1 #include <u.h>
2 #include <libc.h>
3 #include <draw.h>
4 
5 float c1 = 1.402;
6 float c2 = 0.34414;
7 float c3 = 0.71414;
8 float c4 = 1.772;
9 
10 int
11 closest(int Y, int Cb, int Cr)
12 {
13 	double r, g, b;
14 	double diff, min;
15 	int rgb, R, G, B, v, i;
16 	int y1, cb1, cr1;
17 
18 	Cb -= 128;
19 	Cr -= 128;
20 	r = Y+c1*Cr;
21 	g = Y-c2*Cb-c3*Cr;
22 	b = Y+c4*Cb;
23 
24 /*print("YCbCr: %d %d %d, RGB: %g %g %g\n", Y, Cb, Cr, r, g, b); */
25 
26 	min = 1000000.;
27 	v = 1000;
28 	for(i=0; i<256; i++){
29 		rgb =  cmap2rgb(i);
30 		R = (rgb >> 16) & 0xFF;
31 		G = (rgb >> 8) & 0xFF;
32 		B = (rgb >> 0) & 0xFF;
33 		diff = (R-r)*(R-r) + (G-g)*(G-g) + (B-b)*(B-b);
34 		y1 = 0.5870*G + 0.114*B + 0.299*R;
35 		cb1 = (B-y1)/1.772;
36 		cr1 = (R-y1)/1.402;
37 		if(diff < min){
38 /*			if(Y==0 && y1!=0) */
39 /*				continue; */
40 			if(Y==256-16 && y1<256-16)
41 				continue;
42 /*			if(Cb==0 && cb1!=0) */
43 /*				continue; */
44 			if(Cb==256-16 && cb1<256-16)
45 				continue;
46 /*			if(Cr==0 && cr1!=0) */
47 /*				continue; */
48 			if(Cr==256-16 && cr1<256-16)
49 				continue;
50 /*print("%d %d %d\n", R, G, B); */
51 			min = diff;
52 			v = i;
53 		}
54 	}
55 	if(v > 255)
56 		abort();
57 	return v;
58 }
59 
60 void
61 main(int argc, char *argv[])
62 {
63 	int i, rgb;
64 	int r, g, b;
65 	double Y, Cr, Cb;
66 	int y, cb, cr;
67 	uchar close[16*16*16];
68 
69 /*print("%d\n", closest(atoi(argv[1]), atoi(argv[2]), atoi(argv[3]))); */
70 /*exits("X"); */
71 
72 	/* ycbcrmap */
73 	print("uint ycbcrmap[256] = {\n");
74 	for(i=0; i<256; i++){
75 		if(i%8 == 0)
76 			print("\t");
77 		rgb = cmap2rgb(i);
78 		r = (rgb>>16) & 0xFF;
79 		g = (rgb>>8) & 0xFF;
80 		b = (rgb>>0) & 0xFF;
81 		Y = 0.5870*g + 0.114*b + 0.299*r;
82 		Cr = (r-Y)/1.402 + 128.;
83 		Cb = (b-Y)/1.772 + 128.;
84 		if(Y<0. || Y>=256. || Cr<0. || Cr>=256. || Cb<0. || Cb>=256.)
85 			print("bad at %d: %d %d %d; %g %g %g\n", i, r, g, b, Y, Cb, Cr);
86 		r = Y;
87 		g = Cb;
88 		b = Cr;
89 		print("0x%.6ulX, ", (r<<16) | (g<<8) | b);
90 		if(i%8 == 7)
91 			print("\n");
92 	}
93 	print("};\n\n");
94 
95 	/* closestycbcr */
96 	print("uchar closestycbcr[16*16*16] = {\n");
97 	for(y=0; y<256; y+=16)
98 	for(cb=0; cb<256; cb+=16)
99 	for(cr=0; cr<256; cr+=16)
100 		close[(cr/16)+16*((cb/16)+16*(y/16))] = closest(y, cb, cr);
101 if(0){
102 	/*weird: set white for nearly white */
103 	for(cb=128-32; cb<=128+32; cb+=16)
104 	for(cr=128-32; cr<=128+32; cr+=16)
105 		close[(cr/16)+16*((cb/16)+16*(255/16))] = 0;
106 	/*weird: set black for nearly black */
107 	for(cb=128-32; cb<=128+32; cb+=16)
108 	for(cr=128-32; cr<=128+32; cr+=16)
109 		close[(cr/16)+16*((cb/16)+16*(0/16))] = 255;
110 }
111 	for(i=0; i<16*16*16; i++){
112 		if(i%16 == 0)
113 			print("\t");
114 		print("%d,", close[i]);
115 		if(i%16 == 15)
116 			print("\n");
117 	}
118 	print("};\n\n");
119 	exits(nil);
120 }