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/* $Id: x03c.c,v 1.18 2002/12/03 08:39:24 airwin Exp $
Polar plot demo.
*/
#include "plcdemos.h"
/*--------------------------------------------------------------------------*\
* main
*
* Generates polar plot, with 1-1 scaling.
\*--------------------------------------------------------------------------*/
int
main(int argc, char *argv[])
{
int i, j;
PLFLT dtr, theta, dx, dy, r;
char text[4];
static PLFLT x0[361], y0[361];
static PLFLT x[361], y[361];
dtr = PI / 180.0;
for (i = 0; i <= 360; i++) {
x0[i] = cos(dtr * i);
y0[i] = sin(dtr * i);
}
/* Parse and process command line arguments */
(void) plParseOpts(&argc, argv, PL_PARSE_FULL);
/* Initialize plplot */
plinit();
/* Set up viewport and window, but do not draw box */
plenv(-1.3, 1.3, -1.3, 1.3, 1, -2);
for (i = 1; i <= 10; i++) {
for (j = 0; j <= 360; j++) {
x[j] = 0.1 * i * x0[j];
y[j] = 0.1 * i * y0[j];
}
/* Draw circles for polar grid */
plline(361, x, y);
}
plcol0(2);
for (i = 0; i <= 11; i++) {
theta = 30.0 * i;
dx = cos(dtr * theta);
dy = sin(dtr * theta);
/* Draw radial spokes for polar grid */
pljoin(0.0, 0.0, dx, dy);
sprintf(text, "%d", ROUND(theta));
/* Write labels for angle */
/* Slightly off zero to avoid floating point logic flips at 90 and 270 deg. */
if (dx >= -0.00001)
plptex(dx, dy, dx, dy, -0.15, text);
else
plptex(dx, dy, -dx, -dy, 1.15, text);
}
/* Draw the graph */
for (i = 0; i <= 360; i++) {
r = sin(dtr * (5 * i));
x[i] = x0[i] * r;
y[i] = y0[i] * r;
}
plcol0(3);
plline(361, x, y);
plcol0(4);
plmtex("t", 2.0, 0.5, 0.5, "#frPLplot Example 3 - r(#gh)=sin 5#gh");
/* Close the plot at end */
plend();
exit(0);
}
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