XtAddExposureToRegion - Man Page

#include <X11/Intrinsic.h>

void XtAddExposureToRegion(XEvent *event, Region region);

event

Specifies a pointer to the Expose or GraphicsExpose event.

region

Specifies the region object (as defined in <X11/Xutil.h>).

The XtAddExposureToRegion function computes the union of the rectangle defined by the exposure event and the specified region. Then, it stores the results back in region. If the event argument is not an Expose or GraphicsExpose event, XtAddExposureToRegion returns without an error and without modifying region.

This function is used by the exposure compression mechanism (see Section 7.9.3).

X Toolkit Intrinsics - C Language Interface
Xlib - C Language X Interface