src/common/colrops.c

#ifndef lint
static const char       RCSid[] = "$Id: colrops.c,v 2.10 2003/07/27 22:12:01 schorsch Exp $";
#endif
/*
 * Integer operations on COLR scanlines
 */

#include "copyright.h"

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

#include "rtmisc.h"
#include "color.h"


#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,double);
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,double);
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:	2.11
Committed:	Wed Jul 30 10:11:06 2003 UTC (20 years, 9 months ago) by schorsch
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R7P2, rad3R7P1, rad4R0, rad3R6, rad3R6P1, rad3R8, rad3R9
Changes since 2.10:	+5 -4 lines
Log Message:	Added prototypes submitted by Randolph Fritz.
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	schorsch	2.11	static const char RCSid[] = "$Id: colrops.c,v 2.10 2003/07/27 22:12:01 schorsch 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	schorsch	2.11
13			#include "rtmisc.h"
14	greg	1.1	#include "color.h"
15
16
17	greg	2.3	#define MAXGSHIFT 31 /* maximum shift for gamma table */
18	greg	1.1
19	greg	2.3	static BYTE g_mant = NULL, g_nexp = NULL;
20	greg	1.1
21	greg	2.3	static BYTE (*g_bval)[256] = NULL;
22
23
24	greg	2.6	int
25	greg	2.3	setcolrcor(f, a2) /* set brightness correction */
26	schorsch	2.11	double (*f)(double,double);
27	greg	2.3	double a2;
28	greg	1.1	{
29			double mult;
30			register int i, j;
31	greg	2.3	/* allocate tables */
32			if (g_bval == NULL && (g_bval =
33			(BYTE ()[256])bmalloc((MAXGSHIFT+1)256)) == NULL)
34			return(-1);
35	greg	1.1	/* compute colr -> gamb mapping */
36	greg	2.3	mult = 1.0/256.0;
37	greg	1.1	for (i = 0; i <= MAXGSHIFT; i++) {
38			for (j = 0; j < 256; j++)
39	greg	2.3	g_bval[i][j] = 256.0 * (f)((j+.5)mult, a2);
40			mult *= 0.5;
41	greg	1.1	}
42	greg	2.3	return(0);
43			}
44
45
46	greg	2.6	int
47	greg	2.3	setcolrinv(f, a2) /* set inverse brightness correction */
48	schorsch	2.11	double (*f)(double,double);
49	greg	2.3	double a2;
50			{
51			double mult;
52			register int i, j;
53			/* allocate tables */
54			if (g_mant == NULL && (g_mant = (BYTE *)bmalloc(256)) == NULL)
55			return(-1);
56			if (g_nexp == NULL && (g_nexp = (BYTE *)bmalloc(256)) == NULL)
57			return(-1);
58	greg	1.1	/* compute gamb -> colr mapping */
59			i = 0;
60			mult = 256.0;
61	gregl	2.5	for (j = 256; j--; ) {
62			while ((g_mant[j] = mult * (*f)((j+.5)/256.0, a2)) < 128) {
63	greg	1.1	i++;
64			mult *= 2.0;
65			}
66			g_nexp[j] = i;
67			}
68	greg	2.3	return(0);
69	greg	1.1	}
70
71
72	greg	2.6	int
73	greg	2.3	setcolrgam(g) /* set gamma conversion */
74			double g;
75			{
76			if (setcolrcor(pow, 1.0/g) < 0)
77			return(-1);
78			return(setcolrinv(pow, g));
79			}
80
81
82	greg	2.6	int
83	greg	1.1	colrs_gambs(scan, len) /* convert scanline of colrs to gamma bytes */
84			register COLR *scan;
85			int len;
86			{
87			register int i, expo;
88
89	greg	2.3	if (g_bval == NULL)
90			return(-1);
91	greg	1.1	while (len-- > 0) {
92			expo = scan[0][EXP] - COLXS;
93			if (expo < -MAXGSHIFT) {
94			if (expo < -MAXGSHIFT-8) {
95			scan[0][RED] =
96			scan[0][GRN] =
97			scan[0][BLU] = 0;
98			} else {
99			i = (-MAXGSHIFT-1) - expo;
100			scan[0][RED] =
101			g_bval[MAXGSHIFT][((scan[0][RED]>>i)+1)>>1];
102			scan[0][GRN] =
103			g_bval[MAXGSHIFT][((scan[0][GRN]>>i)+1)>>1];
104			scan[0][BLU] =
105			g_bval[MAXGSHIFT][((scan[0][BLU]>>i)+1)>>1];
106			}
107			} else if (expo > 0) {
108			if (expo > 8) {
109			scan[0][RED] =
110			scan[0][GRN] =
111			scan[0][BLU] = 255;
112			} else {
113			i = (scan[0][RED]<<1 \| 1) << (expo-1);
114			scan[0][RED] = i > 255 ? 255 : g_bval[0][i];
115			i = (scan[0][GRN]<<1 \| 1) << (expo-1);
116			scan[0][GRN] = i > 255 ? 255 : g_bval[0][i];
117			i = (scan[0][BLU]<<1 \| 1) << (expo-1);
118			scan[0][BLU] = i > 255 ? 255 : g_bval[0][i];
119			}
120			} else {
121			scan[0][RED] = g_bval[-expo][scan[0][RED]];
122			scan[0][GRN] = g_bval[-expo][scan[0][GRN]];
123			scan[0][BLU] = g_bval[-expo][scan[0][BLU]];
124			}
125			scan[0][EXP] = COLXS;
126			scan++;
127			}
128	greg	2.3	return(0);
129	greg	1.1	}
130
131
132	greg	2.6	int
133	greg	1.1	gambs_colrs(scan, len) /* convert gamma bytes to colr scanline */
134			register COLR *scan;
135			int len;
136			{
137			register int nexpo;
138
139	schorsch	2.10	if ((g_mant == NULL) \| (g_nexp == NULL))
140	greg	2.3	return(-1);
141	greg	1.1	while (len-- > 0) {
142			nexpo = g_nexp[scan[0][RED]];
143			if (g_nexp[scan[0][GRN]] < nexpo)
144			nexpo = g_nexp[scan[0][GRN]];
145			if (g_nexp[scan[0][BLU]] < nexpo)
146			nexpo = g_nexp[scan[0][BLU]];
147			if (nexpo < g_nexp[scan[0][RED]])
148			scan[0][RED] = g_mant[scan[0][RED]]
149			>> (g_nexp[scan[0][RED]]-nexpo);
150			else
151			scan[0][RED] = g_mant[scan[0][RED]];
152			if (nexpo < g_nexp[scan[0][GRN]])
153			scan[0][GRN] = g_mant[scan[0][GRN]]
154			>> (g_nexp[scan[0][GRN]]-nexpo);
155			else
156			scan[0][GRN] = g_mant[scan[0][GRN]];
157			if (nexpo < g_nexp[scan[0][BLU]])
158			scan[0][BLU] = g_mant[scan[0][BLU]]
159			>> (g_nexp[scan[0][BLU]]-nexpo);
160			else
161			scan[0][BLU] = g_mant[scan[0][BLU]];
162			scan[0][EXP] = COLXS - nexpo;
163			scan++;
164			}
165	greg	2.3	return(0);
166	greg	1.1	}
167
168
169	greg	2.6	void
170	greg	1.1	shiftcolrs(scan, len, adjust) /* shift a scanline of colors by 2^adjust */
171			register COLR *scan;
172			register int len;
173			register int adjust;
174			{
175	greg	2.2	int minexp;
176
177			if (adjust == 0)
178			return;
179			minexp = adjust < 0 ? -adjust : 0;
180	greg	1.1	while (len-- > 0) {
181	greg	2.2	if (scan[0][EXP] <= minexp)
182			scan[0][RED] = scan[0][GRN] = scan[0][BLU] =
183			scan[0][EXP] = 0;
184			else
185			scan[0][EXP] += adjust;
186	greg	1.1	scan++;
187			}
188			}
189
190
191	greg	2.6	void
192	greg	1.1	normcolrs(scan, len, adjust) /* normalize a scanline of colrs */
193			register COLR *scan;
194			int len;
195			int adjust;
196			{
197			register int c;
198			register int shift;
199
200			while (len-- > 0) {
201			shift = scan[0][EXP] + adjust - COLXS;
202			if (shift > 0) {
203			if (shift > 8) {
204			scan[0][RED] =
205			scan[0][GRN] =
206			scan[0][BLU] = 255;
207			} else {
208			shift--;
209			c = (scan[0][RED]<<1 \| 1) << shift;
210			scan[0][RED] = c > 255 ? 255 : c;
211			c = (scan[0][GRN]<<1 \| 1) << shift;
212			scan[0][GRN] = c > 255 ? 255 : c;
213			c = (scan[0][BLU]<<1 \| 1) << shift;
214			scan[0][BLU] = c > 255 ? 255 : c;
215			}
216			} else if (shift < 0) {
217			if (shift < -8) {
218			scan[0][RED] =
219			scan[0][GRN] =
220			scan[0][BLU] = 0;
221			} else {
222			shift = -1-shift;
223			scan[0][RED] = ((scan[0][RED]>>shift)+1)>>1;
224			scan[0][GRN] = ((scan[0][GRN]>>shift)+1)>>1;
225			scan[0][BLU] = ((scan[0][BLU]>>shift)+1)>>1;
226			}
227			}
228			scan[0][EXP] = COLXS - adjust;
229			scan++;
230			}
231			}