Path: utzoo!attcan!uunet!samsung!olivea!apple!well!smoke
From: smoke@well.sf.ca.us (Nicholas Jackiw)
Newsgroups: comp.sys.mac.programmer
Subject: Re: How do I get a handle for an existing window? (Think Pascal)
Message-ID: <21099@well.sf.ca.us>
Date: 9 Oct 90 17:34:17 GMT
References: <1990Oct6.063726.19882@agate.berkeley.edu>
Organization: Whole Earth 'Lectronic Link, Sausalito, CA
Lines: 52

In article <1990Oct6.063726.19882@agate.berkeley.edu> bmyers@garnet.berkeley.edu (Brian Myers) writes:
>I want to change the title of the Pascal Drawing window from "Drawing" to
>something else.  
> I could probably do it by using ShowWindow to bring
>the window to the front and the calling the function that gives you the
>handle of the active window, but I want a more versatile algorithm that
>doesn't require bringing the window to the front.  

You couldn't do it that way: Think Pascal patches the function in
question (FrontWindow) so that it never returns a Think Pascal window--
only windows your program creates.   (By the way, it returns a
ptr to windows; windowRecords should never be allocated in a
relocatable fashion.)

Pascal can't interfere with the window record's linked list of windows,
however.  So if you bring up a topmost but invisible window, take the
ptr to it which NewWindow returns, and look through the list starting
at WindowPeek(theWindow)^.nextWindow, you'll eventually find one
such that WindowPeek(someWindow)^.titleHandle^^='Drawing'.  You can
change this title with SetWTitle.

>There's an assembly language constant called, I think, WindowsList, or somethinglike that, but THINK Pascal doesn't recognize it, so I can't get at the
>first entry in the system's linked list of windows.  I also can't find
>any other traps that return a window handle unless you already have some
>other window handle to pass them.  (Unless of course you create brand
>new windows, which is not what I need to do.)

To access WindowList from Pascal:

const WindowList=$9D6;

type longPtr:^longint;

var aWind:WindowPeek;

begin
 aWind:=WindowPeek(longPtr(WindowList)^);
 ...

>I assume there's some simple solution that I as a mere novice creeping
>over from the MS-DOS world haven't yet encountered?
>

Both of these are rather klunky solutions, and depend on specific
implementations of Pascal and low-memory.  The difference between
the drawing window and one you create yourself is minimal--why not
take the plunge?
-- 
                              --- * ---
Nicholas Jackiw                Smoke@well.sf.ca.us | Jackiw@cs.swarthmore.edu
Key Curriculum Press, Inc.     Applelink: D3970    | (415) 548-2304
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