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Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!dewey.soe.berkeley.edu!oster
From: oster@dewey.soe.berkeley.edu (David Phillip Oster)
Newsgroups: comp.sys.mac.programmer,comp.sys.mac
Subject: Re: Need some MF help
Keywords: MultiFinder
Message-ID: <28689@ucbvax.BERKELEY.EDU>
Date: 5 Apr 89 06:05:25 GMT
References: <1562@neoucom.UUCP>
Sender: usenet@ucbvax.BERKELEY.EDU
Reply-To: oster@dewey.soe.berkeley.edu.UUCP (David Phillip Oster)
Organization: School of Education, UC-Berkeley
Lines: 26

In article <1562@neoucom.UUCP> sam@neoucom.UUCP (Scott A. Mason) writes:
>Firstly,  what is the standard way of checking for MultiFinder
>existence?

The standard, from Apple is "Don't even try to do this".  Most people do
it by checking to see if the end of the system heap is close to the
beginning of the application heap. If it is, no multifinder.

>Lastly,  what is the standard way of keeping track of the windows,
>so that it can be redrawn or updated after a MF switch?

You've missed the fundamental point of Mac (or X for that matter)
programming. Mac programs work by associating a data structure with a
window. During the course of the program, it mutates the data structure.
There is a "Draw()" function in the program, that can prowl the data
structure, drawing as it goes.  Call this in response to an Update event,
or if you wish to print, call it with the a grafport from the Printer
Manager.  The specific data structure is what is appropriate for _your_
program. Some programs use an offscreen GrafPort, which they mutate by
standard draw commands, but most use higher level data structures than
just the raw pixels. (Thus allowing zooming, panning, or other alternate
views of the same data.)

"Draw()" defines a function from the internal data structures to screen
graphics. Many programs define the inverse of this function "Pick()" which
lets the user select an object on the screen with the mouse.