[cairo] postscript backend

[Carl Worth]

On Sat, 27 Nov 2004 16:14:43 +0100 (CET), Jost Boekemeier wrote:
> [IMHO level 3 is a little bit too high.  level 2 would
> be sufficient if we want eps.  Some printers reject
> level 3.

At the time we wrote the current PostScript backend, (which is really
nothing more than a proof-of-concept), the only reasonable way to get
good non-patent-encumbered image compression that we could find was with
the /FlateDecode filter which is only available in LanguageLevel 3.

Now, however, as of June 20, 2004, all of the Unisys LZW patents have
expired. But, apparently IBM has *another* patent on the same algorithm
that doesn't expire until August 11, 2006.
(See http://en.wikipedia.org/wiki/LZW )

> It would also be possible to set the device
> demensions for which this postscript file was
> generated]

Yes, that would be a useful addition to the PostScript backend. Patches
are welcome.

-Carl