src/common/colrops.c

/* Copyright (c) 1992 Regents of the University of California */

#ifndef lint
static char SCCSid[] = "$SunId$ LBL";
#endif

/*
 * Integer operations on COLR scanlines
 */

#include "color.h"

#define NULL            0

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;

#ifndef pow
extern double   pow();
#endif


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);
}


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 = 255; j > 0; j--) {
                while ((g_mant[j] = mult * (*f)(j/256.0, a2)) < 128) {
                        i++;
                        mult *= 2.0;
                }
                g_nexp[j] = i;
        }
        g_mant[0] = 0;
        g_nexp[0] = COLXS;
        return(0);
}


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


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);
}


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);
}


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++;
        }
}


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:	2.4
Committed:	Fri Oct 2 16:00:51 1992 UTC (31 years, 7 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.3:	+2 -0 lines
Log Message:	Removed problematic math function declarations
#	User	Rev	Content
1	greg	2.3	/* Copyright (c) 1992 Regents of the University of California */
2	greg	1.1
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* Integer operations on COLR scanlines
9			*/
10
11			#include "color.h"
12
13	greg	2.3	#define NULL 0
14	greg	1.1
15	greg	2.3	extern char *bmalloc();
16	greg	1.1
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	greg	2.4	#ifndef pow
24	greg	2.3	extern double pow();
25	greg	2.4	#endif
26	greg	2.3
27
28			setcolrcor(f, a2) /* set brightness correction */
29			double (*f)();
30			double a2;
31	greg	1.1	{
32			double mult;
33			register int i, j;
34	greg	2.3	/* allocate tables */
35			if (g_bval == NULL && (g_bval =
36			(BYTE ()[256])bmalloc((MAXGSHIFT+1)256)) == NULL)
37			return(-1);
38	greg	1.1	/* compute colr -> gamb mapping */
39	greg	2.3	mult = 1.0/256.0;
40	greg	1.1	for (i = 0; i <= MAXGSHIFT; i++) {
41			for (j = 0; j < 256; j++)
42	greg	2.3	g_bval[i][j] = 256.0 * (f)((j+.5)mult, a2);
43			mult *= 0.5;
44	greg	1.1	}
45	greg	2.3	return(0);
46			}
47
48
49			setcolrinv(f, a2) /* set inverse brightness correction */
50			double (*f)();
51			double a2;
52			{
53			double mult;
54			register int i, j;
55			/* allocate tables */
56			if (g_mant == NULL && (g_mant = (BYTE *)bmalloc(256)) == NULL)
57			return(-1);
58			if (g_nexp == NULL && (g_nexp = (BYTE *)bmalloc(256)) == NULL)
59			return(-1);
60	greg	1.1	/* compute gamb -> colr mapping */
61			i = 0;
62			mult = 256.0;
63	greg	1.2	for (j = 255; j > 0; j--) {
64	greg	2.3	while ((g_mant[j] = mult * (*f)(j/256.0, a2)) < 128) {
65	greg	1.1	i++;
66			mult *= 2.0;
67			}
68			g_nexp[j] = i;
69			}
70	greg	1.2	g_mant[0] = 0;
71			g_nexp[0] = COLXS;
72	greg	2.3	return(0);
73	greg	1.1	}
74
75
76	greg	2.3	setcolrgam(g) /* set gamma conversion */
77			double g;
78			{
79			if (setcolrcor(pow, 1.0/g) < 0)
80			return(-1);
81			return(setcolrinv(pow, g));
82			}
83
84
85	greg	1.1	colrs_gambs(scan, len) /* convert scanline of colrs to gamma bytes */
86			register COLR *scan;
87			int len;
88			{
89			register int i, expo;
90
91	greg	2.3	if (g_bval == NULL)
92			return(-1);
93	greg	1.1	while (len-- > 0) {
94			expo = scan[0][EXP] - COLXS;
95			if (expo < -MAXGSHIFT) {
96			if (expo < -MAXGSHIFT-8) {
97			scan[0][RED] =
98			scan[0][GRN] =
99			scan[0][BLU] = 0;
100			} else {
101			i = (-MAXGSHIFT-1) - expo;
102			scan[0][RED] =
103			g_bval[MAXGSHIFT][((scan[0][RED]>>i)+1)>>1];
104			scan[0][GRN] =
105			g_bval[MAXGSHIFT][((scan[0][GRN]>>i)+1)>>1];
106			scan[0][BLU] =
107			g_bval[MAXGSHIFT][((scan[0][BLU]>>i)+1)>>1];
108			}
109			} else if (expo > 0) {
110			if (expo > 8) {
111			scan[0][RED] =
112			scan[0][GRN] =
113			scan[0][BLU] = 255;
114			} else {
115			i = (scan[0][RED]<<1 \| 1) << (expo-1);
116			scan[0][RED] = i > 255 ? 255 : g_bval[0][i];
117			i = (scan[0][GRN]<<1 \| 1) << (expo-1);
118			scan[0][GRN] = i > 255 ? 255 : g_bval[0][i];
119			i = (scan[0][BLU]<<1 \| 1) << (expo-1);
120			scan[0][BLU] = i > 255 ? 255 : g_bval[0][i];
121			}
122			} else {
123			scan[0][RED] = g_bval[-expo][scan[0][RED]];
124			scan[0][GRN] = g_bval[-expo][scan[0][GRN]];
125			scan[0][BLU] = g_bval[-expo][scan[0][BLU]];
126			}
127			scan[0][EXP] = COLXS;
128			scan++;
129			}
130	greg	2.3	return(0);
131	greg	1.1	}
132
133
134			gambs_colrs(scan, len) /* convert gamma bytes to colr scanline */
135			register COLR *scan;
136			int len;
137			{
138			register int nexpo;
139
140	greg	2.3	if (g_mant == NULL \| g_nexp == NULL)
141			return(-1);
142	greg	1.1	while (len-- > 0) {
143			nexpo = g_nexp[scan[0][RED]];
144			if (g_nexp[scan[0][GRN]] < nexpo)
145			nexpo = g_nexp[scan[0][GRN]];
146			if (g_nexp[scan[0][BLU]] < nexpo)
147			nexpo = g_nexp[scan[0][BLU]];
148			if (nexpo < g_nexp[scan[0][RED]])
149			scan[0][RED] = g_mant[scan[0][RED]]
150			>> (g_nexp[scan[0][RED]]-nexpo);
151			else
152			scan[0][RED] = g_mant[scan[0][RED]];
153			if (nexpo < g_nexp[scan[0][GRN]])
154			scan[0][GRN] = g_mant[scan[0][GRN]]
155			>> (g_nexp[scan[0][GRN]]-nexpo);
156			else
157			scan[0][GRN] = g_mant[scan[0][GRN]];
158			if (nexpo < g_nexp[scan[0][BLU]])
159			scan[0][BLU] = g_mant[scan[0][BLU]]
160			>> (g_nexp[scan[0][BLU]]-nexpo);
161			else
162			scan[0][BLU] = g_mant[scan[0][BLU]];
163			scan[0][EXP] = COLXS - nexpo;
164			scan++;
165			}
166	greg	2.3	return(0);
167	greg	1.1	}
168
169
170			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			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			}