[coreboot] Hi-DPI displays and showing text information for kevin in depthcharge

[Paul Kocialkowski]

Le dimanche 23 juillet 2017 à 16:21 +0300, Paul Kocialkowski a écrit :
> Le lundi 17 juillet 2017 à 22:11 +0200, Patrick Georgi via coreboot a
> écrit :
> > I wouldn't scale at compile time (as said, storage constrained
> > payloads might not be happy about that).
> > 
> > I wouldn't scale each character up on each access though (we won't
> > hardware accelerate the scaling, and yes, that does get slow -
> > framebuffers aren't always the fastest type of memory and that way
> > the
> > access pattern is the same set of memcpy()s as for any other huge
> > font, so we won't need to deal with "fast fonts" and "slow fonts"
> > beyond basic geometry characteristics), but synthesize a new font in
> > the regular font table at init-time and then use it like any pre-
> > existing font (just that it happened to be added after load).
> 
> As it turns out, no scaling in memory is required, either at build
> time
> or run time. This is thanks to the fact that the font is coded with
> each
> bit representing a filled or blank pixel, so the font has to be
> accessed
> bit-by-bit to draw it. I simply modified the access logic to use a
> scale
> factor and I don't think it will impact performance much (that's still
> two extra divisions for each pixel though).
> 
> The changes are up for review at:
> https://review.coreboot.org/#/c/20708/
> https://review.coreboot.org/#/c/20709/
> https://review.coreboot.org/#/c/20710/
> 
> Thanks everyone for the feedback and happy review!

I forgot to mention: I tested this on kevin (with and without scaling)
and the result looks great!

> > 2017-07-17 21:47 GMT+02:00 Julius Werner <jwerner at chromium.org>:
> > > I agree with most of what Patrick said, I think dynamic scaling to
> > > integer multiples may be best. Scaling the font up at compile-time
> > > seems like unnecessary bloat to the binary (although I'm not sure,
> > > how big are these fonts?). If you do want to include them at
> > > compile
> > > time, you may as well include a real larger font rather than just
> > > a
> > > scaled one.
-- 
Paul Kocialkowski,

developer of free digital technology and hardware support.

Website: https://www.paulk.fr/
Coding blog: https://code.paulk.fr/
Git repositories: https://git.paulk.fr/ https://git.code.paulk.fr/
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