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  MAXELEN        0x7fff  /* maximum scanline length for encoding */
#define  MINRUN         4       /* minimum run length */

#ifndef frexp
extern double  frexp();
#endif


char *
tempbuffer(len)                 /* get a temporary buffer */
unsigned  len;
{
        extern char  *malloc(), *realloc();
        static char  *tempbuf = NULL;
        static unsigned  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 > MAXELEN)      /* 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, val;
                                        /* determine scanline type */
        if (len < MINELEN | len > MAXELEN)
                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 */
                    code &= 127;
                    val = getc(fp);
                    while (code--)
                        scanline[j++][i] = val;
                } 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  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:	2.6
Committed:	Tue Mar 2 09:09:51 1993 UTC (31 years, 2 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.5:	+6 -5 lines
Log Message:	minor efficiency improvement in freadcolrs()
#	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	greg	2.6	#define MAXELEN 0x7fff /* maximum scanline length for encoding */
19	greg	1.14	#define MINRUN 4 /* minimum run length */
20	greg	1.5
21	greg	2.4	#ifndef frexp
22			extern double frexp();
23			#endif
24	greg	1.14
25	greg	2.4
26	greg	1.14	char *
27			tempbuffer(len) /* get a temporary buffer */
28			unsigned len;
29			{
30			extern char malloc(), realloc();
31			static char *tempbuf = NULL;
32	greg	2.5	static unsigned tempbuflen = 0;
33	greg	1.14
34			if (len > tempbuflen) {
35			if (tempbuflen > 0)
36			tempbuf = realloc(tempbuf, len);
37			else
38			tempbuf = malloc(len);
39			tempbuflen = tempbuf==NULL ? 0 : len;
40			}
41			return(tempbuf);
42			}
43
44
45	greg	1.1	fwritecolrs(scanline, len, fp) /* write out a colr scanline */
46			register COLR *scanline;
47	greg	2.2	unsigned len;
48	greg	1.1	register FILE *fp;
49			{
50	greg	1.14	register int i, j, beg, cnt;
51			int c2;
52	greg	1.1
53	greg	2.5	if (len < MINELEN \| len > MAXELEN) /* OOBs, write out flat */
54	greg	1.14	return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
55	greg	2.2	/* put magic header */
56			putc(2, fp);
57	greg	1.14	putc(2, fp);
58			putc(len>>8, fp);
59			putc(len&255, fp);
60			/* put components seperately */
61			for (i = 0; i < 4; i++) {
62			for (j = 0; j < len; j += cnt) { /* find next run */
63			for (beg = j; beg < len; beg += cnt) {
64			for (cnt = 1; cnt < 127 && beg+cnt < len &&
65			scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
66			;
67			if (cnt >= MINRUN)
68			break; /* long enough */
69	greg	1.1	}
70	greg	1.15	if (beg-j > 1 && beg-j < MINRUN) {
71			c2 = j+1;
72			while (scanline[c2++][i] == scanline[j][i])
73			if (c2 == beg) { /* short run */
74			putc(128+beg-j, fp);
75			putc(scanline[j][i], fp);
76			j = beg;
77			break;
78			}
79			}
80			while (j < beg) { /* write out non-run */
81	greg	1.14	if ((c2 = beg-j) > 128) c2 = 128;
82			putc(c2, fp);
83			while (c2--)
84			putc(scanline[j++][i], fp);
85			}
86			if (cnt >= MINRUN) { /* write out run */
87			putc(128+cnt, fp);
88			putc(scanline[beg][i], fp);
89			} else
90			cnt = 0;
91			}
92	greg	1.1	}
93			return(ferror(fp) ? -1 : 0);
94			}
95
96
97	greg	1.14	freadcolrs(scanline, len, fp) /* read in an encoded colr scanline */
98	greg	1.1	register COLR *scanline;
99			int len;
100			register FILE *fp;
101			{
102	greg	1.14	register int i, j;
103	greg	2.6	int code, val;
104	greg	1.14	/* determine scanline type */
105	greg	2.5	if (len < MINELEN \| len > MAXELEN)
106	greg	1.14	return(oldreadcolrs(scanline, len, fp));
107			if ((i = getc(fp)) == EOF)
108			return(-1);
109			if (i != 2) {
110			ungetc(i, fp);
111			return(oldreadcolrs(scanline, len, fp));
112			}
113			scanline[0][GRN] = getc(fp);
114			scanline[0][BLU] = getc(fp);
115			if ((i = getc(fp)) == EOF)
116			return(-1);
117			if (scanline[0][GRN] != 2 \|\| scanline[0][BLU] & 128) {
118			scanline[0][RED] = 2;
119			scanline[0][EXP] = i;
120			return(oldreadcolrs(scanline+1, len-1, fp));
121			}
122			if ((scanline[0][BLU]<<8 \| i) != len)
123			return(-1); /* length mismatch! */
124			/* read each component */
125			for (i = 0; i < 4; i++)
126			for (j = 0; j < len; ) {
127			if ((code = getc(fp)) == EOF)
128			return(-1);
129			if (code > 128) { /* run */
130	greg	2.6	code &= 127;
131			val = getc(fp);
132			while (code--)
133			scanline[j++][i] = val;
134	greg	1.14	} else /* non-run */
135			while (code--)
136			scanline[j++][i] = getc(fp);
137			}
138			return(feof(fp) ? -1 : 0);
139			}
140
141
142			oldreadcolrs(scanline, len, fp) /* read in an old colr scanline */
143			register COLR *scanline;
144			int len;
145			register FILE *fp;
146			{
147	greg	1.1	int rshift;
148			register int i;
149
150			rshift = 0;
151
152			while (len > 0) {
153			scanline[0][RED] = getc(fp);
154			scanline[0][GRN] = getc(fp);
155			scanline[0][BLU] = getc(fp);
156			scanline[0][EXP] = getc(fp);
157			if (feof(fp) \|\| ferror(fp))
158			return(-1);
159			if (scanline[0][RED] == 1 &&
160			scanline[0][GRN] == 1 &&
161			scanline[0][BLU] == 1) {
162			for (i = scanline[0][EXP] << rshift; i > 0; i--) {
163			copycolr(scanline[0], scanline[-1]);
164			scanline++;
165			len--;
166			}
167			rshift += 8;
168			} else {
169			scanline++;
170			len--;
171			rshift = 0;
172			}
173			}
174			return(0);
175			}
176
177
178			fwritescan(scanline, len, fp) /* write out a scanline */
179			register COLOR *scanline;
180			int len;
181	greg	1.14	FILE *fp;
182	greg	1.1	{
183	greg	1.14	COLR *clrscan;
184			int n;
185			register COLR *sp;
186			/* get scanline buffer */
187			if ((sp = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
188			return(-1);
189			clrscan = sp;
190			/* convert scanline */
191			n = len;
192			while (n-- > 0) {
193			setcolr(sp[0], scanline[0][RED],
194	greg	1.1	scanline[0][GRN],
195			scanline[0][BLU]);
196			scanline++;
197	greg	1.14	sp++;
198	greg	1.1	}
199	greg	1.14	return(fwritecolrs(clrscan, len, fp));
200	greg	1.1	}
201
202
203			freadscan(scanline, len, fp) /* read in a scanline */
204			register COLOR *scanline;
205			int len;
206	greg	1.14	FILE *fp;
207	greg	1.1	{
208	greg	1.14	register COLR *clrscan;
209
210			if ((clrscan = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
211			return(-1);
212			if (freadcolrs(clrscan, len, fp) < 0)
213			return(-1);
214			/* convert scanline */
215			colr_color(scanline[0], clrscan[0]);
216			while (--len > 0) {
217			scanline++; clrscan++;
218			if (clrscan[0][RED] == clrscan[-1][RED] &&
219			clrscan[0][GRN] == clrscan[-1][GRN] &&
220			clrscan[0][BLU] == clrscan[-1][BLU] &&
221			clrscan[0][EXP] == clrscan[-1][EXP])
222			copycolor(scanline[0], scanline[-1]);
223			else
224			colr_color(scanline[0], clrscan[0]);
225	greg	1.1	}
226			return(0);
227			}
228
229
230			setcolr(clr, r, g, b) /* assign a short color value */
231			register COLR clr;
232			double r, g, b;
233			{
234			double d;
235			int e;
236
237			d = r > g ? r : g;
238			if (b > d) d = b;
239
240	greg	1.4	if (d <= 1e-32) {
241	greg	1.1	clr[RED] = clr[GRN] = clr[BLU] = 0;
242			clr[EXP] = 0;
243			return;
244			}
245
246			d = frexp(d, &e) * 256.0 / d;
247
248			clr[RED] = r * d;
249			clr[GRN] = g * d;
250			clr[BLU] = b * d;
251			clr[EXP] = e + COLXS;
252			}
253
254
255			colr_color(col, clr) /* convert short to float color */
256			register COLOR col;
257			register COLR clr;
258			{
259	greg	1.6	double f;
260	greg	1.1
261			if (clr[EXP] == 0)
262			col[RED] = col[GRN] = col[BLU] = 0.0;
263			else {
264	greg	1.2	f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
265	greg	1.1	col[RED] = (clr[RED] + 0.5)*f;
266			col[GRN] = (clr[GRN] + 0.5)*f;
267			col[BLU] = (clr[BLU] + 0.5)*f;
268			}
269	greg	1.6	}
270
271
272	greg	1.7	bigdiff(c1, c2, md) /* c1 delta c2 > md? */
273			register COLOR c1, c2;
274			double md;
275			{
276			register int i;
277
278			for (i = 0; i < 3; i++)
279			if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) \|\|
280			colval(c2,i)-colval(c1,i) > md*colval(c1,i))
281			return(1);
282			return(0);
283			}