xref: /openbmc/qemu/ui/vnc-enc-tight.c (revision dfeb8679)
1 /*
2  * QEMU VNC display driver: tight encoding
3  *
4  * From libvncserver/libvncserver/tight.c
5  * Copyright (C) 2000, 2001 Const Kaplinsky.  All Rights Reserved.
6  * Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
7  *
8  * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
9  *
10  * Permission is hereby granted, free of charge, to any person obtaining a copy
11  * of this software and associated documentation files (the "Software"), to deal
12  * in the Software without restriction, including without limitation the rights
13  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14  * copies of the Software, and to permit persons to whom the Software is
15  * furnished to do so, subject to the following conditions:
16  *
17  * The above copyright notice and this permission notice shall be included in
18  * all copies or substantial portions of the Software.
19  *
20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
26  * THE SOFTWARE.
27  */
28 
29 #include "config-host.h"
30 
31 /* This needs to be before jpeglib.h line because of conflict with
32    INT32 definitions between jmorecfg.h (included by jpeglib.h) and
33    Win32 basetsd.h (included by windows.h). */
34 #include "qemu-common.h"
35 
36 #ifdef CONFIG_VNC_PNG
37 /* The following define is needed by pngconf.h. Otherwise it won't compile,
38    because setjmp.h was already included by qemu-common.h. */
39 #define PNG_SKIP_SETJMP_CHECK
40 #include <png.h>
41 #endif
42 #ifdef CONFIG_VNC_JPEG
43 #include <stdio.h>
44 #include <jpeglib.h>
45 #endif
46 
47 #include "qemu/bswap.h"
48 #include "qapi/qmp/qint.h"
49 #include "vnc.h"
50 #include "vnc-enc-tight.h"
51 #include "vnc-palette.h"
52 
53 /* Compression level stuff. The following array contains various
54    encoder parameters for each of 10 compression levels (0..9).
55    Last three parameters correspond to JPEG quality levels (0..9). */
56 
57 static const struct {
58     int max_rect_size, max_rect_width;
59     int mono_min_rect_size, gradient_min_rect_size;
60     int idx_zlib_level, mono_zlib_level, raw_zlib_level, gradient_zlib_level;
61     int gradient_threshold, gradient_threshold24;
62     int idx_max_colors_divisor;
63     int jpeg_quality, jpeg_threshold, jpeg_threshold24;
64 } tight_conf[] = {
65     {   512,   32,   6, 65536, 0, 0, 0, 0,   0,   0,   4,  5, 10000, 23000 },
66     {  2048,  128,   6, 65536, 1, 1, 1, 0,   0,   0,   8, 10,  8000, 18000 },
67     {  6144,  256,   8, 65536, 3, 3, 2, 0,   0,   0,  24, 15,  6500, 15000 },
68     { 10240, 1024,  12, 65536, 5, 5, 3, 0,   0,   0,  32, 25,  5000, 12000 },
69     { 16384, 2048,  12, 65536, 6, 6, 4, 0,   0,   0,  32, 37,  4000, 10000 },
70     { 32768, 2048,  12,  4096, 7, 7, 5, 4, 150, 380,  32, 50,  3000,  8000 },
71     { 65536, 2048,  16,  4096, 7, 7, 6, 4, 170, 420,  48, 60,  2000,  5000 },
72     { 65536, 2048,  16,  4096, 8, 8, 7, 5, 180, 450,  64, 70,  1000,  2500 },
73     { 65536, 2048,  32,  8192, 9, 9, 8, 6, 190, 475,  64, 75,   500,  1200 },
74     { 65536, 2048,  32,  8192, 9, 9, 9, 6, 200, 500,  96, 80,   200,   500 }
75 };
76 
77 
78 static int tight_send_framebuffer_update(VncState *vs, int x, int y,
79                                          int w, int h);
80 
81 #ifdef CONFIG_VNC_JPEG
82 static const struct {
83     double jpeg_freq_min;       /* Don't send JPEG if the freq is bellow */
84     double jpeg_freq_threshold; /* Always send JPEG if the freq is above */
85     int jpeg_idx;               /* Allow indexed JPEG */
86     int jpeg_full;              /* Allow full color JPEG */
87 } tight_jpeg_conf[] = {
88     { 0,   8,  1, 1 },
89     { 0,   8,  1, 1 },
90     { 0,   8,  1, 1 },
91     { 0,   8,  1, 1 },
92     { 0,   10, 1, 1 },
93     { 0.1, 10, 1, 1 },
94     { 0.2, 10, 1, 1 },
95     { 0.3, 12, 0, 0 },
96     { 0.4, 14, 0, 0 },
97     { 0.5, 16, 0, 0 },
98 };
99 #endif
100 
101 #ifdef CONFIG_VNC_PNG
102 static const struct {
103     int png_zlib_level, png_filters;
104 } tight_png_conf[] = {
105     { 0, PNG_NO_FILTERS },
106     { 1, PNG_NO_FILTERS },
107     { 2, PNG_NO_FILTERS },
108     { 3, PNG_NO_FILTERS },
109     { 4, PNG_NO_FILTERS },
110     { 5, PNG_ALL_FILTERS },
111     { 6, PNG_ALL_FILTERS },
112     { 7, PNG_ALL_FILTERS },
113     { 8, PNG_ALL_FILTERS },
114     { 9, PNG_ALL_FILTERS },
115 };
116 
117 static int send_png_rect(VncState *vs, int x, int y, int w, int h,
118                          VncPalette *palette);
119 
120 static bool tight_can_send_png_rect(VncState *vs, int w, int h)
121 {
122     if (vs->tight.type != VNC_ENCODING_TIGHT_PNG) {
123         return false;
124     }
125 
126     if (surface_bytes_per_pixel(vs->vd->ds) == 1 ||
127         vs->client_pf.bytes_per_pixel == 1) {
128         return false;
129     }
130 
131     return true;
132 }
133 #endif
134 
135 /*
136  * Code to guess if given rectangle is suitable for smooth image
137  * compression (by applying "gradient" filter or JPEG coder).
138  */
139 
140 static unsigned int
141 tight_detect_smooth_image24(VncState *vs, int w, int h)
142 {
143     int off;
144     int x, y, d, dx;
145     unsigned int c;
146     unsigned int stats[256];
147     int pixels = 0;
148     int pix, left[3];
149     unsigned int errors;
150     unsigned char *buf = vs->tight.tight.buffer;
151 
152     /*
153      * If client is big-endian, color samples begin from the second
154      * byte (offset 1) of a 32-bit pixel value.
155      */
156     off = vs->client_be;
157 
158     memset(stats, 0, sizeof (stats));
159 
160     for (y = 0, x = 0; y < h && x < w;) {
161         for (d = 0; d < h - y && d < w - x - VNC_TIGHT_DETECT_SUBROW_WIDTH;
162              d++) {
163             for (c = 0; c < 3; c++) {
164                 left[c] = buf[((y+d)*w+x+d)*4+off+c] & 0xFF;
165             }
166             for (dx = 1; dx <= VNC_TIGHT_DETECT_SUBROW_WIDTH; dx++) {
167                 for (c = 0; c < 3; c++) {
168                     pix = buf[((y+d)*w+x+d+dx)*4+off+c] & 0xFF;
169                     stats[abs(pix - left[c])]++;
170                     left[c] = pix;
171                 }
172                 pixels++;
173             }
174         }
175         if (w > h) {
176             x += h;
177             y = 0;
178         } else {
179             x = 0;
180             y += w;
181         }
182     }
183 
184     if (pixels == 0) {
185         return 0;
186     }
187 
188     /* 95% smooth or more ... */
189     if (stats[0] * 33 / pixels >= 95) {
190         return 0;
191     }
192 
193     errors = 0;
194     for (c = 1; c < 8; c++) {
195         errors += stats[c] * (c * c);
196         if (stats[c] == 0 || stats[c] > stats[c-1] * 2) {
197             return 0;
198         }
199     }
200     for (; c < 256; c++) {
201         errors += stats[c] * (c * c);
202     }
203     errors /= (pixels * 3 - stats[0]);
204 
205     return errors;
206 }
207 
208 #define DEFINE_DETECT_FUNCTION(bpp)                                     \
209                                                                         \
210     static unsigned int                                                 \
211     tight_detect_smooth_image##bpp(VncState *vs, int w, int h) {        \
212         bool endian;                                                    \
213         uint##bpp##_t pix;                                              \
214         int max[3], shift[3];                                           \
215         int x, y, d, dx;                                                \
216         unsigned int c;                                                 \
217         unsigned int stats[256];                                        \
218         int pixels = 0;                                                 \
219         int sample, sum, left[3];                                       \
220         unsigned int errors;                                            \
221         unsigned char *buf = vs->tight.tight.buffer;                    \
222                                                                         \
223         endian = 0; /* FIXME */                                         \
224                                                                         \
225                                                                         \
226         max[0] = vs->client_pf.rmax;                                  \
227         max[1] = vs->client_pf.gmax;                                  \
228         max[2] = vs->client_pf.bmax;                                  \
229         shift[0] = vs->client_pf.rshift;                              \
230         shift[1] = vs->client_pf.gshift;                              \
231         shift[2] = vs->client_pf.bshift;                              \
232                                                                         \
233         memset(stats, 0, sizeof(stats));                                \
234                                                                         \
235         y = 0, x = 0;                                                   \
236         while (y < h && x < w) {                                        \
237             for (d = 0; d < h - y &&                                    \
238                      d < w - x - VNC_TIGHT_DETECT_SUBROW_WIDTH; d++) {  \
239                 pix = ((uint##bpp##_t *)buf)[(y+d)*w+x+d];              \
240                 if (endian) {                                           \
241                     pix = bswap##bpp(pix);                              \
242                 }                                                       \
243                 for (c = 0; c < 3; c++) {                               \
244                     left[c] = (int)(pix >> shift[c] & max[c]);          \
245                 }                                                       \
246                 for (dx = 1; dx <= VNC_TIGHT_DETECT_SUBROW_WIDTH;       \
247                      dx++) {                                            \
248                     pix = ((uint##bpp##_t *)buf)[(y+d)*w+x+d+dx];       \
249                     if (endian) {                                       \
250                         pix = bswap##bpp(pix);                          \
251                     }                                                   \
252                     sum = 0;                                            \
253                     for (c = 0; c < 3; c++) {                           \
254                         sample = (int)(pix >> shift[c] & max[c]);       \
255                         sum += abs(sample - left[c]);                   \
256                         left[c] = sample;                               \
257                     }                                                   \
258                     if (sum > 255) {                                    \
259                         sum = 255;                                      \
260                     }                                                   \
261                     stats[sum]++;                                       \
262                     pixels++;                                           \
263                 }                                                       \
264             }                                                           \
265             if (w > h) {                                                \
266                 x += h;                                                 \
267                 y = 0;                                                  \
268             } else {                                                    \
269                 x = 0;                                                  \
270                 y += w;                                                 \
271             }                                                           \
272         }                                                               \
273         if (pixels == 0) {                                              \
274             return 0;                                                   \
275         }                                                               \
276         if ((stats[0] + stats[1]) * 100 / pixels >= 90) {               \
277             return 0;                                                   \
278         }                                                               \
279                                                                         \
280         errors = 0;                                                     \
281         for (c = 1; c < 8; c++) {                                       \
282             errors += stats[c] * (c * c);                               \
283             if (stats[c] == 0 || stats[c] > stats[c-1] * 2) {           \
284                 return 0;                                               \
285             }                                                           \
286         }                                                               \
287         for (; c < 256; c++) {                                          \
288             errors += stats[c] * (c * c);                               \
289         }                                                               \
290         errors /= (pixels - stats[0]);                                  \
291                                                                         \
292         return errors;                                                  \
293     }
294 
295 DEFINE_DETECT_FUNCTION(16)
296 DEFINE_DETECT_FUNCTION(32)
297 
298 static int
299 tight_detect_smooth_image(VncState *vs, int w, int h)
300 {
301     unsigned int errors;
302     int compression = vs->tight.compression;
303     int quality = vs->tight.quality;
304 
305     if (!vs->vd->lossy) {
306         return 0;
307     }
308 
309     if (surface_bytes_per_pixel(vs->vd->ds) == 1 ||
310         vs->client_pf.bytes_per_pixel == 1 ||
311         w < VNC_TIGHT_DETECT_MIN_WIDTH || h < VNC_TIGHT_DETECT_MIN_HEIGHT) {
312         return 0;
313     }
314 
315     if (vs->tight.quality != (uint8_t)-1) {
316         if (w * h < VNC_TIGHT_JPEG_MIN_RECT_SIZE) {
317             return 0;
318         }
319     } else {
320         if (w * h < tight_conf[compression].gradient_min_rect_size) {
321             return 0;
322         }
323     }
324 
325     if (vs->client_pf.bytes_per_pixel == 4) {
326         if (vs->tight.pixel24) {
327             errors = tight_detect_smooth_image24(vs, w, h);
328             if (vs->tight.quality != (uint8_t)-1) {
329                 return (errors < tight_conf[quality].jpeg_threshold24);
330             }
331             return (errors < tight_conf[compression].gradient_threshold24);
332         } else {
333             errors = tight_detect_smooth_image32(vs, w, h);
334         }
335     } else {
336         errors = tight_detect_smooth_image16(vs, w, h);
337     }
338     if (quality != (uint8_t)-1) {
339         return (errors < tight_conf[quality].jpeg_threshold);
340     }
341     return (errors < tight_conf[compression].gradient_threshold);
342 }
343 
344 /*
345  * Code to determine how many different colors used in rectangle.
346  */
347 #define DEFINE_FILL_PALETTE_FUNCTION(bpp)                               \
348                                                                         \
349     static int                                                          \
350     tight_fill_palette##bpp(VncState *vs, int x, int y,                 \
351                             int max, size_t count,                      \
352                             uint32_t *bg, uint32_t *fg,                 \
353                             VncPalette **palette) {                     \
354         uint##bpp##_t *data;                                            \
355         uint##bpp##_t c0, c1, ci;                                       \
356         int i, n0, n1;                                                  \
357                                                                         \
358         data = (uint##bpp##_t *)vs->tight.tight.buffer;                 \
359                                                                         \
360         c0 = data[0];                                                   \
361         i = 1;                                                          \
362         while (i < count && data[i] == c0)                              \
363             i++;                                                        \
364         if (i >= count) {                                               \
365             *bg = *fg = c0;                                             \
366             return 1;                                                   \
367         }                                                               \
368                                                                         \
369         if (max < 2) {                                                  \
370             return 0;                                                   \
371         }                                                               \
372                                                                         \
373         n0 = i;                                                         \
374         c1 = data[i];                                                   \
375         n1 = 0;                                                         \
376         for (i++; i < count; i++) {                                     \
377             ci = data[i];                                               \
378             if (ci == c0) {                                             \
379                 n0++;                                                   \
380             } else if (ci == c1) {                                      \
381                 n1++;                                                   \
382             } else                                                      \
383                 break;                                                  \
384         }                                                               \
385         if (i >= count) {                                               \
386             if (n0 > n1) {                                              \
387                 *bg = (uint32_t)c0;                                     \
388                 *fg = (uint32_t)c1;                                     \
389             } else {                                                    \
390                 *bg = (uint32_t)c1;                                     \
391                 *fg = (uint32_t)c0;                                     \
392             }                                                           \
393             return 2;                                                   \
394         }                                                               \
395                                                                         \
396         if (max == 2) {                                                 \
397             return 0;                                                   \
398         }                                                               \
399                                                                         \
400         *palette = palette_new(max, bpp);                               \
401         palette_put(*palette, c0);                                      \
402         palette_put(*palette, c1);                                      \
403         palette_put(*palette, ci);                                      \
404                                                                         \
405         for (i++; i < count; i++) {                                     \
406             if (data[i] == ci) {                                        \
407                 continue;                                               \
408             } else {                                                    \
409                 ci = data[i];                                           \
410                 if (!palette_put(*palette, (uint32_t)ci)) {             \
411                     return 0;                                           \
412                 }                                                       \
413             }                                                           \
414         }                                                               \
415                                                                         \
416         return palette_size(*palette);                                  \
417     }
418 
419 DEFINE_FILL_PALETTE_FUNCTION(8)
420 DEFINE_FILL_PALETTE_FUNCTION(16)
421 DEFINE_FILL_PALETTE_FUNCTION(32)
422 
423 static int tight_fill_palette(VncState *vs, int x, int y,
424                               size_t count, uint32_t *bg, uint32_t *fg,
425                               VncPalette **palette)
426 {
427     int max;
428 
429     max = count / tight_conf[vs->tight.compression].idx_max_colors_divisor;
430     if (max < 2 &&
431         count >= tight_conf[vs->tight.compression].mono_min_rect_size) {
432         max = 2;
433     }
434     if (max >= 256) {
435         max = 256;
436     }
437 
438     switch (vs->client_pf.bytes_per_pixel) {
439     case 4:
440         return tight_fill_palette32(vs, x, y, max, count, bg, fg, palette);
441     case 2:
442         return tight_fill_palette16(vs, x, y, max, count, bg, fg, palette);
443     default:
444         max = 2;
445         return tight_fill_palette8(vs, x, y, max, count, bg, fg, palette);
446     }
447     return 0;
448 }
449 
450 /*
451  * Converting truecolor samples into palette indices.
452  */
453 #define DEFINE_IDX_ENCODE_FUNCTION(bpp)                                 \
454                                                                         \
455     static void                                                         \
456     tight_encode_indexed_rect##bpp(uint8_t *buf, int count,             \
457                                    VncPalette *palette) {               \
458         uint##bpp##_t *src;                                             \
459         uint##bpp##_t rgb;                                              \
460         int i, rep;                                                     \
461         uint8_t idx;                                                    \
462                                                                         \
463         src = (uint##bpp##_t *) buf;                                    \
464                                                                         \
465         for (i = 0; i < count; i++) {                                   \
466                                                                         \
467             rgb = *src++;                                               \
468             rep = 0;                                                    \
469             while (i < count && *src == rgb) {                          \
470                 rep++, src++, i++;                                      \
471             }                                                           \
472             idx = palette_idx(palette, rgb);                            \
473             /*                                                          \
474              * Should never happen, but don't break everything          \
475              * if it does, use the first color instead                  \
476              */                                                         \
477             if (idx == (uint8_t)-1) {                                   \
478                 idx = 0;                                                \
479             }                                                           \
480             while (rep >= 0) {                                          \
481                 *buf++ = idx;                                           \
482                 rep--;                                                  \
483             }                                                           \
484         }                                                               \
485     }
486 
487 DEFINE_IDX_ENCODE_FUNCTION(16)
488 DEFINE_IDX_ENCODE_FUNCTION(32)
489 
490 #define DEFINE_MONO_ENCODE_FUNCTION(bpp)                                \
491                                                                         \
492     static void                                                         \
493     tight_encode_mono_rect##bpp(uint8_t *buf, int w, int h,             \
494                                 uint##bpp##_t bg, uint##bpp##_t fg) {   \
495         uint##bpp##_t *ptr;                                             \
496         unsigned int value, mask;                                       \
497         int aligned_width;                                              \
498         int x, y, bg_bits;                                              \
499                                                                         \
500         ptr = (uint##bpp##_t *) buf;                                    \
501         aligned_width = w - w % 8;                                      \
502                                                                         \
503         for (y = 0; y < h; y++) {                                       \
504             for (x = 0; x < aligned_width; x += 8) {                    \
505                 for (bg_bits = 0; bg_bits < 8; bg_bits++) {             \
506                     if (*ptr++ != bg) {                                 \
507                         break;                                          \
508                     }                                                   \
509                 }                                                       \
510                 if (bg_bits == 8) {                                     \
511                     *buf++ = 0;                                         \
512                     continue;                                           \
513                 }                                                       \
514                 mask = 0x80 >> bg_bits;                                 \
515                 value = mask;                                           \
516                 for (bg_bits++; bg_bits < 8; bg_bits++) {               \
517                     mask >>= 1;                                         \
518                     if (*ptr++ != bg) {                                 \
519                         value |= mask;                                  \
520                     }                                                   \
521                 }                                                       \
522                 *buf++ = (uint8_t)value;                                \
523             }                                                           \
524                                                                         \
525             mask = 0x80;                                                \
526             value = 0;                                                  \
527             if (x >= w) {                                               \
528                 continue;                                               \
529             }                                                           \
530                                                                         \
531             for (; x < w; x++) {                                        \
532                 if (*ptr++ != bg) {                                     \
533                     value |= mask;                                      \
534                 }                                                       \
535                 mask >>= 1;                                             \
536             }                                                           \
537             *buf++ = (uint8_t)value;                                    \
538         }                                                               \
539     }
540 
541 DEFINE_MONO_ENCODE_FUNCTION(8)
542 DEFINE_MONO_ENCODE_FUNCTION(16)
543 DEFINE_MONO_ENCODE_FUNCTION(32)
544 
545 /*
546  * ``Gradient'' filter for 24-bit color samples.
547  * Should be called only when redMax, greenMax and blueMax are 255.
548  * Color components assumed to be byte-aligned.
549  */
550 
551 static void
552 tight_filter_gradient24(VncState *vs, uint8_t *buf, int w, int h)
553 {
554     uint32_t *buf32;
555     uint32_t pix32;
556     int shift[3];
557     int *prev;
558     int here[3], upper[3], left[3], upperleft[3];
559     int prediction;
560     int x, y, c;
561 
562     buf32 = (uint32_t *)buf;
563     memset(vs->tight.gradient.buffer, 0, w * 3 * sizeof(int));
564 
565     if (1 /* FIXME */) {
566         shift[0] = vs->client_pf.rshift;
567         shift[1] = vs->client_pf.gshift;
568         shift[2] = vs->client_pf.bshift;
569     } else {
570         shift[0] = 24 - vs->client_pf.rshift;
571         shift[1] = 24 - vs->client_pf.gshift;
572         shift[2] = 24 - vs->client_pf.bshift;
573     }
574 
575     for (y = 0; y < h; y++) {
576         for (c = 0; c < 3; c++) {
577             upper[c] = 0;
578             here[c] = 0;
579         }
580         prev = (int *)vs->tight.gradient.buffer;
581         for (x = 0; x < w; x++) {
582             pix32 = *buf32++;
583             for (c = 0; c < 3; c++) {
584                 upperleft[c] = upper[c];
585                 left[c] = here[c];
586                 upper[c] = *prev;
587                 here[c] = (int)(pix32 >> shift[c] & 0xFF);
588                 *prev++ = here[c];
589 
590                 prediction = left[c] + upper[c] - upperleft[c];
591                 if (prediction < 0) {
592                     prediction = 0;
593                 } else if (prediction > 0xFF) {
594                     prediction = 0xFF;
595                 }
596                 *buf++ = (char)(here[c] - prediction);
597             }
598         }
599     }
600 }
601 
602 
603 /*
604  * ``Gradient'' filter for other color depths.
605  */
606 
607 #define DEFINE_GRADIENT_FILTER_FUNCTION(bpp)                            \
608                                                                         \
609     static void                                                         \
610     tight_filter_gradient##bpp(VncState *vs, uint##bpp##_t *buf,        \
611                                int w, int h) {                          \
612         uint##bpp##_t pix, diff;                                        \
613         bool endian;                                                    \
614         int *prev;                                                      \
615         int max[3], shift[3];                                           \
616         int here[3], upper[3], left[3], upperleft[3];                   \
617         int prediction;                                                 \
618         int x, y, c;                                                    \
619                                                                         \
620         memset (vs->tight.gradient.buffer, 0, w * 3 * sizeof(int));     \
621                                                                         \
622         endian = 0; /* FIXME */                                         \
623                                                                         \
624         max[0] = vs->client_pf.rmax;                                    \
625         max[1] = vs->client_pf.gmax;                                    \
626         max[2] = vs->client_pf.bmax;                                    \
627         shift[0] = vs->client_pf.rshift;                                \
628         shift[1] = vs->client_pf.gshift;                                \
629         shift[2] = vs->client_pf.bshift;                                \
630                                                                         \
631         for (y = 0; y < h; y++) {                                       \
632             for (c = 0; c < 3; c++) {                                   \
633                 upper[c] = 0;                                           \
634                 here[c] = 0;                                            \
635             }                                                           \
636             prev = (int *)vs->tight.gradient.buffer;                    \
637             for (x = 0; x < w; x++) {                                   \
638                 pix = *buf;                                             \
639                 if (endian) {                                           \
640                     pix = bswap##bpp(pix);                              \
641                 }                                                       \
642                 diff = 0;                                               \
643                 for (c = 0; c < 3; c++) {                               \
644                     upperleft[c] = upper[c];                            \
645                     left[c] = here[c];                                  \
646                     upper[c] = *prev;                                   \
647                     here[c] = (int)(pix >> shift[c] & max[c]);          \
648                     *prev++ = here[c];                                  \
649                                                                         \
650                     prediction = left[c] + upper[c] - upperleft[c];     \
651                     if (prediction < 0) {                               \
652                         prediction = 0;                                 \
653                     } else if (prediction > max[c]) {                   \
654                         prediction = max[c];                            \
655                     }                                                   \
656                     diff |= ((here[c] - prediction) & max[c])           \
657                         << shift[c];                                    \
658                 }                                                       \
659                 if (endian) {                                           \
660                     diff = bswap##bpp(diff);                            \
661                 }                                                       \
662                 *buf++ = diff;                                          \
663             }                                                           \
664         }                                                               \
665     }
666 
667 DEFINE_GRADIENT_FILTER_FUNCTION(16)
668 DEFINE_GRADIENT_FILTER_FUNCTION(32)
669 
670 /*
671  * Check if a rectangle is all of the same color. If needSameColor is
672  * set to non-zero, then also check that its color equals to the
673  * *colorPtr value. The result is 1 if the test is successful, and in
674  * that case new color will be stored in *colorPtr.
675  */
676 
677 static bool
678 check_solid_tile32(VncState *vs, int x, int y, int w, int h,
679                    uint32_t *color, bool samecolor)
680 {
681     VncDisplay *vd = vs->vd;
682     uint32_t *fbptr;
683     uint32_t c;
684     int dx, dy;
685 
686     fbptr = vnc_server_fb_ptr(vd, x, y);
687 
688     c = *fbptr;
689     if (samecolor && (uint32_t)c != *color) {
690         return false;
691     }
692 
693     for (dy = 0; dy < h; dy++) {
694         for (dx = 0; dx < w; dx++) {
695             if (c != fbptr[dx]) {
696                 return false;
697             }
698         }
699         fbptr = (uint32_t *)
700             ((uint8_t *)fbptr + vnc_server_fb_stride(vd));
701     }
702 
703     *color = (uint32_t)c;
704     return true;
705 }
706 
707 static bool check_solid_tile(VncState *vs, int x, int y, int w, int h,
708                              uint32_t* color, bool samecolor)
709 {
710     switch (VNC_SERVER_FB_BYTES) {
711     case 4:
712         return check_solid_tile32(vs, x, y, w, h, color, samecolor);
713     }
714 }
715 
716 static void find_best_solid_area(VncState *vs, int x, int y, int w, int h,
717                                  uint32_t color, int *w_ptr, int *h_ptr)
718 {
719     int dx, dy, dw, dh;
720     int w_prev;
721     int w_best = 0, h_best = 0;
722 
723     w_prev = w;
724 
725     for (dy = y; dy < y + h; dy += VNC_TIGHT_MAX_SPLIT_TILE_SIZE) {
726 
727         dh = MIN(VNC_TIGHT_MAX_SPLIT_TILE_SIZE, y + h - dy);
728         dw = MIN(VNC_TIGHT_MAX_SPLIT_TILE_SIZE, w_prev);
729 
730         if (!check_solid_tile(vs, x, dy, dw, dh, &color, true)) {
731             break;
732         }
733 
734         for (dx = x + dw; dx < x + w_prev;) {
735             dw = MIN(VNC_TIGHT_MAX_SPLIT_TILE_SIZE, x + w_prev - dx);
736 
737             if (!check_solid_tile(vs, dx, dy, dw, dh, &color, true)) {
738                 break;
739             }
740             dx += dw;
741         }
742 
743         w_prev = dx - x;
744         if (w_prev * (dy + dh - y) > w_best * h_best) {
745             w_best = w_prev;
746             h_best = dy + dh - y;
747         }
748     }
749 
750     *w_ptr = w_best;
751     *h_ptr = h_best;
752 }
753 
754 static void extend_solid_area(VncState *vs, int x, int y, int w, int h,
755                               uint32_t color, int *x_ptr, int *y_ptr,
756                               int *w_ptr, int *h_ptr)
757 {
758     int cx, cy;
759 
760     /* Try to extend the area upwards. */
761     for ( cy = *y_ptr - 1;
762           cy >= y && check_solid_tile(vs, *x_ptr, cy, *w_ptr, 1, &color, true);
763           cy-- );
764     *h_ptr += *y_ptr - (cy + 1);
765     *y_ptr = cy + 1;
766 
767     /* ... downwards. */
768     for ( cy = *y_ptr + *h_ptr;
769           cy < y + h &&
770               check_solid_tile(vs, *x_ptr, cy, *w_ptr, 1, &color, true);
771           cy++ );
772     *h_ptr += cy - (*y_ptr + *h_ptr);
773 
774     /* ... to the left. */
775     for ( cx = *x_ptr - 1;
776           cx >= x && check_solid_tile(vs, cx, *y_ptr, 1, *h_ptr, &color, true);
777           cx-- );
778     *w_ptr += *x_ptr - (cx + 1);
779     *x_ptr = cx + 1;
780 
781     /* ... to the right. */
782     for ( cx = *x_ptr + *w_ptr;
783           cx < x + w &&
784               check_solid_tile(vs, cx, *y_ptr, 1, *h_ptr, &color, true);
785           cx++ );
786     *w_ptr += cx - (*x_ptr + *w_ptr);
787 }
788 
789 static int tight_init_stream(VncState *vs, int stream_id,
790                              int level, int strategy)
791 {
792     z_streamp zstream = &vs->tight.stream[stream_id];
793 
794     if (zstream->opaque == NULL) {
795         int err;
796 
797         VNC_DEBUG("VNC: TIGHT: initializing zlib stream %d\n", stream_id);
798         VNC_DEBUG("VNC: TIGHT: opaque = %p | vs = %p\n", zstream->opaque, vs);
799         zstream->zalloc = vnc_zlib_zalloc;
800         zstream->zfree = vnc_zlib_zfree;
801 
802         err = deflateInit2(zstream, level, Z_DEFLATED, MAX_WBITS,
803                            MAX_MEM_LEVEL, strategy);
804 
805         if (err != Z_OK) {
806             fprintf(stderr, "VNC: error initializing zlib\n");
807             return -1;
808         }
809 
810         vs->tight.levels[stream_id] = level;
811         zstream->opaque = vs;
812     }
813 
814     if (vs->tight.levels[stream_id] != level) {
815         if (deflateParams(zstream, level, strategy) != Z_OK) {
816             return -1;
817         }
818         vs->tight.levels[stream_id] = level;
819     }
820     return 0;
821 }
822 
823 static void tight_send_compact_size(VncState *vs, size_t len)
824 {
825     int lpc = 0;
826     int bytes = 0;
827     char buf[3] = {0, 0, 0};
828 
829     buf[bytes++] = len & 0x7F;
830     if (len > 0x7F) {
831         buf[bytes-1] |= 0x80;
832         buf[bytes++] = (len >> 7) & 0x7F;
833         if (len > 0x3FFF) {
834             buf[bytes-1] |= 0x80;
835             buf[bytes++] = (len >> 14) & 0xFF;
836         }
837     }
838     for (lpc = 0; lpc < bytes; lpc++) {
839         vnc_write_u8(vs, buf[lpc]);
840     }
841 }
842 
843 static int tight_compress_data(VncState *vs, int stream_id, size_t bytes,
844                                int level, int strategy)
845 {
846     z_streamp zstream = &vs->tight.stream[stream_id];
847     int previous_out;
848 
849     if (bytes < VNC_TIGHT_MIN_TO_COMPRESS) {
850         vnc_write(vs, vs->tight.tight.buffer, vs->tight.tight.offset);
851         return bytes;
852     }
853 
854     if (tight_init_stream(vs, stream_id, level, strategy)) {
855         return -1;
856     }
857 
858     /* reserve memory in output buffer */
859     buffer_reserve(&vs->tight.zlib, bytes + 64);
860 
861     /* set pointers */
862     zstream->next_in = vs->tight.tight.buffer;
863     zstream->avail_in = vs->tight.tight.offset;
864     zstream->next_out = vs->tight.zlib.buffer + vs->tight.zlib.offset;
865     zstream->avail_out = vs->tight.zlib.capacity - vs->tight.zlib.offset;
866     previous_out = zstream->avail_out;
867     zstream->data_type = Z_BINARY;
868 
869     /* start encoding */
870     if (deflate(zstream, Z_SYNC_FLUSH) != Z_OK) {
871         fprintf(stderr, "VNC: error during tight compression\n");
872         return -1;
873     }
874 
875     vs->tight.zlib.offset = vs->tight.zlib.capacity - zstream->avail_out;
876     /* ...how much data has actually been produced by deflate() */
877     bytes = previous_out - zstream->avail_out;
878 
879     tight_send_compact_size(vs, bytes);
880     vnc_write(vs, vs->tight.zlib.buffer, bytes);
881 
882     buffer_reset(&vs->tight.zlib);
883 
884     return bytes;
885 }
886 
887 /*
888  * Subencoding implementations.
889  */
890 static void tight_pack24(VncState *vs, uint8_t *buf, size_t count, size_t *ret)
891 {
892     uint32_t *buf32;
893     uint32_t pix;
894     int rshift, gshift, bshift;
895 
896     buf32 = (uint32_t *)buf;
897 
898     if (1 /* FIXME */) {
899         rshift = vs->client_pf.rshift;
900         gshift = vs->client_pf.gshift;
901         bshift = vs->client_pf.bshift;
902     } else {
903         rshift = 24 - vs->client_pf.rshift;
904         gshift = 24 - vs->client_pf.gshift;
905         bshift = 24 - vs->client_pf.bshift;
906     }
907 
908     if (ret) {
909         *ret = count * 3;
910     }
911 
912     while (count--) {
913         pix = *buf32++;
914         *buf++ = (char)(pix >> rshift);
915         *buf++ = (char)(pix >> gshift);
916         *buf++ = (char)(pix >> bshift);
917     }
918 }
919 
920 static int send_full_color_rect(VncState *vs, int x, int y, int w, int h)
921 {
922     int stream = 0;
923     ssize_t bytes;
924 
925 #ifdef CONFIG_VNC_PNG
926     if (tight_can_send_png_rect(vs, w, h)) {
927         return send_png_rect(vs, x, y, w, h, NULL);
928     }
929 #endif
930 
931     vnc_write_u8(vs, stream << 4); /* no flushing, no filter */
932 
933     if (vs->tight.pixel24) {
934         tight_pack24(vs, vs->tight.tight.buffer, w * h, &vs->tight.tight.offset);
935         bytes = 3;
936     } else {
937         bytes = vs->client_pf.bytes_per_pixel;
938     }
939 
940     bytes = tight_compress_data(vs, stream, w * h * bytes,
941                                 tight_conf[vs->tight.compression].raw_zlib_level,
942                                 Z_DEFAULT_STRATEGY);
943 
944     return (bytes >= 0);
945 }
946 
947 static int send_solid_rect(VncState *vs)
948 {
949     size_t bytes;
950 
951     vnc_write_u8(vs, VNC_TIGHT_FILL << 4); /* no flushing, no filter */
952 
953     if (vs->tight.pixel24) {
954         tight_pack24(vs, vs->tight.tight.buffer, 1, &vs->tight.tight.offset);
955         bytes = 3;
956     } else {
957         bytes = vs->client_pf.bytes_per_pixel;
958     }
959 
960     vnc_write(vs, vs->tight.tight.buffer, bytes);
961     return 1;
962 }
963 
964 static int send_mono_rect(VncState *vs, int x, int y,
965                           int w, int h, uint32_t bg, uint32_t fg)
966 {
967     ssize_t bytes;
968     int stream = 1;
969     int level = tight_conf[vs->tight.compression].mono_zlib_level;
970 
971 #ifdef CONFIG_VNC_PNG
972     if (tight_can_send_png_rect(vs, w, h)) {
973         int ret;
974         int bpp = vs->client_pf.bytes_per_pixel * 8;
975         VncPalette *palette = palette_new(2, bpp);
976 
977         palette_put(palette, bg);
978         palette_put(palette, fg);
979         ret = send_png_rect(vs, x, y, w, h, palette);
980         palette_destroy(palette);
981         return ret;
982     }
983 #endif
984 
985     bytes = ((w + 7) / 8) * h;
986 
987     vnc_write_u8(vs, (stream | VNC_TIGHT_EXPLICIT_FILTER) << 4);
988     vnc_write_u8(vs, VNC_TIGHT_FILTER_PALETTE);
989     vnc_write_u8(vs, 1);
990 
991     switch (vs->client_pf.bytes_per_pixel) {
992     case 4:
993     {
994         uint32_t buf[2] = {bg, fg};
995         size_t ret = sizeof (buf);
996 
997         if (vs->tight.pixel24) {
998             tight_pack24(vs, (unsigned char*)buf, 2, &ret);
999         }
1000         vnc_write(vs, buf, ret);
1001 
1002         tight_encode_mono_rect32(vs->tight.tight.buffer, w, h, bg, fg);
1003         break;
1004     }
1005     case 2:
1006         vnc_write(vs, &bg, 2);
1007         vnc_write(vs, &fg, 2);
1008         tight_encode_mono_rect16(vs->tight.tight.buffer, w, h, bg, fg);
1009         break;
1010     default:
1011         vnc_write_u8(vs, bg);
1012         vnc_write_u8(vs, fg);
1013         tight_encode_mono_rect8(vs->tight.tight.buffer, w, h, bg, fg);
1014         break;
1015     }
1016     vs->tight.tight.offset = bytes;
1017 
1018     bytes = tight_compress_data(vs, stream, bytes, level, Z_DEFAULT_STRATEGY);
1019     return (bytes >= 0);
1020 }
1021 
1022 struct palette_cb_priv {
1023     VncState *vs;
1024     uint8_t *header;
1025 #ifdef CONFIG_VNC_PNG
1026     png_colorp png_palette;
1027 #endif
1028 };
1029 
1030 static void write_palette(int idx, uint32_t color, void *opaque)
1031 {
1032     struct palette_cb_priv *priv = opaque;
1033     VncState *vs = priv->vs;
1034     uint32_t bytes = vs->client_pf.bytes_per_pixel;
1035 
1036     if (bytes == 4) {
1037         ((uint32_t*)priv->header)[idx] = color;
1038     } else {
1039         ((uint16_t*)priv->header)[idx] = color;
1040     }
1041 }
1042 
1043 static bool send_gradient_rect(VncState *vs, int x, int y, int w, int h)
1044 {
1045     int stream = 3;
1046     int level = tight_conf[vs->tight.compression].gradient_zlib_level;
1047     ssize_t bytes;
1048 
1049     if (vs->client_pf.bytes_per_pixel == 1) {
1050         return send_full_color_rect(vs, x, y, w, h);
1051     }
1052 
1053     vnc_write_u8(vs, (stream | VNC_TIGHT_EXPLICIT_FILTER) << 4);
1054     vnc_write_u8(vs, VNC_TIGHT_FILTER_GRADIENT);
1055 
1056     buffer_reserve(&vs->tight.gradient, w * 3 * sizeof (int));
1057 
1058     if (vs->tight.pixel24) {
1059         tight_filter_gradient24(vs, vs->tight.tight.buffer, w, h);
1060         bytes = 3;
1061     } else if (vs->client_pf.bytes_per_pixel == 4) {
1062         tight_filter_gradient32(vs, (uint32_t *)vs->tight.tight.buffer, w, h);
1063         bytes = 4;
1064     } else {
1065         tight_filter_gradient16(vs, (uint16_t *)vs->tight.tight.buffer, w, h);
1066         bytes = 2;
1067     }
1068 
1069     buffer_reset(&vs->tight.gradient);
1070 
1071     bytes = w * h * bytes;
1072     vs->tight.tight.offset = bytes;
1073 
1074     bytes = tight_compress_data(vs, stream, bytes,
1075                                 level, Z_FILTERED);
1076     return (bytes >= 0);
1077 }
1078 
1079 static int send_palette_rect(VncState *vs, int x, int y,
1080                              int w, int h, VncPalette *palette)
1081 {
1082     int stream = 2;
1083     int level = tight_conf[vs->tight.compression].idx_zlib_level;
1084     int colors;
1085     ssize_t bytes;
1086 
1087 #ifdef CONFIG_VNC_PNG
1088     if (tight_can_send_png_rect(vs, w, h)) {
1089         return send_png_rect(vs, x, y, w, h, palette);
1090     }
1091 #endif
1092 
1093     colors = palette_size(palette);
1094 
1095     vnc_write_u8(vs, (stream | VNC_TIGHT_EXPLICIT_FILTER) << 4);
1096     vnc_write_u8(vs, VNC_TIGHT_FILTER_PALETTE);
1097     vnc_write_u8(vs, colors - 1);
1098 
1099     switch (vs->client_pf.bytes_per_pixel) {
1100     case 4:
1101     {
1102         size_t old_offset, offset;
1103         uint32_t header[palette_size(palette)];
1104         struct palette_cb_priv priv = { vs, (uint8_t *)header };
1105 
1106         old_offset = vs->output.offset;
1107         palette_iter(palette, write_palette, &priv);
1108         vnc_write(vs, header, sizeof(header));
1109 
1110         if (vs->tight.pixel24) {
1111             tight_pack24(vs, vs->output.buffer + old_offset, colors, &offset);
1112             vs->output.offset = old_offset + offset;
1113         }
1114 
1115         tight_encode_indexed_rect32(vs->tight.tight.buffer, w * h, palette);
1116         break;
1117     }
1118     case 2:
1119     {
1120         uint16_t header[palette_size(palette)];
1121         struct palette_cb_priv priv = { vs, (uint8_t *)header };
1122 
1123         palette_iter(palette, write_palette, &priv);
1124         vnc_write(vs, header, sizeof(header));
1125         tight_encode_indexed_rect16(vs->tight.tight.buffer, w * h, palette);
1126         break;
1127     }
1128     default:
1129         return -1; /* No palette for 8bits colors */
1130         break;
1131     }
1132     bytes = w * h;
1133     vs->tight.tight.offset = bytes;
1134 
1135     bytes = tight_compress_data(vs, stream, bytes,
1136                                 level, Z_DEFAULT_STRATEGY);
1137     return (bytes >= 0);
1138 }
1139 
1140 /*
1141  * JPEG compression stuff.
1142  */
1143 #ifdef CONFIG_VNC_JPEG
1144 /*
1145  * Destination manager implementation for JPEG library.
1146  */
1147 
1148 /* This is called once per encoding */
1149 static void jpeg_init_destination(j_compress_ptr cinfo)
1150 {
1151     VncState *vs = cinfo->client_data;
1152     Buffer *buffer = &vs->tight.jpeg;
1153 
1154     cinfo->dest->next_output_byte = (JOCTET *)buffer->buffer + buffer->offset;
1155     cinfo->dest->free_in_buffer = (size_t)(buffer->capacity - buffer->offset);
1156 }
1157 
1158 /* This is called when we ran out of buffer (shouldn't happen!) */
1159 static boolean jpeg_empty_output_buffer(j_compress_ptr cinfo)
1160 {
1161     VncState *vs = cinfo->client_data;
1162     Buffer *buffer = &vs->tight.jpeg;
1163 
1164     buffer->offset = buffer->capacity;
1165     buffer_reserve(buffer, 2048);
1166     jpeg_init_destination(cinfo);
1167     return TRUE;
1168 }
1169 
1170 /* This is called when we are done processing data */
1171 static void jpeg_term_destination(j_compress_ptr cinfo)
1172 {
1173     VncState *vs = cinfo->client_data;
1174     Buffer *buffer = &vs->tight.jpeg;
1175 
1176     buffer->offset = buffer->capacity - cinfo->dest->free_in_buffer;
1177 }
1178 
1179 static int send_jpeg_rect(VncState *vs, int x, int y, int w, int h, int quality)
1180 {
1181     struct jpeg_compress_struct cinfo;
1182     struct jpeg_error_mgr jerr;
1183     struct jpeg_destination_mgr manager;
1184     pixman_image_t *linebuf;
1185     JSAMPROW row[1];
1186     uint8_t *buf;
1187     int dy;
1188 
1189     if (surface_bytes_per_pixel(vs->vd->ds) == 1) {
1190         return send_full_color_rect(vs, x, y, w, h);
1191     }
1192 
1193     buffer_reserve(&vs->tight.jpeg, 2048);
1194 
1195     cinfo.err = jpeg_std_error(&jerr);
1196     jpeg_create_compress(&cinfo);
1197 
1198     cinfo.client_data = vs;
1199     cinfo.image_width = w;
1200     cinfo.image_height = h;
1201     cinfo.input_components = 3;
1202     cinfo.in_color_space = JCS_RGB;
1203 
1204     jpeg_set_defaults(&cinfo);
1205     jpeg_set_quality(&cinfo, quality, true);
1206 
1207     manager.init_destination = jpeg_init_destination;
1208     manager.empty_output_buffer = jpeg_empty_output_buffer;
1209     manager.term_destination = jpeg_term_destination;
1210     cinfo.dest = &manager;
1211 
1212     jpeg_start_compress(&cinfo, true);
1213 
1214     linebuf = qemu_pixman_linebuf_create(PIXMAN_BE_r8g8b8, w);
1215     buf = (uint8_t *)pixman_image_get_data(linebuf);
1216     row[0] = buf;
1217     for (dy = 0; dy < h; dy++) {
1218         qemu_pixman_linebuf_fill(linebuf, vs->vd->server, w, x, y + dy);
1219         jpeg_write_scanlines(&cinfo, row, 1);
1220     }
1221     qemu_pixman_image_unref(linebuf);
1222 
1223     jpeg_finish_compress(&cinfo);
1224     jpeg_destroy_compress(&cinfo);
1225 
1226     vnc_write_u8(vs, VNC_TIGHT_JPEG << 4);
1227 
1228     tight_send_compact_size(vs, vs->tight.jpeg.offset);
1229     vnc_write(vs, vs->tight.jpeg.buffer, vs->tight.jpeg.offset);
1230     buffer_reset(&vs->tight.jpeg);
1231 
1232     return 1;
1233 }
1234 #endif /* CONFIG_VNC_JPEG */
1235 
1236 /*
1237  * PNG compression stuff.
1238  */
1239 #ifdef CONFIG_VNC_PNG
1240 static void write_png_palette(int idx, uint32_t pix, void *opaque)
1241 {
1242     struct palette_cb_priv *priv = opaque;
1243     VncState *vs = priv->vs;
1244     png_colorp color = &priv->png_palette[idx];
1245 
1246     if (vs->tight.pixel24)
1247     {
1248         color->red = (pix >> vs->client_pf.rshift) & vs->client_pf.rmax;
1249         color->green = (pix >> vs->client_pf.gshift) & vs->client_pf.gmax;
1250         color->blue = (pix >> vs->client_pf.bshift) & vs->client_pf.bmax;
1251     }
1252     else
1253     {
1254         int red, green, blue;
1255 
1256         red = (pix >> vs->client_pf.rshift) & vs->client_pf.rmax;
1257         green = (pix >> vs->client_pf.gshift) & vs->client_pf.gmax;
1258         blue = (pix >> vs->client_pf.bshift) & vs->client_pf.bmax;
1259         color->red = ((red * 255 + vs->client_pf.rmax / 2) /
1260                       vs->client_pf.rmax);
1261         color->green = ((green * 255 + vs->client_pf.gmax / 2) /
1262                         vs->client_pf.gmax);
1263         color->blue = ((blue * 255 + vs->client_pf.bmax / 2) /
1264                        vs->client_pf.bmax);
1265     }
1266 }
1267 
1268 static void png_write_data(png_structp png_ptr, png_bytep data,
1269                            png_size_t length)
1270 {
1271     VncState *vs = png_get_io_ptr(png_ptr);
1272 
1273     buffer_reserve(&vs->tight.png, vs->tight.png.offset + length);
1274     memcpy(vs->tight.png.buffer + vs->tight.png.offset, data, length);
1275 
1276     vs->tight.png.offset += length;
1277 }
1278 
1279 static void png_flush_data(png_structp png_ptr)
1280 {
1281 }
1282 
1283 static void *vnc_png_malloc(png_structp png_ptr, png_size_t size)
1284 {
1285     return g_malloc(size);
1286 }
1287 
1288 static void vnc_png_free(png_structp png_ptr, png_voidp ptr)
1289 {
1290     g_free(ptr);
1291 }
1292 
1293 static int send_png_rect(VncState *vs, int x, int y, int w, int h,
1294                          VncPalette *palette)
1295 {
1296     png_byte color_type;
1297     png_structp png_ptr;
1298     png_infop info_ptr;
1299     png_colorp png_palette = NULL;
1300     pixman_image_t *linebuf;
1301     int level = tight_png_conf[vs->tight.compression].png_zlib_level;
1302     int filters = tight_png_conf[vs->tight.compression].png_filters;
1303     uint8_t *buf;
1304     int dy;
1305 
1306     png_ptr = png_create_write_struct_2(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL,
1307                                         NULL, vnc_png_malloc, vnc_png_free);
1308 
1309     if (png_ptr == NULL)
1310         return -1;
1311 
1312     info_ptr = png_create_info_struct(png_ptr);
1313 
1314     if (info_ptr == NULL) {
1315         png_destroy_write_struct(&png_ptr, NULL);
1316         return -1;
1317     }
1318 
1319     png_set_write_fn(png_ptr, (void *) vs, png_write_data, png_flush_data);
1320     png_set_compression_level(png_ptr, level);
1321     png_set_filter(png_ptr, PNG_FILTER_TYPE_DEFAULT, filters);
1322 
1323     if (palette) {
1324         color_type = PNG_COLOR_TYPE_PALETTE;
1325     } else {
1326         color_type = PNG_COLOR_TYPE_RGB;
1327     }
1328 
1329     png_set_IHDR(png_ptr, info_ptr, w, h,
1330                  8, color_type, PNG_INTERLACE_NONE,
1331                  PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
1332 
1333     if (color_type == PNG_COLOR_TYPE_PALETTE) {
1334         struct palette_cb_priv priv;
1335 
1336         png_palette = png_malloc(png_ptr, sizeof(*png_palette) *
1337                                  palette_size(palette));
1338 
1339         priv.vs = vs;
1340         priv.png_palette = png_palette;
1341         palette_iter(palette, write_png_palette, &priv);
1342 
1343         png_set_PLTE(png_ptr, info_ptr, png_palette, palette_size(palette));
1344 
1345         if (vs->client_pf.bytes_per_pixel == 4) {
1346             tight_encode_indexed_rect32(vs->tight.tight.buffer, w * h, palette);
1347         } else {
1348             tight_encode_indexed_rect16(vs->tight.tight.buffer, w * h, palette);
1349         }
1350     }
1351 
1352     png_write_info(png_ptr, info_ptr);
1353 
1354     buffer_reserve(&vs->tight.png, 2048);
1355     linebuf = qemu_pixman_linebuf_create(PIXMAN_BE_r8g8b8, w);
1356     buf = (uint8_t *)pixman_image_get_data(linebuf);
1357     for (dy = 0; dy < h; dy++)
1358     {
1359         if (color_type == PNG_COLOR_TYPE_PALETTE) {
1360             memcpy(buf, vs->tight.tight.buffer + (dy * w), w);
1361         } else {
1362             qemu_pixman_linebuf_fill(linebuf, vs->vd->server, w, x, y + dy);
1363         }
1364         png_write_row(png_ptr, buf);
1365     }
1366     qemu_pixman_image_unref(linebuf);
1367 
1368     png_write_end(png_ptr, NULL);
1369 
1370     if (color_type == PNG_COLOR_TYPE_PALETTE) {
1371         png_free(png_ptr, png_palette);
1372     }
1373 
1374     png_destroy_write_struct(&png_ptr, &info_ptr);
1375 
1376     vnc_write_u8(vs, VNC_TIGHT_PNG << 4);
1377 
1378     tight_send_compact_size(vs, vs->tight.png.offset);
1379     vnc_write(vs, vs->tight.png.buffer, vs->tight.png.offset);
1380     buffer_reset(&vs->tight.png);
1381     return 1;
1382 }
1383 #endif /* CONFIG_VNC_PNG */
1384 
1385 static void vnc_tight_start(VncState *vs)
1386 {
1387     buffer_reset(&vs->tight.tight);
1388 
1389     // make the output buffer be the zlib buffer, so we can compress it later
1390     vs->tight.tmp = vs->output;
1391     vs->output = vs->tight.tight;
1392 }
1393 
1394 static void vnc_tight_stop(VncState *vs)
1395 {
1396     // switch back to normal output/zlib buffers
1397     vs->tight.tight = vs->output;
1398     vs->output = vs->tight.tmp;
1399 }
1400 
1401 static int send_sub_rect_nojpeg(VncState *vs, int x, int y, int w, int h,
1402                                 int bg, int fg, int colors, VncPalette *palette)
1403 {
1404     int ret;
1405 
1406     if (colors == 0) {
1407         if (tight_detect_smooth_image(vs, w, h)) {
1408             ret = send_gradient_rect(vs, x, y, w, h);
1409         } else {
1410             ret = send_full_color_rect(vs, x, y, w, h);
1411         }
1412     } else if (colors == 1) {
1413         ret = send_solid_rect(vs);
1414     } else if (colors == 2) {
1415         ret = send_mono_rect(vs, x, y, w, h, bg, fg);
1416     } else if (colors <= 256) {
1417         ret = send_palette_rect(vs, x, y, w, h, palette);
1418     } else {
1419         ret = 0;
1420     }
1421     return ret;
1422 }
1423 
1424 #ifdef CONFIG_VNC_JPEG
1425 static int send_sub_rect_jpeg(VncState *vs, int x, int y, int w, int h,
1426                               int bg, int fg, int colors,
1427                               VncPalette *palette, bool force)
1428 {
1429     int ret;
1430 
1431     if (colors == 0) {
1432         if (force || (tight_jpeg_conf[vs->tight.quality].jpeg_full &&
1433                       tight_detect_smooth_image(vs, w, h))) {
1434             int quality = tight_conf[vs->tight.quality].jpeg_quality;
1435 
1436             ret = send_jpeg_rect(vs, x, y, w, h, quality);
1437         } else {
1438             ret = send_full_color_rect(vs, x, y, w, h);
1439         }
1440     } else if (colors == 1) {
1441         ret = send_solid_rect(vs);
1442     } else if (colors == 2) {
1443         ret = send_mono_rect(vs, x, y, w, h, bg, fg);
1444     } else if (colors <= 256) {
1445         if (force || (colors > 96 &&
1446                       tight_jpeg_conf[vs->tight.quality].jpeg_idx &&
1447                       tight_detect_smooth_image(vs, w, h))) {
1448             int quality = tight_conf[vs->tight.quality].jpeg_quality;
1449 
1450             ret = send_jpeg_rect(vs, x, y, w, h, quality);
1451         } else {
1452             ret = send_palette_rect(vs, x, y, w, h, palette);
1453         }
1454     } else {
1455         ret = 0;
1456     }
1457     return ret;
1458 }
1459 #endif
1460 
1461 static int send_sub_rect(VncState *vs, int x, int y, int w, int h)
1462 {
1463     VncPalette *palette = NULL;
1464     uint32_t bg = 0, fg = 0;
1465     int colors;
1466     int ret = 0;
1467 #ifdef CONFIG_VNC_JPEG
1468     bool force_jpeg = false;
1469     bool allow_jpeg = true;
1470 #endif
1471 
1472     vnc_framebuffer_update(vs, x, y, w, h, vs->tight.type);
1473 
1474     vnc_tight_start(vs);
1475     vnc_raw_send_framebuffer_update(vs, x, y, w, h);
1476     vnc_tight_stop(vs);
1477 
1478 #ifdef CONFIG_VNC_JPEG
1479     if (!vs->vd->non_adaptive && vs->tight.quality != (uint8_t)-1) {
1480         double freq = vnc_update_freq(vs, x, y, w, h);
1481 
1482         if (freq < tight_jpeg_conf[vs->tight.quality].jpeg_freq_min) {
1483             allow_jpeg = false;
1484         }
1485         if (freq >= tight_jpeg_conf[vs->tight.quality].jpeg_freq_threshold) {
1486             force_jpeg = true;
1487             vnc_sent_lossy_rect(vs, x, y, w, h);
1488         }
1489     }
1490 #endif
1491 
1492     colors = tight_fill_palette(vs, x, y, w * h, &bg, &fg, &palette);
1493 
1494 #ifdef CONFIG_VNC_JPEG
1495     if (allow_jpeg && vs->tight.quality != (uint8_t)-1) {
1496         ret = send_sub_rect_jpeg(vs, x, y, w, h, bg, fg, colors, palette,
1497                                  force_jpeg);
1498     } else {
1499         ret = send_sub_rect_nojpeg(vs, x, y, w, h, bg, fg, colors, palette);
1500     }
1501 #else
1502     ret = send_sub_rect_nojpeg(vs, x, y, w, h, bg, fg, colors, palette);
1503 #endif
1504 
1505     palette_destroy(palette);
1506     return ret;
1507 }
1508 
1509 static int send_sub_rect_solid(VncState *vs, int x, int y, int w, int h)
1510 {
1511     vnc_framebuffer_update(vs, x, y, w, h, vs->tight.type);
1512 
1513     vnc_tight_start(vs);
1514     vnc_raw_send_framebuffer_update(vs, x, y, w, h);
1515     vnc_tight_stop(vs);
1516 
1517     return send_solid_rect(vs);
1518 }
1519 
1520 static int send_rect_simple(VncState *vs, int x, int y, int w, int h,
1521                             bool split)
1522 {
1523     int max_size, max_width;
1524     int max_sub_width, max_sub_height;
1525     int dx, dy;
1526     int rw, rh;
1527     int n = 0;
1528 
1529     max_size = tight_conf[vs->tight.compression].max_rect_size;
1530     max_width = tight_conf[vs->tight.compression].max_rect_width;
1531 
1532     if (split && (w > max_width || w * h > max_size)) {
1533         max_sub_width = (w > max_width) ? max_width : w;
1534         max_sub_height = max_size / max_sub_width;
1535 
1536         for (dy = 0; dy < h; dy += max_sub_height) {
1537             for (dx = 0; dx < w; dx += max_width) {
1538                 rw = MIN(max_sub_width, w - dx);
1539                 rh = MIN(max_sub_height, h - dy);
1540                 n += send_sub_rect(vs, x+dx, y+dy, rw, rh);
1541             }
1542         }
1543     } else {
1544         n += send_sub_rect(vs, x, y, w, h);
1545     }
1546 
1547     return n;
1548 }
1549 
1550 static int find_large_solid_color_rect(VncState *vs, int x, int y,
1551                                        int w, int h, int max_rows)
1552 {
1553     int dx, dy, dw, dh;
1554     int n = 0;
1555 
1556     /* Try to find large solid-color areas and send them separately. */
1557 
1558     for (dy = y; dy < y + h; dy += VNC_TIGHT_MAX_SPLIT_TILE_SIZE) {
1559 
1560         /* If a rectangle becomes too large, send its upper part now. */
1561 
1562         if (dy - y >= max_rows) {
1563             n += send_rect_simple(vs, x, y, w, max_rows, true);
1564             y += max_rows;
1565             h -= max_rows;
1566         }
1567 
1568         dh = MIN(VNC_TIGHT_MAX_SPLIT_TILE_SIZE, (y + h - dy));
1569 
1570         for (dx = x; dx < x + w; dx += VNC_TIGHT_MAX_SPLIT_TILE_SIZE) {
1571             uint32_t color_value;
1572             int x_best, y_best, w_best, h_best;
1573 
1574             dw = MIN(VNC_TIGHT_MAX_SPLIT_TILE_SIZE, (x + w - dx));
1575 
1576             if (!check_solid_tile(vs, dx, dy, dw, dh, &color_value, false)) {
1577                 continue ;
1578             }
1579 
1580             /* Get dimensions of solid-color area. */
1581 
1582             find_best_solid_area(vs, dx, dy, w - (dx - x), h - (dy - y),
1583                                  color_value, &w_best, &h_best);
1584 
1585             /* Make sure a solid rectangle is large enough
1586                (or the whole rectangle is of the same color). */
1587 
1588             if (w_best * h_best != w * h &&
1589                 w_best * h_best < VNC_TIGHT_MIN_SOLID_SUBRECT_SIZE) {
1590                 continue;
1591             }
1592 
1593             /* Try to extend solid rectangle to maximum size. */
1594 
1595             x_best = dx; y_best = dy;
1596             extend_solid_area(vs, x, y, w, h, color_value,
1597                               &x_best, &y_best, &w_best, &h_best);
1598 
1599             /* Send rectangles at top and left to solid-color area. */
1600 
1601             if (y_best != y) {
1602                 n += send_rect_simple(vs, x, y, w, y_best-y, true);
1603             }
1604             if (x_best != x) {
1605                 n += tight_send_framebuffer_update(vs, x, y_best,
1606                                                    x_best-x, h_best);
1607             }
1608 
1609             /* Send solid-color rectangle. */
1610             n += send_sub_rect_solid(vs, x_best, y_best, w_best, h_best);
1611 
1612             /* Send remaining rectangles (at right and bottom). */
1613 
1614             if (x_best + w_best != x + w) {
1615                 n += tight_send_framebuffer_update(vs, x_best+w_best,
1616                                                    y_best,
1617                                                    w-(x_best-x)-w_best,
1618                                                    h_best);
1619             }
1620             if (y_best + h_best != y + h) {
1621                 n += tight_send_framebuffer_update(vs, x, y_best+h_best,
1622                                                    w, h-(y_best-y)-h_best);
1623             }
1624 
1625             /* Return after all recursive calls are done. */
1626             return n;
1627         }
1628     }
1629     return n + send_rect_simple(vs, x, y, w, h, true);
1630 }
1631 
1632 static int tight_send_framebuffer_update(VncState *vs, int x, int y,
1633                                          int w, int h)
1634 {
1635     int max_rows;
1636 
1637     if (vs->client_pf.bytes_per_pixel == 4 && vs->client_pf.rmax == 0xFF &&
1638         vs->client_pf.bmax == 0xFF && vs->client_pf.gmax == 0xFF) {
1639         vs->tight.pixel24 = true;
1640     } else {
1641         vs->tight.pixel24 = false;
1642     }
1643 
1644 #ifdef CONFIG_VNC_JPEG
1645     if (vs->tight.quality != (uint8_t)-1) {
1646         double freq = vnc_update_freq(vs, x, y, w, h);
1647 
1648         if (freq > tight_jpeg_conf[vs->tight.quality].jpeg_freq_threshold) {
1649             return send_rect_simple(vs, x, y, w, h, false);
1650         }
1651     }
1652 #endif
1653 
1654     if (w * h < VNC_TIGHT_MIN_SPLIT_RECT_SIZE) {
1655         return send_rect_simple(vs, x, y, w, h, true);
1656     }
1657 
1658     /* Calculate maximum number of rows in one non-solid rectangle. */
1659 
1660     max_rows = tight_conf[vs->tight.compression].max_rect_size;
1661     max_rows /= MIN(tight_conf[vs->tight.compression].max_rect_width, w);
1662 
1663     return find_large_solid_color_rect(vs, x, y, w, h, max_rows);
1664 }
1665 
1666 int vnc_tight_send_framebuffer_update(VncState *vs, int x, int y,
1667                                       int w, int h)
1668 {
1669     vs->tight.type = VNC_ENCODING_TIGHT;
1670     return tight_send_framebuffer_update(vs, x, y, w, h);
1671 }
1672 
1673 int vnc_tight_png_send_framebuffer_update(VncState *vs, int x, int y,
1674                                           int w, int h)
1675 {
1676     vs->tight.type = VNC_ENCODING_TIGHT_PNG;
1677     return tight_send_framebuffer_update(vs, x, y, w, h);
1678 }
1679 
1680 void vnc_tight_clear(VncState *vs)
1681 {
1682     int i;
1683     for (i=0; i<ARRAY_SIZE(vs->tight.stream); i++) {
1684         if (vs->tight.stream[i].opaque) {
1685             deflateEnd(&vs->tight.stream[i]);
1686         }
1687     }
1688 
1689     buffer_free(&vs->tight.tight);
1690     buffer_free(&vs->tight.zlib);
1691     buffer_free(&vs->tight.gradient);
1692 #ifdef CONFIG_VNC_JPEG
1693     buffer_free(&vs->tight.jpeg);
1694 #endif
1695 #ifdef CONFIG_VNC_PNG
1696     buffer_free(&vs->tight.png);
1697 #endif
1698 }
1699