Legacy Document

Inside Macintosh: Macintosh Toolbox Essentials /

Chapter 4 - Window Manager / Window Manager Reference

Window Manager Routines / Moving Windows

PinRect

The DragGrayRgn function uses the PinRect function to contain a point within a specified rectangle.

FUNCTION PinRect (theRect: Rect; thePt: Point): LongInt;

theRect

The rectangle in which the point is to be contained.

thePt

The point to be contained.

DESCRIPTION

The PinRect function returns a point within the specified rectangle that is as close as possible to the specified point. (The high-order word of the returned long integer is the vertical coordinate; the low-order word is the horizontal coordinate.)

If the specified point is within the rectangle, PinRect returns the point itself. If not, then

• if the horizontal position is to the left of the rectangle, PinRect returns the left edge as the horizontal coordinate
• if the horizontal position is to the right of the rectangle, PinRect returns the right edge minus 1 as the horizontal coordinate
• if the vertical position is above the rectangle, PinRect returns the top edge as the vertical coordinate
• if the vertical position is below the rectangle, PinRect returns the bottom edge minus 1 as the vertical coordinate

Note

The 1 is subtracted when the point is below or to the right of the rectangle so that a pixel drawn at that point lies within the rectangle. If the point is exactly on the bottom or the right edge of the rectangle, however, 1 should be subtracted but isn't.