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;
unsigned  len;
register FILE  *fp;
{
        register int  i, j, beg, cnt;
        int  c2;
        
        if (len < MINELEN | len > 0x7fff)       /* OOBs, write out flat */
                return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
                                        /* put magic header */
        putc(2, fp);
        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 */
                }
                if (beg-j > 1 && beg-j < MINRUN) {
                    c2 = j+1;
                    while (scanline[c2++][i] == scanline[j][i])
                        if (c2 == beg) {        /* short run */
                            putc(128+beg-j, fp);
                            putc(scanline[j][i], fp);
                            j = beg;
                            break;
                        }
                }
                while (j < beg) {               /* write out non-run */
                    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:	2.2
Committed:	Tue Jun 23 10:59:34 1992 UTC (31 years, 10 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.1:	+4 -5 lines
Log Message:	made longer scanlines possible by switching off RLE
#	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	greg	2.2	unsigned len;
43	greg	1.1	register FILE *fp;
44			{
45	greg	1.14	register int i, j, beg, cnt;
46			int c2;
47	greg	1.1
48	greg	2.2	if (len < MINELEN \| len > 0x7fff) /* OOBs, write out flat */
49	greg	1.14	return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
50	greg	2.2	/* put magic header */
51			putc(2, fp);
52	greg	1.14	putc(2, fp);
53			putc(len>>8, fp);
54			putc(len&255, fp);
55			/* put components seperately */
56			for (i = 0; i < 4; i++) {
57			for (j = 0; j < len; j += cnt) { /* find next run */
58			for (beg = j; beg < len; beg += cnt) {
59			for (cnt = 1; cnt < 127 && beg+cnt < len &&
60			scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
61			;
62			if (cnt >= MINRUN)
63			break; /* long enough */
64	greg	1.1	}
65	greg	1.15	if (beg-j > 1 && beg-j < MINRUN) {
66			c2 = j+1;
67			while (scanline[c2++][i] == scanline[j][i])
68			if (c2 == beg) { /* short run */
69			putc(128+beg-j, fp);
70			putc(scanline[j][i], fp);
71			j = beg;
72			break;
73			}
74			}
75			while (j < beg) { /* write out non-run */
76	greg	1.14	if ((c2 = beg-j) > 128) c2 = 128;
77			putc(c2, fp);
78			while (c2--)
79			putc(scanline[j++][i], fp);
80			}
81			if (cnt >= MINRUN) { /* write out run */
82			putc(128+cnt, fp);
83			putc(scanline[beg][i], fp);
84			} else
85			cnt = 0;
86			}
87	greg	1.1	}
88			return(ferror(fp) ? -1 : 0);
89			}
90
91
92	greg	1.14	freadcolrs(scanline, len, fp) /* read in an encoded colr scanline */
93	greg	1.1	register COLR *scanline;
94			int len;
95			register FILE *fp;
96			{
97	greg	1.14	register int i, j;
98			int code;
99			/* determine scanline type */
100			if (len < MINELEN)
101			return(oldreadcolrs(scanline, len, fp));
102			if ((i = getc(fp)) == EOF)
103			return(-1);
104			if (i != 2) {
105			ungetc(i, fp);
106			return(oldreadcolrs(scanline, len, fp));
107			}
108			scanline[0][GRN] = getc(fp);
109			scanline[0][BLU] = getc(fp);
110			if ((i = getc(fp)) == EOF)
111			return(-1);
112			if (scanline[0][GRN] != 2 \|\| scanline[0][BLU] & 128) {
113			scanline[0][RED] = 2;
114			scanline[0][EXP] = i;
115			return(oldreadcolrs(scanline+1, len-1, fp));
116			}
117			if ((scanline[0][BLU]<<8 \| i) != len)
118			return(-1); /* length mismatch! */
119			/* read each component */
120			for (i = 0; i < 4; i++)
121			for (j = 0; j < len; ) {
122			if ((code = getc(fp)) == EOF)
123			return(-1);
124			if (code > 128) { /* run */
125			scanline[j++][i] = getc(fp);
126			for (code &= 127; --code; j++)
127			scanline[j][i] = scanline[j-1][i];
128			} else /* non-run */
129			while (code--)
130			scanline[j++][i] = getc(fp);
131			}
132			return(feof(fp) ? -1 : 0);
133			}
134
135
136			oldreadcolrs(scanline, len, fp) /* read in an old colr scanline */
137			register COLR *scanline;
138			int len;
139			register FILE *fp;
140			{
141	greg	1.1	int rshift;
142			register int i;
143
144			rshift = 0;
145
146			while (len > 0) {
147			scanline[0][RED] = getc(fp);
148			scanline[0][GRN] = getc(fp);
149			scanline[0][BLU] = getc(fp);
150			scanline[0][EXP] = getc(fp);
151			if (feof(fp) \|\| ferror(fp))
152			return(-1);
153			if (scanline[0][RED] == 1 &&
154			scanline[0][GRN] == 1 &&
155			scanline[0][BLU] == 1) {
156			for (i = scanline[0][EXP] << rshift; i > 0; i--) {
157			copycolr(scanline[0], scanline[-1]);
158			scanline++;
159			len--;
160			}
161			rshift += 8;
162			} else {
163			scanline++;
164			len--;
165			rshift = 0;
166			}
167			}
168			return(0);
169			}
170
171
172			fwritescan(scanline, len, fp) /* write out a scanline */
173			register COLOR *scanline;
174			int len;
175	greg	1.14	FILE *fp;
176	greg	1.1	{
177	greg	1.14	COLR *clrscan;
178			int n;
179			register COLR *sp;
180			/* get scanline buffer */
181			if ((sp = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
182			return(-1);
183			clrscan = sp;
184			/* convert scanline */
185			n = len;
186			while (n-- > 0) {
187			setcolr(sp[0], scanline[0][RED],
188	greg	1.1	scanline[0][GRN],
189			scanline[0][BLU]);
190			scanline++;
191	greg	1.14	sp++;
192	greg	1.1	}
193	greg	1.14	return(fwritecolrs(clrscan, len, fp));
194	greg	1.1	}
195
196
197			freadscan(scanline, len, fp) /* read in a scanline */
198			register COLOR *scanline;
199			int len;
200	greg	1.14	FILE *fp;
201	greg	1.1	{
202	greg	1.14	register COLR *clrscan;
203
204			if ((clrscan = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
205			return(-1);
206			if (freadcolrs(clrscan, len, fp) < 0)
207			return(-1);
208			/* convert scanline */
209			colr_color(scanline[0], clrscan[0]);
210			while (--len > 0) {
211			scanline++; clrscan++;
212			if (clrscan[0][RED] == clrscan[-1][RED] &&
213			clrscan[0][GRN] == clrscan[-1][GRN] &&
214			clrscan[0][BLU] == clrscan[-1][BLU] &&
215			clrscan[0][EXP] == clrscan[-1][EXP])
216			copycolor(scanline[0], scanline[-1]);
217			else
218			colr_color(scanline[0], clrscan[0]);
219	greg	1.1	}
220			return(0);
221			}
222
223
224			setcolr(clr, r, g, b) /* assign a short color value */
225			register COLR clr;
226			double r, g, b;
227			{
228			double frexp();
229			double d;
230			int e;
231
232			d = r > g ? r : g;
233			if (b > d) d = b;
234
235	greg	1.4	if (d <= 1e-32) {
236	greg	1.1	clr[RED] = clr[GRN] = clr[BLU] = 0;
237			clr[EXP] = 0;
238			return;
239			}
240
241			d = frexp(d, &e) * 256.0 / d;
242
243			clr[RED] = r * d;
244			clr[GRN] = g * d;
245			clr[BLU] = b * d;
246			clr[EXP] = e + COLXS;
247			}
248
249
250			colr_color(col, clr) /* convert short to float color */
251			register COLOR col;
252			register COLR clr;
253			{
254	greg	1.6	double f;
255	greg	1.1
256			if (clr[EXP] == 0)
257			col[RED] = col[GRN] = col[BLU] = 0.0;
258			else {
259	greg	1.2	f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
260	greg	1.1	col[RED] = (clr[RED] + 0.5)*f;
261			col[GRN] = (clr[GRN] + 0.5)*f;
262			col[BLU] = (clr[BLU] + 0.5)*f;
263			}
264	greg	1.6	}
265
266
267	greg	1.7	bigdiff(c1, c2, md) /* c1 delta c2 > md? */
268			register COLOR c1, c2;
269			double md;
270			{
271			register int i;
272
273			for (i = 0; i < 3; i++)
274			if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) \|\|
275			colval(c2,i)-colval(c1,i) > md*colval(c1,i))
276			return(1);
277			return(0);
278			}