Inside Macintosh: Imaging With QuickDraw /

Chapter 3 - QuickDraw Drawing / QuickDraw Drawing Reference

Routines / Creating and Managing Regions

PtInRgn

To determine whether a pixel is within a region, use the PtInRgn function.

FUNCTION PtInRgn (pt:†Point; rgn:†RgnHandle):†Boolean;

pt

The point whose pixel is to be checked.

rgn

A handle to the region to test.

DESCRIPTION

The PtInRgn function checks whether the pixel below and to the right of the point you specify in the pt parameter is within the region whose handle you pass in the rgn parameter. The PtInRgn function returns TRUE if so or FALSE if not.