[126] | 1 | #ifndef lint
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| 2 | static const char RCSid[] = "$Id: color.c,v 2.10 2003/02/25 02:47:21 greg Exp $";
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| 3 | #endif
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| 4 | /*
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| 5 | * color.c - routines for color calculations.
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| 6 | *
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| 7 | * Externals declared in color.h
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| 8 | */
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| 9 |
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| 10 | //#include "copyright.h"
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| 11 |
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| 12 | #include <stdio.h>
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| 13 |
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| 14 | #include <stdlib.h>
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| 15 |
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| 16 | #include <math.h>
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| 17 |
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| 18 | #include "color.h"
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| 19 |
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| 20 | #define MINELEN 8 /* minimum scanline length for encoding */
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| 21 | #define MAXELEN 0x7fff /* maximum scanline length for encoding */
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| 22 | #define MINRUN 4 /* minimum run length */
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| 23 |
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| 24 |
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| 25 | char *
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| 26 | tempbuffer(len) /* get a temporary buffer */
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| 27 | unsigned int len;
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| 28 | {
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| 29 | static char *tempbuf = NULL;
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| 30 | static unsigned tempbuflen = 0;
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| 31 |
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| 32 | if (len > tempbuflen) {
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| 33 | if (tempbuflen > 0)
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| 34 | tempbuf = (char *)realloc(tempbuf, len);
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| 35 | else
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| 36 | tempbuf = (char *)malloc(len);
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| 37 | tempbuflen = tempbuf==NULL ? 0 : len;
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| 38 | }
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| 39 | return(tempbuf);
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| 40 | }
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| 41 |
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| 42 |
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| 43 | int
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| 44 | fwritecolrs(scanline, len, fp) /* write out a colr scanline */
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| 45 | register COLR *scanline;
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| 46 | int len;
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| 47 | register FILE *fp;
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| 48 | {
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| 49 | register int i, j, beg, cnt = 1;
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| 50 | int c2;
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| 51 |
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| 52 | if (len < MINELEN | len > MAXELEN) /* OOBs, write out flat */
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| 53 | return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
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| 54 | /* put magic header */
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| 55 | putc(2, fp);
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| 56 | putc(2, fp);
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| 57 | putc(len>>8, fp);
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| 58 | putc(len&255, fp);
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| 59 | /* put components seperately */
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| 60 | for (i = 0; i < 4; i++) {
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| 61 | for (j = 0; j < len; j += cnt) { /* find next run */
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| 62 | for (beg = j; beg < len; beg += cnt) {
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| 63 | for (cnt = 1; cnt < 127 && beg+cnt < len &&
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| 64 | scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
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| 65 | ;
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| 66 | if (cnt >= MINRUN)
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| 67 | break; /* long enough */
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| 68 | }
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| 69 | if (beg-j > 1 && beg-j < MINRUN) {
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| 70 | c2 = j+1;
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| 71 | while (scanline[c2++][i] == scanline[j][i])
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| 72 | if (c2 == beg) { /* short run */
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| 73 | putc(128+beg-j, fp);
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| 74 | putc(scanline[j][i], fp);
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| 75 | j = beg;
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| 76 | break;
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| 77 | }
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| 78 | }
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| 79 | while (j < beg) { /* write out non-run */
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| 80 | if ((c2 = beg-j) > 128) c2 = 128;
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| 81 | putc(c2, fp);
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| 82 | while (c2--)
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| 83 | putc(scanline[j++][i], fp);
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| 84 | }
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| 85 | if (cnt >= MINRUN) { /* write out run */
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| 86 | putc(128+cnt, fp);
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| 87 | putc(scanline[beg][i], fp);
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| 88 | } else
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| 89 | cnt = 0;
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| 90 | }
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| 91 | }
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| 92 | return(ferror(fp) ? -1 : 0);
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| 93 | }
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| 94 |
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| 95 |
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| 96 | static int
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| 97 | oldreadcolrs(scanline, len, fp) /* read in an old colr scanline */
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| 98 | register COLR *scanline;
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| 99 | int len;
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| 100 | register FILE *fp;
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| 101 | {
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| 102 | int rshift;
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| 103 | register int i;
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| 104 |
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| 105 | rshift = 0;
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| 106 |
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| 107 | while (len > 0) {
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| 108 | scanline[0][RED] = getc(fp);
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| 109 | scanline[0][GRN] = getc(fp);
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| 110 | scanline[0][BLU] = getc(fp);
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| 111 | scanline[0][EXP] = getc(fp);
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| 112 | if (feof(fp) || ferror(fp))
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| 113 | return(-1);
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| 114 | if (scanline[0][RED] == 1 &&
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| 115 | scanline[0][GRN] == 1 &&
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| 116 | scanline[0][BLU] == 1) {
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| 117 | for (i = scanline[0][EXP] << rshift; i > 0; i--) {
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| 118 | copycolr(scanline[0], scanline[-1]);
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| 119 | scanline++;
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| 120 | len--;
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| 121 | }
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| 122 | rshift += 8;
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| 123 | } else {
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| 124 | scanline++;
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| 125 | len--;
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| 126 | rshift = 0;
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| 127 | }
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| 128 | }
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| 129 | return(0);
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| 130 | }
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| 131 |
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| 132 |
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| 133 | int
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| 134 | freadcolrs(scanline, len, fp) /* read in an encoded colr scanline */
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| 135 | register COLR *scanline;
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| 136 | int len;
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| 137 | register FILE *fp;
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| 138 | {
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| 139 | register int i, j;
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| 140 | int code, val;
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| 141 | /* determine scanline type */
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| 142 | if (len < MINELEN | len > MAXELEN)
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| 143 | return(oldreadcolrs(scanline, len, fp));
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| 144 | if ((i = getc(fp)) == EOF)
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| 145 | return(-1);
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| 146 | if (i != 2) {
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| 147 | ungetc(i, fp);
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| 148 | return(oldreadcolrs(scanline, len, fp));
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| 149 | }
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| 150 | scanline[0][GRN] = getc(fp);
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| 151 | scanline[0][BLU] = getc(fp);
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| 152 | if ((i = getc(fp)) == EOF)
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| 153 | return(-1);
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| 154 | if (scanline[0][GRN] != 2 || scanline[0][BLU] & 128) {
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| 155 | scanline[0][RED] = 2;
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| 156 | scanline[0][EXP] = i;
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| 157 | return(oldreadcolrs(scanline+1, len-1, fp));
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| 158 | }
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| 159 | if ((scanline[0][BLU]<<8 | i) != len)
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| 160 | return(-1); /* length mismatch! */
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| 161 | /* read each component */
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| 162 | for (i = 0; i < 4; i++)
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| 163 | for (j = 0; j < len; ) {
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| 164 | if ((code = getc(fp)) == EOF)
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| 165 | return(-1);
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| 166 | if (code > 128) { /* run */
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| 167 | code &= 127;
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| 168 | if ((val = getc(fp)) == EOF)
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| 169 | return -1;
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| 170 | while (code--)
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| 171 | scanline[j++][i] = val;
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| 172 | } else /* non-run */
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| 173 | while (code--) {
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| 174 | if ((val = getc(fp)) == EOF)
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| 175 | return -1;
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| 176 | scanline[j++][i] = val;
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| 177 | }
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| 178 | }
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| 179 | return(0);
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| 180 | }
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| 181 |
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| 182 |
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| 183 | int
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| 184 | fwritescan(scanline, len, fp) /* write out a scanline */
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| 185 | register COLOR *scanline;
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| 186 | int len;
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| 187 | FILE *fp;
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| 188 | {
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| 189 | COLR *clrscan;
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| 190 | int n;
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| 191 | register COLR *sp;
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| 192 | /* get scanline buffer */
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| 193 | if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
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| 194 | return(-1);
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| 195 | clrscan = sp;
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| 196 | /* convert scanline */
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| 197 | n = len;
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| 198 | while (n-- > 0) {
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| 199 | setcolr(sp[0], scanline[0][RED],
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| 200 | scanline[0][GRN],
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| 201 | scanline[0][BLU]);
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| 202 | scanline++;
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| 203 | sp++;
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| 204 | }
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| 205 | return(fwritecolrs(clrscan, len, fp));
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| 206 | }
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| 207 |
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| 208 |
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| 209 | int
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| 210 | freadscan(scanline, len, fp) /* read in a scanline */
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| 211 | register COLOR *scanline;
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| 212 | int len;
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| 213 | FILE *fp;
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| 214 | {
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| 215 | register COLR *clrscan;
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| 216 |
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| 217 | if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
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| 218 | return(-1);
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| 219 | if (freadcolrs(clrscan, len, fp) < 0)
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| 220 | return(-1);
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| 221 | /* convert scanline */
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| 222 | colr_color(scanline[0], clrscan[0]);
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| 223 | while (--len > 0) {
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| 224 | scanline++; clrscan++;
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| 225 | if (clrscan[0][RED] == clrscan[-1][RED] &&
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| 226 | clrscan[0][GRN] == clrscan[-1][GRN] &&
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| 227 | clrscan[0][BLU] == clrscan[-1][BLU] &&
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| 228 | clrscan[0][EXP] == clrscan[-1][EXP])
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| 229 | copycolor(scanline[0], scanline[-1]);
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| 230 | else
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| 231 | colr_color(scanline[0], clrscan[0]);
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| 232 | }
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| 233 | return(0);
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| 234 | }
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| 235 |
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| 236 |
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| 237 | void
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| 238 | setcolr(clr, r, g, b) /* assign a short color value */
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| 239 | register COLR clr;
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| 240 | double r, g, b;
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| 241 | {
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| 242 | double d;
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| 243 | int e;
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| 244 |
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| 245 | d = r > g ? r : g;
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| 246 | if (b > d) d = b;
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| 247 |
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| 248 | if (d <= 1e-32) {
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| 249 | clr[RED] = clr[GRN] = clr[BLU] = 0;
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| 250 | clr[EXP] = 0;
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| 251 | return;
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| 252 | }
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| 253 |
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| 254 | d = frexp(d, &e) * 255.9999 / d;
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| 255 |
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| 256 | clr[RED] = r * d;
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| 257 | clr[GRN] = g * d;
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| 258 | clr[BLU] = b * d;
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| 259 | clr[EXP] = e + COLXS;
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| 260 | }
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| 261 |
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| 262 |
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| 263 | void
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| 264 | colr_color(col, clr) /* convert short to float color */
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| 265 | register COLOR col;
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| 266 | register COLR clr;
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| 267 | {
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| 268 | double f;
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| 269 |
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| 270 | if (clr[EXP] == 0)
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| 271 | col[RED] = col[GRN] = col[BLU] = 0.0;
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| 272 | else {
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| 273 | f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
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| 274 | col[RED] = (clr[RED] + 0.5)*f;
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| 275 | col[GRN] = (clr[GRN] + 0.5)*f;
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| 276 | col[BLU] = (clr[BLU] + 0.5)*f;
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| 277 | }
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| 278 | }
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| 279 |
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| 280 |
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| 281 | int
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| 282 | bigdiff(c1, c2, md) /* c1 delta c2 > md? */
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| 283 | register COLOR c1, c2;
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| 284 | double md;
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| 285 | {
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| 286 | register int i;
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| 287 |
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| 288 | for (i = 0; i < 3; i++)
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| 289 | if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) ||
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| 290 | colval(c2,i)-colval(c1,i) > md*colval(c1,i))
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| 291 | return(1);
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| 292 | return(0);
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| 293 | }
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