| 1 |
greg |
1.1 |
#ifndef lint |
| 2 |
greg |
2.2 |
static const char RCSid[] = "$Id$"; |
| 3 |
greg |
1.1 |
#endif |
| 4 |
greg |
1.2 |
/* |
| 5 |
greg |
1.1 |
CIQ - main program for color image quantization |
| 6 |
|
|
options for Floyd-Steinberg dithering by minimization of accumulated error |
| 7 |
|
|
or undithered quantization |
| 8 |
|
|
|
| 9 |
|
|
Paul Heckbert 16 April 82, cleaned up 8 June 86 |
| 10 |
|
|
Greg Ward 1 March 88, modified for arbitrary picture sizes |
| 11 |
|
|
*/ |
| 12 |
|
|
|
| 13 |
greg |
1.6 |
#include "standard.h" |
| 14 |
greg |
1.1 |
#include "ciq.h" |
| 15 |
|
|
|
| 16 |
|
|
#define table(m,r,g,b) hist[m[0][r]|m[1][g]|m[2][b]] /* histogram/pvtable */ |
| 17 |
|
|
|
| 18 |
|
|
int hist[len]; /* list of frequencies or pixelvalues for coded color */ |
| 19 |
|
|
|
| 20 |
|
|
colormap color; /* quantization colormap */ |
| 21 |
|
|
int n; /* number of colors in it */ |
| 22 |
|
|
|
| 23 |
ph |
1.4 |
#define ERRMAX 20 /* maximum allowed propagated error, |
| 24 |
|
|
if >=255 then no clamping */ |
| 25 |
|
|
|
| 26 |
greg |
1.1 |
/*----------------------------------------------------------------------*/ |
| 27 |
|
|
|
| 28 |
|
|
ciq(dith,nw,synth,cm) |
| 29 |
|
|
int dith; /* is dithering desired? 0=no, 1=yes */ |
| 30 |
|
|
int nw; /* number of colors wanted in output image */ |
| 31 |
|
|
int synth; /* synthesize colormap? 0=no, 1=yes */ |
| 32 |
|
|
colormap cm; /* quantization colormap */ |
| 33 |
|
|
/* read if synth=0; always written */ |
| 34 |
|
|
{ |
| 35 |
|
|
int na,i; |
| 36 |
|
|
colormap ocm; |
| 37 |
|
|
|
| 38 |
|
|
picreadcm(ocm); /* read original picture's colormap (usually identity)*/ |
| 39 |
|
|
sample(ocm); /* find histogram */ |
| 40 |
|
|
|
| 41 |
|
|
if (synth) |
| 42 |
|
|
n = makecm(nw,&na); /* analyze histogram and synthesize colormap */ |
| 43 |
|
|
else { |
| 44 |
greg |
2.3 |
bcopy((void *)cm,(void *)color,sizeof color); |
| 45 |
greg |
1.1 |
n = nw; |
| 46 |
|
|
na = 0; |
| 47 |
|
|
for (i=0; i<len; i++) if (hist[i]) na++; |
| 48 |
|
|
/*printf("from %d to %d colors\n",na,n);*/ |
| 49 |
|
|
} |
| 50 |
|
|
picwritecm(color); |
| 51 |
|
|
|
| 52 |
ph |
1.4 |
initializeclosest(); |
| 53 |
greg |
1.1 |
if (dith) |
| 54 |
|
|
draw_dith(ocm); |
| 55 |
|
|
else { |
| 56 |
|
|
for (i=0; i<len; i++) |
| 57 |
|
|
if (hist[i]) hist[i] = closest(red(i),gre(i),blu(i)); |
| 58 |
|
|
draw_nodith(ocm); |
| 59 |
|
|
} |
| 60 |
|
|
|
| 61 |
greg |
2.3 |
bcopy((void *)color,(void *)cm,sizeof color); |
| 62 |
greg |
1.1 |
/*endclosest();*/ |
| 63 |
|
|
} |
| 64 |
|
|
|
| 65 |
|
|
/*----------------------------------------------------------------------*/ |
| 66 |
|
|
|
| 67 |
|
|
sample(ocm) /* make color frequency table (histogram) */ |
| 68 |
|
|
colormap ocm; |
| 69 |
|
|
{ |
| 70 |
|
|
register int x,y; |
| 71 |
|
|
register rgbpixel *lp; |
| 72 |
|
|
rgbpixel *line; |
| 73 |
|
|
colormap map; |
| 74 |
|
|
|
| 75 |
greg |
1.3 |
for (x = 0; x < len; x++) /* clear histogram */ |
| 76 |
|
|
hist[x] = 0; |
| 77 |
|
|
|
| 78 |
greg |
1.1 |
line = line3alloc(xmax); |
| 79 |
|
|
convertmap(ocm,map); |
| 80 |
|
|
|
| 81 |
|
|
for (y=0; y<ymax; y++) { |
| 82 |
|
|
picreadline3(y,line); |
| 83 |
|
|
for (lp=line, x=0; x<xmax; x++, lp++) |
| 84 |
|
|
table(map,lp->r,lp->g,lp->b)++; |
| 85 |
|
|
} |
| 86 |
greg |
2.2 |
free((void *)line); |
| 87 |
greg |
1.1 |
} |
| 88 |
|
|
|
| 89 |
|
|
convertmap(in,out) /* convert to shifted color map */ |
| 90 |
|
|
register colormap in,out; |
| 91 |
|
|
{ |
| 92 |
|
|
register int j; |
| 93 |
|
|
|
| 94 |
|
|
for (j=0; j<256; j++) { |
| 95 |
|
|
out[0][j] = (in[0][j]&0xf8)<<7; |
| 96 |
|
|
out[1][j] = (in[1][j]&0xf8)<<2; |
| 97 |
|
|
out[2][j] = (in[2][j]&0xf8)>>3; |
| 98 |
|
|
} |
| 99 |
|
|
} |
| 100 |
|
|
|
| 101 |
|
|
draw_nodith(ocm) /* quantize without dithering */ |
| 102 |
|
|
colormap ocm; /* colormap for orig */ |
| 103 |
|
|
{ |
| 104 |
|
|
register int x,y; |
| 105 |
|
|
register rgbpixel *lp; |
| 106 |
|
|
rgbpixel *iline; |
| 107 |
|
|
pixel *oline; |
| 108 |
|
|
colormap map; |
| 109 |
|
|
|
| 110 |
|
|
iline = line3alloc(xmax); |
| 111 |
|
|
oline = linealloc(xmax); |
| 112 |
|
|
convertmap(ocm,map); |
| 113 |
|
|
|
| 114 |
|
|
for (y=0; y<ymax; y++) { |
| 115 |
|
|
picreadline3(y,iline); |
| 116 |
|
|
for (lp=iline, x=0; x<xmax; x++, lp++) |
| 117 |
|
|
oline[x] = table(map,lp->r,lp->g,lp->b); |
| 118 |
|
|
picwriteline(y,oline); |
| 119 |
|
|
} |
| 120 |
greg |
2.2 |
free((void *)iline); |
| 121 |
|
|
free((void *)oline); |
| 122 |
greg |
1.1 |
} |
| 123 |
|
|
|
| 124 |
|
|
draw_dith(ocm) /* quantize with dithering */ |
| 125 |
|
|
colormap ocm; /* colormap for orig */ |
| 126 |
|
|
{ |
| 127 |
|
|
register int *p,*q,rr,gg,bb,v,x,y,*P,*Q,*R; |
| 128 |
|
|
int *buf; |
| 129 |
|
|
rgbpixel *iline; /* input scanline */ |
| 130 |
|
|
pixel *oline; /* output scanline */ |
| 131 |
|
|
|
| 132 |
|
|
buf = (int *)ecalloc(2,3*sizeof(int)*(xmax+1)); |
| 133 |
|
|
iline = line3alloc(xmax); |
| 134 |
|
|
oline = linealloc(xmax); |
| 135 |
|
|
/* reuse hist array as quantization table */ |
| 136 |
|
|
for (v=0; v<len; v++) hist[v] = -1; |
| 137 |
|
|
|
| 138 |
|
|
P = &buf[0]; |
| 139 |
|
|
Q = &buf[3*(xmax+1)]; |
| 140 |
|
|
for (y=0; y<ymax; y++, R=P, P=Q, Q=R) { |
| 141 |
|
|
Q[0] = Q[1] = Q[2] = 0; |
| 142 |
|
|
picreadline3(y,iline); |
| 143 |
|
|
for (p=P, q=Q, x=0; x<xmax; x++, p+=3, q+=3) { |
| 144 |
ph |
1.4 |
rr = p[0]; |
| 145 |
|
|
if (rr<-ERRMAX) rr = -ERRMAX; else if (rr>ERRMAX) rr = ERRMAX; |
| 146 |
|
|
gg = p[1]; |
| 147 |
|
|
if (gg<-ERRMAX) gg = -ERRMAX; else if (gg>ERRMAX) gg = ERRMAX; |
| 148 |
|
|
bb = p[2]; |
| 149 |
|
|
if (bb<-ERRMAX) bb = -ERRMAX; else if (bb>ERRMAX) bb = ERRMAX; |
| 150 |
|
|
/* now rr,gg,bb is propagated color */ |
| 151 |
|
|
rr += ocm[0][iline[x].r]; |
| 152 |
|
|
gg += ocm[1][iline[x].g]; /* ideal */ |
| 153 |
|
|
bb += ocm[2][iline[x].b]; |
| 154 |
greg |
1.1 |
if (rr<0) rr = 0; else if (rr>255) rr = 255; |
| 155 |
|
|
if (gg<0) gg = 0; else if (gg>255) gg = 255; |
| 156 |
|
|
if (bb<0) bb = 0; else if (bb>255) bb = 255; |
| 157 |
|
|
v = (rr&0xf8)<<7 | (gg&0xf8)<<2 | (bb&0xf8)>>3; |
| 158 |
|
|
if (hist[v]<0) |
| 159 |
|
|
hist[v] = closest(rr,gg,bb); /* nearest to ideal */ |
| 160 |
|
|
oline[x] = v = hist[v]; |
| 161 |
|
|
rr -= color[0][v]; |
| 162 |
|
|
gg -= color[1][v]; /* error */ |
| 163 |
|
|
bb -= color[2][v]; |
| 164 |
|
|
v = rr*3>>3; p[3] += v; q[0] += v; q[3] = rr-(v<<1); |
| 165 |
|
|
v = gg*3>>3; p[4] += v; q[1] += v; q[4] = gg-(v<<1); |
| 166 |
|
|
v = bb*3>>3; p[5] += v; q[2] += v; q[5] = bb-(v<<1); |
| 167 |
|
|
} |
| 168 |
|
|
picwriteline(y,oline); |
| 169 |
|
|
} |
| 170 |
greg |
2.2 |
free((void *)iline); |
| 171 |
|
|
free((void *)oline); |
| 172 |
|
|
free((void *)buf); |
| 173 |
greg |
1.1 |
} |
