Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!nosc!humu!uhccux!mikem
From: mikem@uhccux.uhcc.hawaii.edu (Mike Morton)
Newsgroups: comp.sys.mac.programmer
Subject: how do I find bit-depth of a window?
Keywords: QuickDraw BitMap PixMap
Message-ID: <2127@uhccux.uhcc.hawaii.edu>
Date: 27 Jul 88 02:29:00 GMT
Organization: University of Hawaii
Lines: 25


I just MCI-mailed a note to Mac Tech support, and got a note back saying
they're busy this week and will answer me later.  In hopes that someone
on the net can answer more quickly than the "experts", here's a summary
of what I asked:

I have a subroutine which accesses a BitMap's graphical data directly.  When
the screen is one bit deep (2 colors) I believe I can do this safely.  If
it's more than 2 colors, I'll just back off and use QuickDraw calls.  My
questions are:

#1: Given a window, and a Rect in that window's coordinates, how can I tell
if that rectangle's contents are currently displayed on a single monitor
with one-bit color, addressable as an old-style BitMap?

#2: If that rectangle is indeed addressable as a BitMap, but the window
overlaps several monitors, how do I find the address for the Rect in
question?  (In other words, how can a window's single BitMap *or* PixMap
cover an area of the QuickDraw plane which has varyiing bit-depth because
it spans several monitors?)

Please post replies, as I rarely read my mail ;-)

 -- Mike Morton // P.O. Box 11378, Honolulu, HI  96828, (808) 456-8455 HST
      Internet: msm@ceta.ics.hawaii.edu
    (anagrams): Mr. Machine Tool; Ethical Mormon; Chosen Immortal; etc.