src/common/color.c

#ifndef lint
static const char       RCSid[] = "$Id: color.c,v 2.20 2019/02/23 19:11:25 greg Exp $";
#endif
/*
 *  color.c - routines for color calculations.
 *
 *  Externals declared in color.h
 */

#include "copyright.h"

#include  <stdio.h>
#include  <stdlib.h>
#include  <math.h>
#include  "color.h"

#ifdef getc_unlocked            /* avoid horrendous overhead of flockfile */
#undef getc
#undef putc
#undef ferror
#define getc    getc_unlocked
#define putc    putc_unlocked
#define ferror  ferror_unlocked
#endif

#define  MINELEN        8       /* minimum scanline length for encoding */
#define  MAXELEN        0x7fff  /* maximum scanline length for encoding */
#define  MINRUN         4       /* minimum run length */


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

        if (!len | (len > tempbuflen)) {
                if (tempbuflen)
                        free(tempbuf);
                tempbuf = len ? (char *)malloc(len) : (char *)NULL;
                tempbuflen = len*(tempbuf != NULL);
        }
        return(tempbuf);
}


int
fwritecolrs(                    /* write out a colr scanline */
        COLR  *scanline,
        int  len,
        FILE  *fp
)
{
        int  i, j, beg, cnt = 1;
        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&0xff, 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);
}


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


int
freadcolrs(                     /* read in an encoded colr scanline */
        COLR  *scanline,
        int  len,
        FILE  *fp
)
{
        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] & 0x80) != 0)) {
                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;
                    if ((val = getc(fp)) == EOF)
                        return -1;
                    if (j + code > len)
                        return -1;      /* overrun */
                    while (code--)
                        scanline[j++][i] = val;
                } else {                /* non-run */
                    if (j + code > len)
                        return -1;      /* overrun */
                    while (code--) {
                        if ((val = getc(fp)) == EOF)
                            return -1;
                        scanline[j++][i] = val;
                    }
                }
            }
        return(0);
}


int
fwritescan(                     /* write out a scanline */
        COLOR  *scanline,
        int  len,
        FILE  *fp
)
{
        COLR  *clrscan;
        int  n;
        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));
}


int
freadscan(                      /* read in a scanline */
        COLOR  *scanline,
        int  len,
        FILE  *fp
)
{
        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][GRN] == clrscan[-1][GRN] &&
                            (clrscan[0][RED] == clrscan[-1][RED]) &
                            (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);
}


void
setcolr(                        /* assign a short color value */
        COLR  clr,
        double  r,
        double  g,
        double  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;

        if (r > 0.0)
                clr[RED] = r * d;
        else
                clr[RED] = 0;
        if (g > 0.0)
                clr[GRN] = g * d;
        else
                clr[GRN] = 0;
        if (b > 0.0)
                clr[BLU] = b * d;
        else
                clr[BLU] = 0;

        clr[EXP] = e + COLXS;
}


void
colr_color(                     /* convert short to float color */
        COLOR  col,
        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;
        }
}


int
bigdiff(                                /* c1 delta c2 > md? */
        COLOR  c1,
        COLOR  c2,
        double  md
)
{
        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:	2.21
Committed:	Mon May 27 15:44:26 2019 UTC (4 years, 11 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad5R3
Changes since 2.20:	+4 -4 lines
Log Message:	Fixed potential bug where RGB=(0.01953125 0.01953125 1)*2^N for any N could encode as an RLE start sequence
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.21	static const char RCSid[] = "$Id: color.c,v 2.20 2019/02/23 19:11:25 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* color.c - routines for color calculations.
6			*
7	greg	2.9	* Externals declared in color.h
8			*/
9
10	greg	2.10	#include "copyright.h"
11	greg	1.1
12			#include <stdio.h>
13	greg	2.9	#include <stdlib.h>
14	greg	2.7	#include <math.h>
15	greg	1.1	#include "color.h"
16	greg	2.14
17			#ifdef getc_unlocked /* avoid horrendous overhead of flockfile */
18	greg	2.15	#undef getc
19			#undef putc
20	greg	2.19	#undef ferror
21	greg	2.14	#define getc getc_unlocked
22			#define putc putc_unlocked
23	greg	2.18	#define ferror ferror_unlocked
24	greg	2.14	#endif
25	greg	1.1
26	greg	1.14	#define MINELEN 8 /* minimum scanline length for encoding */
27	greg	2.6	#define MAXELEN 0x7fff /* maximum scanline length for encoding */
28	greg	1.14	#define MINRUN 4 /* minimum run length */
29
30	greg	2.4
31	greg	1.14	char *
32	greg	2.17	tempbuffer( /* get a temporary buffer */
33			unsigned int len
34			)
35	greg	1.14	{
36			static char *tempbuf = NULL;
37	greg	2.5	static unsigned tempbuflen = 0;
38	greg	1.14
39	greg	2.20	if (!len \| (len > tempbuflen)) {
40			if (tempbuflen)
41			free(tempbuf);
42			tempbuf = len ? (char )malloc(len) : (char )NULL;
43			tempbuflen = len*(tempbuf != NULL);
44	greg	1.14	}
45			return(tempbuf);
46			}
47
48
49	greg	2.9	int
50	greg	2.17	fwritecolrs( /* write out a colr scanline */
51			COLR *scanline,
52			int len,
53			FILE *fp
54			)
55	greg	1.1	{
56	greg	2.17	int i, j, beg, cnt = 1;
57	greg	1.14	int c2;
58	greg	1.1
59	schorsch	2.13	if ((len < MINELEN) \| (len > MAXELEN)) /* OOBs, write out flat */
60	greg	1.14	return(fwrite((char *)scanline,sizeof(COLR),len,fp) - len);
61	greg	2.2	/* put magic header */
62			putc(2, fp);
63	greg	1.14	putc(2, fp);
64			putc(len>>8, fp);
65	greg	2.21	putc(len&0xff, fp);
66	greg	1.14	/* put components seperately */
67			for (i = 0; i < 4; i++) {
68			for (j = 0; j < len; j += cnt) { /* find next run */
69			for (beg = j; beg < len; beg += cnt) {
70	greg	2.20	for (cnt = 1; (cnt < 127) & (beg+cnt < len) &&
71	greg	1.14	scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
72			;
73			if (cnt >= MINRUN)
74			break; /* long enough */
75	greg	1.1	}
76	greg	2.20	if ((beg-j > 1) & (beg-j < MINRUN)) {
77	greg	1.15	c2 = j+1;
78			while (scanline[c2++][i] == scanline[j][i])
79			if (c2 == beg) { /* short run */
80			putc(128+beg-j, fp);
81			putc(scanline[j][i], fp);
82			j = beg;
83			break;
84			}
85			}
86			while (j < beg) { /* write out non-run */
87	greg	1.14	if ((c2 = beg-j) > 128) c2 = 128;
88			putc(c2, fp);
89			while (c2--)
90			putc(scanline[j++][i], fp);
91			}
92			if (cnt >= MINRUN) { /* write out run */
93			putc(128+cnt, fp);
94			putc(scanline[beg][i], fp);
95			} else
96			cnt = 0;
97			}
98	greg	1.1	}
99			return(ferror(fp) ? -1 : 0);
100			}
101
102
103	greg	2.9	static int
104	greg	2.19	oldreadcolrs( /* read in an old-style colr scanline */
105	greg	2.17	COLR *scanline,
106			int len,
107			FILE *fp
108			)
109	greg	2.9	{
110	greg	2.18	int rshift = 0;
111	greg	2.17	int i;
112	greg	2.9
113			while (len > 0) {
114			scanline[0][RED] = getc(fp);
115			scanline[0][GRN] = getc(fp);
116			scanline[0][BLU] = getc(fp);
117	greg	2.18	scanline[0][EXP] = i = getc(fp);
118			if (i == EOF)
119	greg	2.9	return(-1);
120	greg	2.20	if (scanline[0][GRN] == 1 &&
121			(scanline[0][RED] == 1) &
122			(scanline[0][BLU] == 1)) {
123			i = scanline[0][EXP] << rshift;
124			while (i--) {
125	greg	2.9	copycolr(scanline[0], scanline[-1]);
126	greg	2.20	if (--len <= 0)
127			return(0);
128	greg	2.9	scanline++;
129			}
130			rshift += 8;
131			} else {
132			scanline++;
133			len--;
134			rshift = 0;
135			}
136			}
137			return(0);
138			}
139
140
141			int
142	greg	2.17	freadcolrs( /* read in an encoded colr scanline */
143			COLR *scanline,
144			int len,
145			FILE *fp
146			)
147	greg	1.1	{
148	greg	2.17	int i, j;
149	greg	2.6	int code, val;
150	greg	1.14	/* determine scanline type */
151	schorsch	2.13	if ((len < MINELEN) \| (len > MAXELEN))
152	greg	1.14	return(oldreadcolrs(scanline, len, fp));
153			if ((i = getc(fp)) == EOF)
154			return(-1);
155			if (i != 2) {
156			ungetc(i, fp);
157			return(oldreadcolrs(scanline, len, fp));
158			}
159			scanline[0][GRN] = getc(fp);
160			scanline[0][BLU] = getc(fp);
161			if ((i = getc(fp)) == EOF)
162			return(-1);
163	greg	2.21	if ((scanline[0][GRN] != 2) \| ((scanline[0][BLU] & 0x80) != 0)) {
164	greg	1.14	scanline[0][RED] = 2;
165			scanline[0][EXP] = i;
166			return(oldreadcolrs(scanline+1, len-1, fp));
167			}
168			if ((scanline[0][BLU]<<8 \| i) != len)
169			return(-1); /* length mismatch! */
170			/* read each component */
171			for (i = 0; i < 4; i++)
172			for (j = 0; j < len; ) {
173			if ((code = getc(fp)) == EOF)
174			return(-1);
175			if (code > 128) { /* run */
176	greg	2.6	code &= 127;
177	greg	2.9	if ((val = getc(fp)) == EOF)
178			return -1;
179	greg	2.16	if (j + code > len)
180			return -1; /* overrun */
181	greg	2.6	while (code--)
182			scanline[j++][i] = val;
183	greg	2.16	} else { /* non-run */
184			if (j + code > len)
185			return -1; /* overrun */
186	greg	2.9	while (code--) {
187			if ((val = getc(fp)) == EOF)
188			return -1;
189			scanline[j++][i] = val;
190			}
191	greg	2.16	}
192	greg	1.14	}
193	greg	1.1	return(0);
194			}
195
196
197	greg	2.9	int
198	greg	2.17	fwritescan( /* write out a scanline */
199			COLOR *scanline,
200			int len,
201			FILE *fp
202			)
203	greg	1.1	{
204	greg	1.14	COLR *clrscan;
205			int n;
206	greg	2.17	COLR *sp;
207	greg	1.14	/* get scanline buffer */
208			if ((sp = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
209			return(-1);
210			clrscan = sp;
211			/* convert scanline */
212			n = len;
213			while (n-- > 0) {
214			setcolr(sp[0], scanline[0][RED],
215	greg	1.1	scanline[0][GRN],
216			scanline[0][BLU]);
217			scanline++;
218	greg	1.14	sp++;
219	greg	1.1	}
220	greg	1.14	return(fwritecolrs(clrscan, len, fp));
221	greg	1.1	}
222
223
224	greg	2.9	int
225	greg	2.17	freadscan( /* read in a scanline */
226			COLOR *scanline,
227			int len,
228			FILE *fp
229			)
230	greg	1.1	{
231	greg	2.17	COLR *clrscan;
232	greg	1.14
233			if ((clrscan = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
234			return(-1);
235			if (freadcolrs(clrscan, len, fp) < 0)
236			return(-1);
237			/* convert scanline */
238			colr_color(scanline[0], clrscan[0]);
239			while (--len > 0) {
240			scanline++; clrscan++;
241	greg	2.20	if (clrscan[0][GRN] == clrscan[-1][GRN] &&
242			(clrscan[0][RED] == clrscan[-1][RED]) &
243			(clrscan[0][BLU] == clrscan[-1][BLU]) &
244			(clrscan[0][EXP] == clrscan[-1][EXP]))
245	greg	1.14	copycolor(scanline[0], scanline[-1]);
246			else
247			colr_color(scanline[0], clrscan[0]);
248	greg	1.1	}
249			return(0);
250			}
251
252
253	greg	2.9	void
254	greg	2.17	setcolr( /* assign a short color value */
255			COLR clr,
256			double r,
257			double g,
258			double b
259			)
260	greg	1.1	{
261			double d;
262			int e;
263
264			d = r > g ? r : g;
265			if (b > d) d = b;
266
267	greg	1.4	if (d <= 1e-32) {
268	greg	1.1	clr[RED] = clr[GRN] = clr[BLU] = 0;
269			clr[EXP] = 0;
270			return;
271			}
272
273	greg	2.21	d = frexp(d, &e) * 256.0 / d;
274	greg	1.1
275	greg	2.11	if (r > 0.0)
276			clr[RED] = r * d;
277			else
278			clr[RED] = 0;
279			if (g > 0.0)
280			clr[GRN] = g * d;
281			else
282			clr[GRN] = 0;
283			if (b > 0.0)
284			clr[BLU] = b * d;
285			else
286			clr[BLU] = 0;
287
288	greg	1.1	clr[EXP] = e + COLXS;
289			}
290
291
292	greg	2.9	void
293	greg	2.17	colr_color( /* convert short to float color */
294			COLOR col,
295			COLR clr
296			)
297	greg	1.1	{
298	greg	1.6	double f;
299	greg	1.1
300			if (clr[EXP] == 0)
301			col[RED] = col[GRN] = col[BLU] = 0.0;
302			else {
303	greg	1.2	f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
304	greg	1.1	col[RED] = (clr[RED] + 0.5)*f;
305			col[GRN] = (clr[GRN] + 0.5)*f;
306			col[BLU] = (clr[BLU] + 0.5)*f;
307			}
308	greg	1.6	}
309
310
311	greg	2.9	int
312	greg	2.17	bigdiff( /* c1 delta c2 > md? */
313			COLOR c1,
314			COLOR c2,
315			double md
316			)
317	greg	1.7	{
318	greg	2.17	int i;
319	greg	1.7
320			for (i = 0; i < 3; i++)
321			if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) \|\|
322	greg	2.20	colval(c2,i)-colval(c1,i) > md*colval(c1,i))
323	greg	1.7	return(1);
324			return(0);
325			}