[comp.windows.x] Mac II color graphics

howard@cpocd2.UUCP (Howard A. Landman) (03/06/87)

In article <1338@husc6.UUCP> hadeishi@husc7.UUCP (Mitsuharu Hadeishi) writes:
>	As far as I know (haven't seen the spec sheets from Apple yet)
>the software of the color workstation will support up to a full 16-bits
>per R, G, B.  The software queries the display device by sending it
>a 16-bit RGB value (16-bits per R, G, and B) and getting back the
>"closest" value the display device can handle.

This sounds like X windows.  Perhaps Apple is migrating toward X compatibility.
Good idea if so.  For more info peruse comp.windows.x, or get an X manual.

>That is,
>the "color monitor" has extra logic to communicate with the host
>machine and tell it the closest 16-bit RGB value it can produce
>for a requested value.

No, no, no (I hope)!  This can all be done in software if necessary, and most
present implementations of X do it that way.  On the other hand, full X allows
you to open a window on *someone* *else's* *machine* if you have permission,
and in that case ("color monitor" == other machine) you are close to right.

>So software written today should be able to handle the full 16-bits of RGB,
>but the actual card can only support 8-bits (for a total of
>2^(8*3) or about 4 million colors).  The card can display 8 bit planes,
>for 256 colors per display.

8 * 3 = 24.  2^24 =~ 16M (not 4M).  So you can choose any 256 colors out of
a palette of 16 million.  This is typical of many graphics controllers
(e.g. AED 512, Metheus Omega series, etc.).
-- 

	Howard A. Landman
	...!intelca!mipos3!cpocd2!howard

shebanow@ernie.Berkeley.EDU (Mike Shebanow) (03/07/87)

Here is the scoop on Mac II graphics, X-Windows, etc.

The Mac II software (QuickDraw) supports up to 48 bits per pixel. The
current video board in the Mac II only supports 8 bits per pixel, with
a 24 bit pallette. However, if some company puts out the video board to
support it, there is no reason why you couldn't go much higher. Apple's
software has a color-map allocation scheme very similar to that used
by X-Windows. Not only that, but X-Windows is ALREADY running on the Mac II,
under A/UX (Apple's System V.2 UNIX). It was ported here at Berkeley.

All of this info comes from a demo I saw and from Apple's own press
releases.

PLEASE DO NOT REPLY TO THIS ACCOUNT

Andrew Shebanow

dwb@well.UUCP (David W. Berry) (03/07/87)

In article <474@cpocd2.UUCP> howard@cpocd2.UUCP (Howard A. Landman) writes:
>This sounds like X windows.  Perhaps Apple is migrating toward X compatibility.
>Good idea if so.  For more info peruse comp.windows.x, or get an X manual.

At AppleWorld they were demoing Magic running on XWindows running on
a Mac II.


	David
-- 
	David W. Berry
	dwb@well.uucp                   dwb@Delphi
	dwb@GEnie                       293-0752@408.MaBell