
void stbi_flip_vertically_on_write(int flag); // flag is non-zero to flip data vertically
There are also five equivalent functions that use an arbitrary write function. You are
expected to open/close your file-equivalent before and after calling these:
int stbi_write_png_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data, int stride_in_bytes);
int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
int stbi_write_tga_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const float *data);
int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality);
where the callback is:
void stbi_write_func(void *context, void *data, int size);
You can configure it with these global variables:
int stbi_write_tga_with_rle; // defaults to true; set to 0 to disable RLE
int stbi_write_png_compression_level; // defaults to 8; set to higher for more compression
int stbi_write_force_png_filter; // defaults to -1; set to 0..5 to force a filter mode
You can define STBI_WRITE_NO_STDIO to disable the file variant of these
functions, so the library will not use stdio.h at all. However, this will
also disable HDR writing, because it requires stdio for formatted output.
Each function returns 0 on failure and non-0 on success.
The functions create an image file defined by the parameters. The image
is a rectangle of pixels stored from left-to-right, top-to-bottom.
Each pixel contains 'comp' channels of data stored interleaved with 8-bits
per channel, in the following order: 1=Y, 2=YA, 3=RGB, 4=RGBA. (Y is
monochrome color.) The rectangle is 'w' pixels wide and 'h' pixels tall.
The *data pointer points to the first byte of the top-left-most pixel.
For PNG, "stride_in_bytes" is the distance in bytes from the first byte of
a row of pixels to the first byte of the next row of pixels.
PNG creates output files with the same number of components as the input.
The BMP format expands Y to RGB in the file format and does not
output alpha.
PNG supports writing rectangles of data even when the bytes storing rows of
data are not consecutive in memory (e.g. sub-rectangles of a larger image),
by supplying the stride between the beginning of adjacent rows. The other
formats do not. (Thus you cannot write a native-format BMP through the BMP
writer, both because it is in BGR order and because it may have padding
at the end of the line.)
PNG allows you to set the deflate compression level by setting the global
variable 'stbi_write_png_level' (it defaults to 8).
HDR expects linear float data. Since the format is always 32-bit rgb(e)
data, alpha (if provided) is discarded, and for monochrome data it is
replicated across all three channels.
TGA supports RLE or non-RLE compressed data. To use non-RLE-compressed
data, set the global variable 'stbi_write_tga_with_rle' to 0.
JPEG does ignore alpha channels in input data; quality is between 1 and 100.
Higher quality looks better but results in a bigger image.
JPEG baseline (no JPEG progressive).
CREDITS:
Sean Barrett - PNG/BMP/TGA
Baldur Karlsson - HDR
Jean-Sebastien Guay - TGA monochrome
Tim Kelsey - misc enhancements
Alan Hickman - TGA RLE
Emmanuel Julien - initial file IO callback implementation
Jon Olick - original jo_jpeg.cpp code
Daniel Gibson - integrate JPEG, allow external zlib
Aarni Koskela - allow choosing PNG filter
bugfixes:
github:Chribba
Guillaume Chereau
github:jry2
github:romigrou
Sergio Gonzalez
Jonas Karlsson
Filip Wasil
Thatcher Ulrich
github:poppolopoppo
Patrick Boettcher
github:xeekworx
LICENSE
See end of file for license information.
*/
#ifndef INCLUDE_STB_IMAGE_WRITE_H
#define INCLUDE_STB_IMAGE_WRITE_H
#ifdef __cplusplus
extern "C" {
#endif
#ifdef STB_IMAGE_WRITE_STATIC
#define STBIWDEF static
#else
#define STBIWDEF extern
#endif
STBIWDEF int stbi_write_tga_with_rle;
STBIWDEF int stbi_write_png_comperssion_level;
STBIWDEF int stbi_write_force_png_filter;
#ifndef STBI_WRITE_NO_STDIO
STBIWDEF int stbi_write_png(char const *filename, int w, int h, int comp, const void *data, int stride_in_bytes);
STBIWDEF int stbi_write_bmp(char const *filename, int w, int h, int comp, const void *data);
STBIWDEF int stbi_write_tga(char const *filename, int w, int h, int comp, const void *data);
STBIWDEF int stbi_write_hdr(char const *filename, int w, int h, int comp, const float *data);
STBIWDEF int stbi_write_jpg(char const *filename, int x, int y, int comp, const void *data, int quality);
#endif
typedef void stbi_write_func(void *context, void *data, int size);
STBIWDEF int stbi_write_png_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data, int stride_in_bytes);
STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const void *data);
STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int w, int h, int comp, const float *data);
STBIWDEF int stbi_write_jpg_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data, int quality);
STBIWDEF void stbi_flip_vertically_on_write(int flip_boolean);
#ifdef __cplusplus
}
#endif
#endif//INCLUDE_STB_IMAGE_WRITE_H
#ifdef STB_IMAGE_WRITE_IMPLEMENTATION
#ifdef _WIN32
#ifndef _CRT_SECURE_NO_WARNINGS
#define _CRT_SECURE_NO_WARNINGS
#endif
#ifndef _CRT_NONSTDC_NO_DEPRECATE
#define _CRT_NONSTDC_NO_DEPRECATE
#endif
#endif
#ifndef STBI_WRITE_NO_STDIO
#include <stdio.h>
#endif // STBI_WRITE_NO_STDIO
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#if defined(STBIW_MALLOC) && defined(STBIW_FREE) && (defined(STBIW_REALLOC) || defined(STBIW_REALLOC_SIZED))
// ok
#elif !defined(STBIW_MALLOC) && !defined(STBIW_FREE) && !defined(STBIW_REALLOC) && !defined(STBIW_REALLOC_SIZED)
// ok
#else
#error "Must define all or none of STBIW_MALLOC, STBIW_FREE, and STBIW_REALLOC (or STBIW_REALLOC_SIZED)."
#endif
#ifndef STBIW_MALLOC
#define STBIW_MALLOC(sz) malloc(sz)
#define STBIW_REALLOC(p,newsz) realloc(p,newsz)
#define STBIW_FREE(p) free(p)
#endif
#ifndef STBIW_REALLOC_SIZED
#define STBIW_REALLOC_SIZED(p,oldsz,newsz) STBIW_REALLOC(p,newsz)
#endif
#ifndef STBIW_MEMMOVE
#define STBIW_MEMMOVE(a,b,sz) memmove(a,b,sz)
#endif
#ifndef STBIW_ASSERT
#include <assert.h>
#define STBIW_ASSERT(x) assert(x)
#endif
#define STBIW_UCHAR(x) (unsigned char) ((x) & 0xff)
#ifdef STB_IMAGE_WRITE_STATIC
static stbi__flip_vertically_on_write=0;
static int stbi_write_png_compression level = 8;
static int stbi_write_tga_with_rle = 1;
static int stbi_write_force_png_filter = -1;
#else
int stbi_write_png_compression_level = 8;
int stbi__flip_vertically_on_write=0;
int stbi_write_tga_with_rle = 1;
int stbi_write_force_png_filter = -1;
#endif
STBIWDEF void stbi_flip_vertically_on_write(int flag)
{
stbi__flip_vertically_on_write = flag;
}
typedef struct
{
stbi_write_func *func;
void *context;
} stbi__write_context;
// initialize a callback-based context
static void stbi__start_write_callbacks(stbi__write_context *s, stbi_write_func *c, void *context)
{
s->func = c;
s->context = context;
}
#ifndef STBI_WRITE_NO_STDIO
static void stbi__stdio_write(void *context, void *data, int size)
{
fwrite(data,1,size,(FILE*) context);
}
static int stbi__start_write_file(stbi__write_context *s, const char *filename)
{
FILE *f;
#ifdef STBI_MSC_SECURE_CRT
if (fopen_s(&f, filename, "wb"))
f = NULL;
#else
f = fopen(filename, "wb");
#endif
stbi__start_write_callbacks(s, stbi__stdio_write, (void *) f);
return f != NULL;
}
static void stbi__end_write_file(stbi__write_context *s)
{
fclose((FILE *)s->context);
}
#endif // !STBI_WRITE_NO_STDIO
typedef unsigned int stbiw_uint32;
typedef int stb_image_write_test[sizeof(stbiw_uint32)==4 ? 1 : -1];
static void stbiw__writefv(stbi__write_context *s, const char *fmt, va_list v)
{
while (*fmt) {
switch (*fmt++) {
case ' ': break;
case '1': { unsigned char x = STBIW_UCHAR(va_arg(v, int));
s->func(s->context,&x,1);
break; }
case '2': { int x = va_arg(v,int);
unsigned char b[2];
b[0] = STBIW_UCHAR(x);
b[1] = STBIW_UCHAR(x>>8);
s->func(s->context,b,2);
break; }
case '4': { stbiw_uint32 x = va_arg(v,int);
unsigned char b[4];
b[0]=STBIW_UCHAR(x);
b[1]=STBIW_UCHAR(x>>8);
b[2]=STBIW_UCHAR(x>>16);
b[3]=STBIW_UCHAR(x>>24);
s->func(s->context,b,4);
break; }
default:
STBIW_ASSERT(0);
return;
}
}
}
static void stbiw__writef(stbi__write_context *s, const char *fmt, ...)
{
va_list v;
va_start(v, fmt);
stbiw__writefv(s, fmt, v);
va_end(v);
}
static void stbiw__putc(stbi__write_context *s, unsigned char c)
{
s->func(s->context, &c, 1);
}
static void stbiw__write3(stbi__write_context *s, unsigned char a, unsigned char b, unsigned char c)
{
unsigned char arr[3];
arr[0] = a, arr[1] = b, arr[2] = c;
s->func(s->context, arr, 3);
}
static void stbiw__write_pixel(stbi__write_context *s, int rgb_dir, int comp, int write_alpha, int expand_mono, unsigned char *d)
{
unsigned char bg[3] = { 255, 0, 255}, px[3];
int k;
if (write_alpha < 0)
s->func(s->context, &d[comp - 1], 1);
switch (comp) {
case 2: // 2 pixels = mono + alpha, alpha is written separately, so same as 1-channel case
case 1:
if (expand_mono)
stbiw__write3(s, d[0], d[0], d[0]); // monochrome bmp
else
s->func(s->context, d, 1); // monochrome TGA
break;
case 4:
if (!write_alpha) {
// composite against pink background
for (k = 0; k < 3; ++k)
px[k] = bg[k] + ((d[k] - bg[k]) * d[3]) / 255;
stbiw__write3(s, px[1 - rgb_dir], px[1], px[1 + rgb_dir]);
break;
}
/* FALLTHROUGH */
case 3:
stbiw__write3(s, d[1 - rgb_dir], d[1], d[1 + rgb_dir]);
break;
}
if (write_alpha > 0)
s->func(s->context, &d[comp - 1], 1);
}
static void stbiw__write_pixels(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, void *data, int write_alpha, int scanline_pad, int expand_mono)
{
stbiw_uint32 zero = 0;
int i,j, j_end;
if (y <= 0)
return;
if (stbi__flip_vertically_on_write)
vdir *= -1;
if (vdir < 0)
j_end = -1, j = y-1;
else
j_end = y, j = 0;
for (; j != j_end; j += vdir) {
for (i=0; i < x; ++i) {
unsigned char *d = (unsigned char *) data + (j*x+i)*comp;
stbiw__write_pixel(s, rgb_dir, comp, write_alpha, expand_mono, d);
}
s->func(s->context, &zero, scanline_pad);
}
}
static int stbiw__outfile(stbi__write_context *s, int rgb_dir, int vdir, int x, int y, int comp, int expand_mono, void *data, int alpha, int pad, const char *fmt, ...)
{
if (y < 0 || x < 0) {
return 0;
} else {
va_list v;
va_start(v, fmt);
stbiw__writefv(s, fmt, v);
va_end(v);
stbiw__write_pixels(s,rgb_dir,vdir,x,y,comp,data,alpha,pad, expand_mono);
return 1;
}
}
static int stbi_write_bmp_core(stbi__write_context *s, int x, int y, int comp, const void *data)
{
int pad = (-x*3) & 3;
return stbiw__outfile(s,-1,-1,x,y,comp,1,(void *) data,0,pad,
"11 4 22 4" "4 44 22 444444",
'B', 'M', 14+40+(x*3+pad)*y, 0,0, 14+40, // file header
40, x,y, 1,24, 0,0,0,0,0,0); // bitmap header
}
STBIWDEF int stbi_write_bmp_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
{
stbi__write_context s;
stbi__start_write_callbacks(&s, func, context);
return stbi_write_bmp_core(&s, x, y, comp, data);
}
#ifndef STBI_WRITE_NO_STDIO
STBIWDEF int stbi_write_bmp(char const *filename, int x, int y, int comp, const void *data)
{
stbi__write_context s;
if (stbi__start_write_file(&s,filename)) {
int r = stbi_write_bmp_core(&s, x, y, comp, data);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
#endif //!STBI_WRITE_NO_STDIO
static int stbi_write_tga_core(stbi__write_context *s, int x, int y, int comp, void *data)
{
int has_alpha = (comp == 2 || comp == 4);
int colorbytes = has_alpha ? comp-1 : comp;
int format = colorbytes < 2 ? 3 : 2; // 3 color channels (RGB/RGBA) = 2, 1 color channel (Y/YA) = 3
if (y < 0 || x < 0)
return 0;
if (!stbi_write_tga_with_rle) {
return stbiw__outfile(s, -1, -1, x, y, comp, 0, (void *) data, has_alpha, 0,
"111 221 2222 11", 0, 0, format, 0, 0, 0, 0, 0, x, y, (colorbytes + has_alpha) * 8, has_alpha * 8);
} else {
int i,j,k;
int jend, jdir;
stbiw__writef(s, "111 221 2222 11", 0,0,format+8, 0,0,0, 0,0,x,y, (colorbytes + has_alpha) * 8, has_alpha * 8);
if (stbi__flip_vertically_on_write) {
j = 0;
jend = y;
jdir = 1;
} else {
j = y-1;
jend = -1;
jdir = -1;
}
for (; j != jend; j += jdir) {
unsigned char *row = (unsigned char *) data + j * x * comp;
int len;
for (i = 0; i < x; i += len) {
unsigned char *begin = row + i * comp;
int diff = 1;
len = 1;
if (i < x - 1) {
++len;
diff = memcmp(begin, row + (i + 1) * comp, comp);
if (diff) {
const unsigned char *prev = begin;
for (k = i + 2; k < x && len < 128; ++k) {
if (memcmp(prev, row + k * comp, comp)) {
prev += comp;
++len;
} else {
--len;
break;
}
}
} else {
for (k = i + 2; k < x && len < 128; ++k) {
if (!memcmp(begin, row + k * comp, comp)) {
++len;
} else {
break;
}
}
}
}
if (diff) {
unsigned char header = STBIW_UCHAR(len - 1);
s->func(s->context, &header, 1);
for (k = 0; k < len; ++k) {
stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin + k * comp);
}
} else {
unsigned char header = STBIW_UCHAR(len - 129);
s->func(s->context, &header, 1);
stbiw__write_pixel(s, -1, comp, has_alpha, 0, begin);
}
}
}
}
return 1;
}
STBIWDEF int stbi_write_tga_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const void *data)
{
stbi__write_context s;
stbi__start_write_callbacks(&s, func, context);
return stbi_write_tga_core(&s, x, y, comp, (void *) data);
}
#ifndef STBI_WRITE_NO_STDIO
STBIWDEF int stbi_write_tga(char const *filename, int x, int y, int comp, const void *data)
{
stbi__write_context s;
if (stbi__start_write_file(&s,filename)) {
int r = stbi_write_tga_core(&s, x, y, comp, (void *) data);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
#endif
// *************************************************************************************************
// Radiance RGBE HDR writer
// by Baldur Karlsson
#define stbiw__max(a, b) ((a) > (b) ? (a) : (b))
void stbiw__linear_to_rgbe(unsigned char *rgbe, float *linear)
{
int exponent;
float maxcomp = stbiw__max(linear[0], stbiw__max(linear[1], linear[2]));
if (maxcomp < 1e-32f) {
rgbe[0] = rgbe[1] = rgbe[2] = rgbe[3] = 0;
} else {
float normalize = (float) frexp(maxcomp, &exponent) * 256.0f/maxcomp;
rgbe[0] = (unsigned char)(linear[0] * normalize);
rgbe[1] = (unsigned char)(linear[1] * normalize);
rgbe[2] = (unsigned char)(linear[2] * normalize);
rgbe[3] = (unsigned char)(exponent + 128);
}
}
void stbiw__write_run_data(stbi__write_context *s, int length, unsigned char databyte)
{
unsigned char lengthbyte = STBIW_UCHAR(length+128);
STBIW_ASSERT(length+128 <= 255);
s->func(s->context, &lengthbyte, 1);
s->func(s->context, &databyte, 1);
}
void stbiw__write_dump_data(stbi__write_context *s, int length, unsigned char *data)
{
unsigned char lengthbyte = STBIW_UCHAR(length);
STBIW_ASSERT(length <= 128); // inconsistent with spec but consistent with official code
s->func(s->context, &lengthbyte, 1);
s->func(s->context, data, length);
}
void stbiw__write_hdr_scanline(stbi__write_context *s, int width, int ncomp, unsigned char *scratch, float *scanline)
{
unsigned char scanlineheader[4] = { 2, 2, 0, 0 };
unsigned char rgbe[4];
float linear[3];
int x;
scanlineheader[2] = (width&0xff00)>>8;
scanlineheader[3] = (width&0x00ff);
/* skip RLE for images too small or large */
if (width < 8 || width >= 32768) {
for (x=0; x < width; x++) {
switch (ncomp) {
case 4: /* fallthrough */
case 3: linear[2] = scanline[x*ncomp + 2];
linear[1] = scanline[x*ncomp + 1];
linear[0] = scanline[x*ncomp + 0];
break;
default:
linear[0] = linear[1] = linear[2] = scanline[x*ncomp + 0];
break;
}
stbiw__linear_to_rgbe(rgbe, linear);
s->func(s->context, rgbe, 4);
}
} else {
int c,r;
/* encode into scratch buffer */
for (x=0; x < width; x++) {
switch(ncomp) {
case 4: /* fallthrough */
case 3: linear[2] = scanline[x*ncomp + 2];
linear[1] = scanline[x*ncomp + 1];
linear[0] = scanline[x*ncomp + 0];
break;
default:
linear[0] = linear[1] = linear[2] = scanline[x*ncomp + 0];
break;
}
stbiw__linear_to_rgbe(rgbe, linear);
scratch[x + width*0] = rgbe[0];
scratch[x + width*1] = rgbe[1];
scratch[x + width*2] = rgbe[2];
scratch[x + width*3] = rgbe[3];
}
s->func(s->context, scanlineheader, 4);
/* RLE each component separately */
for (c=0; c < 4; c++) {
unsigned char *comp = &scratch[width*c];
x = 0;
while (x < width) {
// find first run
r = x;
while (r+2 < width) {
if (comp[r] == comp[r+1] && comp[r] == comp[r+2])
break;
++r;
}
if (r+2 >= width)
r = width;
// dump up to first run
while (x < r) {
int len = r-x;
if (len > 128) len = 128;
stbiw__write_dump_data(s, len, &comp[x]);
x += len;
}
// if there's a run, output it
if (r+2 < width) { // same test as what we break out of in search loop, so only true if we break'd
// find next byte after run
while (r < width && comp[r] == comp[x])
++r;
// output run up to r
while (x < r) {
int len = r-x;
if (len > 127) len = 127;
stbiw__write_run_data(s, len, comp[x]);
x += len;
}
}
}
}
}
}
static int stbi_write_hdr_core(stbi__write_context *s, int x, int y, int comp, float *data)
{
if (y <= 0 || x <= 0 || data == NULL)
return 0;
else {
// Each component is stored separately. Allocate scratch space for full output scanline.
unsigned char *scratch = (unsigned char *) STBIW_MALLOC(x*4);
int i, len;
char buffer[128];
char header[] = "#?RADIANCE\n# Written by stb_image_write.h\nFORMAT=32-bit_rle_rgbe\n";
s->func(s->context, header, sizeof(header)-1);
#ifdef STBI_MSC_SECURE_CRT
len = sprintf_s(buffer, "EXPOSURE= 1.0000000000000\n\n-Y %d +X %d\n", y, x);
#else
len = sprintf(buffer, "EXPOSURE= 1.0000000000000\n\n-Y %d +X %d\n", y, x);
#endif
s->func(s->context, buffer, len);
for(i=0; i < y; i++)
stbiw__write_hdr_scanline(s, x, comp, scratch, data + comp*x*(stbi__flip_vertically_on_write ? y-1-i : i)*x);
STBIW_FREE(scratch);
return 1;
}
}
STBIWDEF int stbi_write_hdr_to_func(stbi_write_func *func, void *context, int x, int y, int comp, const float *data)
{
stbi__write_context s;
stbi__start_write_callbacks(&s, func, context);
return stbi_write_hdr_core(&s, x, y, comp, (float *) data);
}
#ifndef STBI_WRITE_NO_STDIO
STBIWDEF int stbi_write_hdr(char const *filename, int x, int y, int comp, const float *data)
{
stbi__write_context s;
if (stbi__start_write_file(&s,filename)) {
int r = stbi_write_hdr_core(&s, x, y, comp, (float *) data);
stbi__end_write_file(&s);
return r;
} else
return 0;
}
#endif // STBI_WRITE_NO_STDIO
//////////////////////////////////////////////////////////////////////////////
//
// PNG writer
//
#ifndef STBIW_ZLIB_COMPRESS
// stretchy buffer; stbiw__sbpush() == vector<>::push_back() -- stbiw__sbcount() == vector<>::size()
#define stbiw__sbraw(a) ((int *) (a) - 2)
#define stbiw__sbm(a) stbiw__sbraw(a)[0]
#define stbiw__sbn(a) stbiw__sbraw(a)[1]
#define stbiw__sbneedgrow(a,n) ((a)==0 || stbiw__sbn(a)+n >= stbiw__sbm(a))
#define stbiw__sbmaybegrow(a,n) (stbiw__sbneedgrow(a,(n)) ? stbiw__sbgrow(a,n) : 0)
#define stbiw__sbgrow(a,n) stbiw__sbgrowf((void **) &(a), (n), sizeof(*(a)))
#define stbiw__sbpush(a, v) (stbiw__sbmaybegrow(a,1), (a)[stbiw__sbn(a)++] = (v))
#define stbiw__sbcount(a) ((a) ? stbiw__sbn(a) : 0)
#define stbiw__sbfree(a) ((a) ? STBIW_FREE(stbiw__sbraw(a)),0 : 0)
static void *stbiw__sbgrowf(void **arr, int increment, int itemsize)
{
int m = *arr ? 2*stbiw__sbm(*arr)+increment : increment+1;
void *p = STBIW_REALLOC_SIZED(*arr ? stbiw__sbraw(*arr) : 0, *arr ? (stbiw__sbm(*arr)*itemsize + sizeof(int)*2) : 0, itemsize * m + sizeof(int)*2);
STBIW_ASSERT(p);
if (p) {
if (!*arr) ((int *) p)[1] = 0;
*arr = (void *) ((int *) p + 2);
stbiw__sbm(*arr) = m;
}
return *arr;
}
static unsigned char *stbiw__zlib_flushf(unsigned char *data, unsigned int *bitbuffer, int *bitcount)
{
while (*bitcount >= 8) {
stbiw__sbpush(data, STBIW_UCHAR(*bitbuffer));
*bitbuffer >>= 8;
*bitcount -= 8;
}
return data;
}
static int stbiw__zlib_bitrev(int code, int codebits)
{
int res=0;
while (codebits--) {
res = (res << 1) | (code & 1);
code >>= 1;
}
return res;
}
static unsigned int stbiw__zlib_countm(unsigned char *a, unsigned char *b, int limit)
{
int i;
for (i=0; i < limit && i < 258; ++i)
if (a[i] != b[i]) break;
return i;
}
static unsigned int stbiw__zhash(unsigned char *data)
{
stbiw_uint32 hash = data[0] + (data[1] << 8) + (data[2] << 16);
hash ^= hash << 3;
hash += hash >> 5;
hash ^= hash << 4;
hash += hash >> 17;
hash ^= hash << 25;
hash += hash >> 6;
return hash;
}
#define stbiw__zlib_flush() (out = stbiw__zlib_flushf(out, &bitbuf, &bitcount))
#define stbiw__zlib_add(code,codebits) \
(bitbuf |= (code) << bitcount, bitcount += (codebits), stbiw__zlib_flush())
#define stbiw__zlib_huffa(b,c) stbiw__zlib_add(stbiw__zlib_bitrev(b,c),c)
// default huffman tables
#define stbiw__zlib_huff1(n) stbiw__zlib_huffa(0x30 + (n), 8)
#define stbiw__zlib_huff2(n) stbiw__zlib_huffa(0x190 + (n)-144, 9)
#define stbiw__zlib_huff3(n) stbiw__zlib_huffa(0 + (n)-256,7)
#define stbiw__zlib_huff4(n) stbiw__zlib_huffa(0xc0 + (n)-280,8)
#define stbiw__zlib_huff(n) ((n) <= 143 ? stbiw__zlib_huff1(n) : (n) <= 255 ? stbiw__zlib_huff2(n) : (n) <= 279 ? stbiw__zlib_huff3(n) : stbiw__zlib_huff4(n))
#define stbiw__zlib_huffb(n) ((n) <= 143 ? stbiw__zlib_huff1(n) : stbiw__zlib_huff2(n))
#define stbiw__ZHASH 16384
#endif // STBIW_ZLIB_COMPRESS
unsigned char * stbi_zlib_compress(unsigned char *data, int data_len, int *out_len, int quality)
{
#ifdef STBIW_ZLIB_COMPRESS
// user provided a zlib compress implementation, use that
return STBIW_ZLIB_COMPRESS(data, data_len, out_len, quality);
#else // use builtin
static unsigned short lengthc[] = { 3,4,5,6,7,8,9,10,11,13,15,17,19,23,27,31,35,43,51,59,67,83,99,115,131,163,195,227,258, 259 };
static unsigned char lengtheb[]= { 0,0,0,0,0,0,0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0 };
static unsigned short distc[] = { 1,2,3,4,5,7,9,13,17,25,33,49,65,97,129,193,257,385,513,769,1025,1537,2049,3073,4097,6145,8193,12289,16385,24577, 32768 };
static unsigned char disteb[] = { 0,0,0,0,1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,13,13 };
unsigned int bitbuf=0;
int i,j, bitcount=0;
unsigned char *out = NULL;
unsigned char ***hash_table = (unsigned char***) STBIW_MALLOC(stbiw__ZHASH * sizeof(char**));
if (hash_table == NULL)
return NULL;
if (quality < 5) quality = 5;
stbiw__sbpush(out, 0x78); // DEFLATE 32K window
stbiw__sbpush(out, 0x5e); // FLEVEL = 1
stbiw__zlib_add(1,1); // BFINAL = 1
stbiw__zlib_add(1,2); // BTYPE = 1 -- fixed huffman
for (i=0; i < stbiw__ZHASH; ++i)
hash_table[i] = NULL;
i=0;
while (i < data_len-3) {
// hash next 3 bytes of data to be compressed
int h = stbiw__zhash(data+i)&(stbiw__ZHASH-1), best=3;
unsigned char *bestloc = 0;
unsigned char **hlist = hash_table[h];
int n = stbiw__sbcount(hlist);
for (j=0; j < n; ++j) {
if (hlist[j]-data > i-32768) { // if entry lies within window
int d = stbiw__zlib_countm(hlist[j], data+i, data_len-i);
if (d >= best) best=d,bestloc=hlist[j];
}
}
// when hash table entry is too long, delete half the entries
if (hash_table[h] && stbiw__sbn(hash_table[h]) == 2*quality) {
STBIW_MEMMOVE(hash_table[h], hash_table[h]+quality, sizeof(hash_table[h][0])*quality);
stbiw__sbn(hash_table[h]) = quality;
}
stbiw__sbpush(hash_table[h],data+i);
if (bestloc) {
// "lazy matching" - check match at *next* byte, and if it's better, do cur byte as literal
h = stbiw__zhash(data+i+1)&(stbiw__ZHASH-1);
hlist = hash_table[h];
n = stbiw__sbcount(hlist);
for (j=0; j < n; ++j) {
if (hlist[j]-data > i-32767) {
int e = stbiw__zlib_countm(hlist[j], data+i+1, data_len-i-1);
if (e > best) { // if next match is better, bail on current match
bestloc = NULL;
break;
}
}
}
}
if (bestloc) {
int d = (int) (data+i - bestloc); // distance back
STBIW_ASSERT(d <= 32767 && best <= 258);
for (j=0; best > lengthc[j+1]-1; ++j);
stbiw__zlib_huff(j+257);
if (lengtheb[j]) stbiw__zlib_add(best - lengthc[j], lengtheb[j]);
for (j=0; d > distc[j+1]-1; ++j);
stbiw__zlib_add(stbiw__zlib_bitrev(j,5),5);
if (disteb[j]) stbiw__zlib_add(d - distc[j], disteb[j]);
i += best;
} else {
stbiw__zlib_huffb(data[i]);
++i;
}
}
// write out final bytes
for (;i < data_len; ++i)
stbiw__zlib_huffb(data[i]);
stbiw__zlib_huff(256); // end of block
// pad with 0 bits to byte boundary
while (bitcount)
stbiw__zlib_add(0,1);
for (i=0; i < stbiw__ZHASH; ++i)
(void) stbiw__sbfree(hash_table[i]);
STBIW_FREE(hash_table);
{
// compute adler32 on input
unsigned int s1=1, s2=0;
int blocklen = (int) (data_len % 5552);
j=0;
while (j < data_len) {
for (i=0; i < blocklen; ++i) s1 += data[j+i], s2 += s1;
s1 %= 65521, s2 %= 65521;
j += blocklen;
blocklen = 5552;
}
stbiw__sbpush(out, STBIW_UCHAR(s2 >> 8));
stbiw__sbpush(out, STBIW_UCHAR(s2));
stbiw__sbpush(out, STBIW_UCHAR(s1 >> 8));
stbiw__sbpush(out, STBIW_UCHAR(s1));
}
*out_len = stbiw__sbn(out);
// make returned pointer freeable
STBIW_MEMMOVE(stbiw__sbraw(out), out, *out_len);
return (unsigned char *) stbiw__sbraw(out);
#endif // STBIW_ZLIB_COMPRESS
}
static unsigned int stbiw__crc32(unsigned char *buffer, int len)
{
static unsigned int crc_table[256] =
{
0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA, 0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
0x0eDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988, 0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE, 0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC, 0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172, 0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940, 0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116, 0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924, 0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A, 0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818, 0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E, 0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C, 0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2, 0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0, 0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086, 0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4, 0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A, 0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8, 0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE, 0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC, 0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252, 0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60, 0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236, 0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04, 0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A, 0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38, 0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E, 0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C, 0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2, 0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0, 0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6, 0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94, 0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
};
unsigned int crc = ~0u;
int i;
for (i=0; i < len; ++i)
crc = (crc >> 8) ^ crc_table[buffer[i] ^ (crc & 0xff)];
return ~crc;
}
#define stbiw__wpng4(o,a,b,c,d) ((o)[0]=STBIW_UCHAR(a),(o)[1]=STBIW_UCHAR(b),(o)[2]=STBIW_UCHAR(c),(o)[3]=STBIW_UCHAR(d),(o)+=4)
#define stbiw__wp32(data,v) stbiw__wpng4(data, (v)>>24,(v)>>16,(v)>>8,(v));
#define stbiw__wptag(data,s) stbiw__wpng4(data, s[0],s[1],s[2],s[3])
static void stbiw__wpcrc(unsigned char **data, int len)
{
unsigned int crc = stbiw__crc32(*data - len - 4, len+4);
stbiw__wp32(*data, crc);
}
static unsigned char stbiw__paeth(int a, int b, int c)
{
int p = a + b - c, pa = abs(p-a), pb = abs(p-b), pc = abs(p-c);
if (pa <= pb && pa <= pc) return STBIW_UCHAR(a);
if (pb <= pc) return STBIW_UCHAR(b);
return STBIW_UCHAR(c);
}
// @OPTIMIZE: provide an option that always forces left-predict or paeth predict
static void stbiw__encode_png_line(unsigned char *pixels, int stride_bytes, int width, int height, int y, int n, int filter_type, signed char *line_buffer)
{
static int mapping[] = { 0,1,2,3,4 };
static int firstmap[] = { 0,1,0,5,6 };
int *mymap = (y != 0) ? mapping : firstmap;
int i;
int type = mymap[filter_type];
unsigned char *z = pixels + stride_bytes * (stbi__flip_vertically_on_write ? height-1-y : y);
for (i = 0; i < n; ++i) {
switch (type) {
case 0: line_buffer[i] = z[i]; break;
case 1: line_buffer[i] = z[i]; break;
case 2: line_buffer[i] = z[i] - z[i-stride_bytes]; break;
case 3: line_buffer[i] = z[i] - (z[i-stride_bytes]>>1); break;
case 4: line_buffer[i] = (signed char) (z[i] - stbiw__paeth(0,z[i-stride_bytes],0)); break;
case 5: line_buffer[i] = z[i]; break;
case 6: line_buffer[i] = z[i]; break;
}
}