Repository navigation
Expand file tree
/
Copy pathSDL_bmp.c
More file actions
858 lines (794 loc) · 27.6 KB
/
Copy pathSDL_bmp.c
File metadata and controls
858 lines (794 loc) · 27.6 KB
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
/*
Simple DirectMedia Layer
Copyright (C) 1997-2025 Sam Lantinga <slouken@libsdl.org>
This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.
Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:
1. The origin of this software must not be misrepresented; you must not
claim that you wrote the original software. If you use this software
in a product, an acknowledgment in the product documentation would be
appreciated but is not required.
2. Altered source versions must be plainly marked as such, and must not be
misrepresented as being the original software.
3. This notice may not be removed or altered from any source distribution.
*/
#include "../SDL_internal.h"
/*
Code to load and save surfaces in Windows BMP format.
Why support BMP format? Well, it's a native format for Windows, and
most image processing programs can read and write it. It would be nice
to be able to have at least one image format that we can natively load
and save, and since PNG is so complex that it would bloat the library,
BMP is a good alternative.
This code currently supports Win32 DIBs in uncompressed 8 and 24 bpp.
*/
#include "SDL_hints.h"
#include "SDL_video.h"
#include "SDL_endian.h"
#include "SDL_pixels_c.h"
#define SAVE_32BIT_BMP
/* Compression encodings for BMP files */
#ifndef BI_RGB
#define BI_RGB 0
#define BI_RLE8 1
#define BI_RLE4 2
#define BI_BITFIELDS 3
#endif
/* Logical color space values for BMP files */
#ifndef LCS_WINDOWS_COLOR_SPACE
/* 0x57696E20 == "Win " */
#define LCS_WINDOWS_COLOR_SPACE 0x57696E20
#endif
static SDL_bool readRlePixels(SDL_Surface *surface, SDL_RWops *src, int isRle8)
{
/*
| Sets the surface pixels from src. A bmp image is upside down.
*/
int pitch = surface->pitch;
int height = surface->h;
Uint8 *start = (Uint8 *)surface->pixels;
Uint8 *end = start + (height * pitch);
Uint8 *bits = end - pitch, *spot;
int ofs = 0;
Uint8 ch;
Uint8 needsPad;
#define COPY_PIXEL(x) \
spot = &bits[ofs++]; \
if (spot >= start && spot < end) \
*spot = (x)
for (;;) {
if (!SDL_RWread(src, &ch, 1, 1)) {
return SDL_TRUE;
}
/*
| encoded mode starts with a run length, and then a byte
| with two colour indexes to alternate between for the run
*/
if (ch) {
Uint8 pixel;
if (!SDL_RWread(src, &pixel, 1, 1)) {
return SDL_TRUE;
}
if (isRle8) { /* 256-color bitmap, compressed */
do {
COPY_PIXEL(pixel);
} while (--ch);
} else { /* 16-color bitmap, compressed */
Uint8 pixel0 = pixel >> 4;
Uint8 pixel1 = pixel & 0x0F;
for (;;) {
COPY_PIXEL(pixel0); /* even count, high nibble */
if (!--ch) {
break;
}
COPY_PIXEL(pixel1); /* odd count, low nibble */
if (!--ch) {
break;
}
}
}
} else {
/*
| A leading zero is an escape; it may signal the end of the bitmap,
| a cursor move, or some absolute data.
| zero tag may be absolute mode or an escape
*/
if (!SDL_RWread(src, &ch, 1, 1)) {
return SDL_TRUE;
}
switch (ch) {
case 0: /* end of line */
ofs = 0;
bits -= pitch; /* go to previous */
break;
case 1: /* end of bitmap */
return SDL_FALSE; /* success! */
case 2: /* delta */
if (!SDL_RWread(src, &ch, 1, 1)) {
return SDL_TRUE;
}
ofs += ch;
if (!SDL_RWread(src, &ch, 1, 1)) {
return SDL_TRUE;
}
bits -= (ch * pitch);
break;
default: /* no compression */
if (isRle8) {
needsPad = (ch & 1);
do {
Uint8 pixel;
if (!SDL_RWread(src, &pixel, 1, 1)) {
return SDL_TRUE;
}
COPY_PIXEL(pixel);
} while (--ch);
} else {
needsPad = (((ch + 1) >> 1) & 1); /* (ch+1)>>1: bytes size */
for (;;) {
Uint8 pixel;
if (!SDL_RWread(src, &pixel, 1, 1)) {
return SDL_TRUE;
}
COPY_PIXEL(pixel >> 4);
if (!--ch) {
break;
}
COPY_PIXEL(pixel & 0x0F);
if (!--ch) {
break;
}
}
}
/* pad at even boundary */
if (needsPad && !SDL_RWread(src, &ch, 1, 1)) {
return SDL_TRUE;
}
break;
}
}
}
}
static void CorrectAlphaChannel(SDL_Surface *surface)
{
/* Check to see if there is any alpha channel data */
SDL_bool hasAlpha = SDL_FALSE;
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
int alphaChannelOffset = 0;
#else
int alphaChannelOffset = 3;
#endif
Uint8 *alpha = ((Uint8 *)surface->pixels) + alphaChannelOffset;
Uint8 *end = alpha + surface->h * surface->pitch;
while (alpha < end) {
if (*alpha != 0) {
hasAlpha = SDL_TRUE;
break;
}
alpha += 4;
}
if (!hasAlpha) {
alpha = ((Uint8 *)surface->pixels) + alphaChannelOffset;
while (alpha < end) {
*alpha = SDL_ALPHA_OPAQUE;
alpha += 4;
}
}
}
SDL_Surface *SDL_LoadBMP_RW(SDL_RWops *src, int freesrc)
{
SDL_bool was_error;
Sint64 fp_offset = 0;
int bmpPitch;
int i, pad;
SDL_Surface *surface;
Uint32 Rmask = 0;
Uint32 Gmask = 0;
Uint32 Bmask = 0;
Uint32 Amask = 0;
SDL_Palette *palette;
Uint8 *bits;
Uint8 *top, *end;
SDL_bool topDown;
int ExpandBMP;
SDL_bool haveRGBMasks = SDL_FALSE;
SDL_bool haveAlphaMask = SDL_FALSE;
SDL_bool correctAlpha = SDL_FALSE;
/* The Win32 BMP file header (14 bytes) */
char magic[2];
/* Uint32 bfSize; */
/* Uint16 bfReserved1; */
/* Uint16 bfReserved2; */
Uint32 bfOffBits;
/* The Win32 BITMAPINFOHEADER struct (40 bytes) */
Uint32 biSize;
Sint32 biWidth = 0;
Sint32 biHeight = 0;
/* Uint16 biPlanes; */
Uint16 biBitCount = 0;
Uint32 biCompression = 0;
/* Uint32 biSizeImage; */
/* Sint32 biXPelsPerMeter; */
/* Sint32 biYPelsPerMeter; */
Uint32 biClrUsed = 0;
/* Uint32 biClrImportant; */
/* Make sure we are passed a valid data source */
surface = NULL;
was_error = SDL_FALSE;
if (!src) {
SDL_InvalidParamError("src");
was_error = SDL_TRUE;
goto done;
}
/* Read in the BMP file header */
fp_offset = SDL_RWtell(src);
if (fp_offset < 0) {
was_error = SDL_TRUE;
goto done;
}
SDL_ClearError();
if (SDL_RWread(src, magic, 1, 2) != 2) {
SDL_Error(SDL_EFREAD);
was_error = SDL_TRUE;
goto done;
}
if (SDL_strncmp(magic, "BM", 2) != 0) {
SDL_SetError("File is not a Windows BMP file");
was_error = SDL_TRUE;
goto done;
}
/* bfSize = */ SDL_ReadLE32(src);
/* bfReserved1 = */ SDL_ReadLE16(src);
/* bfReserved2 = */ SDL_ReadLE16(src);
bfOffBits = SDL_ReadLE32(src);
/* Read the Win32 BITMAPINFOHEADER */
biSize = SDL_ReadLE32(src);
if (biSize == 12) { /* really old BITMAPCOREHEADER */
biWidth = (Uint32)SDL_ReadLE16(src);
biHeight = (Uint32)SDL_ReadLE16(src);
/* biPlanes = */ SDL_ReadLE16(src);
biBitCount = SDL_ReadLE16(src);
biCompression = BI_RGB;
/* biSizeImage = 0; */
/* biXPelsPerMeter = 0; */
/* biYPelsPerMeter = 0; */
biClrUsed = 0;
/* biClrImportant = 0; */
} else if (biSize >= 40) { /* some version of BITMAPINFOHEADER */
Uint32 headerSize;
biWidth = SDL_ReadLE32(src);
biHeight = SDL_ReadLE32(src);
/* biPlanes = */ SDL_ReadLE16(src);
biBitCount = SDL_ReadLE16(src);
biCompression = SDL_ReadLE32(src);
/* biSizeImage = */ SDL_ReadLE32(src);
/* biXPelsPerMeter = */ SDL_ReadLE32(src);
/* biYPelsPerMeter = */ SDL_ReadLE32(src);
biClrUsed = SDL_ReadLE32(src);
/* biClrImportant = */ SDL_ReadLE32(src);
/* 64 == BITMAPCOREHEADER2, an incompatible OS/2 2.x extension. Skip this stuff for now. */
if (biSize != 64) {
/* This is complicated. If compression is BI_BITFIELDS, then
we have 3 DWORDS that specify the RGB masks. This is either
stored here in an BITMAPV2INFOHEADER (which only differs in
that it adds these RGB masks) and biSize >= 52, or we've got
these masks stored in the exact same place, but strictly
speaking, this is the bmiColors field in BITMAPINFO immediately
following the legacy v1 info header, just past biSize. */
if (biCompression == BI_BITFIELDS) {
haveRGBMasks = SDL_TRUE;
Rmask = SDL_ReadLE32(src);
Gmask = SDL_ReadLE32(src);
Bmask = SDL_ReadLE32(src);
/* ...v3 adds an alpha mask. */
if (biSize >= 56) { /* BITMAPV3INFOHEADER; adds alpha mask */
haveAlphaMask = SDL_TRUE;
Amask = SDL_ReadLE32(src);
}
} else {
/* the mask fields are ignored for v2+ headers if not BI_BITFIELD. */
if (biSize >= 52) { /* BITMAPV2INFOHEADER; adds RGB masks */
/*Rmask = */ SDL_ReadLE32(src);
/*Gmask = */ SDL_ReadLE32(src);
/*Bmask = */ SDL_ReadLE32(src);
}
if (biSize >= 56) { /* BITMAPV3INFOHEADER; adds alpha mask */
/*Amask = */ SDL_ReadLE32(src);
}
}
/* Insert other fields here; Wikipedia and MSDN say we're up to
v5 of this header, but we ignore those for now (they add gamma,
color spaces, etc). Ignoring the weird OS/2 2.x format, we
currently parse up to v3 correctly (hopefully!). */
}
/* skip any header bytes we didn't handle... */
headerSize = (Uint32)(SDL_RWtell(src) - (fp_offset + 14));
if (biSize > headerSize) {
SDL_RWseek(src, (biSize - headerSize), RW_SEEK_CUR);
}
}
if (biWidth <= 0 || biHeight == 0) {
SDL_SetError("BMP file with bad dimensions (%" SDL_PRIs32 "x%" SDL_PRIs32 ")", biWidth, biHeight);
was_error = SDL_TRUE;
goto done;
}
if (biHeight < 0) {
topDown = SDL_TRUE;
biHeight = -biHeight;
} else {
topDown = SDL_FALSE;
}
/* Check for read error */
if (SDL_strcmp(SDL_GetError(), "") != 0) {
was_error = SDL_TRUE;
goto done;
}
/* Expand 1, 2 and 4 bit bitmaps to 8 bits per pixel */
switch (biBitCount) {
case 1:
case 2:
case 4:
ExpandBMP = biBitCount;
biBitCount = 8;
break;
case 0:
case 3:
case 5:
case 6:
case 7:
SDL_SetError("%d-bpp BMP images are not supported", biBitCount);
was_error = SDL_TRUE;
goto done;
default:
ExpandBMP = 0;
break;
}
/* RLE4 and RLE8 BMP compression is supported */
switch (biCompression) {
case BI_RGB:
/* If there are no masks, use the defaults */
SDL_assert(!haveRGBMasks);
SDL_assert(!haveAlphaMask);
/* Default values for the BMP format */
switch (biBitCount) {
case 15:
case 16:
Rmask = 0x7C00;
Gmask = 0x03E0;
Bmask = 0x001F;
break;
case 24:
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
Rmask = 0x000000FF;
Gmask = 0x0000FF00;
Bmask = 0x00FF0000;
#else
Rmask = 0x00FF0000;
Gmask = 0x0000FF00;
Bmask = 0x000000FF;
#endif
break;
case 32:
/* We don't know if this has alpha channel or not */
correctAlpha = SDL_TRUE;
Amask = 0xFF000000;
Rmask = 0x00FF0000;
Gmask = 0x0000FF00;
Bmask = 0x000000FF;
break;
default:
break;
}
break;
case BI_BITFIELDS:
break; /* we handled this in the info header. */
default:
break;
}
/* Create a compatible surface, note that the colors are RGB ordered */
surface =
SDL_CreateRGBSurface(0, biWidth, biHeight, biBitCount, Rmask, Gmask,
Bmask, Amask);
if (!surface) {
was_error = SDL_TRUE;
goto done;
}
/* Load the palette, if any */
palette = (surface->format)->palette;
if (palette) {
if (SDL_RWseek(src, fp_offset + 14 + biSize, RW_SEEK_SET) < 0) {
SDL_Error(SDL_EFSEEK);
was_error = SDL_TRUE;
goto done;
}
if (biBitCount >= 32) { /* we shift biClrUsed by this value later. */
SDL_SetError("Unsupported or incorrect biBitCount field");
was_error = SDL_TRUE;
goto done;
}
if (biClrUsed == 0) {
biClrUsed = 1 << biBitCount;
}
if (biClrUsed > (Uint32)palette->ncolors) {
biClrUsed = 1 << biBitCount; /* try forcing it? */
if (biClrUsed > (Uint32)palette->ncolors) {
SDL_SetError("Unsupported or incorrect biClrUsed field");
was_error = SDL_TRUE;
goto done;
}
}
if (biSize == 12) {
for (i = 0; i < (int)biClrUsed; ++i) {
SDL_RWread(src, &palette->colors[i].b, 1, 1);
SDL_RWread(src, &palette->colors[i].g, 1, 1);
SDL_RWread(src, &palette->colors[i].r, 1, 1);
palette->colors[i].a = SDL_ALPHA_OPAQUE;
}
} else {
for (i = 0; i < (int)biClrUsed; ++i) {
SDL_RWread(src, &palette->colors[i].b, 1, 1);
SDL_RWread(src, &palette->colors[i].g, 1, 1);
SDL_RWread(src, &palette->colors[i].r, 1, 1);
SDL_RWread(src, &palette->colors[i].a, 1, 1);
/* According to Microsoft documentation, the fourth element
is reserved and must be zero, so we shouldn't treat it as
alpha.
*/
palette->colors[i].a = SDL_ALPHA_OPAQUE;
}
}
palette->ncolors = biClrUsed;
}
/* Read the surface pixels. Note that the bmp image is upside down */
if (SDL_RWseek(src, fp_offset + bfOffBits, RW_SEEK_SET) < 0) {
SDL_Error(SDL_EFSEEK);
was_error = SDL_TRUE;
goto done;
}
if ((biCompression == BI_RLE4) || (biCompression == BI_RLE8)) {
was_error = readRlePixels(surface, src, biCompression == BI_RLE8);
if (was_error) {
SDL_Error(SDL_EFREAD);
}
goto done;
}
top = (Uint8 *)surface->pixels;
end = (Uint8 *)surface->pixels + (surface->h * surface->pitch);
switch (ExpandBMP) {
case 1:
bmpPitch = (biWidth + 7) >> 3;
pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
break;
case 2:
bmpPitch = (biWidth + 3) >> 2;
pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
break;
case 4:
bmpPitch = (biWidth + 1) >> 1;
pad = (((bmpPitch) % 4) ? (4 - ((bmpPitch) % 4)) : 0);
break;
default:
pad = ((surface->pitch % 4) ? (4 - (surface->pitch % 4)) : 0);
break;
}
if (topDown) {
bits = top;
} else {
bits = end - surface->pitch;
}
while (bits >= top && bits < end) {
switch (ExpandBMP) {
case 1:
case 2:
case 4:
{
Uint8 pixel = 0;
int shift = (8 - ExpandBMP);
for (i = 0; i < surface->w; ++i) {
if (i % (8 / ExpandBMP) == 0) {
if (!SDL_RWread(src, &pixel, 1, 1)) {
SDL_Error(SDL_EFREAD);
was_error = SDL_TRUE;
goto done;
}
}
bits[i] = (pixel >> shift);
if (bits[i] >= biClrUsed) {
SDL_SetError("A BMP image contains a pixel with a color out of the palette");
was_error = SDL_TRUE;
goto done;
}
pixel <<= ExpandBMP;
}
} break;
default:
if (SDL_RWread(src, bits, 1, surface->pitch) != surface->pitch) {
SDL_Error(SDL_EFREAD);
was_error = SDL_TRUE;
goto done;
}
if (biBitCount == 8 && palette && biClrUsed < (1u << biBitCount)) {
for (i = 0; i < surface->w; ++i) {
if (bits[i] >= biClrUsed) {
SDL_SetError("A BMP image contains a pixel with a color out of the palette");
was_error = SDL_TRUE;
goto done;
}
}
}
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
/* Byte-swap the pixels if needed. Note that the 24bpp
case has already been taken care of above. */
switch (biBitCount) {
case 15:
case 16:
{
Uint16 *pix = (Uint16 *)bits;
for (i = 0; i < surface->w; i++) {
pix[i] = SDL_Swap16(pix[i]);
}
break;
}
case 32:
{
Uint32 *pix = (Uint32 *)bits;
for (i = 0; i < surface->w; i++) {
pix[i] = SDL_Swap32(pix[i]);
}
break;
}
}
#endif
break;
}
/* Skip padding bytes, ugh */
if (pad) {
Uint8 padbyte;
for (i = 0; i < pad; ++i) {
SDL_RWread(src, &padbyte, 1, 1);
}
}
if (topDown) {
bits += surface->pitch;
} else {
bits -= surface->pitch;
}
}
if (correctAlpha) {
CorrectAlphaChannel(surface);
}
done:
if (was_error) {
if (src) {
SDL_RWseek(src, fp_offset, RW_SEEK_SET);
}
SDL_FreeSurface(surface);
surface = NULL;
}
if (freesrc && src) {
SDL_RWclose(src);
}
return surface;
}
int SDL_SaveBMP_RW(SDL_Surface *surface, SDL_RWops *dst, int freedst)
{
Sint64 fp_offset;
int i, pad;
SDL_Surface *intermediate_surface;
Uint8 *bits;
SDL_bool save32bit = SDL_FALSE;
SDL_bool saveLegacyBMP = SDL_FALSE;
/* The Win32 BMP file header (14 bytes) */
char magic[2] = { 'B', 'M' };
Uint32 bfSize;
Uint16 bfReserved1;
Uint16 bfReserved2;
Uint32 bfOffBits;
/* The Win32 BITMAPINFOHEADER struct (40 bytes) */
Uint32 biSize;
Sint32 biWidth;
Sint32 biHeight;
Uint16 biPlanes;
Uint16 biBitCount;
Uint32 biCompression;
Uint32 biSizeImage;
Sint32 biXPelsPerMeter;
Sint32 biYPelsPerMeter;
Uint32 biClrUsed;
Uint32 biClrImportant;
/* The additional header members from the Win32 BITMAPV4HEADER struct (108 bytes in total) */
Uint32 bV4RedMask = 0;
Uint32 bV4GreenMask = 0;
Uint32 bV4BlueMask = 0;
Uint32 bV4AlphaMask = 0;
Uint32 bV4CSType = 0;
Sint32 bV4Endpoints[3 * 3] = { 0 };
Uint32 bV4GammaRed = 0;
Uint32 bV4GammaGreen = 0;
Uint32 bV4GammaBlue = 0;
/* Make sure we have somewhere to save */
intermediate_surface = NULL;
if (dst) {
#ifdef SAVE_32BIT_BMP
/* We can save alpha information in a 32-bit BMP */
if (surface->format->BitsPerPixel >= 8 &&
(surface->format->Amask != 0 ||
surface->map->info.flags & SDL_COPY_COLORKEY)) {
save32bit = SDL_TRUE;
}
#endif /* SAVE_32BIT_BMP */
if (surface->format->palette && !save32bit) {
if (surface->format->BitsPerPixel == 8) {
intermediate_surface = surface;
} else {
SDL_SetError("%d bpp BMP files not supported",
surface->format->BitsPerPixel);
}
} else if ((surface->format->BitsPerPixel == 24) && !save32bit &&
#if SDL_BYTEORDER == SDL_LIL_ENDIAN
(surface->format->Rmask == 0x00FF0000) &&
(surface->format->Gmask == 0x0000FF00) &&
(surface->format->Bmask == 0x000000FF)
#else
(surface->format->Rmask == 0x000000FF) &&
(surface->format->Gmask == 0x0000FF00) &&
(surface->format->Bmask == 0x00FF0000)
#endif
) {
intermediate_surface = surface;
} else {
SDL_PixelFormat format;
/* If the surface has a colorkey or alpha channel we'll save a
32-bit BMP with alpha channel, otherwise save a 24-bit BMP. */
if (save32bit) {
SDL_InitFormat(&format, SDL_PIXELFORMAT_BGRA32);
} else {
SDL_InitFormat(&format, SDL_PIXELFORMAT_BGR24);
}
intermediate_surface = SDL_ConvertSurface(surface, &format, 0);
if (!intermediate_surface) {
SDL_SetError("Couldn't convert image to %d bpp",
format.BitsPerPixel);
}
}
} else {
/* Set no error here because it may overwrite a more useful message from
SDL_RWFromFile() if SDL_SaveBMP_RW() is called from SDL_SaveBMP(). */
return -1;
}
if (save32bit) {
saveLegacyBMP = SDL_GetHintBoolean(SDL_HINT_BMP_SAVE_LEGACY_FORMAT, SDL_FALSE);
}
if (intermediate_surface && (SDL_LockSurface(intermediate_surface) == 0)) {
const int bw = intermediate_surface->w * intermediate_surface->format->BytesPerPixel;
/* Set the BMP file header values */
bfSize = 0; /* We'll write this when we're done */
bfReserved1 = 0;
bfReserved2 = 0;
bfOffBits = 0; /* We'll write this when we're done */
/* Write the BMP file header values */
fp_offset = SDL_RWtell(dst);
SDL_ClearError();
SDL_RWwrite(dst, magic, 2, 1);
SDL_WriteLE32(dst, bfSize);
SDL_WriteLE16(dst, bfReserved1);
SDL_WriteLE16(dst, bfReserved2);
SDL_WriteLE32(dst, bfOffBits);
/* Set the BMP info values */
biSize = 40;
biWidth = intermediate_surface->w;
biHeight = intermediate_surface->h;
biPlanes = 1;
biBitCount = intermediate_surface->format->BitsPerPixel;
biCompression = BI_RGB;
biSizeImage = intermediate_surface->h * intermediate_surface->pitch;
biXPelsPerMeter = 0;
biYPelsPerMeter = 0;
if (intermediate_surface->format->palette) {
biClrUsed = intermediate_surface->format->palette->ncolors;
} else {
biClrUsed = 0;
}
biClrImportant = 0;
/* Set the BMP info values for the version 4 header */
if (save32bit && !saveLegacyBMP) {
biSize = 108;
biCompression = BI_BITFIELDS;
/* The BMP format is always little endian, these masks stay the same */
bV4RedMask = 0x00ff0000;
bV4GreenMask = 0x0000ff00;
bV4BlueMask = 0x000000ff;
bV4AlphaMask = 0xff000000;
bV4CSType = LCS_WINDOWS_COLOR_SPACE;
bV4GammaRed = 0;
bV4GammaGreen = 0;
bV4GammaBlue = 0;
}
/* Write the BMP info values */
SDL_WriteLE32(dst, biSize);
SDL_WriteLE32(dst, biWidth);
SDL_WriteLE32(dst, biHeight);
SDL_WriteLE16(dst, biPlanes);
SDL_WriteLE16(dst, biBitCount);
SDL_WriteLE32(dst, biCompression);
SDL_WriteLE32(dst, biSizeImage);
SDL_WriteLE32(dst, biXPelsPerMeter);
SDL_WriteLE32(dst, biYPelsPerMeter);
SDL_WriteLE32(dst, biClrUsed);
SDL_WriteLE32(dst, biClrImportant);
/* Write the BMP info values for the version 4 header */
if (save32bit && !saveLegacyBMP) {
SDL_WriteLE32(dst, bV4RedMask);
SDL_WriteLE32(dst, bV4GreenMask);
SDL_WriteLE32(dst, bV4BlueMask);
SDL_WriteLE32(dst, bV4AlphaMask);
SDL_WriteLE32(dst, bV4CSType);
for (i = 0; i < 3 * 3; i++) {
SDL_WriteLE32(dst, bV4Endpoints[i]);
}
SDL_WriteLE32(dst, bV4GammaRed);
SDL_WriteLE32(dst, bV4GammaGreen);
SDL_WriteLE32(dst, bV4GammaBlue);
}
/* Write the palette (in BGR color order) */
if (intermediate_surface->format->palette) {
SDL_Color *colors;
int ncolors;
colors = intermediate_surface->format->palette->colors;
ncolors = intermediate_surface->format->palette->ncolors;
for (i = 0; i < ncolors; ++i) {
SDL_RWwrite(dst, &colors[i].b, 1, 1);
SDL_RWwrite(dst, &colors[i].g, 1, 1);
SDL_RWwrite(dst, &colors[i].r, 1, 1);
SDL_RWwrite(dst, &colors[i].a, 1, 1);
}
}
/* Write the bitmap offset */
bfOffBits = (Uint32)(SDL_RWtell(dst) - fp_offset);
if (SDL_RWseek(dst, fp_offset + 10, RW_SEEK_SET) < 0) {
SDL_Error(SDL_EFSEEK);
}
SDL_WriteLE32(dst, bfOffBits);
if (SDL_RWseek(dst, fp_offset + bfOffBits, RW_SEEK_SET) < 0) {
SDL_Error(SDL_EFSEEK);
}
/* Write the bitmap image upside down */
bits = (Uint8 *)intermediate_surface->pixels + (intermediate_surface->h * intermediate_surface->pitch);
pad = ((bw % 4) ? (4 - (bw % 4)) : 0);
while (bits > (Uint8 *)intermediate_surface->pixels) {
bits -= intermediate_surface->pitch;
if (SDL_RWwrite(dst, bits, 1, bw) != bw) {
SDL_Error(SDL_EFWRITE);
break;
}
if (pad) {
const Uint8 padbyte = 0;
for (i = 0; i < pad; ++i) {
SDL_RWwrite(dst, &padbyte, 1, 1);
}
}
}
/* Write the BMP file size */
bfSize = (Uint32)(SDL_RWtell(dst) - fp_offset);
if (SDL_RWseek(dst, fp_offset + 2, RW_SEEK_SET) < 0) {
SDL_Error(SDL_EFSEEK);
}
SDL_WriteLE32(dst, bfSize);
if (SDL_RWseek(dst, fp_offset + bfSize, RW_SEEK_SET) < 0) {
SDL_Error(SDL_EFSEEK);
}
/* Close it up.. */
SDL_UnlockSurface(intermediate_surface);
if (intermediate_surface != surface) {
SDL_FreeSurface(intermediate_surface);
}
}
if (freedst && dst) {
SDL_RWclose(dst);
}
return (SDL_strcmp(SDL_GetError(), "") == 0) ? 0 : -1;
}
/* vi: set ts=4 sw=4 expandtab: */