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 "nr-pixops.h"
  14 #include "nr-pixblock-pattern.h"
  15
  16 #define NR_NOISE_SIZE 1024
  17
  18 void
  19 nr_pixblock_render_gray_noise (NRPixBlock *pb, NRPixBlock *mask)
  20 {
  21         static unsigned char *noise = NULL;
  22         static unsigned int seed = 0;
  23         unsigned int v;
  24         NRRectL clip;
  25         int x, y, bpp;
  26
  27         if (mask) {
  28                 if (mask->empty) return;
  29                 nr_rect_l_intersect (&clip, &pb->area, &mask->area);
  30                 if (nr_rect_l_test_empty (&clip)) return;
  31         } else {
  32                 clip = pb->area;
  33         }
  34
  35         if (!noise) {
  36                 int i;
  37                 noise = nr_new (unsigned char, NR_NOISE_SIZE);
  38                 for (i = 0; i < NR_NOISE_SIZE; i++) noise[i] = (rand () / (RAND_MAX >> 8)) & 0xff;
  39         }
  40
  41         bpp = NR_PIXBLOCK_BPP (pb);
  42
  43         v = (rand () / (RAND_MAX >> 8)) & 0xff;
  44
  45         if (mask) {
  46                 for (y = clip.y0; y < clip.y1; y++) {
  47                         unsigned char *d, *m;
  48                         d = NR_PIXBLOCK_PX (pb) + (y - pb->area.y0) * pb->rs + (clip.x0 - pb->area.x0) * bpp;
  49                         m = NR_PIXBLOCK_PX (mask) + (y - mask->area.y0) * pb->rs + (clip.x0 - mask->area.x0);
  50                         for (x = clip.x0; x < clip.x1; x++) {
  51                                 v = v ^ noise[seed];
  52                                 switch (pb->mode) {
  53                                 case NR_PIXBLOCK_MODE_A8:
  54                                         d[0] = (65025 - (255 - m[0]) * (255 - d[0]) + 127) / 255;
  55                                         break;
  56                                 case NR_PIXBLOCK_MODE_R8G8B8:
  57                                         d[0] = NR_COMPOSEN11 (v, m[0], d[0]);
  58                                         d[1] = NR_COMPOSEN11 (v, m[0], d[1]);
  59                                         d[2] = NR_COMPOSEN11 (v, m[0], d[2]);
  60                                         break;
  61                                 case NR_PIXBLOCK_MODE_R8G8B8A8N:
  62                                         if (m[0] != 0) {
  63                                                 unsigned int ca;
  64                                                 ca = NR_A7 (m[0], d[3]);
  65                                                 d[0] = NR_COMPOSENNN_A7 (v, m[0], d[0], d[3], ca);
  66                                                 d[1] = NR_COMPOSENNN_A7 (v, m[0], d[1], d[3], ca);
  67                                                 d[2] = NR_COMPOSENNN_A7 (v, m[0], d[2], d[3], ca);
  68                                                 d[3] = (ca + 127) / 255;
  69                                         }
  70                                         break;
  71                                 case NR_PIXBLOCK_MODE_R8G8B8A8P:
  72                                         d[0] = NR_COMPOSENPP (v, m[0], d[0], d[3]);
  73                                         d[1] = NR_COMPOSENPP (v, m[0], d[1], d[3]);
  74                                         d[2] = NR_COMPOSENPP (v, m[0], d[2], d[3]);
  75                                         d[3] = (NR_A7 (d[3], m[0]) + 127) / 255;
  76                                         break;
  77                                 default:
  78                                         break;
  79                                 }
  80                                 d += bpp;
  81                                 m += 1;
  82                                 if (++seed >= NR_NOISE_SIZE) {
  83                                         int i;
  84                                         i = (rand () / (RAND_MAX / NR_NOISE_SIZE)) % NR_NOISE_SIZE;
  85                                         noise[i] ^= v;
  86                                         seed = i % (NR_NOISE_SIZE >> 2);
  87                                 }
  88                         }
  89                 }
  90         } else {
  91                 for (y = clip.y0; y < clip.y1; y++) {
  92                         unsigned char *d;
  93                         d = NR_PIXBLOCK_PX (pb) + (y - pb->area.y0) * pb->rs + (clip.x0 - pb->area.x0) * bpp;
  94                         for (x = clip.x0; x < clip.x1; x++) {
  95                                 v = v ^ noise[seed];
  96                                 switch (pb->mode) {
  97                                 case NR_PIXBLOCK_MODE_A8:
  98                                         d[0] = 255;
  99                                         break;
 100                                 case NR_PIXBLOCK_MODE_R8G8B8:
 101                                         d[0] = v;
 102                                         d[1] = v;
 103                                         d[2] = v;
 104                                         break;
 105                                 case NR_PIXBLOCK_MODE_R8G8B8A8N:
 106                                 case NR_PIXBLOCK_MODE_R8G8B8A8P:
 107                                         d[0] = v;
 108                                         d[1] = v;
 109                                         d[2] = v;
 110                                         d[3] = 255;
 111                                 default:
 112                                         break;
 113                                 }
 114                                 d += bpp;
 115                                 if (++seed >= NR_NOISE_SIZE) {
 116                                         int i;
 117                                         i = (rand () / (RAND_MAX / NR_NOISE_SIZE)) % NR_NOISE_SIZE;
 118                                         noise[i] ^= v;
 119                                         seed = i % (NR_NOISE_SIZE >> 2);
 120                                 }
 121                         }
 122                 }
 123         }
 124
 125         pb->empty = 0;
 126 }