squeak portability problem

Tim Rowledge rowledge at interval.com
Tue Aug 10 17:32:49 UTC 1999

On Tue 10 Aug, Stefan Rieken wrote:

> The Windows version went black. The Linux version however seemed to have
> a check for this and thus returned an error message "depth 1 not
> supported".
> Further checks made clear that a depth lower than 16 (8 or 1) could not
> in anyway be set on either Windows or Linux Squeak 2.4c. This is in
> conflict with the promise that Squeak code would run on any machine that
> has a VM for it. So how on earth could this be?
Unless the OS for a machine provides depth conversion functions, the VM
implementor is left with some really high-effort work in order to support the
total range of possible Display depths and screen depths. Add pixel reversal
for little endian machines, and you have a _large_ chunk of code. Since
1/2/4bpp usage is pretty rare, I'm not at all surprised that they may not have
been implemented on some platforms.

This seems a clear place where the recently added prims to check for supported
display depths would help. The current small.image doesn't know how to make use
of it, so it will need rebuilding sometime; but then again IIRC this image is
_very_ old and missing many useful fixes etc by now!

Useful random insult:- All hat and no cattle.
Tim Rowledge:  rowledge at interval.com (w)  +1 (650) 842-6110 (w)
 tim at sumeru.stanford.edu (h)  <http://sumeru.stanford.edu/tim>

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