src/px/pf3.c

/* Copyright (c) 1986 Regents of the University of California */

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

/*
 *  pf3.c - routines for gaussian and box filtering
 *
 *     8/13/86
 */

#include  <stdio.h>

#include  "color.h"

#define  FTINY          1e-7

extern double  rad;             /* output pixel radius for filtering */

extern int  nrows;              /* number of rows for output */
extern int  ncols;              /* number of columns for output */

extern int  boxfilt;            /* do box filtering? */

extern int  xres, yres;         /* resolution of input */

extern double  x_c, y_r;        /* conversion factors */

extern int  xrad;               /* x window size */
extern int  yrad;               /* y window size */

extern int  barsize;            /* size of input scan bar */
extern COLOR  **scanin;         /* input scan bar */
extern COLOR  *scanout;         /* output scan line */

extern char  *progname;

float  *exptable;               /* exponent table */

#define  lookexp(x)             exptable[(int)(-10.*(x)+.5)]


initmask()                      /* initialize gaussian lookup table */
{
        extern char  *malloc();
        extern double  exp();
        register int  x;

        exptable = (float *)malloc(100*sizeof(float));
        if (exptable == NULL) {
                fprintf(stderr, "%s: out of memory in initmask\n", progname);
                quit(1);
        }
        for (x = 0; x < 100; x++)
                exptable[x] = exp(-x*0.1);
}


dobox(csum, xcent, ycent, c, r)                 /* simple box filter */
COLOR  csum;
int  xcent, ycent;
int  c, r;
{
        static int  wsum;
        static double  d;
        static int  y;
        register int  x;
        register COLOR  *scan;

        wsum = 0;
        setcolor(csum, 0.0, 0.0, 0.0);
        for (y = ycent+1-yrad; y <= ycent+yrad; y++) {
                if (y < 0 || y >= yres)
                        continue;
                d = y_r < 1.0 ? y_r*y - r : y - ycent;
                if (d > 0.5+FTINY || d < -0.5-FTINY)
                        continue;
                scan = scanin[y%barsize];
                for (x = xcent+1-xrad; x <= xcent+xrad; x++) {
                        if (x < 0 || x >= xres)
                                continue;
                        d = x_c < 1.0 ? x_c*x - c : x - xcent;
                        if (d > 0.5+FTINY || d < -0.5-FTINY)
                                continue;
                        wsum++;
                        addcolor(csum, scan[x]);
                }
        }
        if (wsum > 1)
                scalecolor(csum, 1.0/wsum);
}


dogauss(csum, xcent, ycent, c, r)               /* gaussian filter */
COLOR  csum;
int  xcent, ycent;
int  c, r;
{
        static double  dy, dx, weight, wsum;
        static COLOR  ctmp;
        static int  y;
        register int  x;
        register COLOR  *scan;

        wsum = FTINY;
        setcolor(csum, 0.0, 0.0, 0.0);
        for (y = ycent-yrad; y <= ycent+yrad; y++) {
                if (y < 0 || y >= yres)
                        continue;
                dy = (y_r*(y+.5) - (r+.5))/rad;
                scan = scanin[y%barsize];
                for (x = xcent-xrad; x <= xcent+xrad; x++) {
                        if (x < 0 || x >= xres)
                                continue;
                        dx = (x_c*(x+.5) - (c+.5))/rad;
                        weight = lookexp(-(dx*dx + dy*dy));
                        wsum += weight;
                        copycolor(ctmp, scan[x]);
                        scalecolor(ctmp, weight);
                        addcolor(csum, ctmp);
                }
        }
        scalecolor(csum, 1.0/wsum);
}
Revision:	2.1
Committed:	Tue Nov 12 16:05:26 1991 UTC (33 years, 11 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+0 -0 lines
Log Message:	updated revision number for release 2.0
#	User	Rev	Content
1	greg	1.1	/* Copyright (c) 1986 Regents of the University of California */
2
3			#ifndef lint
4			static char SCCSid[] = "$SunId$ LBL";
5			#endif
6
7			/*
8			* pf3.c - routines for gaussian and box filtering
9			*
10			* 8/13/86
11			*/
12
13			#include <stdio.h>
14
15			#include "color.h"
16
17			#define FTINY 1e-7
18
19			extern double rad; /* output pixel radius for filtering */
20
21			extern int nrows; /* number of rows for output */
22			extern int ncols; /* number of columns for output */
23
24			extern int boxfilt; /* do box filtering? */
25
26			extern int xres, yres; /* resolution of input */
27
28			extern double x_c, y_r; /* conversion factors */
29
30			extern int xrad; /* x window size */
31			extern int yrad; /* y window size */
32
33			extern int barsize; /* size of input scan bar */
34			extern COLOR *scanin; / input scan bar */
35			extern COLOR scanout; / output scan line */
36
37			extern char *progname;
38
39			float exptable; / exponent table */
40
41			#define lookexp(x) exptable[(int)(-10.*(x)+.5)]
42
43
44			initmask() /* initialize gaussian lookup table */
45			{
46			extern char *malloc();
47			extern double exp();
48			register int x;
49
50			exptable = (float )malloc(100sizeof(float));
51			if (exptable == NULL) {
52			fprintf(stderr, "%s: out of memory in initmask\n", progname);
53			quit(1);
54			}
55			for (x = 0; x < 100; x++)
56			exptable[x] = exp(-x*0.1);
57			}
58
59
60			dobox(csum, xcent, ycent, c, r) /* simple box filter */
61			COLOR csum;
62			int xcent, ycent;
63			int c, r;
64			{
65			static int wsum;
66			static double d;
67			static int y;
68			register int x;
69			register COLOR *scan;
70
71			wsum = 0;
72			setcolor(csum, 0.0, 0.0, 0.0);
73			for (y = ycent+1-yrad; y <= ycent+yrad; y++) {
74			if (y < 0 \|\| y >= yres)
75			continue;
76			d = y_r < 1.0 ? y_r*y - r : y - ycent;
77			if (d > 0.5+FTINY \|\| d < -0.5-FTINY)
78			continue;
79			scan = scanin[y%barsize];
80			for (x = xcent+1-xrad; x <= xcent+xrad; x++) {
81			if (x < 0 \|\| x >= xres)
82			continue;
83			d = x_c < 1.0 ? x_c*x - c : x - xcent;
84			if (d > 0.5+FTINY \|\| d < -0.5-FTINY)
85			continue;
86			wsum++;
87			addcolor(csum, scan[x]);
88			}
89			}
90			if (wsum > 1)
91			scalecolor(csum, 1.0/wsum);
92			}
93
94
95			dogauss(csum, xcent, ycent, c, r) /* gaussian filter */
96			COLOR csum;
97			int xcent, ycent;
98			int c, r;
99			{
100			static double dy, dx, weight, wsum;
101			static COLOR ctmp;
102			static int y;
103			register int x;
104			register COLOR *scan;
105
106			wsum = FTINY;
107			setcolor(csum, 0.0, 0.0, 0.0);
108	greg	1.2	for (y = ycent-yrad; y <= ycent+yrad; y++) {
109	greg	1.1	if (y < 0 \|\| y >= yres)
110			continue;
111	greg	1.2	dy = (y_r*(y+.5) - (r+.5))/rad;
112	greg	1.1	scan = scanin[y%barsize];
113	greg	1.2	for (x = xcent-xrad; x <= xcent+xrad; x++) {
114	greg	1.1	if (x < 0 \|\| x >= xres)
115			continue;
116	greg	1.2	dx = (x_c*(x+.5) - (c+.5))/rad;
117	greg	1.1	weight = lookexp(-(dxdx + dydy));
118			wsum += weight;
119			copycolor(ctmp, scan[x]);
120			scalecolor(ctmp, weight);
121			addcolor(csum, ctmp);
122			}
123			}
124			scalecolor(csum, 1.0/wsum);
125			}