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1
/*
2
 * PNG image format
3
 * Copyright (c) 2003 Fabrice Bellard.
4
 *
5
 * This library is free software; you can redistribute it and/or
6
 * modify it under the terms of the GNU Lesser General Public
7
 * License as published by the Free Software Foundation; either
8
 * version 2 of the License, or (at your option) any later version.
9
 *
10
 * This library is distributed in the hope that it will be useful,
11
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13
 * Lesser General Public License for more details.
14
 *
15
 * You should have received a copy of the GNU Lesser General Public
16
 * License along with this library; if not, write to the Free Software
17
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
18
 */
19
#include "avformat.h"
20

    
21
/* TODO:
22
 * - add 2, 4 and 16 bit depth support
23
 * - use filters when generating a png (better compression)
24
 */
25

    
26
#ifdef CONFIG_ZLIB
27
#include <zlib.h>
28

    
29
//#define DEBUG
30

    
31
#define PNG_COLOR_MASK_PALETTE    1
32
#define PNG_COLOR_MASK_COLOR      2
33
#define PNG_COLOR_MASK_ALPHA      4
34

    
35
#define PNG_COLOR_TYPE_GRAY 0
36
#define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
37
#define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
38
#define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
39
#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
40

    
41
#define PNG_FILTER_VALUE_NONE  0
42
#define PNG_FILTER_VALUE_SUB   1
43
#define PNG_FILTER_VALUE_UP    2
44
#define PNG_FILTER_VALUE_AVG   3
45
#define PNG_FILTER_VALUE_PAETH 4
46

    
47
#define PNG_IHDR      0x0001
48
#define PNG_IDAT      0x0002
49
#define PNG_ALLIMAGE  0x0004
50
#define PNG_PLTE      0x0008
51

    
52
#define NB_PASSES 7
53

    
54
#define IOBUF_SIZE 4096
55

    
56
typedef struct PNGDecodeState {
57
    int state;
58
    int width, height;
59
    int bit_depth;
60
    int color_type;
61
    int compression_type;
62
    int interlace_type;
63
    int filter_type;
64
    int channels;
65
    int bits_per_pixel;
66
    int bpp;
67
    
68
    uint8_t *image_buf;
69
    int image_linesize;
70
    uint32_t palette[256];
71
    uint8_t *crow_buf;
72
    uint8_t *last_row;
73
    uint8_t *tmp_row;
74
    int pass;
75
    int crow_size; /* compressed row size (include filter type) */
76
    int row_size; /* decompressed row size */
77
    int pass_row_size; /* decompress row size of the current pass */
78
    int y;
79
    z_stream zstream;
80
} PNGDecodeState;
81

    
82
static const uint8_t pngsig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
83

    
84
/* Mask to determine which y pixels are valid in a pass */
85
static const uint8_t png_pass_ymask[NB_PASSES] = {
86
    0x80, 0x80, 0x08, 0x88, 0x22, 0xaa, 0x55,
87
};
88

    
89
/* Mask to determine which y pixels can be written in a pass */
90
static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
91
    0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
92
};
93

    
94
/* minimum x value */
95
static const uint8_t png_pass_xmin[NB_PASSES] = {
96
    0, 4, 0, 2, 0, 1, 0
97
};
98

    
99
/* x shift to get row width */
100
static const uint8_t png_pass_xshift[NB_PASSES] = {
101
    3, 3, 2, 2, 1, 1, 0
102
};
103

    
104
/* Mask to determine which pixels are valid in a pass */
105
static const uint8_t png_pass_mask[NB_PASSES] = {
106
    0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff
107
};
108

    
109
/* Mask to determine which pixels to overwrite while displaying */
110
static const uint8_t png_pass_dsp_mask[NB_PASSES] = { 
111
    0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
112
};
113

    
114
static int png_probe(AVProbeData *pd)
115
{
116
    if (pd->buf_size >= 8 &&
117
        memcmp(pd->buf, pngsig, 8) == 0)
118
        return AVPROBE_SCORE_MAX;
119
    else
120
        return 0;
121
}
122

    
123
static void *png_zalloc(void *opaque, unsigned int items, unsigned int size)
124
{
125
    return av_malloc(items * size);
126
}
127

    
128
static void png_zfree(void *opaque, void *ptr)
129
{
130
    av_free(ptr);
131
}
132

    
133
static int png_get_nb_channels(int color_type)
134
{
135
    int channels;
136
    channels = 1;
137
    if ((color_type & (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)) ==
138
        PNG_COLOR_MASK_COLOR)
139
        channels = 3;
140
    if (color_type & PNG_COLOR_MASK_ALPHA)
141
        channels++;
142
    return channels;
143
}
144

    
145
/* compute the row size of an interleaved pass */
146
static int png_pass_row_size(int pass, int bits_per_pixel, int width)
147
{
148
    int shift, xmin, pass_width;
149

    
150
    xmin = png_pass_xmin[pass];
151
    if (width <= xmin)
152
        return 0;
153
    shift = png_pass_xshift[pass];
154
    pass_width = (width - xmin + (1 << shift) - 1) >> shift;
155
    return (pass_width * bits_per_pixel + 7) >> 3;
156
}
157

    
158
/* NOTE: we try to construct a good looking image at each pass. width
159
   is the original image width. We also do pixel format convertion at
160
   this stage */
161
static void png_put_interlaced_row(uint8_t *dst, int width, 
162
                                   int bits_per_pixel, int pass, 
163
                                   int color_type, const uint8_t *src)
164
{
165
    int x, mask, dsp_mask, j, src_x, b, bpp;
166
    uint8_t *d;
167
    const uint8_t *s;
168
    
169
    mask = png_pass_mask[pass];
170
    dsp_mask = png_pass_dsp_mask[pass];
171
    switch(bits_per_pixel) {
172
    case 1:
173
        /* we must intialize the line to zero before writing to it */
174
        if (pass == 0)
175
            memset(dst, 0, (width + 7) >> 3);
176
        src_x = 0;
177
        for(x = 0; x < width; x++) {
178
            j = (x & 7);
179
            if ((dsp_mask << j) & 0x80) {
180
                b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
181
                dst[x >> 3] |= b << (7 - j);
182
            }
183
            if ((mask << j) & 0x80)
184
                src_x++;
185
        }
186
        break;
187
    default:
188
        bpp = bits_per_pixel >> 3;
189
        d = dst;
190
        s = src;
191
        if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
192
            for(x = 0; x < width; x++) {
193
                j = x & 7;
194
                if ((dsp_mask << j) & 0x80) {
195
                    *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
196
                }
197
                d += bpp;
198
                if ((mask << j) & 0x80)
199
                    s += bpp;
200
            }
201
        } else {
202
            for(x = 0; x < width; x++) {
203
                j = x & 7;
204
                if ((dsp_mask << j) & 0x80) {
205
                    memcpy(d, s, bpp);
206
                }
207
                d += bpp;
208
                if ((mask << j) & 0x80)
209
                    s += bpp;
210
            }
211
        }
212
        break;
213
    }
214
}
215

    
216
static void png_get_interlaced_row(uint8_t *dst, int row_size, 
217
                                   int bits_per_pixel, int pass, 
218
                                   const uint8_t *src, int width)
219
{
220
    int x, mask, dst_x, j, b, bpp;
221
    uint8_t *d;
222
    const uint8_t *s;
223

    
224
    mask = png_pass_mask[pass];
225
    switch(bits_per_pixel) {
226
    case 1:
227
        memset(dst, 0, row_size);
228
        dst_x = 0;
229
        for(x = 0; x < width; x++) {
230
            j = (x & 7);
231
            if ((mask << j) & 0x80) {
232
                b = (src[x >> 3] >> (7 - j)) & 1;
233
                dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
234
                dst_x++;
235
            }
236
        }
237
        break;
238
    default:
239
        bpp = bits_per_pixel >> 3;
240
        d = dst;
241
        s = src;
242
        for(x = 0; x < width; x++) {
243
            j = x & 7;
244
            if ((mask << j) & 0x80) {
245
                memcpy(d, s, bpp);
246
                d += bpp;
247
            }
248
            s += bpp;
249
        }
250
        break;
251
    }
252
}
253

    
254
/* XXX: optimize */
255
/* NOTE: 'dst' can be equal to 'last' */
256
static void png_filter_row(uint8_t *dst, int filter_type, 
257
                           uint8_t *src, uint8_t *last, int size, int bpp)
258
{
259
    int i, p;
260

    
261
    switch(filter_type) {
262
    case PNG_FILTER_VALUE_NONE:
263
        memcpy(dst, src, size);
264
        break;
265
    case PNG_FILTER_VALUE_SUB:
266
        for(i = 0; i < bpp; i++) {
267
            dst[i] = src[i];
268
        }
269
        for(i = bpp; i < size; i++) {
270
            p = dst[i - bpp];
271
            dst[i] = p + src[i];
272
        }
273
        break;
274
    case PNG_FILTER_VALUE_UP:
275
        for(i = 0; i < size; i++) {
276
            p = last[i];
277
            dst[i] = p + src[i];
278
        }
279
        break;
280
    case PNG_FILTER_VALUE_AVG:
281
        for(i = 0; i < bpp; i++) {
282
            p = (last[i] >> 1);
283
            dst[i] = p + src[i];
284
        }
285
        for(i = bpp; i < size; i++) {
286
            p = ((dst[i - bpp] + last[i]) >> 1);
287
            dst[i] = p + src[i];
288
        }
289
        break;
290
    case PNG_FILTER_VALUE_PAETH:
291
        for(i = 0; i < bpp; i++) {
292
            p = last[i];
293
            dst[i] = p + src[i];
294
        }
295
        for(i = bpp; i < size; i++) {
296
            int a, b, c, pa, pb, pc;
297

    
298
            a = dst[i - bpp];
299
            b = last[i];
300
            c = last[i - bpp];
301

    
302
            p = b - c;
303
            pc = a - c;
304

    
305
            pa = abs(p);
306
            pb = abs(pc);
307
            pc = abs(p + pc);
308

    
309
            if (pa <= pb && pa <= pc)
310
                p = a;
311
            else if (pb <= pc)
312
                p = b;
313
            else
314
                p = c;
315
            dst[i] = p + src[i];
316
        }
317
        break;
318
    }
319
}
320

    
321
static void convert_from_rgba32(uint8_t *dst, const uint8_t *src, int width)
322
{
323
    uint8_t *d;
324
    int j;
325
    unsigned int v;
326
    
327
    d = dst;
328
    for(j = 0; j < width; j++) {
329
        v = ((uint32_t *)src)[j];
330
        d[0] = v >> 16;
331
        d[1] = v >> 8;
332
        d[2] = v;
333
        d[3] = v >> 24;
334
        d += 4;
335
    }
336
}
337

    
338
static void convert_to_rgba32(uint8_t *dst, const uint8_t *src, int width)
339
{
340
    int j;
341
    unsigned int r, g, b, a;
342

    
343
    for(j = 0;j < width; j++) {
344
        r = src[0];
345
        g = src[1];
346
        b = src[2];
347
        a = src[3];
348
        *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
349
        dst += 4;
350
        src += 4;
351
    }
352
}
353

    
354
/* process exactly one decompressed row */
355
static void png_handle_row(PNGDecodeState *s)
356
{
357
    uint8_t *ptr, *last_row;
358
    int got_line;
359
    
360
    if (!s->interlace_type) {
361
        ptr = s->image_buf + s->image_linesize * s->y;
362
        /* need to swap bytes correctly for RGB_ALPHA */
363
        if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
364
            png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1, 
365
                           s->last_row, s->row_size, s->bpp);
366
            memcpy(s->last_row, s->tmp_row, s->row_size);
367
            convert_to_rgba32(ptr, s->tmp_row, s->width);
368
        } else {
369
            /* in normal case, we avoid one copy */
370
            if (s->y == 0)
371
                last_row = s->last_row;
372
            else
373
                last_row = ptr - s->image_linesize;
374
            
375
            png_filter_row(ptr, s->crow_buf[0], s->crow_buf + 1, 
376
                           last_row, s->row_size, s->bpp);
377
        }
378
        s->y++;
379
        if (s->y == s->height) {
380
            s->state |= PNG_ALLIMAGE;
381
        }
382
    } else {
383
        got_line = 0;
384
        for(;;) {
385
            ptr = s->image_buf + s->image_linesize * s->y;
386
            if ((png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
387
                /* if we already read one row, it is time to stop to
388
                   wait for the next one */
389
                if (got_line)
390
                    break;
391
                png_filter_row(s->tmp_row, s->crow_buf[0], s->crow_buf + 1, 
392
                               s->last_row, s->pass_row_size, s->bpp);
393
                memcpy(s->last_row, s->tmp_row, s->pass_row_size);
394
                got_line = 1;
395
            }
396
            if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
397
                /* NOTE: rgba32 is handled directly in png_put_interlaced_row */
398
                png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass, 
399
                                       s->color_type, s->last_row);
400
            }
401
            s->y++;
402
            if (s->y == s->height) {
403
                for(;;) {
404
                    if (s->pass == NB_PASSES - 1) {
405
                        s->state |= PNG_ALLIMAGE;
406
                        goto the_end;
407
                    } else {
408
                        s->pass++;
409
                        s->y = 0;
410
                        s->pass_row_size = png_pass_row_size(s->pass, 
411
                                                             s->bits_per_pixel, 
412
                                                             s->width);
413
                        s->crow_size = s->pass_row_size + 1;
414
                        if (s->pass_row_size != 0)
415
                            break;
416
                        /* skip pass if empty row */
417
                    }
418
                }
419
            }
420
        }
421
    the_end: ;
422
    }
423
}
424

    
425
static int png_decode_idat(PNGDecodeState *s, ByteIOContext *f, int length)
426
{
427
    uint8_t buf[IOBUF_SIZE];
428
    int buf_size;
429
    int ret;
430
    while (length > 0) {
431
        /* read the buffer */
432
        buf_size = IOBUF_SIZE;
433
        if (buf_size > length)
434
            buf_size = length;
435
        ret = get_buffer(f, buf, buf_size);
436
        if (ret != buf_size)
437
            return -1;
438
        s->zstream.avail_in = buf_size;
439
        s->zstream.next_in = buf;
440
        /* decode one line if possible */
441
        while (s->zstream.avail_in > 0) {
442
            ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
443
            if (ret != Z_OK && ret != Z_STREAM_END) {
444
                return -1;
445
            }
446
            if (s->zstream.avail_out == 0) {
447
                if (!(s->state & PNG_ALLIMAGE)) {
448
                    png_handle_row(s);
449
                }
450
                s->zstream.avail_out = s->crow_size;
451
                s->zstream.next_out = s->crow_buf;
452
            }
453
        }
454
        length -= buf_size;
455
    }
456
    return 0;
457
}
458

    
459
static int png_read(ByteIOContext *f, 
460
                    int (*alloc_cb)(void *opaque, AVImageInfo *info), void *opaque)
461
{
462
    AVImageInfo info1, *info = &info1;
463
    PNGDecodeState s1, *s = &s1;
464
    uint32_t tag, length;
465
    int ret, crc;
466
    uint8_t buf[8];
467

    
468
    /* check signature */
469
    ret = get_buffer(f, buf, 8);
470
    if (ret != 8)
471
        return -1;
472
    if (memcmp(buf, pngsig, 8) != 0)
473
        return -1;
474
    memset(s, 0, sizeof(PNGDecodeState));
475
    /* init the zlib */
476
    s->zstream.zalloc = png_zalloc;
477
    s->zstream.zfree = png_zfree;
478
    s->zstream.opaque = NULL;
479
    ret = inflateInit(&s->zstream);
480
    if (ret != Z_OK)
481
        return -1;
482
    for(;;) {
483
        if (url_feof(f))
484
            goto fail;
485
        length = get_be32(f);
486
        if (length > 0x7fffffff)
487
            goto fail;
488
        tag = get_le32(f);
489
#ifdef DEBUG
490
        printf("png: tag=%c%c%c%c length=%u\n", 
491
               (tag & 0xff),
492
               ((tag >> 8) & 0xff),
493
               ((tag >> 16) & 0xff),
494
               ((tag >> 24) & 0xff), length);
495
#endif
496
        switch(tag) {
497
        case MKTAG('I', 'H', 'D', 'R'):
498
            if (length != 13)
499
                goto fail;
500
            s->width = get_be32(f);
501
            s->height = get_be32(f);
502
            s->bit_depth = get_byte(f);
503
            s->color_type = get_byte(f);
504
            s->compression_type = get_byte(f);
505
            s->filter_type = get_byte(f);
506
            s->interlace_type = get_byte(f);
507
            crc = get_be32(f);
508
            s->state |= PNG_IHDR;
509
#ifdef DEBUG
510
            printf("width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n", 
511
                   s->width, s->height, s->bit_depth, s->color_type, 
512
                   s->compression_type, s->filter_type, s->interlace_type);
513
#endif
514
            break;
515
        case MKTAG('I', 'D', 'A', 'T'):
516
            if (!(s->state & PNG_IHDR))
517
                goto fail;
518
            if (!(s->state & PNG_IDAT)) {
519
                /* init image info */
520
                info->width = s->width;
521
                info->height = s->height;
522
                info->interleaved = (s->interlace_type != 0);
523

    
524
                s->channels = png_get_nb_channels(s->color_type);
525
                s->bits_per_pixel = s->bit_depth * s->channels;
526
                s->bpp = (s->bits_per_pixel + 7) >> 3;
527
                s->row_size = (info->width * s->bits_per_pixel + 7) >> 3;
528

    
529
                if (s->bit_depth == 8 && 
530
                    s->color_type == PNG_COLOR_TYPE_RGB) {
531
                    info->pix_fmt = PIX_FMT_RGB24;
532
                } else if (s->bit_depth == 8 && 
533
                           s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
534
                    info->pix_fmt = PIX_FMT_RGBA32;
535
                } else if (s->bit_depth == 8 && 
536
                           s->color_type == PNG_COLOR_TYPE_GRAY) {
537
                    info->pix_fmt = PIX_FMT_GRAY8;
538
                } else if (s->bit_depth == 1 && 
539
                           s->color_type == PNG_COLOR_TYPE_GRAY) {
540
                    info->pix_fmt = PIX_FMT_MONOBLACK;
541
                } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
542
                    info->pix_fmt = PIX_FMT_PAL8;
543
                } else {
544
                    goto fail;
545
                }
546
                ret = alloc_cb(opaque, info);
547
                if (ret) 
548
                    goto the_end;
549

    
550
                /* compute the compressed row size */
551
                if (!s->interlace_type) {
552
                    s->crow_size = s->row_size + 1;
553
                } else {
554
                    s->pass = 0;
555
                    s->pass_row_size = png_pass_row_size(s->pass, 
556
                                                         s->bits_per_pixel, 
557
                                                         s->width);
558
                    s->crow_size = s->pass_row_size + 1;
559
                }
560
#ifdef DEBUG
561
                printf("row_size=%d crow_size =%d\n", 
562
                       s->row_size, s->crow_size);
563
#endif
564
                s->image_buf = info->pict.data[0];
565
                s->image_linesize = info->pict.linesize[0];
566
                /* copy the palette if needed */
567
                if (s->color_type == PNG_COLOR_TYPE_PALETTE)
568
                    memcpy(info->pict.data[1], s->palette, 256 * sizeof(uint32_t));
569
                /* empty row is used if differencing to the first row */
570
                s->last_row = av_mallocz(s->row_size);
571
                if (!s->last_row)
572
                    goto fail;
573
                if (s->interlace_type ||
574
                    s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
575
                    s->tmp_row = av_malloc(s->row_size);
576
                    if (!s->tmp_row)
577
                        goto fail;
578
                }
579
                /* compressed row */
580
                s->crow_buf = av_malloc(s->row_size + 1);
581
                if (!s->crow_buf)
582
                    goto fail;
583
                s->zstream.avail_out = s->crow_size;
584
                s->zstream.next_out = s->crow_buf;
585
            }
586
            s->state |= PNG_IDAT;
587
            if (png_decode_idat(s, f, length) < 0)
588
                goto fail;
589
            /* skip crc */
590
            crc = get_be32(f);
591
            break;
592
        case MKTAG('P', 'L', 'T', 'E'):
593
            {
594
                int n, i, r, g, b;
595
                
596
                if ((length % 3) != 0 || length > 256 * 3)
597
                    goto skip_tag;
598
                /* read the palette */
599
                n = length / 3;
600
                for(i=0;i<n;i++) {
601
                    r = get_byte(f);
602
                    g = get_byte(f);
603
                    b = get_byte(f);
604
                    s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
605
                }
606
                for(;i<256;i++) {
607
                    s->palette[i] = (0xff << 24);
608
                }
609
                s->state |= PNG_PLTE;
610
                crc = get_be32(f);
611
            }
612
            break;
613
        case MKTAG('t', 'R', 'N', 'S'):
614
            {
615
                int v, i;
616

    
617
                /* read the transparency. XXX: Only palette mode supported */
618
                if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
619
                    length > 256 ||
620
                    !(s->state & PNG_PLTE))
621
                    goto skip_tag;
622
                for(i=0;i<length;i++) {
623
                    v = get_byte(f);
624
                    s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
625
                }
626
                crc = get_be32(f);
627
            }
628
            break;
629
        case MKTAG('I', 'E', 'N', 'D'):
630
            if (!(s->state & PNG_ALLIMAGE))
631
                goto fail;
632
            crc = get_be32(f);
633
            goto exit_loop;
634
        default:
635
            /* skip tag */
636
        skip_tag:
637
            url_fskip(f, length + 4);
638
            break;
639
        }
640
    }
641
 exit_loop:
642
    ret = 0;
643
 the_end:
644
    inflateEnd(&s->zstream);
645
    av_free(s->crow_buf);
646
    av_free(s->last_row);
647
    av_free(s->tmp_row);
648
    return ret;
649
 fail:
650
    ret = -1;
651
    goto the_end;
652
}
653

    
654
static void png_write_chunk(ByteIOContext *f, uint32_t tag,
655
                            const uint8_t *buf, int length)
656
{
657
    uint32_t crc;
658
    uint8_t tagbuf[4];
659

    
660
    put_be32(f, length);
661
    crc = crc32(0, Z_NULL, 0);
662
    tagbuf[0] = tag;
663
    tagbuf[1] = tag >> 8;
664
    tagbuf[2] = tag >> 16;
665
    tagbuf[3] = tag >> 24;
666
    crc = crc32(crc, tagbuf, 4);
667
    put_le32(f, tag);
668
    if (length > 0) {
669
        crc = crc32(crc, buf, length);
670
        put_buffer(f, buf, length);
671
    }
672
    put_be32(f, crc);
673
}
674

    
675
/* XXX: use avcodec generic function ? */
676
static void to_be32(uint8_t *p, uint32_t v)
677
{
678
    p[0] = v >> 24;
679
    p[1] = v >> 16;
680
    p[2] = v >> 8;
681
    p[3] = v;
682
}
683

    
684
typedef struct PNGEncodeState {
685
    ByteIOContext *f;
686
    z_stream zstream;
687
    uint8_t buf[IOBUF_SIZE];
688
} PNGEncodeState;
689

    
690

    
691
/* XXX: do filtering */
692
static int png_write_row(PNGEncodeState *s, const uint8_t *data, int size)
693
{
694
    int ret;
695

    
696
    s->zstream.avail_in = size;
697
    s->zstream.next_in = (uint8_t *)data;
698
    while (s->zstream.avail_in > 0) {
699
        ret = deflate(&s->zstream, Z_NO_FLUSH);
700
        if (ret != Z_OK)
701
            return -1;
702
        if (s->zstream.avail_out == 0) {
703
            png_write_chunk(s->f, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
704
            s->zstream.avail_out = IOBUF_SIZE;
705
            s->zstream.next_out = s->buf;
706
        }
707
    }
708
    return 0;
709
}
710

    
711
static int png_write(ByteIOContext *f, AVImageInfo *info)
712
{
713
    PNGEncodeState s1, *s = &s1;
714
    int bit_depth, color_type, y, len, row_size, ret, is_progressive;
715
    int bits_per_pixel, pass_row_size;
716
    uint8_t *ptr;
717
    uint8_t *crow_buf = NULL;
718
    uint8_t *tmp_buf = NULL;
719
    
720
    s->f = f;
721
    is_progressive = info->interleaved;
722
    switch(info->pix_fmt) {
723
    case PIX_FMT_RGBA32:
724
        bit_depth = 8;
725
        color_type = PNG_COLOR_TYPE_RGB_ALPHA;
726
        break;
727
    case PIX_FMT_RGB24:
728
        bit_depth = 8;
729
        color_type = PNG_COLOR_TYPE_RGB;
730
        break;
731
    case PIX_FMT_GRAY8:
732
        bit_depth = 8;
733
        color_type = PNG_COLOR_TYPE_GRAY;
734
        break;
735
    case PIX_FMT_MONOBLACK:
736
        bit_depth = 1;
737
        color_type = PNG_COLOR_TYPE_GRAY;
738
        break;
739
    case PIX_FMT_PAL8:
740
        bit_depth = 8;
741
        color_type = PNG_COLOR_TYPE_PALETTE;
742
        break;
743
    default:
744
        return -1;
745
    }
746
    bits_per_pixel = png_get_nb_channels(color_type) * bit_depth;
747
    row_size = (info->width * bits_per_pixel + 7) >> 3;
748

    
749
    s->zstream.zalloc = png_zalloc;
750
    s->zstream.zfree = png_zfree;
751
    s->zstream.opaque = NULL;
752
    ret = deflateInit2(&s->zstream, Z_DEFAULT_COMPRESSION,
753
                       Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
754
    if (ret != Z_OK)
755
        return -1;
756
    crow_buf = av_malloc(row_size + 1);
757
    if (!crow_buf)
758
        goto fail;
759
    if (is_progressive) {
760
        tmp_buf = av_malloc(row_size + 1);
761
        if (!tmp_buf)
762
            goto fail;
763
    }
764

    
765
    /* write png header */
766
    put_buffer(f, pngsig, 8);
767
    
768
    to_be32(s->buf, info->width);
769
    to_be32(s->buf + 4, info->height);
770
    s->buf[8] = bit_depth;
771
    s->buf[9] = color_type;
772
    s->buf[10] = 0; /* compression type */
773
    s->buf[11] = 0; /* filter type */
774
    s->buf[12] = is_progressive; /* interlace type */
775
    
776
    png_write_chunk(f, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
777

    
778
    /* put the palette if needed */
779
    if (color_type == PNG_COLOR_TYPE_PALETTE) {
780
        int has_alpha, alpha, i;
781
        unsigned int v;
782
        uint32_t *palette;
783
        uint8_t *alpha_ptr;
784
        
785
        palette = (uint32_t *)info->pict.data[1];
786
        ptr = s->buf;
787
        alpha_ptr = s->buf + 256 * 3;
788
        has_alpha = 0;
789
        for(i = 0; i < 256; i++) {
790
            v = palette[i];
791
            alpha = v >> 24;
792
            if (alpha != 0xff)
793
                has_alpha = 1;
794
            *alpha_ptr++ = alpha;
795
            ptr[0] = v >> 16;
796
            ptr[1] = v >> 8;
797
            ptr[2] = v;
798
            ptr += 3;
799
        }
800
        png_write_chunk(f, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
801
        if (has_alpha) {
802
            png_write_chunk(f, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
803
        }
804
    }
805

    
806
    /* now put each row */
807
    s->zstream.avail_out = IOBUF_SIZE;
808
    s->zstream.next_out = s->buf;
809
    if (is_progressive) {
810
        uint8_t *ptr1;
811
        int pass;
812

    
813
        for(pass = 0; pass < NB_PASSES; pass++) {
814
            /* NOTE: a pass is completely omited if no pixels would be
815
               output */
816
            pass_row_size = png_pass_row_size(pass, bits_per_pixel, info->width);
817
            if (pass_row_size > 0) {
818
                for(y = 0; y < info->height; y++) {
819
                    if ((png_pass_ymask[pass] << (y & 7)) & 0x80) {
820
                        ptr = info->pict.data[0] + y * info->pict.linesize[0];
821
                        if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
822
                            convert_from_rgba32(tmp_buf, ptr, info->width);
823
                            ptr1 = tmp_buf;
824
                        } else {
825
                            ptr1 = ptr;
826
                        }
827
                        png_get_interlaced_row(crow_buf + 1, pass_row_size, 
828
                                               bits_per_pixel, pass, 
829
                                               ptr1, info->width);
830
                        crow_buf[0] = PNG_FILTER_VALUE_NONE;
831
                        png_write_row(s, crow_buf, pass_row_size + 1);
832
                    }
833
                }
834
            }
835
        }
836
    } else {
837
        for(y = 0; y < info->height; y++) {
838
            ptr = info->pict.data[0] + y * info->pict.linesize[0];
839
            if (color_type == PNG_COLOR_TYPE_RGB_ALPHA)
840
                convert_from_rgba32(crow_buf + 1, ptr, info->width);
841
            else
842
                memcpy(crow_buf + 1, ptr, row_size);
843
            crow_buf[0] = PNG_FILTER_VALUE_NONE;
844
            png_write_row(s, crow_buf, row_size + 1);
845
        }
846
    }
847
    /* compress last bytes */
848
    for(;;) {
849
        ret = deflate(&s->zstream, Z_FINISH);
850
        if (ret == Z_OK || ret == Z_STREAM_END) {
851
            len = IOBUF_SIZE - s->zstream.avail_out;
852
            if (len > 0) {
853
                png_write_chunk(f, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
854
            }
855
            s->zstream.avail_out = IOBUF_SIZE;
856
            s->zstream.next_out = s->buf;
857
            if (ret == Z_STREAM_END)
858
                break;
859
        } else {
860
            goto fail;
861
        }
862
    }
863
    png_write_chunk(f, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
864

    
865
    put_flush_packet(f);
866
    ret = 0;
867
 the_end:
868
    av_free(crow_buf);
869
    av_free(tmp_buf);
870
    deflateEnd(&s->zstream);
871
    return ret;
872
 fail:
873
    ret = -1;
874
    goto the_end;
875
}
876

    
877
AVImageFormat png_image_format = {
878
    "png",
879
    "png",
880
    png_probe,
881
    png_read,
882
    (1 << PIX_FMT_RGBA32) | (1 << PIX_FMT_RGB24) | (1 << PIX_FMT_GRAY8) | 
883
    (1 << PIX_FMT_MONOBLACK) | (1 << PIX_FMT_PAL8),
884
    png_write,
885
    AVIMAGE_INTERLEAVED,
886
};
887
#endif