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1.1 root 1: #include <stdio.h>
2: #define SAVCOLOR mapr[i]=255.499*r;mapg[i]=255.499*g;mapb[i]=255.499*b;
3:
4: int
5: cvmap ( map, maxi, mapr,mapg,mapb ) /* load color map, return black index*/
6: char *map; /* string describing kind of map */
7: int maxi;
8: int mapr[],mapg[],mapb[]; /* colors, 0 through maxi */
9: {
10: int i, j;
11: int max1, max2;
12: double r, g, b;
13: double dm = maxi;
14: double sqrt();
15: FILE *mapf;
16: if(maxi<0) error("maxi must be >= 0");
17: if(maxi>=254) error("maxi must be < 254");
18: switch(*map){
19: case 'f': /* input from file */
20: mapf = fopen(map+1,"r");
21: if( mapf==NULL ) error("can't open %s",map+1);
22: for(i=0; i<=maxi; i++){
23: if(fscanf(mapf,"%d %d %d",&mapr[i],&mapg[i],&mapb[i])!=3)
24: error("trouble reading color map %d",i);
25: }
26: fclose(mapf);
27: break;
28: case 'r': /* red v. blue */
29: for(i=0; i<=maxi; i++){
30: r=sqrt(i/dm); g=sqrt(0.); b=sqrt(1-i/dm);
31: brit(&r,&g,&b);
32: SAVCOLOR;
33: }
34: break;
35: case NULL:
36: case 's': /* blue-to-red rainbow */
37: for(i=0; i<=maxi; i++){
38: rainbow(1-i/dm,1.,1.,&r,&g,&b);
39: r=sqrt(r); g=sqrt(g); b=sqrt(b);
40: SAVCOLOR;
41: }
42: break;
43: case 'g': /* normal map, corrected for gamma */
44: for(i=0; i<=maxi; i++){
45: r=sqrt(i/dm); g=sqrt(i/dm); b=sqrt(i/dm);
46: SAVCOLOR;
47: }
48: break;
49: case 'i': /* like g, but inverse video */
50: for(i=0; i<=maxi; i++){
51: r=sqrt(1-i/dm); g=sqrt(1-i/dm); b=sqrt(1-i/dm);
52: SAVCOLOR;
53: }
54: break;
55: default:
56: err:
57: fprintf(stderr,"unrecognized color map %s\n",map);
58: }
59: colmap(maxi,mapr,mapg,mapb);
60: return(255);
61: }
62:
63: brit(r,g,b)
64: double *r, *g, *b;
65: {
66: /* convert from r+g+b=1 to max(r,g,b)=1 */
67: double t;
68: t = (*r>*b)?*r:*b;
69: if(*g>t) t = *g;
70: *r /= t;
71: *g /= t;
72: *b /= t;
73: }
74:
75:
76:
77: /**** taken from /n/research/netlib/misc/rainbow *****/
78: /* rainbow(h, s, v, r, g, b)
79: double h, s, v, *r, *g, *b;
80:
81: This routine computes colors suitable for use in color level plots.
82: Typically s=v=1 and h varies from 0 (red) to 1 (blue) in
83: equally spaced steps. (h>1 gives magenta.)
84: To convert for frame buffer, use R = (int)(255.999*sqrt(*r)) etc.
85: complaints => Eric Grosse research!ehg 201-582-5828
86: */
87:
88: #include <math.h>
89: double huextab[] = {
90: .0000,.0156,.0313,.0469,.0625,.0781,.0938,.1094,.1250,.1406,
91: .1563,.1719,.1875,.2031,.2188,.2344,.2500,.2656,.2813,.2969,
92: .3125,.3281,.3438,.3594,.3750,.3906,.4063,.4219,.4375,.4531,
93: .4688,.4844,.5000,.5156,.5313,.5469,.5625,.5781,.5938,.6094,
94: .6250,.6406,.6563,.6719,.6875,.7031,.7188,.7344,.7500,.7656,
95: .7813,.7969,.8125,.8281,.8438,.8594,.8750,.8906,.9063,.9219,
96: .9375,.9531,.9688,.9844,1. };
97: double huettab[] = {
98: .0000,.0052,.0105,.0160,.0218,.0277,.0339,.0404,.0471,.0542,
99: .0616,.0693,.0775,.0862,.0954,.1052,.1157,.1269,.1390,.1519,
100: .1660,.1824,.1974,.2115,.2248,.2374,.2495,.2609,.2719,.2824,
101: .2926,.3023,.3118,.3210,.3300,.3456,.3600,.3761,.3943,.4153,
102: .4399,.4688,.5048,.5211,.5359,.5494,.5617,.5729,.5832,.5925,
103: .6010,.6088,.6160,.6225,.6285,.6340,.6390,.6436,.6478,.6516,
104: .6552,.6584,.6614,.6642,.6667 };
105: /* computed from the FMC-1 color difference formula */
106: /* Hitachi monitor, max(r,g,b)=1, n=65, 7 Jan 1985 */
107:
108: rainbow(h, s, v, r, g, b)
109: double h, s, v, *r, *g, *b;
110: {
111: double *x = huextab;
112: double *t = huettab;
113: while( (x[1]<=h) && (x[1]<1.) ){ ++x; ++t; }
114: h = t[0] + (t[1]-t[0])*(h-x[0])/(x[1]-x[0]);
115: dhsv2rgb(h,s,v,r,g,b);
116: }
117:
118: dhsv2rgb(h, s, v, r, g, b) /*...hexcone model...*/
119: double h, s, v, *r, *g, *b; /* all variables in range [0,1] */
120: {
121: int i;
122: double f, m, n, k;
123: h *= 6;
124: i = (int)floor(h);
125: f = h-i;
126: m = (1-s);
127: n = (1-s*f);
128: k = (1-(s*(1-f)));
129: switch(i){
130: case 0: *r=1; *g=k; *b=m; break;
131: case 1: *r=n; *g=1; *b=m; break;
132: case 2: *r=m; *g=1; *b=k; break;
133: case 3: *r=m; *g=n; *b=1; break;
134: case 4: *r=k; *g=m; *b=1; break;
135: case 5: *r=1; *g=m; *b=n; break;
136: default: error("bad i: %f %d",h,i);
137: }
138: f = *r;
139: if( f < *g ) f = *g;
140: if( f < *b ) f = *b;
141: f = v / f;
142: *r *= f;
143: *g *= f;
144: *b *= f;
145: }
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