Function:s2circxy
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s2circxy
Draw a circle in the xy plane at a given z coordinate.
Prototype
void s2circxy(float px, float py, float pz, float r, int nseg, float asp);
Description
Draw a circle in the xy plane at a given z coordinate. Use nseg to control how many line segments are used to draw the circle. Low values of nseg (>= 3) can be used to draw n-sided polygons!
Argument asp controls the aspect ratio and whether a circle or ellipse is drawn. asp<0 will produce a circle by calculating the radius as the functions s2disk?? do. asp=1.0 will produce a circle when the x and y axes have the same device scale and an ellipse otherwise; asp < 1.0 will squash the ellipse further in y (z, x); asp > 1.0 stretch in the y (z, x) direction.
See Also
| s2circxz | Draw a circle in the xz plane at a given y coordinate. |
| s2circyz | Draw a circle in the yz plane at a given x coordinate. |
| s2diskxy | Draw a disk in the xy plane at a given z coordinate. |
| s2diskxz | Draw a disk in the xz plane at a given y coordinate. |
| s2diskyz | Draw a disk in the yz plane at a given x coordinate. |
PGPLOT Equivalent
Code Example
#include <stdio.h>
#include <stdlib.h>
#include "s2plot.h"
int main(int argc, char *argv[])
{
float r = 0.5; /* Radius */
int nseg = 32; /* Segments for circle */
float asp = 1.0; /* Circle not ellipse */
s2opend("/?",argc, argv); /* Open the display */
s2swin(-1.,1., -1.,1., -1.,1.); /* Set the window coordinates */
s2box("BCDET",0,0,"BCDET",0,0,"BCDET",0,0); /* Draw coordinate box */
s2sci(S2_PG_RED);
s2circxy(0.0,0.0,-0.5, r, nseg,asp); /* Circle in x-y plane */
s2sci(S2_PG_BLUE);
s2circxy(0.0,0.0,+0.5, r/2.0, nseg,asp); /* Circle in x-y plane */
s2show(1); /* Open the s2plot window */
return 1;
}
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