Drawing Marker Primitives

You can draw either a single marker or a series of markers using the current marker symbol. To draw a single marker, set the fields in a POINTL structure to correspond to the desired position in world coordinates. Then call GpiMarker passing it the address of the POINTL structure as the second argument.

To draw a series of markers, set the fields in an array of POINTL structures to correspond to the desired positions in world coordinates. Then call GpiPolyMarker, passing it the number of points in the array as the second argument and the name of the array as the third argument.

The following figure shows how to draw a graph with GpiPolyLine and GpiPolyMarker.

#include <os2.h>
void fncMARK01(void){
    HPS hps;                                  /* Presentation-space handle */
    POINTL aptl[6];                           /* Array of points           */

    aptl[0].x = 10; aptl[0].y = 15;           /* Assigns points            */
    aptl[1].x = 150; aptl[1].y = 30;
    aptl[2].x = 200; aptl[2].y = 32;
    aptl[3].x = 250; aptl[3].y = 70;
    aptl[4].x = 360; aptl[4].y = 120;
    aptl[5].x = 380; aptl[5].y = 98;
    GpiPolyMarker(hps, sizeof(aptl) / sizeof(POINTL),aptl);
                                              /* Plots points              */
    GpiMove(hps, aptl);                       /* Sets current position     */
    GpiPolyLine(hps, sizeof(aptl) / sizeof(POINTL),aptl);
                                              /* Draws lines               */
} /* fncMARK01 */