DrawNew
void DrawNew( theWindow, updateFlag ); WindowPeek theWindow ; window of interest
This low-level function is used by the Window Manager to determine what
portions of a window need to be updated. It must be preceded by a matching call
theWindow is the WindowPeek (pointer to a WindowRecord) of the window that is to be updated.
updateFlag specifies whether to update the changed area or just erase it. It
must be one of:
FALSE Just erase the area; paint it white TRUE Erase the area; then update it as needed
Notes: This first determines which portions of a window have changed by
performing the following calculation:
(OldStruc XOR NewStruc ) UNION (OldContent XOR NewContent )
Where OldStruc and OldContent are regions saved by SaveOld and NewStruc and NewContent are regions of theWindow .
If updateFlag = TRUE, this resulting region is stored into the update region of theWindow (so that an update event will be generated eventually). If
updateFlag = FALSE, the resulting region is painted white.