XtAddExposureToRegion − merge Expose and GraphicsExpose events into a region. 

Synopsis

void XtAddExposureToRegion(event, region)

    XEvent *event;
    Region region;

Inputs

eventSpecifies a pointer to a Expose or GraphicsExpose event. 

regionSpecifies a region to be added to. 

Outputs

regionReturns the specified region merged with the rectangle of the expose event. 

Description

XtAddExposureToRegion() computes the union of the exposed rectangle specified by event and the region specified by region and stores the results back into region.  If the event argument is not an Expose or GraphicsExpose event, XtAddExposureToRegion() returns without an error and without modifying region. 

Usage

This is a utility function that allows the caller to merge expose events into a region that can be processed all at once instead of as a series of individual rectangles.  It is used by the Intrinsics exposure compression mechanism, and could be of use within event handlers, action procedures, or a widget’s expose() method. 

Structures

Region is a pointer to an opaque type. 

See Also

expose(4). 

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