HowToC:DrawPoints

From S2PLOT

Revision as of 22:49, 10 December 2007

Drawing Points

Perhaps the most common object you will need to draw as a point. There are two different ways to do this, using either the PGPLOT-style functions or the native S2PLOT point functions.

For PGPLOT programmers, the functional interface to s2pt1 (draw a single point), s2pt (draw multiple points) and s2pnts (draw multiple points with different symbols) will seem very familiar. In each case, x, y and z coordinates are passed to the functions along with an integer value for the "marker" style to use.

Points example

Copy and paste the following code, and save the file as s2points.c

#include <stdio.h>
#include <stdlib.h>
#include "s2plot.h"

int main(int argc, char *argv[])
{
   float xmin = -1, xmax = +1;          /* X data range */
   float ymin = -1, ymax = +1;          /* Y data range */
   float zmin = -1, zmax = +1;          /* Z data range */

   s2opend("/?",argc,argv);             /* Which S2PLOT device to open? */
   s2swin(xmin, xmax, ymin, ymax, zmin, zmax);  /* Set the display coordinates */

   s2pt1(0, 0, 0, 1);
  
   float x[10], y[10],z[10];
   int i;
   for (i=0;i<10;i++) {
      x = drand48()*(xmax-xmin) + xmin;
      y = drand48()*(ymax-ymin) + ymin;
      z = drand48()*(zmax-zmin) + zmin;
   }
   s2pt(10, x, y, z, 1);

   s2show(1);                           /* Hand over to the display */

   return 1;
}

Compile using: cbuild.csh s2example<tt> and then run by typing <tt>s2example at the command prompt.

Experiment for yourself

Function Overview

For more information on the functions we have introduced so far, see:

• s2pt1
• s2pt
• s2pnts
• ns2m
• ns2vm
• ns2vpoint
• ns2vnpoint
• ns2thpoint
• ns2vthpoint
• Colours
• struct COLOUR

Common Problems

Test code: s2points.c

This is the full test code for the point-drawing example.

Where to Next?

• Back to S2PLOT How To...
• Drawing lines