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Inside Macintosh: Macintosh Toolbox Essentials /

Chapter 4 - Window Manager / Window Manager Reference

Window Manager Routines / Low-Level Routines

DrawNew

The Window Manager uses the DrawNew procedure to erase and update changed window regions.

PROCEDURE DrawNew (window: WindowPeek; update: Boolean);

window

A pointer to the window's complete window record.

update

A Boolean value that determines whether the regions are updated.

DESCRIPTION

The DrawNew procedure erases the parts of a window's structure and content regions that are part of the window's former state and part of its new state but not both. That is,

(OldStructure XOR NewStructure) UNION (OldContent XOR NewContent)

If the update parameter is set to TRUE, DrawNew also updates the erased regions.

WARNING

In Pascal, SaveOld and DrawNew are not nestable.

ASSEMBLY-LANGUAGE INFORMATION

In assembly language, you can nest SaveOld and DrawNew if you save and restore the values of the global variables OldStructure and OldContent.