src/common/color.c

#ifndef lint
static const char       RCSid[] = "$Id: color.c,v 2.17 2014/05/31 20:13:31 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
#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 > tempbuflen) {
                if (tempbuflen > 0)
                        tempbuf = (char *)realloc((void *)tempbuf, len);
                else
                        tempbuf = (char *)malloc(len);
                tempbuflen = tempbuf==NULL ? 0 : len;
        }
        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&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);
}


static int
oldreadcolrs(                   /* read in an old 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][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);
}


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] & 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;
                    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][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);
}


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) * 255.9999 / 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:	2.18
Committed:	Tue Apr 10 23:38:40 2018 UTC (6 years, 1 month ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.17:	+5 -6 lines
Log Message:	Made reading uncompressed scanlines a bit faster
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.18	static const char RCSid[] = "$Id: color.c,v 2.17 2014/05/31 20:13:31 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	2.14	#define getc getc_unlocked
21			#define putc putc_unlocked
22	greg	2.18	#define ferror ferror_unlocked
23	greg	2.14	#endif
24	greg	1.1
25	greg	1.14	#define MINELEN 8 /* minimum scanline length for encoding */
26	greg	2.6	#define MAXELEN 0x7fff /* maximum scanline length for encoding */
27	greg	1.14	#define MINRUN 4 /* minimum run length */
28
29	greg	2.4
30	greg	1.14	char *
31	greg	2.17	tempbuffer( /* get a temporary buffer */
32			unsigned int len
33			)
34	greg	1.14	{
35			static char *tempbuf = NULL;
36	greg	2.5	static unsigned tempbuflen = 0;
37	greg	1.14
38			if (len > tempbuflen) {
39			if (tempbuflen > 0)
40	greg	2.12	tempbuf = (char )realloc((void )tempbuf, len);
41	greg	1.14	else
42	greg	2.9	tempbuf = (char *)malloc(len);
43	greg	1.14	tempbuflen = tempbuf==NULL ? 0 : len;
44			}
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			putc(len&255, fp);
66			/* 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			for (cnt = 1; cnt < 127 && beg+cnt < len &&
71			scanline[beg+cnt][i] == scanline[beg][i]; cnt++)
72			;
73			if (cnt >= MINRUN)
74			break; /* long enough */
75	greg	1.1	}
76	greg	1.15	if (beg-j > 1 && beg-j < MINRUN) {
77			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	2.17	oldreadcolrs( /* read in an old colr scanline */
105			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			if (scanline[0][RED] == 1 &&
121			scanline[0][GRN] == 1 &&
122			scanline[0][BLU] == 1) {
123			for (i = scanline[0][EXP] << rshift; i > 0; i--) {
124			copycolr(scanline[0], scanline[-1]);
125			scanline++;
126			len--;
127			}
128			rshift += 8;
129			} else {
130			scanline++;
131			len--;
132			rshift = 0;
133			}
134			}
135			return(0);
136			}
137
138
139			int
140	greg	2.17	freadcolrs( /* read in an encoded colr scanline */
141			COLR *scanline,
142			int len,
143			FILE *fp
144			)
145	greg	1.1	{
146	greg	2.17	int i, j;
147	greg	2.6	int code, val;
148	greg	1.14	/* determine scanline type */
149	schorsch	2.13	if ((len < MINELEN) \| (len > MAXELEN))
150	greg	1.14	return(oldreadcolrs(scanline, len, fp));
151			if ((i = getc(fp)) == EOF)
152			return(-1);
153			if (i != 2) {
154			ungetc(i, fp);
155			return(oldreadcolrs(scanline, len, fp));
156			}
157			scanline[0][GRN] = getc(fp);
158			scanline[0][BLU] = getc(fp);
159			if ((i = getc(fp)) == EOF)
160			return(-1);
161			if (scanline[0][GRN] != 2 \|\| scanline[0][BLU] & 128) {
162			scanline[0][RED] = 2;
163			scanline[0][EXP] = i;
164			return(oldreadcolrs(scanline+1, len-1, fp));
165			}
166			if ((scanline[0][BLU]<<8 \| i) != len)
167			return(-1); /* length mismatch! */
168			/* read each component */
169			for (i = 0; i < 4; i++)
170			for (j = 0; j < len; ) {
171			if ((code = getc(fp)) == EOF)
172			return(-1);
173			if (code > 128) { /* run */
174	greg	2.6	code &= 127;
175	greg	2.9	if ((val = getc(fp)) == EOF)
176			return -1;
177	greg	2.16	if (j + code > len)
178			return -1; /* overrun */
179	greg	2.6	while (code--)
180			scanline[j++][i] = val;
181	greg	2.16	} else { /* non-run */
182			if (j + code > len)
183			return -1; /* overrun */
184	greg	2.9	while (code--) {
185			if ((val = getc(fp)) == EOF)
186			return -1;
187			scanline[j++][i] = val;
188			}
189	greg	2.16	}
190	greg	1.14	}
191	greg	1.1	return(0);
192			}
193
194
195	greg	2.9	int
196	greg	2.17	fwritescan( /* write out a scanline */
197			COLOR *scanline,
198			int len,
199			FILE *fp
200			)
201	greg	1.1	{
202	greg	1.14	COLR *clrscan;
203			int n;
204	greg	2.17	COLR *sp;
205	greg	1.14	/* get scanline buffer */
206			if ((sp = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
207			return(-1);
208			clrscan = sp;
209			/* convert scanline */
210			n = len;
211			while (n-- > 0) {
212			setcolr(sp[0], scanline[0][RED],
213	greg	1.1	scanline[0][GRN],
214			scanline[0][BLU]);
215			scanline++;
216	greg	1.14	sp++;
217	greg	1.1	}
218	greg	1.14	return(fwritecolrs(clrscan, len, fp));
219	greg	1.1	}
220
221
222	greg	2.9	int
223	greg	2.17	freadscan( /* read in a scanline */
224			COLOR *scanline,
225			int len,
226			FILE *fp
227			)
228	greg	1.1	{
229	greg	2.17	COLR *clrscan;
230	greg	1.14
231			if ((clrscan = (COLR )tempbuffer(lensizeof(COLR))) == NULL)
232			return(-1);
233			if (freadcolrs(clrscan, len, fp) < 0)
234			return(-1);
235			/* convert scanline */
236			colr_color(scanline[0], clrscan[0]);
237			while (--len > 0) {
238			scanline++; clrscan++;
239			if (clrscan[0][RED] == clrscan[-1][RED] &&
240			clrscan[0][GRN] == clrscan[-1][GRN] &&
241			clrscan[0][BLU] == clrscan[-1][BLU] &&
242			clrscan[0][EXP] == clrscan[-1][EXP])
243			copycolor(scanline[0], scanline[-1]);
244			else
245			colr_color(scanline[0], clrscan[0]);
246	greg	1.1	}
247			return(0);
248			}
249
250
251	greg	2.9	void
252	greg	2.17	setcolr( /* assign a short color value */
253			COLR clr,
254			double r,
255			double g,
256			double b
257			)
258	greg	1.1	{
259			double d;
260			int e;
261
262			d = r > g ? r : g;
263			if (b > d) d = b;
264
265	greg	1.4	if (d <= 1e-32) {
266	greg	1.1	clr[RED] = clr[GRN] = clr[BLU] = 0;
267			clr[EXP] = 0;
268			return;
269			}
270
271	greg	2.8	d = frexp(d, &e) * 255.9999 / d;
272	greg	1.1
273	greg	2.11	if (r > 0.0)
274			clr[RED] = r * d;
275			else
276			clr[RED] = 0;
277			if (g > 0.0)
278			clr[GRN] = g * d;
279			else
280			clr[GRN] = 0;
281			if (b > 0.0)
282			clr[BLU] = b * d;
283			else
284			clr[BLU] = 0;
285
286	greg	1.1	clr[EXP] = e + COLXS;
287			}
288
289
290	greg	2.9	void
291	greg	2.17	colr_color( /* convert short to float color */
292			COLOR col,
293			COLR clr
294			)
295	greg	1.1	{
296	greg	1.6	double f;
297	greg	1.1
298			if (clr[EXP] == 0)
299			col[RED] = col[GRN] = col[BLU] = 0.0;
300			else {
301	greg	1.2	f = ldexp(1.0, (int)clr[EXP]-(COLXS+8));
302	greg	1.1	col[RED] = (clr[RED] + 0.5)*f;
303			col[GRN] = (clr[GRN] + 0.5)*f;
304			col[BLU] = (clr[BLU] + 0.5)*f;
305			}
306	greg	1.6	}
307
308
309	greg	2.9	int
310	greg	2.17	bigdiff( /* c1 delta c2 > md? */
311			COLOR c1,
312			COLOR c2,
313			double md
314			)
315	greg	1.7	{
316	greg	2.17	int i;
317	greg	1.7
318			for (i = 0; i < 3; i++)
319			if (colval(c1,i)-colval(c2,i) > md*colval(c2,i) \|\|
320			colval(c2,i)-colval(c1,i) > md*colval(c1,i))
321			return(1);
322			return(0);
323			}