| 1 |
greg |
1.1 |
/* Copyright (c) 1990 Regents of the University of California */ |
| 2 |
|
|
|
| 3 |
|
|
#ifndef lint |
| 4 |
|
|
static char SCCSid[] = "$SunId$ LBL"; |
| 5 |
|
|
#endif |
| 6 |
|
|
|
| 7 |
|
|
/* |
| 8 |
|
|
* Integer operations on COLR scanlines |
| 9 |
|
|
*/ |
| 10 |
|
|
|
| 11 |
|
|
#include "color.h" |
| 12 |
|
|
|
| 13 |
greg |
1.3 |
#define MAXGSHIFT 15 /* maximum shift for gamma table */ |
| 14 |
greg |
1.1 |
|
| 15 |
|
|
static BYTE g_mant[256], g_nexp[256]; |
| 16 |
|
|
|
| 17 |
|
|
static BYTE g_bval[MAXGSHIFT+1][256]; |
| 18 |
|
|
|
| 19 |
|
|
|
| 20 |
|
|
setcolrgam(g) /* set gamma conversion */ |
| 21 |
|
|
double g; |
| 22 |
|
|
{ |
| 23 |
|
|
extern double pow(); |
| 24 |
|
|
double mult; |
| 25 |
|
|
register int i, j; |
| 26 |
|
|
/* compute colr -> gamb mapping */ |
| 27 |
|
|
for (i = 0; i <= MAXGSHIFT; i++) { |
| 28 |
|
|
mult = pow(0.5, (double)(i+8)); |
| 29 |
|
|
for (j = 0; j < 256; j++) |
| 30 |
|
|
g_bval[i][j] = 256.0 * pow((j+.5)*mult, 1.0/g); |
| 31 |
|
|
} |
| 32 |
|
|
/* compute gamb -> colr mapping */ |
| 33 |
|
|
i = 0; |
| 34 |
|
|
mult = 256.0; |
| 35 |
greg |
1.2 |
for (j = 255; j > 0; j--) { |
| 36 |
|
|
while ((g_mant[j] = mult * pow(j/256.0, g)) < 128) { |
| 37 |
greg |
1.1 |
i++; |
| 38 |
|
|
mult *= 2.0; |
| 39 |
|
|
} |
| 40 |
|
|
g_nexp[j] = i; |
| 41 |
|
|
} |
| 42 |
greg |
1.2 |
g_mant[0] = 0; |
| 43 |
|
|
g_nexp[0] = COLXS; |
| 44 |
greg |
1.1 |
} |
| 45 |
|
|
|
| 46 |
|
|
|
| 47 |
|
|
colrs_gambs(scan, len) /* convert scanline of colrs to gamma bytes */ |
| 48 |
|
|
register COLR *scan; |
| 49 |
|
|
int len; |
| 50 |
|
|
{ |
| 51 |
|
|
register int i, expo; |
| 52 |
|
|
|
| 53 |
|
|
while (len-- > 0) { |
| 54 |
|
|
expo = scan[0][EXP] - COLXS; |
| 55 |
|
|
if (expo < -MAXGSHIFT) { |
| 56 |
|
|
if (expo < -MAXGSHIFT-8) { |
| 57 |
|
|
scan[0][RED] = |
| 58 |
|
|
scan[0][GRN] = |
| 59 |
|
|
scan[0][BLU] = 0; |
| 60 |
|
|
} else { |
| 61 |
|
|
i = (-MAXGSHIFT-1) - expo; |
| 62 |
|
|
scan[0][RED] = |
| 63 |
|
|
g_bval[MAXGSHIFT][((scan[0][RED]>>i)+1)>>1]; |
| 64 |
|
|
scan[0][GRN] = |
| 65 |
|
|
g_bval[MAXGSHIFT][((scan[0][GRN]>>i)+1)>>1]; |
| 66 |
|
|
scan[0][BLU] = |
| 67 |
|
|
g_bval[MAXGSHIFT][((scan[0][BLU]>>i)+1)>>1]; |
| 68 |
|
|
} |
| 69 |
|
|
} else if (expo > 0) { |
| 70 |
|
|
if (expo > 8) { |
| 71 |
|
|
scan[0][RED] = |
| 72 |
|
|
scan[0][GRN] = |
| 73 |
|
|
scan[0][BLU] = 255; |
| 74 |
|
|
} else { |
| 75 |
|
|
i = (scan[0][RED]<<1 | 1) << (expo-1); |
| 76 |
|
|
scan[0][RED] = i > 255 ? 255 : g_bval[0][i]; |
| 77 |
|
|
i = (scan[0][GRN]<<1 | 1) << (expo-1); |
| 78 |
|
|
scan[0][GRN] = i > 255 ? 255 : g_bval[0][i]; |
| 79 |
|
|
i = (scan[0][BLU]<<1 | 1) << (expo-1); |
| 80 |
|
|
scan[0][BLU] = i > 255 ? 255 : g_bval[0][i]; |
| 81 |
|
|
} |
| 82 |
|
|
} else { |
| 83 |
|
|
scan[0][RED] = g_bval[-expo][scan[0][RED]]; |
| 84 |
|
|
scan[0][GRN] = g_bval[-expo][scan[0][GRN]]; |
| 85 |
|
|
scan[0][BLU] = g_bval[-expo][scan[0][BLU]]; |
| 86 |
|
|
} |
| 87 |
|
|
scan[0][EXP] = COLXS; |
| 88 |
|
|
scan++; |
| 89 |
|
|
} |
| 90 |
|
|
} |
| 91 |
|
|
|
| 92 |
|
|
|
| 93 |
|
|
gambs_colrs(scan, len) /* convert gamma bytes to colr scanline */ |
| 94 |
|
|
register COLR *scan; |
| 95 |
|
|
int len; |
| 96 |
|
|
{ |
| 97 |
|
|
register int nexpo; |
| 98 |
|
|
|
| 99 |
|
|
while (len-- > 0) { |
| 100 |
|
|
nexpo = g_nexp[scan[0][RED]]; |
| 101 |
|
|
if (g_nexp[scan[0][GRN]] < nexpo) |
| 102 |
|
|
nexpo = g_nexp[scan[0][GRN]]; |
| 103 |
|
|
if (g_nexp[scan[0][BLU]] < nexpo) |
| 104 |
|
|
nexpo = g_nexp[scan[0][BLU]]; |
| 105 |
|
|
if (nexpo < g_nexp[scan[0][RED]]) |
| 106 |
|
|
scan[0][RED] = g_mant[scan[0][RED]] |
| 107 |
|
|
>> (g_nexp[scan[0][RED]]-nexpo); |
| 108 |
|
|
else |
| 109 |
|
|
scan[0][RED] = g_mant[scan[0][RED]]; |
| 110 |
|
|
if (nexpo < g_nexp[scan[0][GRN]]) |
| 111 |
|
|
scan[0][GRN] = g_mant[scan[0][GRN]] |
| 112 |
|
|
>> (g_nexp[scan[0][GRN]]-nexpo); |
| 113 |
|
|
else |
| 114 |
|
|
scan[0][GRN] = g_mant[scan[0][GRN]]; |
| 115 |
|
|
if (nexpo < g_nexp[scan[0][BLU]]) |
| 116 |
|
|
scan[0][BLU] = g_mant[scan[0][BLU]] |
| 117 |
|
|
>> (g_nexp[scan[0][BLU]]-nexpo); |
| 118 |
|
|
else |
| 119 |
|
|
scan[0][BLU] = g_mant[scan[0][BLU]]; |
| 120 |
|
|
scan[0][EXP] = COLXS - nexpo; |
| 121 |
|
|
scan++; |
| 122 |
|
|
} |
| 123 |
|
|
} |
| 124 |
|
|
|
| 125 |
|
|
|
| 126 |
|
|
shiftcolrs(scan, len, adjust) /* shift a scanline of colors by 2^adjust */ |
| 127 |
|
|
register COLR *scan; |
| 128 |
|
|
register int len; |
| 129 |
|
|
register int adjust; |
| 130 |
|
|
{ |
| 131 |
|
|
while (len-- > 0) { |
| 132 |
|
|
scan[0][EXP] += adjust; |
| 133 |
|
|
scan++; |
| 134 |
|
|
} |
| 135 |
|
|
} |
| 136 |
|
|
|
| 137 |
|
|
|
| 138 |
|
|
normcolrs(scan, len, adjust) /* normalize a scanline of colrs */ |
| 139 |
|
|
register COLR *scan; |
| 140 |
|
|
int len; |
| 141 |
|
|
int adjust; |
| 142 |
|
|
{ |
| 143 |
|
|
register int c; |
| 144 |
|
|
register int shift; |
| 145 |
|
|
|
| 146 |
|
|
while (len-- > 0) { |
| 147 |
|
|
shift = scan[0][EXP] + adjust - COLXS; |
| 148 |
|
|
if (shift > 0) { |
| 149 |
|
|
if (shift > 8) { |
| 150 |
|
|
scan[0][RED] = |
| 151 |
|
|
scan[0][GRN] = |
| 152 |
|
|
scan[0][BLU] = 255; |
| 153 |
|
|
} else { |
| 154 |
|
|
shift--; |
| 155 |
|
|
c = (scan[0][RED]<<1 | 1) << shift; |
| 156 |
|
|
scan[0][RED] = c > 255 ? 255 : c; |
| 157 |
|
|
c = (scan[0][GRN]<<1 | 1) << shift; |
| 158 |
|
|
scan[0][GRN] = c > 255 ? 255 : c; |
| 159 |
|
|
c = (scan[0][BLU]<<1 | 1) << shift; |
| 160 |
|
|
scan[0][BLU] = c > 255 ? 255 : c; |
| 161 |
|
|
} |
| 162 |
|
|
} else if (shift < 0) { |
| 163 |
|
|
if (shift < -8) { |
| 164 |
|
|
scan[0][RED] = |
| 165 |
|
|
scan[0][GRN] = |
| 166 |
|
|
scan[0][BLU] = 0; |
| 167 |
|
|
} else { |
| 168 |
|
|
shift = -1-shift; |
| 169 |
|
|
scan[0][RED] = ((scan[0][RED]>>shift)+1)>>1; |
| 170 |
|
|
scan[0][GRN] = ((scan[0][GRN]>>shift)+1)>>1; |
| 171 |
|
|
scan[0][BLU] = ((scan[0][BLU]>>shift)+1)>>1; |
| 172 |
|
|
} |
| 173 |
|
|
} |
| 174 |
|
|
scan[0][EXP] = COLXS - adjust; |
| 175 |
|
|
scan++; |
| 176 |
|
|
} |
| 177 |
|
|
} |
