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Path: utzoo!decvax!wanginst!ulowell!miner
From: miner@ulowell.UUCP
Newsgroups: mod.amiga
Subject: Problems With On-Screen Bitmaps
Message-ID: <677@ulowell.UUCP>
Date: Thu, 16-Oct-86 16:14:20 EDT
Article-I.D.: ulowell.677
Posted: Thu Oct 16 16:14:20 1986
Date-Received: Thu, 16-Oct-86 22:39:28 EDT
Sender: page@ulowell.UUCP
Reply-To: miner@ulowell.UUCP (Richard Miner)
Organization: University of Lowell
Lines: 42
Keywords: Custom Screen, Image Processing, Graphics, DMA, PIC, Zorro Expansion
Approved: page@ulowell.UUCP


I have been working with image processing routines on images loaded into
my own window on a CUSTOM screen.  For what I was doing in the past I could 
use the commands in the graphics library (and my own routines) for accessing 
this image memory.  We have built a piece of image processing hardware that
sits as a plug in card (PIC) in a Zorro expansion box, and performs DMA 
reads and writes to chip memory.  I need to have a several open windows on a 
screen that have their own bitmaps so that the PIC can DMA-read my window 
as one contiguous bitmap.

 +-------------+ Normally the windows use the screen's memory and do not
 | +-----+     | have their own bitmaps.  I have considered using super-
 | |win#1|     | bitmapped windows.  The benefit is that I get my own
 | |_____+---+ | bitmap made up of individual bitplanes whose size I can
 |     |win#2| | control.  The problem is that doing image processing
 |     |_____+ | requires deep bitmaps - four to five bitplanes.  When
 +-------------+ I open a super bitmap window 256 x 256 x n (0<n<5)
on a hires interlaced screen it eats at least 128K (640 x 400 x 4) for
Intuition to do house cleaning for my little 256 x 256 images.  I cannot
afford to waste this much chip RAM for each image buffer.  

It seems like a waste to use super-bit mapped windows anyway - they are
really designed to handle bitmaps larger then the window - not what I need.
I talked with the people at Westchester, they gave me new ideas but nothing
I am completely happy with.  Two other alternatives are to either create my
own off-screen bitmap and then do a bit blit to rastport or to use the layers
library.  The creation of my own bitmap off screen would work out great, but
I like the idea of seeing the PIC, or my routines, process the image while
it is on the screen. I would have to process it off screen and then copy the 
result to the screen. The problem with the layers library is that I have to 
say goodbye to Intuition, something we all try to avoid.

What I need is the ability to just point a window, which can be fixed 
in both size and location, to its own bitmap.  Any ideas?

Thanks,    Rich Miner

UUCP: ...wanginst!ulowell!miner 
ARPA: miner@ulowell.CSNET        University of Lowell, Comp Sci Dept
TALK: (617) 452-5000 x2693       Lowell MA 01854 USA
HAL hears the 9000 series is not selling. "Please explain Dave. Why 
aren't HAL's selling?"  Bowman hesitates. "You aren't Amiga compatible."