jenlan@eos.arc.nasa.gov (Jennifer S Lanham) (02/09/91)
Hi, I understand it is a no-no to write to the main screen frame buffer on a Mac II ( x, fx, etc.). In fact, the base address of the graphics device's pixMap is 0x0000. Does some one know how to get around this? Thanx, Jennifer Lanham jenlan@eos.arc.nasa.gov
bskendig@bow.Princeton.EDU (Brian Kendig) (02/09/91)
In article <7876@eos.arc.nasa.gov> jenlan@eos.arc.nasa.gov (Jennifer S Lanham) writes: > I understand it is a no-no to write to the main screen frame buffer on > a Mac II ( x, fx, etc.). In fact, the base address of the graphics > device's pixMap is 0x0000. Does some one know how to get around this? Um, use QuickDraw routines? I don't see your problem. You don't need to know what the base address is; you don't need to flip bits by hand -- just call the appropriate QuickDraw procedures, and you should be okay. Could you clarify your difficulty? << Brian >> | Brian S. Kendig \ Macintosh | Engineering, | bskendig | | Computer Engineering |\ Thought | USS Enterprise | @phoenix.Princeton.EDU | Princeton University |_\ Police | -= NCC-1701-D =- | @PUCC.BITNET | "It's not that I don't have the work to *do* -- I don't do the work I *have*."
jenlan@eos.arc.nasa.gov (Jennifer S Lanham) (02/09/91)
>In article <7876@eos.arc.nasa.gov> I write: >> I understand it is a no-no to write to the main screen frame buffer on >> a Mac II ( x, fx, etc.). In fact, the base address of the graphics >> device's pixMap is 0x0000. Does some one know how to get around this? In article <6091@idunno.Princeton.EDU> Brian Kendig replies: >Um, use QuickDraw routines? >I don't see your problem.... -- just call the >appropriate QuickDraw procedures, and you should be okay. >Could you clarify your difficulty? Sorry, I should have stated that QuickDraw is too slow for what I am trying to do. I WANT to get around its slowness by drawing directly to the frame buffer. I can do it on a plus. Does anyone know how to draw directly to the frame buffer on a Mac II? Any suggestions welcome and appreciated. E-mail is fine if the general audience is not interested. Thank you, J Lanham jenlan@eos.arc.nasa.gov
Lawson.English@p88.f15.n300.z1.fidonet.org (Lawson English) (02/10/91)
Jennifer S Lanham writes in a message to All
JSL> Sorry, I should have stated that QuickDraw is too slow for what
JSL> I am trying to do. I WANT to get around its slowness by drawing
JSL> directly to the frame buffer. I can do it on a plus. Does anyone
JSL> know how to draw directly to the frame buffer on a Mac II? Any
JSL> suggestions welcome and appreciated.
Sorry, I have problems with E_Mail, but I'd like to point out that QD can be
speeded up through various means:\
1) bypass the trap dispatcher; if you are doing lots of pixel manipulation,
the 100+ cycles-per-trap-call overhead can kill you. Use NGetTrapAddress to
jump directly to where you need to go.
2) offscreen bit/pixel maps can speep things up amazingly as you don't need
to worry about clipRgns, etc whilest drawing.
3) I seem to recall that FillRect can actually be faster than LineTo for drawing
lines...
Just some suggestions for keeping withing Apple guidelines.
Lawson
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Uucp: ...{gatech,ames,rutgers}!ncar!asuvax!stjhmc!300!15.88!Lawson.English
Internet: Lawson.English@p88.f15.n300.z1.fidonet.orgegw.weakm@p3.lanl.gov (Eric Wasserman) (02/11/91)
In the previous posting I neglected to mention that the code assumes that the video card is in 8-bit mode. If you can live with a slightly slower method you might try making an offscreen pixMap, hacking its pixels directly, and then using CopyBits to put it into a window. I think that would be a lot less likely to break and should get rid of those nasty null pointer problems (since QuickDraw handles the access to the video ram for you). Eric egw.weakm@p3.lanl.gov