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Inside Macintosh: Macintosh Toolbox Essentials /

Chapter 4 - Window Manager / Window Manager Reference

Window Manager Routines / Low-Level Routines

PaintOne

The Window Manager uses the PaintOne procedure to redraw the invalid, exposed portions of one window on the desktop.

PROCEDURE PaintOne (window: WindowPeek; clobberedRgn: RgnHandle);

window

A pointer to the window's complete window record.

clobberedRgn

A handle to the region that has become invalid.

DESCRIPTION

The PaintOne procedure "paints" the invalid portion of the specified window and
all windows above it. It draws as much of the window frame as is in clobberedRgn and, if some content region is exposed, erases the exposed area (paints it with the background pattern) and adds it to the window's update region. If the value of the window parameter is NIL, the window is the desktop, and PaintOne paints it with
the desktop pattern.

ASSEMBLY-LANGUAGE INFORMATION

The global variables SaveUpdate and PaintWhite are flags used by PaintOne. Normally both flags are set. Clearing SaveUpdate prevents clobberedRgn from being added to the window's update region. Clearing PaintWhite prevents clobberedRgn from being erased before being added to the update region (this is useful, for example, if the background pattern of the window isn't the background pattern of the desktop). The Window Manager sets both flags periodically, so you should clear the appropriate flags each time you need them to be clear.