RectRgn (IM: Im)

Inside Macintosh: Imaging With QuickDraw /

Chapter 3 - QuickDraw Drawing / QuickDraw Drawing Reference

Routines / Creating and Managing Regions

RectRgn
To change the structure of an existing region to that of a rectangle, you can use the RectRgn procedure.
PROCEDURE RectRgn (rgn:æRgnHandle; r:æRect);
rgn
A handle to the region to restructure as a rectangle.
r
The rectangle structure to use.

DESCRIPTION
The RectRgn procedure destroys the previous structure of the SetRectRgn procedure, and it then sets the new structure to a rectangle that you specify in the r parameter.
As an alternative to the RectRgn procedure, you can use the SetRectRgn procedure, which accepts as parameters four coordinates instead of a rectangle.

SPECIAL CONSIDERATIONS
The RectRgn procedure may move or purge memory blocks in the application heap. Your application should not call this procedure at interrupt time.