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From: aries@rhi.hi.is (Reynir Hugason)
Newsgroups: comp.sys.mac.programmer
Subject: Re: WindowObject in Object Pascal
Message-ID: <2399@krafla.rhi.hi.is>
Date: 9 Nov 90 19:06:40 GMT
References: <311@rusux1.rus.uni-stuttgart.de>
Organization: University of Iceland
Lines: 33

The way I usually solve this is to introduce a new data structure, some-
thing like this:

   MyWindowRec = RECORD
                   oldWindowRec: WindowRec;

                  { what-ever stuff I need to use }
                 END;
   MyWindowPeek = ^MyWindowRec;
   MyWindowPtr = WindowPtr;

This is the same trick as Apple uses to hide the special window parameters
behind a grafport, so you can simply say SetPort(myWindow).

Then I stuff a windowlist structure in there too, mainly to reduce heap
fragmentation if the windows are opened and closed frequently but also
to enable me to check whether the window reference I receive is actually
one of my windows. This is very easy to implement, you either declare a
constant array of a fixed size or a dynamic list of fixed size buckets
(in either case, the storage should be non-relocatable). You initialize
it, by NILing some field, in each slot, that shouldn't be NIL if the
slot was occupied. Then when-ever you need a window you find a free slot
and pass the address of the slot to GetNewWindow. And when your through
with the window you simply call CloseWindow (NOT DisposeWindow!!!).
On receiving mouse-clicks you check whether the window is actually in
your windowlist, if it ain't then the event is SEP (Somebody Elses Problem).

Pretty strightforward stuff, eh??

Mimir (aries@rhi.hi.is)
Aries, inc.

/// With greetings from Sweet Mama Jankins ... and her friends.