Region Creation

Areas and paths are created and defined within a bracket. Regions are defined by a single function, GpiCreateRegion. As input to GpiCreateRegion, supply the total number of, and the coordinates for, each rectangle that contributes to the region. The following applies to region coordinates:

• They define the bottom left and top right coordinates of each rectangle that makes up the region.

• They must be in the range -32768 through +32767.

• They always are device coordinates, because regions always are created and drawn in an application's device space.

The output from GpiCreateRegion is the region handle, which identifies the region for subsequent operations. Because each region can be distinctly identified, the region functions allow applications to work with more than one region at a time.

For example, an application can combine two regions with GpiCombineRegion or compare two regions with GpiEqualRegion. GpiQueryRegionRects retrieves the coordinates of the rectangles that make up a region, enabling an application to create a copy of that region. To create the copy, you supply, as input to a new GpiCreateRegion, the exact rectangles returned from GpiQueryRegionRects.