src/common/colrops.c

#ifndef lint
static const char       RCSid[] = "$Id: colrops.c,v 2.9 2003/06/30 19:04:29 greg Exp $";
#endif
/*
 * Integer operations on COLR scanlines
 */

#include "copyright.h"

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

extern char     *bmalloc();

#define MAXGSHIFT       31              /* maximum shift for gamma table */

static BYTE     *g_mant = NULL, *g_nexp = NULL;

static BYTE     (*g_bval)[256] = NULL;


int
setcolrcor(f, a2)               /* set brightness correction */
double  (*f)();
double  a2;
{
        double  mult;
        register int    i, j;
                                        /* allocate tables */
        if (g_bval == NULL && (g_bval =
                        (BYTE (*)[256])bmalloc((MAXGSHIFT+1)*256)) == NULL)
                return(-1);
                                        /* compute colr -> gamb mapping */
        mult = 1.0/256.0;
        for (i = 0; i <= MAXGSHIFT; i++) {
                for (j = 0; j < 256; j++)
                        g_bval[i][j] = 256.0 * (*f)((j+.5)*mult, a2);
                mult *= 0.5;
        }
        return(0);
}


int
setcolrinv(f, a2)               /* set inverse brightness correction */
double  (*f)();
double  a2;
{
        double  mult;
        register int    i, j;
                                        /* allocate tables */
        if (g_mant == NULL && (g_mant = (BYTE *)bmalloc(256)) == NULL)
                return(-1);
        if (g_nexp == NULL && (g_nexp = (BYTE *)bmalloc(256)) == NULL)
                return(-1);
                                        /* compute gamb -> colr mapping */
        i = 0;
        mult = 256.0;
        for (j = 256; j--; ) {
                while ((g_mant[j] = mult * (*f)((j+.5)/256.0, a2)) < 128) {
                        i++;
                        mult *= 2.0;
                }
                g_nexp[j] = i;
        }
        return(0);
}


int
setcolrgam(g)                   /* set gamma conversion */
double  g;
{
        if (setcolrcor(pow, 1.0/g) < 0)
                return(-1);
        return(setcolrinv(pow, g));
}


int
colrs_gambs(scan, len)          /* convert scanline of colrs to gamma bytes */
register COLR   *scan;
int     len;
{
        register int    i, expo;

        if (g_bval == NULL)
                return(-1);
        while (len-- > 0) {
                expo = scan[0][EXP] - COLXS;
                if (expo < -MAXGSHIFT) {
                        if (expo < -MAXGSHIFT-8) {
                                scan[0][RED] =
                                scan[0][GRN] =
                                scan[0][BLU] = 0;
                        } else {
                                i = (-MAXGSHIFT-1) - expo;
                                scan[0][RED] = 
                                g_bval[MAXGSHIFT][((scan[0][RED]>>i)+1)>>1];
                                scan[0][GRN] =
                                g_bval[MAXGSHIFT][((scan[0][GRN]>>i)+1)>>1];
                                scan[0][BLU] =
                                g_bval[MAXGSHIFT][((scan[0][BLU]>>i)+1)>>1];
                        }
                } else if (expo > 0) {
                        if (expo > 8) {
                                scan[0][RED] =
                                scan[0][GRN] =
                                scan[0][BLU] = 255;
                        } else {
                                i = (scan[0][RED]<<1 | 1) << (expo-1);
                                scan[0][RED] = i > 255 ? 255 : g_bval[0][i];
                                i = (scan[0][GRN]<<1 | 1) << (expo-1);
                                scan[0][GRN] = i > 255 ? 255 : g_bval[0][i];
                                i = (scan[0][BLU]<<1 | 1) << (expo-1);
                                scan[0][BLU] = i > 255 ? 255 : g_bval[0][i];
                        }
                } else {
                        scan[0][RED] = g_bval[-expo][scan[0][RED]];
                        scan[0][GRN] = g_bval[-expo][scan[0][GRN]];
                        scan[0][BLU] = g_bval[-expo][scan[0][BLU]];
                }
                scan[0][EXP] = COLXS;
                scan++;
        }
        return(0);
}


int
gambs_colrs(scan, len)          /* convert gamma bytes to colr scanline */
register COLR   *scan;
int     len;
{
        register int    nexpo;

        if ((g_mant == NULL) | (g_nexp == NULL))
                return(-1);
        while (len-- > 0) {
                nexpo = g_nexp[scan[0][RED]];
                if (g_nexp[scan[0][GRN]] < nexpo)
                        nexpo = g_nexp[scan[0][GRN]];
                if (g_nexp[scan[0][BLU]] < nexpo)
                        nexpo = g_nexp[scan[0][BLU]];
                if (nexpo < g_nexp[scan[0][RED]])
                        scan[0][RED] = g_mant[scan[0][RED]]
                                        >> (g_nexp[scan[0][RED]]-nexpo);
                else
                        scan[0][RED] = g_mant[scan[0][RED]];
                if (nexpo < g_nexp[scan[0][GRN]])
                        scan[0][GRN] = g_mant[scan[0][GRN]]
                                        >> (g_nexp[scan[0][GRN]]-nexpo);
                else
                        scan[0][GRN] = g_mant[scan[0][GRN]];
                if (nexpo < g_nexp[scan[0][BLU]])
                        scan[0][BLU] = g_mant[scan[0][BLU]]
                                        >> (g_nexp[scan[0][BLU]]-nexpo);
                else
                        scan[0][BLU] = g_mant[scan[0][BLU]];
                scan[0][EXP] = COLXS - nexpo;
                scan++;
        }
        return(0);
}


void
shiftcolrs(scan, len, adjust)   /* shift a scanline of colors by 2^adjust */
register COLR   *scan;
register int    len;
register int    adjust;
{
        int     minexp;

        if (adjust == 0)
                return;
        minexp = adjust < 0 ? -adjust : 0;
        while (len-- > 0) {
                if (scan[0][EXP] <= minexp)
                        scan[0][RED] = scan[0][GRN] = scan[0][BLU] =
                        scan[0][EXP] = 0;
                else
                        scan[0][EXP] += adjust;
                scan++;
        }
}


void
normcolrs(scan, len, adjust)    /* normalize a scanline of colrs */
register COLR  *scan;
int  len;
int  adjust;
{
        register int  c;
        register int  shift;

        while (len-- > 0) {
                shift = scan[0][EXP] + adjust - COLXS;
                if (shift > 0) {
                        if (shift > 8) {
                                scan[0][RED] =
                                scan[0][GRN] =
                                scan[0][BLU] = 255;
                        } else {
                                shift--;
                                c = (scan[0][RED]<<1 | 1) << shift;
                                scan[0][RED] = c > 255 ? 255 : c;
                                c = (scan[0][GRN]<<1 | 1) << shift;
                                scan[0][GRN] = c > 255 ? 255 : c;
                                c = (scan[0][BLU]<<1 | 1) << shift;
                                scan[0][BLU] = c > 255 ? 255 : c;
                        }
                } else if (shift < 0) {
                        if (shift < -8) {
                                scan[0][RED] =
                                scan[0][GRN] =
                                scan[0][BLU] = 0;
                        } else {
                                shift = -1-shift;
                                scan[0][RED] = ((scan[0][RED]>>shift)+1)>>1;
                                scan[0][GRN] = ((scan[0][GRN]>>shift)+1)>>1;
                                scan[0][BLU] = ((scan[0][BLU]>>shift)+1)>>1;
                        }
                }
                scan[0][EXP] = COLXS - adjust;
                scan++;
        }
}
Revision:	2.10
Committed:	Sun Jul 27 22:12:01 2003 UTC (20 years, 9 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
Changes since 2.9:	+2 -2 lines
Log Message:	Added grouping parens to reduce ambiguity warnings.
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	schorsch	2.10	static const char RCSid[] = "$Id: colrops.c,v 2.9 2003/06/30 19:04:29 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* Integer operations on COLR scanlines
6			*/
7
8	greg	2.7	#include "copyright.h"
9	greg	2.6
10	greg	2.9	#include <stdio.h>
11	greg	2.6	#include <math.h>
12	greg	1.1	#include "color.h"
13
14	greg	2.3	extern char *bmalloc();
15	greg	1.1
16	greg	2.3	#define MAXGSHIFT 31 /* maximum shift for gamma table */
17	greg	1.1
18	greg	2.3	static BYTE g_mant = NULL, g_nexp = NULL;
19	greg	1.1
20	greg	2.3	static BYTE (*g_bval)[256] = NULL;
21
22
23	greg	2.6	int
24	greg	2.3	setcolrcor(f, a2) /* set brightness correction */
25			double (*f)();
26			double a2;
27	greg	1.1	{
28			double mult;
29			register int i, j;
30	greg	2.3	/* allocate tables */
31			if (g_bval == NULL && (g_bval =
32			(BYTE ()[256])bmalloc((MAXGSHIFT+1)256)) == NULL)
33			return(-1);
34	greg	1.1	/* compute colr -> gamb mapping */
35	greg	2.3	mult = 1.0/256.0;
36	greg	1.1	for (i = 0; i <= MAXGSHIFT; i++) {
37			for (j = 0; j < 256; j++)
38	greg	2.3	g_bval[i][j] = 256.0 * (f)((j+.5)mult, a2);
39			mult *= 0.5;
40	greg	1.1	}
41	greg	2.3	return(0);
42			}
43
44
45	greg	2.6	int
46	greg	2.3	setcolrinv(f, a2) /* set inverse brightness correction */
47			double (*f)();
48			double a2;
49			{
50			double mult;
51			register int i, j;
52			/* allocate tables */
53			if (g_mant == NULL && (g_mant = (BYTE *)bmalloc(256)) == NULL)
54			return(-1);
55			if (g_nexp == NULL && (g_nexp = (BYTE *)bmalloc(256)) == NULL)
56			return(-1);
57	greg	1.1	/* compute gamb -> colr mapping */
58			i = 0;
59			mult = 256.0;
60	gregl	2.5	for (j = 256; j--; ) {
61			while ((g_mant[j] = mult * (*f)((j+.5)/256.0, a2)) < 128) {
62	greg	1.1	i++;
63			mult *= 2.0;
64			}
65			g_nexp[j] = i;
66			}
67	greg	2.3	return(0);
68	greg	1.1	}
69
70
71	greg	2.6	int
72	greg	2.3	setcolrgam(g) /* set gamma conversion */
73			double g;
74			{
75			if (setcolrcor(pow, 1.0/g) < 0)
76			return(-1);
77			return(setcolrinv(pow, g));
78			}
79
80
81	greg	2.6	int
82	greg	1.1	colrs_gambs(scan, len) /* convert scanline of colrs to gamma bytes */
83			register COLR *scan;
84			int len;
85			{
86			register int i, expo;
87
88	greg	2.3	if (g_bval == NULL)
89			return(-1);
90	greg	1.1	while (len-- > 0) {
91			expo = scan[0][EXP] - COLXS;
92			if (expo < -MAXGSHIFT) {
93			if (expo < -MAXGSHIFT-8) {
94			scan[0][RED] =
95			scan[0][GRN] =
96			scan[0][BLU] = 0;
97			} else {
98			i = (-MAXGSHIFT-1) - expo;
99			scan[0][RED] =
100			g_bval[MAXGSHIFT][((scan[0][RED]>>i)+1)>>1];
101			scan[0][GRN] =
102			g_bval[MAXGSHIFT][((scan[0][GRN]>>i)+1)>>1];
103			scan[0][BLU] =
104			g_bval[MAXGSHIFT][((scan[0][BLU]>>i)+1)>>1];
105			}
106			} else if (expo > 0) {
107			if (expo > 8) {
108			scan[0][RED] =
109			scan[0][GRN] =
110			scan[0][BLU] = 255;
111			} else {
112			i = (scan[0][RED]<<1 \| 1) << (expo-1);
113			scan[0][RED] = i > 255 ? 255 : g_bval[0][i];
114			i = (scan[0][GRN]<<1 \| 1) << (expo-1);
115			scan[0][GRN] = i > 255 ? 255 : g_bval[0][i];
116			i = (scan[0][BLU]<<1 \| 1) << (expo-1);
117			scan[0][BLU] = i > 255 ? 255 : g_bval[0][i];
118			}
119			} else {
120			scan[0][RED] = g_bval[-expo][scan[0][RED]];
121			scan[0][GRN] = g_bval[-expo][scan[0][GRN]];
122			scan[0][BLU] = g_bval[-expo][scan[0][BLU]];
123			}
124			scan[0][EXP] = COLXS;
125			scan++;
126			}
127	greg	2.3	return(0);
128	greg	1.1	}
129
130
131	greg	2.6	int
132	greg	1.1	gambs_colrs(scan, len) /* convert gamma bytes to colr scanline */
133			register COLR *scan;
134			int len;
135			{
136			register int nexpo;
137
138	schorsch	2.10	if ((g_mant == NULL) \| (g_nexp == NULL))
139	greg	2.3	return(-1);
140	greg	1.1	while (len-- > 0) {
141			nexpo = g_nexp[scan[0][RED]];
142			if (g_nexp[scan[0][GRN]] < nexpo)
143			nexpo = g_nexp[scan[0][GRN]];
144			if (g_nexp[scan[0][BLU]] < nexpo)
145			nexpo = g_nexp[scan[0][BLU]];
146			if (nexpo < g_nexp[scan[0][RED]])
147			scan[0][RED] = g_mant[scan[0][RED]]
148			>> (g_nexp[scan[0][RED]]-nexpo);
149			else
150			scan[0][RED] = g_mant[scan[0][RED]];
151			if (nexpo < g_nexp[scan[0][GRN]])
152			scan[0][GRN] = g_mant[scan[0][GRN]]
153			>> (g_nexp[scan[0][GRN]]-nexpo);
154			else
155			scan[0][GRN] = g_mant[scan[0][GRN]];
156			if (nexpo < g_nexp[scan[0][BLU]])
157			scan[0][BLU] = g_mant[scan[0][BLU]]
158			>> (g_nexp[scan[0][BLU]]-nexpo);
159			else
160			scan[0][BLU] = g_mant[scan[0][BLU]];
161			scan[0][EXP] = COLXS - nexpo;
162			scan++;
163			}
164	greg	2.3	return(0);
165	greg	1.1	}
166
167
168	greg	2.6	void
169	greg	1.1	shiftcolrs(scan, len, adjust) /* shift a scanline of colors by 2^adjust */
170			register COLR *scan;
171			register int len;
172			register int adjust;
173			{
174	greg	2.2	int minexp;
175
176			if (adjust == 0)
177			return;
178			minexp = adjust < 0 ? -adjust : 0;
179	greg	1.1	while (len-- > 0) {
180	greg	2.2	if (scan[0][EXP] <= minexp)
181			scan[0][RED] = scan[0][GRN] = scan[0][BLU] =
182			scan[0][EXP] = 0;
183			else
184			scan[0][EXP] += adjust;
185	greg	1.1	scan++;
186			}
187			}
188
189
190	greg	2.6	void
191	greg	1.1	normcolrs(scan, len, adjust) /* normalize a scanline of colrs */
192			register COLR *scan;
193			int len;
194			int adjust;
195			{
196			register int c;
197			register int shift;
198
199			while (len-- > 0) {
200			shift = scan[0][EXP] + adjust - COLXS;
201			if (shift > 0) {
202			if (shift > 8) {
203			scan[0][RED] =
204			scan[0][GRN] =
205			scan[0][BLU] = 255;
206			} else {
207			shift--;
208			c = (scan[0][RED]<<1 \| 1) << shift;
209			scan[0][RED] = c > 255 ? 255 : c;
210			c = (scan[0][GRN]<<1 \| 1) << shift;
211			scan[0][GRN] = c > 255 ? 255 : c;
212			c = (scan[0][BLU]<<1 \| 1) << shift;
213			scan[0][BLU] = c > 255 ? 255 : c;
214			}
215			} else if (shift < 0) {
216			if (shift < -8) {
217			scan[0][RED] =
218			scan[0][GRN] =
219			scan[0][BLU] = 0;
220			} else {
221			shift = -1-shift;
222			scan[0][RED] = ((scan[0][RED]>>shift)+1)>>1;
223			scan[0][GRN] = ((scan[0][GRN]>>shift)+1)>>1;
224			scan[0][BLU] = ((scan[0][BLU]>>shift)+1)>>1;
225			}
226			}
227			scan[0][EXP] = COLXS - adjust;
228			scan++;
229			}
230			}