Important: The information in this document is obsolete and should not be used for new development.
Drawing RegionsAfter defining a region by using the
OpenRgnprocedure, a number of drawing procedures, and the
CloseRgnprocedure, you can draw the region's outline with the
FrameRgnprocedure. You can draw its interior with the
FillRgnprocedures. You can erase it by using the
EraseRgnprocedure, and you can use the
InvertRgnprocedure to reverse the colors of the pixels within it. In all of these procedures, you refer to a region by the handle returned by the
NewRgnfunction when you first created the region.
These routines depend on the local coordinate system of the current graphics port. If you draw a region in a graphics port different from the one in which you defined the region, it may not appear in the proper position in the graphics port.
- If any horizontal or vertical line drawn through the region would intersect the region's outline more than 50 times, the results of these graphics operations are undefined. The
FrameRgnprocedure in particular requires that there would be no more than 25 such intersections.