src/common/color.c

/* Copyright (c) 1991 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 *  color.c - routines for color calculations.
 *
 *     10/10/85
 */

#include  <stdio.h>

#include  "color.h"

#define  MINELEN        8       /* minimum scanline length for encoding */
#define  MINRUN         4       /* minimum run length */


char *
tempbuffer(len)                 /* get a temporary buffer */
unsigned  len;
{
        extern char  *malloc(), *realloc();
        static char  *tempbuf = NULL;
        static int  tempbuflen = 0;

        if (len > tempbuflen) {
                if (tempbuflen > 0)
                        tempbuf = realloc(tempbuf, len);
                else
                        tempbuf = malloc(len);
                tempbuflen = tempbuf==NULL ? 0 : len;
        }
        return(tempbuf);
}


fwritecolrs(scanline, len, fp)          /* write out a colr scanline */
register COLR  *scanline;
int  len;
register FILE  *fp;
{
        register int  i, j, beg, cnt;
        int  c2;
        
        if (len < MINELEN)              /* too small to encode */
                return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
        if (len > 32767)                /* too big! */
                return(-1);
        putc(2, fp);                    /* put magic header */
        putc(2, fp);
        putc(len>>8, fp);
        putc(len&255, fp);
                                        /* put components seperately */
        for (i = 0; i < 4; i++) {
            for (j = 0; j < len; j += cnt) {    /* find next run */
                for (beg = j; beg < len; beg += cnt) {
                    for (cnt = 1; cnt < 127 && beg+cnt < len &&
                            scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
                        ;
                    if (cnt >= MINRUN)
                        break;                  /* long enough */
                }
                while (j < beg) {               /* write out non-run(s) */
                    if ((c2 = beg-j) > 128) c2 = 128;
                    putc(c2, fp);
                    while (c2--)
                        putc(scanline[j++][i], fp);
                }
                if (cnt >= MINRUN) {            /* write out run */
                    putc(128+cnt, fp);
                    putc(scanline[beg][i], fp);
                } else
                    cnt = 0;
            }
        }
        return(ferror(fp) ? -1 : 0);
}


freadcolrs(scanline, len, fp)           /* read in an encoded colr scanline */
register COLR  *scanline;
int  len;
register FILE  *fp;
{
        register int  i, j;
        int  code;
                                        /* determine scanline type */
        if (len < MINELEN)
                return(oldreadcolrs(scanline, len, fp));
        if ((i = getc(fp)) == EOF)
                return(-1);
        if (i != 2) {
                ungetc(i, fp);
                return(oldreadcolrs(scanline, len, fp));
        }
        scanline[0][GRN] = getc(fp);
        scanline[0][BLU] = getc(fp);
        if ((i = getc(fp)) == EOF)
                return(-1);
        if (scanline[0][GRN] != 2 || scanline[0][BLU] & 128) {
                scanline[0][RED] = 2;
                scanline[0][EXP] = i;
                return(oldreadcolrs(scanline+1, len-1, fp));
        }
        if ((scanline[0][BLU]<<8 | i) != len)
                return(-1);             /* length mismatch! */
                                        /* read each component */
        for (i = 0; i < 4; i++)
            for (j = 0; j < len; ) {
                if ((code = getc(fp)) == EOF)
                    return(-1);
                if (code > 128) {       /* run */
                    scanline[j++][i] = getc(fp);
                    for (code &= 127; --code; j++)
                        scanline[j][i] = scanline[j-1][i];
                } else                  /* non-run */
                    while (code--)
                        scanline[j++][i] = getc(fp);
            }
        return(feof(fp) ? -1 : 0);
}


oldreadcolrs(scanline, len, fp)         /* read in an old colr scanline */
register COLR  *scanline;
int  len;
register FILE  *fp;
{
        int  rshift;
        register int  i;
        
        rshift = 0;
        
        while (len > 0) {
                scanline[0][RED] = getc(fp);
                scanline[0][GRN] = getc(fp);
                scanline[0][BLU] = getc(fp);
                scanline[0][EXP] = getc(fp);
                if (feof(fp) || ferror(fp))
                        return(-1);
                if (scanline[0][RED] == 1 &&
                                scanline[0][GRN] == 1 &&
                                scanline[0][BLU] == 1) {
                        for (i = scanline[0][EXP] << rshift; i > 0; i--) {
                                copycolr(scanline[0], scanline[-1]);
                                scanline++;
                                len--;
                        }
                        rshift += 8;
                } else {
                        scanline++;
                        len--;
                        rshift = 0;
                }
        }
        return(0);
}


fwritescan(scanline, len, fp)           /* write out a scanline */
register COLOR  *scanline;
int  len;
FILE  *fp;
{
        COLR  *clrscan;
        int  n;
        register COLR  *sp;
                                        /* get scanline buffer */
        if ((sp = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
                return(-1);
        clrscan = sp;
                                        /* convert scanline */
        n = len;
        while (n-- > 0) {
                setcolr(sp[0], scanline[0][RED],
                                  scanline[0][GRN],
                                  scanline[0][BLU]);
                scanline++;
                sp++;
        }
        return(fwritecolrs(clrscan, len, fp));
}


freadscan(scanline, len, fp)            /* read in a scanline */
register COLOR  *scanline;
int  len;
FILE  *fp;
{
        register COLR  *clrscan;

        if ((clrscan = (COLR *)tempbuffer(len*sizeof(COLR))) == NULL)
                return(-1);
        if (freadcolrs(clrscan, len, fp) < 0)
                return(-1);
                                        /* convert scanline */
        colr_color(scanline[0], clrscan[0]);
        while (--len > 0) {
                scanline++; clrscan++;
                if (clrscan[0][RED] == clrscan[-1][RED] &&
                            clrscan[0][GRN] == clrscan[-1][GRN] &&
                            clrscan[0][BLU] == clrscan[-1][BLU] &&
                            clrscan[0][EXP] == clrscan[-1][EXP])
                        copycolor(scanline[0], scanline[-1]);
                else
                        colr_color(scanline[0], clrscan[0]);
        }
        return(0);
}


setcolr(clr, r, g, b)           /* assign a short color value */
register COLR  clr;
double  r, g, b;
{
        double  frexp();
        double  d;
        int  e;
        
        d = r > g ? r : g;
        if (b > d) d = b;

        if (d <= 1e-32) {
                clr[RED] = clr[GRN] = clr[BLU] = 0;
                clr[EXP] = 0;
                return;
        }

        d = frexp(d, &e) * 256.0 / d;

        clr[RED] = r * d;
        clr[GRN] = g * d;
        clr[BLU] = b * d;
        clr[EXP] = e + COLXS;
}


colr_color(col, clr)            /* convert short to float color */
register COLOR  col;
register COLR  clr;
{
        double  f;
        
        if (clr[EXP] == 0)
                col[RED] = col[GRN] = col[BLU] = 0.0;
        else {
                f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
                col[RED] = (clr[RED] + 0.5)*f;
                col[GRN] = (clr[GRN] + 0.5)*f;
                col[BLU] = (clr[BLU] + 0.5)*f;
        }
}


bigdiff(c1, c2, md)                     /* c1 delta c2 > md? */
register COLOR  c1, c2;
double  md;
{
        register int  i;

        for (i = 0; i < 3; i++)
                if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) ||
                        colval(c2,i)-colval(c1,i) > md*colval(c1,i))
                        return(1);
        return(0);
}
Revision:	1.14
Committed:	Fri Aug 23 12:33:49 1991 UTC (32 years, 8 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.13:	+131 -105 lines
Log Message:	changed encoding of scanlines
#	User	Rev	Content
1	greg	1.14	/* Copyright (c) 1991 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* color.c - routines for color calculations.
9			*
10			* 10/10/85
11			*/
12
13			#include <stdio.h>
14
15			#include "color.h"
16
17	greg	1.14	#define MINELEN 8 /* minimum scanline length for encoding */
18			#define MINRUN 4 /* minimum run length */
19	greg	1.5
20	greg	1.14
21			char *
22			tempbuffer(len) /* get a temporary buffer */
23			unsigned len;
24			{
25			extern char malloc(), realloc();
26			static char *tempbuf = NULL;
27			static int tempbuflen = 0;
28
29			if (len > tempbuflen) {
30			if (tempbuflen > 0)
31			tempbuf = realloc(tempbuf, len);
32			else
33			tempbuf = malloc(len);
34			tempbuflen = tempbuf==NULL ? 0 : len;
35			}
36			return(tempbuf);
37			}
38
39
40	greg	1.1	fwritecolrs(scanline, len, fp) /* write out a colr scanline */
41			register COLR *scanline;
42			int len;
43			register FILE *fp;
44			{
45	greg	1.14	register int i, j, beg, cnt;
46			int c2;
47	greg	1.1
48	greg	1.14	if (len < MINELEN) /* too small to encode */
49			return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
50			if (len > 32767) /* too big! */
51			return(-1);
52			putc(2, fp); /* put magic header */
53			putc(2, fp);
54			putc(len>>8, fp);
55			putc(len&255, fp);
56			/* put components seperately */
57			for (i = 0; i < 4; i++) {
58			for (j = 0; j < len; j += cnt) { /* find next run */
59			for (beg = j; beg < len; beg += cnt) {
60			for (cnt = 1; cnt < 127 && beg+cnt < len &&
61			scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
62			;
63			if (cnt >= MINRUN)
64			break; /* long enough */
65	greg	1.1	}
66	greg	1.14	while (j < beg) { /* write out non-run(s) */
67			if ((c2 = beg-j) > 128) c2 = 128;
68			putc(c2, fp);
69			while (c2--)
70			putc(scanline[j++][i], fp);
71			}
72			if (cnt >= MINRUN) { /* write out run */
73			putc(128+cnt, fp);
74			putc(scanline[beg][i], fp);
75			} else
76			cnt = 0;
77			}
78	greg	1.1	}
79			return(ferror(fp) ? -1 : 0);
80			}
81
82
83	greg	1.14	freadcolrs(scanline, len, fp) /* read in an encoded colr scanline */
84	greg	1.1	register COLR *scanline;
85			int len;
86			register FILE *fp;
87			{
88	greg	1.14	register int i, j;
89			int code;
90			/* determine scanline type */
91			if (len < MINELEN)
92			return(oldreadcolrs(scanline, len, fp));
93			if ((i = getc(fp)) == EOF)
94			return(-1);
95			if (i != 2) {
96			ungetc(i, fp);
97			return(oldreadcolrs(scanline, len, fp));
98			}
99			scanline[0][GRN] = getc(fp);
100			scanline[0][BLU] = getc(fp);
101			if ((i = getc(fp)) == EOF)
102			return(-1);
103			if (scanline[0][GRN] != 2 \|\| scanline[0][BLU] & 128) {
104			scanline[0][RED] = 2;
105			scanline[0][EXP] = i;
106			return(oldreadcolrs(scanline+1, len-1, fp));
107			}
108			if ((scanline[0][BLU]<<8 \| i) != len)
109			return(-1); /* length mismatch! */
110			/* read each component */
111			for (i = 0; i < 4; i++)
112			for (j = 0; j < len; ) {
113			if ((code = getc(fp)) == EOF)
114			return(-1);
115			if (code > 128) { /* run */
116			scanline[j++][i] = getc(fp);
117			for (code &= 127; --code; j++)
118			scanline[j][i] = scanline[j-1][i];
119			} else /* non-run */
120			while (code--)
121			scanline[j++][i] = getc(fp);
122			}
123			return(feof(fp) ? -1 : 0);
124			}
125
126
127			oldreadcolrs(scanline, len, fp) /* read in an old colr scanline */
128			register COLR *scanline;
129			int len;
130			register FILE *fp;
131			{
132	greg	1.1	int rshift;
133			register int i;
134
135			rshift = 0;
136
137			while (len > 0) {
138			scanline[0][RED] = getc(fp);
139			scanline[0][GRN] = getc(fp);
140			scanline[0][BLU] = getc(fp);
141			scanline[0][EXP] = getc(fp);
142			if (feof(fp) \|\| ferror(fp))
143			return(-1);
144			if (scanline[0][RED] == 1 &&
145			scanline[0][GRN] == 1 &&
146			scanline[0][BLU] == 1) {
147			for (i = scanline[0][EXP] << rshift; i > 0; i--) {
148			copycolr(scanline[0], scanline[-1]);
149			scanline++;
150			len--;
151			}
152			rshift += 8;
153			} else {
154			scanline++;
155			len--;
156			rshift = 0;
157			}
158			}
159			return(0);
160			}
161
162
163			fwritescan(scanline, len, fp) /* write out a scanline */
164			register COLOR *scanline;
165			int len;
166	greg	1.14	FILE *fp;
167	greg	1.1	{
168	greg	1.14	COLR *clrscan;
169			int n;
170			register COLR *sp;
171			/* get scanline buffer */
172			if ((sp = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
173			return(-1);
174			clrscan = sp;
175			/* convert scanline */
176			n = len;
177			while (n-- > 0) {
178			setcolr(sp[0], scanline[0][RED],
179	greg	1.1	scanline[0][GRN],
180			scanline[0][BLU]);
181			scanline++;
182	greg	1.14	sp++;
183	greg	1.1	}
184	greg	1.14	return(fwritecolrs(clrscan, len, fp));
185	greg	1.1	}
186
187
188			freadscan(scanline, len, fp) /* read in a scanline */
189			register COLOR *scanline;
190			int len;
191	greg	1.14	FILE *fp;
192	greg	1.1	{
193	greg	1.14	register COLR *clrscan;
194
195			if ((clrscan = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
196			return(-1);
197			if (freadcolrs(clrscan, len, fp) < 0)
198			return(-1);
199			/* convert scanline */
200			colr_color(scanline[0], clrscan[0]);
201			while (--len > 0) {
202			scanline++; clrscan++;
203			if (clrscan[0][RED] == clrscan[-1][RED] &&
204			clrscan[0][GRN] == clrscan[-1][GRN] &&
205			clrscan[0][BLU] == clrscan[-1][BLU] &&
206			clrscan[0][EXP] == clrscan[-1][EXP])
207			copycolor(scanline[0], scanline[-1]);
208			else
209			colr_color(scanline[0], clrscan[0]);
210	greg	1.1	}
211			return(0);
212			}
213
214
215			setcolr(clr, r, g, b) /* assign a short color value */
216			register COLR clr;
217			double r, g, b;
218			{
219			double frexp();
220			double d;
221			int e;
222
223			d = r > g ? r : g;
224			if (b > d) d = b;
225
226	greg	1.4	if (d <= 1e-32) {
227	greg	1.1	clr[RED] = clr[GRN] = clr[BLU] = 0;
228			clr[EXP] = 0;
229			return;
230			}
231
232			d = frexp(d, &e) * 256.0 / d;
233
234			clr[RED] = r * d;
235			clr[GRN] = g * d;
236			clr[BLU] = b * d;
237			clr[EXP] = e + COLXS;
238			}
239
240
241			colr_color(col, clr) /* convert short to float color */
242			register COLOR col;
243			register COLR clr;
244			{
245	greg	1.6	double f;
246	greg	1.1
247			if (clr[EXP] == 0)
248			col[RED] = col[GRN] = col[BLU] = 0.0;
249			else {
250	greg	1.2	f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
251	greg	1.1	col[RED] = (clr[RED] + 0.5)*f;
252			col[GRN] = (clr[GRN] + 0.5)*f;
253			col[BLU] = (clr[BLU] + 0.5)*f;
254			}
255	greg	1.6	}
256
257
258	greg	1.7	bigdiff(c1, c2, md) /* c1 delta c2 > md? */
259			register COLOR c1, c2;
260			double md;
261			{
262			register int i;
263
264			for (i = 0; i < 3; i++)
265			if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) \|\|
266			colval(c2,i)-colval(c1,i) > md*colval(c1,i))
267			return(1);
268			return(0);
269			}