Re: A plug for Second Sight card

[at217@chebucto.ns.ca (Michael Hackett)]

Tilghman Lesher (NO%lesh%SPAM%erjt%HERE@vuse.vanderbilt.edu) wrote:
> If a program "follows the rules," i.e. uses only the toolbox to access
> the screen, how much of a problem would occur?

Unfortunately, Apple's rules allowed programs to bypass QD and write
directly to screen memory, provided they checked the address first.
(One of the tech notes documents this -- I don't have them handy so I
can't look up the number.)

> Are there other sections of the toolbox which do NOT go through the
> QuickDraw II set to access the screen?

Short answer: yes, but not in too many places. QD Auxiliary (of all
places) is the worst. I'm in the middle of working through the
internals of a couple of particularly naughty (and buggy) routines.

> Or, are programs simply not working because they
> "broke the rules" (pounding on the metal, so to speak)?

I've never had any intention of supporting anything that writes
directly to the screen (nor is it possible in software), but
hopefully there are enough programs that stick strictly to the
toolbox, or can be easily modified to do so, to have made this
whole effort worthwhile.

> Another thing I'm wondering is if the libraries in the current
> versions of the ByteWorks products ever "violate the rules."

No, the ByteWorks interfaces to the Toolbox are just header files
with codes to tell the compiler to generate tool calls inline.
All that's in the libraries are the standard C library functions
(and a few GS-specific ones), and, in as much as they use the 
Toolbox, they follow the rules.