Legacy Document

Inside Macintosh: Macintosh Toolbox Essentials /

Chapter 4 - Window Manager / Window Manager Reference

Window Manager Routines / Maintaining the Update Region

InvalRect

Use the InvalRect procedure to add a rectangle to a window's update region.

PROCEDURE InvalRect (badRect: Rect);

badRect

A rectangle, in local coordinates, that is to be added to a window's
update region.

DESCRIPTION

The InvalRect procedure adds a specified rectangle to the update region of the window whose graphics port is the current port. Specify the rectangle in local coordinates. The Window Manager clips it, if necessary, to fit in the window's
content region.

Both your application and the Window Manager use the InvalRect procedure.
When the user enlarges a window, for example, the Window Manager uses InvalRect to add the newly created content region to the update region. Your application uses InvalRect to add the two rectangles formerly occupied by the scroll bars in the smaller content area.