#ifndef DITHERS_H_INCLUDED
#define DITHERS_H_INCLUDED
/*
** dithers.h
**
** Here are some dithering matrices.  They are all taken from "Digital
** Halftoning" by Robert Ulichney, MIT Press, ISBN 0-262-21009-6.
*/


#if 0
/*
** Order-6 ordered dithering matrix.  Note that smaller ordered dithers
** have no advantage over larger ones, so use dither8 instead.
*/
static int const dither6[8][8] = {
  {  1, 59, 15, 55,  2, 56, 12, 52 },
  { 33, 17, 47, 31, 34, 18, 44, 28 },
  {  9, 49,  5, 63, 10, 50,  6, 60 },
  { 41, 25, 37, 21, 42, 26, 38, 22 },
  {  3, 57, 13, 53,  0, 58, 14, 54 },
  { 35, 19, 45, 29, 32, 16, 46, 30 },
  { 11, 51,  7, 61,  8, 48,  4, 62 },
  { 43, 27, 39, 23, 40, 24, 36, 20 }
  };
#endif

/* Order-8 ordered dithering matrix. */
static int const dither8[16][16] = {
  {   1,235, 59,219, 15,231, 55,215,  2,232, 56,216, 12,228, 52,212},
  { 129, 65,187,123,143, 79,183,119,130, 66,184,120,140, 76,180,116},
  {  33,193, 17,251, 47,207, 31,247, 34,194, 18,248, 44,204, 28,244},
  { 161, 97,145, 81,175,111,159, 95,162, 98,146, 82,172,108,156, 92},
  {   9,225, 49,209,  5,239, 63,223, 10,226, 50,210,  6,236, 60,220},
  { 137, 73,177,113,133, 69,191,127,138, 74,178,114,134, 70,188,124},
  {  41,201, 25,241, 37,197, 21,255, 42,202, 26,242, 38,198, 22,252},
  { 169,105,153, 89,165,101,149, 85,170,106,154, 90,166,102,150, 86},
  {   3,233, 57,217, 13,229, 53,213,  0,234, 58,218, 14,230, 54,214},
  { 131, 67,185,121,141, 77,181,117,128, 64,186,122,142, 78,182,118},
  {  35,195, 19,249, 45,205, 29,245, 32,192, 16,250, 46,206, 30,246},
  { 163, 99,147, 83,173,109,157, 93,160, 96,144, 80,174,110,158, 94},
  {  11,227, 51,211,  7,237, 61,221,  8,224, 48,208,  4,238, 62,222},
  { 139, 75,179,115,135, 71,189,125,136, 72,176,112,132, 68,190,126},
  {  43,203, 27,243, 39,199, 23,253, 40,200, 24,240, 36,196, 20,254},
  { 171,107,155, 91,167,103,151, 87,168,104,152, 88,164,100,148, 84}
};

/* Order-3 clustered dithering matrix. */
static int const cluster3[6][6] = {
  {  9,11,10, 8, 6, 7},
  { 12,17,16, 5, 0, 1},
  { 13,14,15, 4, 3, 2},
  {  8, 6, 7, 9,11,10},
  {  5, 0, 1,12,17,16},
  {  4, 3, 2,13,14,15}
};

/* Order-4 clustered dithering matrix. */
static int const cluster4[8][8] = {
  { 18,20,19,16,13,11,12,15},
  { 27,28,29,22, 4, 3, 2, 9},
  { 26,31,30,21, 5, 0, 1,10},
  { 23,25,24,17, 8, 6, 7,14},
  { 13,11,12,15,18,20,19,16},
  {  4, 3, 2, 9,27,28,29,22},
  {  5, 0, 1,10,26,31,30,21},
  {  8, 6, 7,14,23,25,24,17}
};

/* Order-8 clustered dithering matrix. */
static int const cluster8[16][16] = {
   { 64, 69, 77, 87, 86, 76, 68, 67, 63, 58, 50, 40, 41, 51, 59, 60},
   { 70, 94,100,109,108, 99, 93, 75, 57, 33, 27, 18, 19, 28, 34, 52},
   { 78,101,114,116,115,112, 98, 83, 49, 26, 13, 11, 12, 15, 29, 44},
   { 88,110,123,124,125,118,107, 85, 39, 17,  4,  3,  2,  9, 20, 42},
   { 89,111,122,127,126,117,106, 84, 38, 16,  5,  0,  1, 10, 21, 43},
   { 79,102,119,121,120,113, 97, 82, 48, 25,  8,  6,  7, 14, 30, 45},
   { 71, 95,103,104,105, 96, 92, 74, 56, 32, 24, 23, 22, 31, 35, 53},
   { 65, 72, 80, 90, 91, 81, 73, 66, 62, 55, 47, 37, 36, 46, 54, 61},
   { 63, 58, 50, 40, 41, 51, 59, 60, 64, 69, 77, 87, 86, 76, 68, 67},
   { 57, 33, 27, 18, 19, 28, 34, 52, 70, 94,100,109,108, 99, 93, 75},
   { 49, 26, 13, 11, 12, 15, 29, 44, 78,101,114,116,115,112, 98, 83},
   { 39, 17,  4,  3,  2,  9, 20, 42, 88,110,123,124,125,118,107, 85},
   { 38, 16,  5,  0,  1, 10, 21, 43, 89,111,122,127,126,117,106, 84},
   { 48, 25,  8,  6,  7, 14, 30, 45, 79,102,119,121,120,113, 97, 82},
   { 56, 32, 24, 23, 22, 31, 35, 53, 71, 95,103,104,105, 96, 92, 74},
   { 62, 55, 47, 37, 36, 46, 54, 61, 65, 72, 80, 90, 91, 81, 73, 66}
};

#endif