src/px/pf3.c

#ifndef lint
static const char RCSid[] = "$Id: pf3.c,v 2.20 2023/12/07 21:15:54 greg Exp $";
#endif
/*
 *  pf3.c - routines for gaussian and box filtering
 *
 *     8/13/86
 */

#include  "pfilt.h"

#define  RSCA           1.13    /* square-radius multiplier: sqrt(4/PI) */
#define  TEPS           0.2     /* threshold proximity goal */
#define  REPS           0.1     /* radius proximity goal */

float  *gausstable;             /* gauss lookup table */

float  *ringsum;                /* sum of ring values */
short  *ringwt;                 /* weight (count) of ring values */
short  *ringndx;                /* ring index table */
float  *warr;                   /* array of pixel weights */

#define  lookgauss(x)           gausstable[(int)(20.*(x)+.5)]

static double pickfilt(double  p0);
static void sumans(int  px, int  py, int  rcent, int  ccent, double  m);


void
initmask(void)                  /* initialize gaussian lookup table */
{
        int  gtabsiz;
        double  gaussN;
        double  d;
        int  x;

        gtabsiz = 444*CHECKRAD*CHECKRAD;
        gausstable = (float *)malloc(gtabsiz*sizeof(float));
        if (gausstable == NULL)
                goto memerr;
        d = x_c*y_r*0.25/(rad*rad);
        gausstable[0] = exp(-d);
        for (x = 1; x < gtabsiz; x++)
                if (x*0.05 <= d)
                        gausstable[x] = gausstable[0];
                else
                        gausstable[x] = exp(-x*0.05);
        if (obarsize == 0)
                return;
                                        /* compute integral of filter */
        gaussN = PI*d*exp(-d);                  /* plateau */
        for (d = sqrt(d)+0.05; d <= RSCA*CHECKRAD; d += 0.1)
                gaussN += 0.1*2.0*PI*d*exp(-d*d);
                                        /* normalize filter */
        gaussN = x_c*y_r/(rad*rad*gaussN);
        for (x = 0; x < gtabsiz; x++)
                gausstable[x] *= gaussN;
                                        /* create ring averages table */
        ringndx = (short *)malloc((2*orad*orad+1)*sizeof(short));
        if (ringndx == NULL)
                goto memerr;
        for (x = 2*orad*orad+1; --x > orad*orad; )
                ringndx[x] = -1;
        do
                ringndx[x] = sqrt((double)x);
        while (x--);
        ringsum = (float *)malloc((orad+1)*sizeof(float));
        ringwt = (short *)malloc((orad+1)*sizeof(short));
        warr = (float *)malloc(obarsize*obarsize*sizeof(float));
        if ((ringsum == NULL) | (ringwt == 0) | (warr == NULL))
                goto memerr;
        return;
memerr:
        fprintf(stderr, "%s: out of memory in initmask\n", progname);
        quit(1);
}


void
dobox(                  /* simple box filter */
        SCOLOR  csum,
        int  xcent,
        int  ycent,
        int  c,
        int  r
)
{
        int  wsum;
        double  d;
        int  y;
        int  x, offs;
        COLORV  *scan, *scp;
        
        wsum = 0;
        scolorblack(csum);
        for (y = ycent+1-ybrad; y <= ycent+ybrad; y++) {
                if (y < 0) continue;
                if (y >= yres) break;
                d = y_r < 1.0 ? y_r*y - (r+.5) : (double)(y - ycent);
                if (d < -0.5) continue;
                if (d >= 0.5) break;
                scan = scanin[y%barsize];
                for (x = xcent+1-xbrad; x <= xcent+xbrad; x++) {
                        offs = x < 0 ? xres : x >= xres ? -xres : 0;
                        if (offs && !wrapfilt)
                                continue;
                        d = x_c < 1.0 ? x_c*x - (c+.5) : (double)(x - xcent);
                        if (d < -0.5) continue;
                        if (d >= 0.5) break;
                        wsum++;
                        scp = scan + (x+offs)*NCSAMP;
                        saddscolor(csum, scp);
                }
        }
        if (wsum > 1) {
                d = 1.0/wsum;
                scalescolor(csum, d);
        }
}


void
dogauss(                /* gaussian filter */
        SCOLOR  csum,
        int  xcent,
        int  ycent,
        int  c,
        int  r
)
{
        double  dy, dx, weight, wsum;
        SCOLOR  ctmp;
        int  y;
        int  x, offs;
        COLORV  *scan;

        wsum = FTINY;
        scolorblack(csum);
        for (y = ycent-yrad; y <= ycent+yrad; y++) {
                if (y < 0) continue;
                if (y >= yres) break;
                dy = (y_r*(y+.5) - (r+.5))/rad;
                scan = scanin[y%barsize];
                for (x = xcent-xrad; x <= xcent+xrad; x++) {
                        offs = x < 0 ? xres : x >= xres ? -xres : 0;
                        if (offs && !wrapfilt)
                                continue;
                        dx = (x_c*(x+.5) - (c+.5))/rad;
                        weight = lookgauss(dx*dx + dy*dy);
                        wsum += weight;
                        copyscolor(ctmp, scan+(x+offs)*NCSAMP);
                        scalescolor(ctmp, weight);
                        saddscolor(csum, ctmp);
                }
        }
        weight = 1.0/wsum;
        scalescolor(csum, weight);
}


void
dothresh(       /* gaussian threshold filter */
        int  xcent,
        int  ycent,
        int  ccent,
        int  rcent
)
{
        double  d;
        int  r, y, offs;
        int  c, x;
        float  *gscan;
                                        /* compute ring sums */
        memset((char *)ringsum, '\0', (orad+1)*sizeof(float));
        memset((char *)ringwt, '\0', (orad+1)*sizeof(short));
        for (r = -orad; r <= orad; r++) {
                if (rcent+r < 0) continue;
                if (rcent+r >= nrows) break;
                gscan = greybar[(rcent+r)%obarsize];
                for (c = -orad; c <= orad; c++) {
                        offs = ccent+c < 0 ? ncols :
                                        ccent+c >= ncols ? -ncols : 0;
                        if (offs && !wrapfilt)
                                continue;
                        x = ringndx[c*c + r*r];
                        if (x < 0) continue;
                        ringsum[x] += gscan[ccent+c+offs];
                        ringwt[x]++;
                }
        }
                                        /* filter each subpixel */
        for (y = ycent+1-ybrad; y <= ycent+ybrad; y++) {
                if (y < 0) continue;
                if (y >= yres) break;
                d = y_r < 1.0 ? y_r*y - (rcent+.5) : (double)(y - ycent);
                if (d < -0.5) continue;
                if (d >= 0.5) break;
                for (x = xcent+1-xbrad; x <= xcent+xbrad; x++) {
                        offs = x < 0 ? xres : x >= xres ? -xres : 0;
                        if (offs && !wrapfilt)
                                continue;
                        d = x_c < 1.0 ? x_c*x - (ccent+.5) : (double)(x - xcent);
                        if (d < -0.5) continue;
                        if (d >= 0.5) break;
                        sumans(x, y, rcent, ccent,
                        pickfilt((*ourbright)(scanin[y%barsize]+(x+offs)*NCSAMP)));
                }
        }
}


static double
pickfilt(                       /* find filter multiplier for p0 */
        double  p0
)
{
        double  m = 1.0;
        double  t, num, denom, avg, wsum;
        double  mlimit[2];
        int  ilimit = 4.0/TEPS;
        int  i;
                                /* iterative search for m */
        mlimit[0] = 1.0; mlimit[1] = orad/rad/CHECKRAD;
        do {
                                        /* compute grey weighted average */
                i = RSCA*CHECKRAD*rad*m + .5;
                if (i > orad) i = orad;
                avg = wsum = 0.0;
                while (i--) {
                        t = (i+.5)/(m*rad);
                        t = lookgauss(t*t);
                        avg += t*ringsum[i];
                        wsum += t*ringwt[i];
                }
                if (avg < 1e-20)                /* zero inclusive average */
                        return(1.0);
                avg /= wsum;
                                        /* check threshold */
                denom = m*m/gausstable[0] - p0/avg;
                if (denom <= FTINY) {           /* zero exclusive average */
                        if (m >= mlimit[1]-REPS)
                                break;
                        m = mlimit[1];
                        continue;
                }
                num = p0/avg - 1.0;
                if (num < 0.0) num = -num;
                t = num/denom;
                if (t <= thresh) {
                        if (m <= mlimit[0]+REPS || (thresh-t)/thresh <= TEPS)
                                break;
                } else {
                        if (m >= mlimit[1]-REPS || (t-thresh)/thresh <= TEPS)
                                break;
                }
                t = m;                  /* remember current m */
                                        /* next guesstimate */
                m = sqrt(gausstable[0]*(num/thresh + p0/avg));
                if (m < t) {            /* bound it */
                        if (m <= mlimit[0]+FTINY)
                                m = 0.5*(mlimit[0] + t);
                        mlimit[1] = t;
                } else {
                        if (m >= mlimit[1]-FTINY)
                                m = 0.5*(mlimit[1] + t);
                        mlimit[0] = t;
                }
        } while (--ilimit > 0);
        return(m);
}


static void
sumans(         /* sum input pixel to output */
        int  px,
        int  py,
        int  rcent,
        int  ccent,
        double  m
)
{
        double  dy2, dx;
        SCOLOR  pval, ctmp;
        int  ksiz, r, offs;
        double  pc, pr, norm;
        int  i, c;
        COLORV  *scan, *scp;
        /*
         * This normalization method fails at the picture borders because
         * a different number of input pixels contribute there.
         */
        scan = scanin[py%barsize] + (px < 0 ? xres : px >= xres ? -xres : 0)*NCSAMP;
        copyscolor(pval, scan+px*NCSAMP);
        pc = x_c*(px+.5);
        pr = y_r*(py+.5);
        ksiz = CHECKRAD*m*rad + 1;
        if (ksiz > orad) ksiz = orad;
                                                /* compute normalization */
        norm = 0.0;
        i = 0;
        for (r = rcent-ksiz; r <= rcent+ksiz; r++) {
                if (r < 0) continue;
                if (r >= nrows) break;
                dy2 = (pr - (r+.5))/(m*rad);
                dy2 *= dy2;
                for (c = ccent-ksiz; c <= ccent+ksiz; c++) {
                        if (!wrapfilt) {
                                if (c < 0) continue;
                                if (c >= ncols) break;
                        }
                        dx = (pc - (c+.5))/(m*rad);
                        norm += warr[i++] = lookgauss(dx*dx + dy2);
                }
        }
        norm = 1.0/norm;
        if (x_c < 1.0) norm *= x_c;
        if (y_r < 1.0) norm *= y_r;
                                                /* sum pixels */
        i = 0;
        for (r = rcent-ksiz; r <= rcent+ksiz; r++) {
                if (r < 0) continue;
                if (r >= nrows) break;
                scan = scoutbar[r%obarsize];
                for (c = ccent-ksiz; c <= ccent+ksiz; c++) {
                        offs = c < 0 ? ncols : c >= ncols ? -ncols : 0;
                        if ((offs != 0) & !wrapfilt)
                                continue;
                        copyscolor(ctmp, pval);
                        dx = norm*warr[i++];
                        scalescolor(ctmp, dx);
                        scp = scan + (c+offs)*NCSAMP;
                        saddscolor(scp, ctmp);
                }
        }
}
Revision:	2.21
Committed:	Fri Dec 8 17:56:26 2023 UTC (16 months, 4 weeks ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.20:	+24 -22 lines
Log Message:	feat(pfilt): Added support for hyperspectral image filtering
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.21	static const char RCSid[] = "$Id: pf3.c,v 2.20 2023/12/07 21:15:54 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* pf3.c - routines for gaussian and box filtering
6			*
7			* 8/13/86
8			*/
9
10	schorsch	2.18	#include "pfilt.h"
11	greg	1.1
12	greg	2.14	#define RSCA 1.13 /* square-radius multiplier: sqrt(4/PI) */
13	greg	2.9	#define TEPS 0.2 /* threshold proximity goal */
14	greg	2.10	#define REPS 0.1 /* radius proximity goal */
15	greg	1.1
16	greg	2.5	float gausstable; / gauss lookup table */
17	greg	1.1
18	greg	2.7	float ringsum; / sum of ring values */
19			short ringwt; / weight (count) of ring values */
20			short ringndx; / ring index table */
21			float warr; / array of pixel weights */
22
23	greg	2.19	#define lookgauss(x) gausstable[(int)(20.*(x)+.5)]
24	greg	2.7
25	schorsch	2.18	static double pickfilt(double p0);
26			static void sumans(int px, int py, int rcent, int ccent, double m);
27	greg	1.1
28
29	greg	2.19	void
30	schorsch	2.18	initmask(void) /* initialize gaussian lookup table */
31	greg	1.1	{
32	greg	2.7	int gtabsiz;
33			double gaussN;
34	greg	2.5	double d;
35	greg	2.19	int x;
36	greg	1.1
37	greg	2.19	gtabsiz = 444CHECKRADCHECKRAD;
38	greg	2.7	gausstable = (float )malloc(gtabsizsizeof(float));
39			if (gausstable == NULL)
40			goto memerr;
41			d = x_cy_r0.25/(rad*rad);
42	greg	2.14	gausstable[0] = exp(-d);
43	greg	2.7	for (x = 1; x < gtabsiz; x++)
44	greg	2.19	if (x*0.05 <= d)
45	greg	2.5	gausstable[x] = gausstable[0];
46	greg	2.14	else
47	greg	2.19	gausstable[x] = exp(-x*0.05);
48	greg	2.7	if (obarsize == 0)
49			return;
50			/* compute integral of filter */
51	greg	2.14	gaussN = PIdexp(-d); /* plateau */
52			for (d = sqrt(d)+0.05; d <= RSCA*CHECKRAD; d += 0.1)
53			gaussN += 0.12.0PIdexp(-d*d);
54	greg	2.7	/* normalize filter */
55			gaussN = x_cy_r/(radrad*gaussN);
56			for (x = 0; x < gtabsiz; x++)
57			gausstable[x] *= gaussN;
58			/* create ring averages table */
59			ringndx = (short )malloc((2oradorad+1)sizeof(short));
60			if (ringndx == NULL)
61			goto memerr;
62			for (x = 2oradorad+1; --x > orad*orad; )
63			ringndx[x] = -1;
64			do
65	greg	2.8	ringndx[x] = sqrt((double)x);
66	greg	2.7	while (x--);
67			ringsum = (float )malloc((orad+1)sizeof(float));
68			ringwt = (short )malloc((orad+1)sizeof(short));
69			warr = (float )malloc(obarsizeobarsize*sizeof(float));
70	schorsch	2.17	if ((ringsum == NULL) \| (ringwt == 0) \| (warr == NULL))
71	greg	2.7	goto memerr;
72			return;
73			memerr:
74			fprintf(stderr, "%s: out of memory in initmask\n", progname);
75			quit(1);
76	greg	1.1	}
77
78
79	greg	2.19	void
80	schorsch	2.18	dobox( /* simple box filter */
81	greg	2.21	SCOLOR csum,
82	schorsch	2.18	int xcent,
83			int ycent,
84			int c,
85			int r
86			)
87	greg	1.1	{
88	greg	2.6	int wsum;
89			double d;
90			int y;
91	greg	2.19	int x, offs;
92	greg	2.21	COLORV scan, scp;
93	greg	2.7
94	greg	1.1	wsum = 0;
95	greg	2.21	scolorblack(csum);
96	greg	2.7	for (y = ycent+1-ybrad; y <= ycent+ybrad; y++) {
97	greg	2.4	if (y < 0) continue;
98			if (y >= yres) break;
99	greg	2.13	d = y_r < 1.0 ? y_r*y - (r+.5) : (double)(y - ycent);
100	greg	2.7	if (d < -0.5) continue;
101			if (d >= 0.5) break;
102	greg	1.1	scan = scanin[y%barsize];
103	greg	2.7	for (x = xcent+1-xbrad; x <= xcent+xbrad; x++) {
104	greg	2.12	offs = x < 0 ? xres : x >= xres ? -xres : 0;
105			if (offs && !wrapfilt)
106			continue;
107	greg	2.13	d = x_c < 1.0 ? x_c*x - (c+.5) : (double)(x - xcent);
108	greg	2.7	if (d < -0.5) continue;
109			if (d >= 0.5) break;
110	greg	1.1	wsum++;
111	greg	2.21	scp = scan + (x+offs)*NCSAMP;
112			saddscolor(csum, scp);
113	greg	1.1	}
114			}
115	greg	2.14	if (wsum > 1) {
116			d = 1.0/wsum;
117	greg	2.21	scalescolor(csum, d);
118	greg	2.14	}
119	greg	1.1	}
120
121
122	greg	2.19	void
123	schorsch	2.18	dogauss( /* gaussian filter */
124	greg	2.21	SCOLOR csum,
125	schorsch	2.18	int xcent,
126			int ycent,
127			int c,
128			int r
129			)
130	greg	1.1	{
131	greg	2.6	double dy, dx, weight, wsum;
132	greg	2.21	SCOLOR ctmp;
133	greg	2.6	int y;
134	greg	2.19	int x, offs;
135	greg	2.21	COLORV *scan;
136	greg	1.1
137			wsum = FTINY;
138	greg	2.21	scolorblack(csum);
139	greg	1.2	for (y = ycent-yrad; y <= ycent+yrad; y++) {
140	greg	2.4	if (y < 0) continue;
141			if (y >= yres) break;
142	greg	1.2	dy = (y_r*(y+.5) - (r+.5))/rad;
143	greg	1.1	scan = scanin[y%barsize];
144	greg	1.2	for (x = xcent-xrad; x <= xcent+xrad; x++) {
145	greg	2.12	offs = x < 0 ? xres : x >= xres ? -xres : 0;
146			if (offs && !wrapfilt)
147			continue;
148	greg	1.2	dx = (x_c*(x+.5) - (c+.5))/rad;
149	greg	2.6	weight = lookgauss(dxdx + dydy);
150	greg	1.1	wsum += weight;
151	greg	2.21	copyscolor(ctmp, scan+(x+offs)*NCSAMP);
152			scalescolor(ctmp, weight);
153			saddscolor(csum, ctmp);
154	greg	1.1	}
155			}
156	greg	2.14	weight = 1.0/wsum;
157	greg	2.21	scalescolor(csum, weight);
158	greg	2.7	}
159
160
161	greg	2.19	void
162	schorsch	2.18	dothresh( /* gaussian threshold filter */
163			int xcent,
164			int ycent,
165			int ccent,
166			int rcent
167			)
168	greg	2.7	{
169			double d;
170	greg	2.12	int r, y, offs;
171	greg	2.19	int c, x;
172			float *gscan;
173	greg	2.7	/* compute ring sums */
174	schorsch	2.16	memset((char )ringsum, '\0', (orad+1)sizeof(float));
175			memset((char )ringwt, '\0', (orad+1)sizeof(short));
176	greg	2.7	for (r = -orad; r <= orad; r++) {
177			if (rcent+r < 0) continue;
178	greg	2.8	if (rcent+r >= nrows) break;
179	greg	2.7	gscan = greybar[(rcent+r)%obarsize];
180			for (c = -orad; c <= orad; c++) {
181	greg	2.12	offs = ccent+c < 0 ? ncols :
182			ccent+c >= ncols ? -ncols : 0;
183			if (offs && !wrapfilt)
184			continue;
185	greg	2.7	x = ringndx[cc + rr];
186			if (x < 0) continue;
187	greg	2.12	ringsum[x] += gscan[ccent+c+offs];
188	greg	2.7	ringwt[x]++;
189			}
190			}
191			/* filter each subpixel */
192			for (y = ycent+1-ybrad; y <= ycent+ybrad; y++) {
193			if (y < 0) continue;
194			if (y >= yres) break;
195	greg	2.13	d = y_r < 1.0 ? y_r*y - (rcent+.5) : (double)(y - ycent);
196	greg	2.7	if (d < -0.5) continue;
197			if (d >= 0.5) break;
198			for (x = xcent+1-xbrad; x <= xcent+xbrad; x++) {
199	greg	2.12	offs = x < 0 ? xres : x >= xres ? -xres : 0;
200			if (offs && !wrapfilt)
201			continue;
202	greg	2.13	d = x_c < 1.0 ? x_c*x - (ccent+.5) : (double)(x - xcent);
203	greg	2.7	if (d < -0.5) continue;
204			if (d >= 0.5) break;
205	greg	2.12	sumans(x, y, rcent, ccent,
206	greg	2.21	pickfilt((ourbright)(scanin[y%barsize]+(x+offs)NCSAMP)));
207	greg	2.7	}
208			}
209			}
210
211
212	schorsch	2.18	static double
213			pickfilt( /* find filter multiplier for p0 */
214			double p0
215			)
216	greg	2.7	{
217			double m = 1.0;
218	greg	2.10	double t, num, denom, avg, wsum;
219			double mlimit[2];
220	greg	2.14	int ilimit = 4.0/TEPS;
221	greg	2.19	int i;
222	greg	2.7	/* iterative search for m */
223	greg	2.11	mlimit[0] = 1.0; mlimit[1] = orad/rad/CHECKRAD;
224	greg	2.7	do {
225			/* compute grey weighted average */
226	greg	2.14	i = RSCACHECKRADrad*m + .5;
227	greg	2.8	if (i > orad) i = orad;
228	greg	2.7	avg = wsum = 0.0;
229			while (i--) {
230	greg	2.8	t = (i+.5)/(m*rad);
231	greg	2.7	t = lookgauss(t*t);
232			avg += t*ringsum[i];
233			wsum += t*ringwt[i];
234			}
235	greg	2.10	if (avg < 1e-20) /* zero inclusive average */
236			return(1.0);
237	greg	2.7	avg /= wsum;
238			/* check threshold */
239	greg	2.10	denom = m*m/gausstable[0] - p0/avg;
240	greg	2.11	if (denom <= FTINY) { /* zero exclusive average */
241			if (m >= mlimit[1]-REPS)
242			break;
243			m = mlimit[1];
244			continue;
245			}
246	greg	2.10	num = p0/avg - 1.0;
247			if (num < 0.0) num = -num;
248			t = num/denom;
249			if (t <= thresh) {
250			if (m <= mlimit[0]+REPS \|\| (thresh-t)/thresh <= TEPS)
251			break;
252			} else {
253			if (m >= mlimit[1]-REPS \|\| (t-thresh)/thresh <= TEPS)
254			break;
255			}
256			t = m; /* remember current m */
257	greg	2.7	/* next guesstimate */
258	greg	2.10	m = sqrt(gausstable[0]*(num/thresh + p0/avg));
259			if (m < t) { /* bound it */
260			if (m <= mlimit[0]+FTINY)
261			m = 0.5*(mlimit[0] + t);
262			mlimit[1] = t;
263			} else {
264			if (m >= mlimit[1]-FTINY)
265			m = 0.5*(mlimit[1] + t);
266			mlimit[0] = t;
267			}
268	greg	2.7	} while (--ilimit > 0);
269			return(m);
270			}
271
272
273	schorsch	2.18	static void
274			sumans( /* sum input pixel to output */
275			int px,
276			int py,
277			int rcent,
278			int ccent,
279			double m
280			)
281	greg	2.7	{
282	greg	2.14	double dy2, dx;
283	greg	2.21	SCOLOR pval, ctmp;
284	greg	2.12	int ksiz, r, offs;
285	greg	2.7	double pc, pr, norm;
286	greg	2.19	int i, c;
287	greg	2.21	COLORV scan, scp;
288	greg	2.12	/*
289			* This normalization method fails at the picture borders because
290			* a different number of input pixels contribute there.
291			*/
292	greg	2.21	scan = scanin[py%barsize] + (px < 0 ? xres : px >= xres ? -xres : 0)*NCSAMP;
293			copyscolor(pval, scan+px*NCSAMP);
294	greg	2.7	pc = x_c*(px+.5);
295			pr = y_r*(py+.5);
296			ksiz = CHECKRADmrad + 1;
297			if (ksiz > orad) ksiz = orad;
298			/* compute normalization */
299			norm = 0.0;
300			i = 0;
301			for (r = rcent-ksiz; r <= rcent+ksiz; r++) {
302			if (r < 0) continue;
303			if (r >= nrows) break;
304	greg	2.14	dy2 = (pr - (r+.5))/(m*rad);
305			dy2 *= dy2;
306	greg	2.7	for (c = ccent-ksiz; c <= ccent+ksiz; c++) {
307	greg	2.12	if (!wrapfilt) {
308			if (c < 0) continue;
309			if (c >= ncols) break;
310			}
311	greg	2.7	dx = (pc - (c+.5))/(m*rad);
312	greg	2.14	norm += warr[i++] = lookgauss(dx*dx + dy2);
313	greg	2.7	}
314			}
315			norm = 1.0/norm;
316			if (x_c < 1.0) norm *= x_c;
317			if (y_r < 1.0) norm *= y_r;
318			/* sum pixels */
319			i = 0;
320			for (r = rcent-ksiz; r <= rcent+ksiz; r++) {
321			if (r < 0) continue;
322			if (r >= nrows) break;
323			scan = scoutbar[r%obarsize];
324			for (c = ccent-ksiz; c <= ccent+ksiz; c++) {
325	greg	2.12	offs = c < 0 ? ncols : c >= ncols ? -ncols : 0;
326	greg	2.19	if ((offs != 0) & !wrapfilt)
327	greg	2.12	continue;
328	greg	2.21	copyscolor(ctmp, pval);
329	greg	2.7	dx = norm*warr[i++];
330	greg	2.21	scalescolor(ctmp, dx);
331			scp = scan + (c+offs)*NCSAMP;
332			saddscolor(scp, ctmp);
333	greg	2.7	}
334			}
335	greg	1.1	}