Combining Regions

To combine two regions:

• Create a region that the operating system can use as the destination region when it combines the source regions.

• Determine which of the five combining methods to use.

• Call GpiCombineRegion.

The following figure shows how to combine two regions by using the OR operation:

#define INCL_GPIREGIONS#include <os2.h>
void fncREGN02(void){
    HPS  hps;
    HRGN hrgn1, hrgn2, hrgn3;          /* Region handles                    */
    RECTL rcl1, rcl2;

    rcl1.xLeft = 50; rcl1.yBottom = 100;
    rcl1.xRight = 200; rcl1.yTop = 175;
    hrgn1 = GpiCreateRegion(hps, 1L, &rcl1);        /* First source region  */

    rcl2.xLeft = 125; rcl2.yBottom = 150;
    rcl2.xRight = 225; rcl2.yTop = 200;
    hrgn2 = GpiCreateRegion(hps, 1L, &rcl2);        /* Second source region */

    hrgn3 = GpiCreateRegion(hps, 0L, (PRECTL) NULL); /* Destination region  */

    /* Combine the regions. */
    GpiCombineRegion(hps, hrgn3, hrgn1, hrgn2, CRGN_OR);
} /* fncREGN02 */