On Sun, Nov 30, 2025 at 01:32:18PM -0800, Bakul Shah via 9fans wrote:
> What I would love to see is a cross-platform 2D DisplayPDF engine,
> incrementally optimized over time. All done on the CPU. May be we
> can use it on BSDs (in place of X11) as well as Plan9.
As far as I'm concerned, I will aim to a cross-platform 2D displayDVI
engine (DVI being extended to include some features that PDF provides, for
example the ability to append data without modifying the previous
pages series, this allowing for example signing, hence locking, a
portion of the file but applying clearly identified and not previously
signed modifications---DVI already have a postamble, so these
extensions fit in the general concept).
Contrary to PDF, DVI is not a text file, but a binary (bigEndian)
program for a virtual processor with defined opcodes (for the
moment, 0 to 249) [*]. The plan is simply to add in the not used
slots the few features necessary for *roff support (the quadratic
splines) and the ability to switch to another page of 256 other
opcodes, allowing extensions (and allowing a DVI renderer to pass
pages of opcodes it doesn't implement or that the user forbids to
execute---security feature).
And the "reference" implementation will use, when needed, the
rasterizing routines of METAFONT (extracted).
DVI is fully described in "TeX: The Program", part 31 (pages 235--243)
for the curious.
*: and if someone, one day, wants to build a core able to interpret
the file directly in hardware...---thinking about the instructions as
really an instructions set that could be fed to a real graphics processor
is perhaps not a bad Ariadne thread.
--
Thierry Laronde <tlaronde +AT+ kergis +dot+ com>
http://www.kergis.com/
http://kertex.kergis.com/
Key fingerprint = 0FF7 E906 FBAF FE95 FD89 250D 52B1 AE95 6006 F40C
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