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#ifndef lint
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static const char RCSid[] = "$Id: color.c,v 2.15 2004/09/14 02:53:50 greg Exp $";
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#endif
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/*
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* color.c - routines for color calculations.
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*
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* Externals declared in color.h
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*/
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#include "copyright.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include "color.h"
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#ifdef getc_unlocked /* avoid horrendous overhead of flockfile */
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#undef getc
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#undef putc
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#define getc getc_unlocked
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#define putc putc_unlocked
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#endif
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#define MINELEN 8 /* minimum scanline length for encoding */
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#define MAXELEN 0x7fff /* maximum scanline length for encoding */
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#define MINRUN 4 /* minimum run length */
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char *
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tempbuffer(len) /* get a temporary buffer */
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unsigned int len;
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{
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static char *tempbuf = NULL;
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static unsigned tempbuflen = 0;
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if (len > tempbuflen) {
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if (tempbuflen > 0)
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tempbuf = (char *)realloc((void *)tempbuf, len);
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else
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tempbuf = (char *)malloc(len);
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tempbuflen = tempbuf==NULL ? 0 : len;
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}
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return(tempbuf);
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}
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int
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fwritecolrs(scanline, len, fp) /* write out a colr scanline */
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register COLR *scanline;
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int len;
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register FILE *fp;
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{
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register int i, j, beg, cnt = 1;
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int c2;
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if ((len < MINELEN) | (len > MAXELEN)) /* OOBs, write out flat */
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return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
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/* put magic header */
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putc(2, fp);
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putc(2, fp);
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putc(len>>8, fp);
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putc(len&255, fp);
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/* put components seperately */
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for (i = 0; i < 4; i++) {
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for (j = 0; j < len; j += cnt) { /* find next run */
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for (beg = j; beg < len; beg += cnt) {
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for (cnt = 1; cnt < 127 && beg+cnt < len &&
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scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
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;
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if (cnt >= MINRUN)
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break; /* long enough */
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}
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if (beg-j > 1 && beg-j < MINRUN) {
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c2 = j+1;
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while (scanline[c2++][i] == scanline[j][i])
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if (c2 == beg) { /* short run */
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putc(128+beg-j, fp);
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putc(scanline[j][i], fp);
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j = beg;
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break;
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}
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}
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while (j < beg) { /* write out non-run */
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if ((c2 = beg-j) > 128) c2 = 128;
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putc(c2, fp);
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while (c2--)
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putc(scanline[j++][i], fp);
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}
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if (cnt >= MINRUN) { /* write out run */
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putc(128+cnt, fp);
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putc(scanline[beg][i], fp);
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} else
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cnt = 0;
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}
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}
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return(ferror(fp) ? -1 : 0);
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}
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static int
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oldreadcolrs(scanline, len, fp) /* read in an old colr scanline */
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register COLR *scanline;
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int len;
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register FILE *fp;
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{
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int rshift;
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register int i;
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rshift = 0;
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while (len > 0) {
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scanline[0][RED] = getc(fp);
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scanline[0][GRN] = getc(fp);
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scanline[0][BLU] = getc(fp);
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scanline[0][EXP] = getc(fp);
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if (feof(fp) || ferror(fp))
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return(-1);
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if (scanline[0][RED] == 1 &&
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scanline[0][GRN] == 1 &&
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scanline[0][BLU] == 1) {
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for (i = scanline[0][EXP] << rshift; i > 0; i--) {
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copycolr(scanline[0], scanline[-1]);
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scanline++;
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len--;
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}
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rshift += 8;
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} else {
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scanline++;
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len--;
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rshift = 0;
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}
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}
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return(0);
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}
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int
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freadcolrs(scanline, len, fp) /* read in an encoded colr scanline */
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register COLR *scanline;
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int len;
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register FILE *fp;
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{
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register int i, j;
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int code, val;
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/* determine scanline type */
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if ((len < MINELEN) | (len > MAXELEN))
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return(oldreadcolrs(scanline, len, fp));
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if ((i = getc(fp)) == EOF)
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return(-1);
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if (i != 2) {
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ungetc(i, fp);
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return(oldreadcolrs(scanline, len, fp));
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}
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scanline[0][GRN] = getc(fp);
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scanline[0][BLU] = getc(fp);
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if ((i = getc(fp)) == EOF)
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return(-1);
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if (scanline[0][GRN] != 2 || scanline[0][BLU] & 128) {
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scanline[0][RED] = 2;
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scanline[0][EXP] = i;
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return(oldreadcolrs(scanline+1, len-1, fp));
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}
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if ((scanline[0][BLU]<<8 | i) != len)
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return(-1); /* length mismatch! */
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/* read each component */
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for (i = 0; i < 4; i++)
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for (j = 0; j < len; ) {
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if ((code = getc(fp)) == EOF)
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return(-1);
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if (code > 128) { /* run */
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code &= 127;
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if ((val = getc(fp)) == EOF)
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return -1;
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if (j + code > len)
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return -1; /* overrun */
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while (code--)
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scanline[j++][i] = val;
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} else { /* non-run */
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if (j + code > len)
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return -1; /* overrun */
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while (code--) {
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if ((val = getc(fp)) == EOF)
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return -1;
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scanline[j++][i] = val;
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}
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}
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}
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return(0);
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}
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int
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fwritescan(scanline, len, fp) /* write out a scanline */
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register COLOR *scanline;
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int len;
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FILE *fp;
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{
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COLR *clrscan;
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int n;
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register COLR *sp;
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/* get scanline buffer */
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if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
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return(-1);
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clrscan = sp;
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/* convert scanline */
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n = len;
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while (n-- > 0) {
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setcolr(sp[0], scanline[0][RED],
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scanline[0][GRN],
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scanline[0][BLU]);
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scanline++;
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sp++;
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}
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return(fwritecolrs(clrscan, len, fp));
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}
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int
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freadscan(scanline, len, fp) /* read in a scanline */
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register COLOR *scanline;
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int len;
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FILE *fp;
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{
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register COLR *clrscan;
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if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
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return(-1);
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if (freadcolrs(clrscan, len, fp) < 0)
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return(-1);
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/* convert scanline */
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colr_color(scanline[0], clrscan[0]);
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while (--len > 0) {
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scanline++; clrscan++;
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if (clrscan[0][RED] == clrscan[-1][RED] &&
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clrscan[0][GRN] == clrscan[-1][GRN] &&
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clrscan[0][BLU] == clrscan[-1][BLU] &&
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clrscan[0][EXP] == clrscan[-1][EXP])
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copycolor(scanline[0], scanline[-1]);
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else
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colr_color(scanline[0], clrscan[0]);
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}
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return(0);
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}
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void
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setcolr(clr, r, g, b) /* assign a short color value */
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register COLR clr;
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double r, g, b;
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{
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double d;
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int e;
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d = r > g ? r : g;
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if (b > d) d = b;
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if (d <= 1e-32) {
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clr[RED] = clr[GRN] = clr[BLU] = 0;
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clr[EXP] = 0;
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return;
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}
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d = frexp(d, &e) * 255.9999 / d;
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if (r > 0.0)
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clr[RED] = r * d;
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else
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clr[RED] = 0;
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if (g > 0.0)
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clr[GRN] = g * d;
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else
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clr[GRN] = 0;
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if (b > 0.0)
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clr[BLU] = b * d;
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else
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clr[BLU] = 0;
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clr[EXP] = e + COLXS;
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}
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void
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colr_color(col, clr) /* convert short to float color */
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register COLOR col;
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register COLR clr;
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{
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double f;
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if (clr[EXP] == 0)
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col[RED] = col[GRN] = col[BLU] = 0.0;
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else {
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f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
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col[RED] = (clr[RED] + 0.5)*f;
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col[GRN] = (clr[GRN] + 0.5)*f;
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col[BLU] = (clr[BLU] + 0.5)*f;
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}
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}
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int
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bigdiff(c1, c2, md) /* c1 delta c2 > md? */
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register COLOR c1, c2;
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double md;
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{
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register int i;
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for (i = 0; i < 3; i++)
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if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) ||
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colval(c2,i)-colval(c1,i) > md*colval(c1,i))
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return(1);
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return(0);
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}
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