lsr@apple.UUCP (Larry Rosenstein) (12/01/84)
I want to solicit some input from the net community regarding Macintosh
development techniques.
I am working on a project at Apple that involves making Macintosh
development much easier. The approach we are taking is similar to that
used in the Lisa Toolkit (if anyone is familiar with that). Briefly, we
are developing an Expandable Application that implements the standard
Macintosh behavior (eg., printing, resizing/moving windows, handling desk
accessories, etc.). Programmers make extensions to the Expandable
Application to add specific behavior (eg., drawing an image in the window).
What we try to do is figure out the best way to do a particular task (eg.,
scrolling), and implement it once in the Expandable Application where
everyone can take advantage of it. I would like to hear: (1) any reactions
you have to this idea, and (more importantly) (2) any helpful hints/tricks
you have for implementing certain features or for debugging.
The following techniques will give you an idea of what I mean (and might be
useful in your own applications):
(1) Instead of reading in the menus into a global array (like the FILE
program does) use the GetMHandle trap, which takes in a menuID of a menu in
the menu bar and returns the handle. (So far the Expandable Application
has not had to access an item of a menu NOT in the menu bar.)
(2) Calling EnableItem, CheckItem, etc. causes the menu to recompute its
size each time, which takes some time. Before making these calls, replace
the menuProc by a HANDLE to a dummy procedure that does nothing (but has
the right interface). Afterwards, you restore the original menuProc and
can call CalcMenuSize to compute the new menu size. (You can skip the call
the CalcMenuSize if you are sure the menu didn't change size, which is
usually the case.)
(3) When moving the scroll bars (because the window changed size), don't
call HideControl/ShowControl. Instead, set the clipping to a zero-sized
rectangle. (Remember that you also need to invalidate the old and new
positions of the grow box.)
(4) When printing, send the spool file to the same volume as the document
(since the program disk is likely to be full and/or write-protected). The
volume used for the spool file is specified in the iFileVol field of the
TPrJob record, which is described in the "Printing From Macintosh
Applications" section of Inside Macintosh.
I am interested in any comments you have. I hope that my mailbox can stand
the strain! :-)
Larry Rosenstein
Apple Computer, Inc.
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