src/libnr/nr-pixblock-pattern.cpp

   1 #define __NR_PIXBLOCK_PATTERN_C__
   2
   3 /*
   4  * Pixel buffer rendering library
   5  *
   6  * Authors:
   7  *   Lauris Kaplinski <lauris@kaplinski.com>
   8  *
   9  * This code is in public domain
  10  */
  11
  12
  13 #include <glib/gmem.h>
  14 #include "nr-pixops.h"
  15 #include "nr-pixblock-pattern.h"
  16
  17 #define NR_NOISE_SIZE 1024
  18
  19 void
  20 nr_pixblock_render_gray_noise (NRPixBlock *pb, NRPixBlock *mask)
  21 {
  22         static unsigned char *noise = NULL;
  23         static unsigned int seed = 0;
  24         unsigned int v;
  25         NRRectL clip;
  26         int x, y, bpp;
  27
  28         if (mask) {
  29                 if (mask->empty) return;
  30                 nr_rect_l_intersect (&clip, &pb->area, &mask->area);
  31                 if (nr_rect_l_test_empty(clip)) return;
  32         } else {
  33                 clip = pb->area;
  34         }
  35
  36         if (!noise) {
  37                 int i;
  38                 noise = g_new (unsigned char, NR_NOISE_SIZE);
  39                 for (i = 0; i < NR_NOISE_SIZE; i++) noise[i] = (rand () / (RAND_MAX >> 8)) & 0xff;
  40         }
  41
  42         bpp = NR_PIXBLOCK_BPP (pb);
  43
  44         v = (rand () / (RAND_MAX >> 8)) & 0xff;
  45
  46         if (mask) {
  47                 for (y = clip.y0; y < clip.y1; y++) {
  48                         unsigned char *d, *m;
  49                         d = NR_PIXBLOCK_PX (pb) + (y - pb->area.y0) * pb->rs + (clip.x0 - pb->area.x0) * bpp;
  50                         m = NR_PIXBLOCK_PX (mask) + (y - mask->area.y0) * pb->rs + (clip.x0 - mask->area.x0);
  51                         for (x = clip.x0; x < clip.x1; x++) {
  52                                 v = v ^ noise[seed];
  53                                 switch (pb->mode) {
  54                                 case NR_PIXBLOCK_MODE_A8:
  55                                         d[0] = NR_COMPOSEA_111(m[0], d[0]);
  56                                         break;
  57                                 case NR_PIXBLOCK_MODE_R8G8B8:
  58                                         d[0] = NR_COMPOSEN11_1111 (v, m[0], d[0]);
  59                                         d[1] = NR_COMPOSEN11_1111 (v, m[0], d[1]);
  60                                         d[2] = NR_COMPOSEN11_1111 (v, m[0], d[2]);
  61                                         break;
  62                                 case NR_PIXBLOCK_MODE_R8G8B8A8N:
  63                                         if (m[0] != 0) {
  64                                                 unsigned int ca;
  65                                                 ca = NR_COMPOSEA_112(m[0], d[3]);
  66                                                 d[0] = NR_COMPOSENNN_111121 (v, m[0], d[0], d[3], ca);
  67                                                 d[1] = NR_COMPOSENNN_111121 (v, m[0], d[1], d[3], ca);
  68                                                 d[2] = NR_COMPOSENNN_111121 (v, m[0], d[2], d[3], ca);
  69                                                 d[3] = NR_NORMALIZE_21(ca);
  70                                         }
  71                                         break;
  72                                 case NR_PIXBLOCK_MODE_R8G8B8A8P:
  73                                         d[0] = NR_COMPOSENPP_1111 (v, m[0], d[0]);
  74                                         d[1] = NR_COMPOSENPP_1111 (v, m[0], d[1]);
  75                                         d[2] = NR_COMPOSENPP_1111 (v, m[0], d[2]);
  76                                         d[3] = NR_COMPOSEA_111(d[3], m[0]);
  77                                         break;
  78                                 default:
  79                                         break;
  80                                 }
  81                                 d += bpp;
  82                                 m += 1;
  83                                 if (++seed >= NR_NOISE_SIZE) {
  84                                         int i;
  85                                         i = (rand () / (RAND_MAX / NR_NOISE_SIZE)) % NR_NOISE_SIZE;
  86                                         noise[i] ^= v;
  87                                         seed = i % (NR_NOISE_SIZE >> 2);
  88                                 }
  89                         }
  90                 }
  91         } else {
  92                 for (y = clip.y0; y < clip.y1; y++) {
  93                         unsigned char *d;
  94                         d = NR_PIXBLOCK_PX (pb) + (y - pb->area.y0) * pb->rs + (clip.x0 - pb->area.x0) * bpp;
  95                         for (x = clip.x0; x < clip.x1; x++) {
  96                                 v = v ^ noise[seed];
  97                                 switch (pb->mode) {
  98                                 case NR_PIXBLOCK_MODE_A8:
  99                                         d[0] = 255;
 100                                         break;
 101                                 case NR_PIXBLOCK_MODE_R8G8B8:
 102                                         d[0] = v;
 103                                         d[1] = v;
 104                                         d[2] = v;
 105                                         break;
 106                                 case NR_PIXBLOCK_MODE_R8G8B8A8N:
 107                                 case NR_PIXBLOCK_MODE_R8G8B8A8P:
 108                                         d[0] = v;
 109                                         d[1] = v;
 110                                         d[2] = v;
 111                                         d[3] = 255;
 112                                 default:
 113                                         break;
 114                                 }
 115                                 d += bpp;
 116                                 if (++seed >= NR_NOISE_SIZE) {
 117                                         int i;
 118                                         i = (rand () / (RAND_MAX / NR_NOISE_SIZE)) % NR_NOISE_SIZE;
 119                                         noise[i] ^= v;
 120                                         seed = i % (NR_NOISE_SIZE >> 2);
 121                                 }
 122                         }
 123                 }
 124         }
 125
 126         pb->empty = 0;
 127 }