Creating a Chained Segment

To create a chained segment, you must:

• Set the drawing mode to DM_RETAIN.

• Check to see if the chained attribute is one of the initial segment attributes using GpiQueryInitialSegmentAttrs.

• Set the chained attribute, if necessary, with GpiSetInitialSegmentAttrs.

• Open the segment using GpiOpenSegment.

• Perform the necessary drawing operations.

• Close the segment using GpiCloseSegment.

The following figure is an example of a segment containing a box primitive and calling another segment using GpiCallSegmentMatrix.

#define INCL_GPISEGMENTS#define INCL_GPITRANSFORMS
#include <os2.h>
void fncSEGS01(void){
    POINTL ptl;
    HPS hps;
    LONG idSegment    = 1;
    LONG idNonChained = 2;
    MATRIXLF matlfTransform = { MAKEFIXED(2,0), MAKEFIXED(0,0), 0,
                                MAKEFIXED(0,0), MAKEFIXED(1,0), 0,
                                0, 0, 1 };

    /************************************************************************/
    /* Turns chaining on. Adds the new segment to the segment chain.        */
    /* Segment idNonChained is called, whether chained or not.              */
    /************************************************************************/

    if (ATTR_OFF == GpiQueryInitialSegmentAttrs(hps, ATTR_CHAINED)
        GpiSetInitialSegmentAttrs(hps, ATTR_CHAINED, ATTR_ON);
    GpiOpenSegment(hps, idSegment);
    ptl.x = 150; ptl.y = 150;
    GpiMove(hps, &ptl);
    ptl.x = 225; ptl.y = 225;
    GpiBox(hps, DRO_FILL, &ptl, 0L, 0L);
    GpiCallSegmentMatrix(hps, idNonChained, 9L, &matlfTransform,
        TRANSFORM_REPLACE);
    GpiCloseSegment(hps);
} /* fncSEGS01 */