Re: [9fans] ttf2subf + VeraMono rendering

[erik quanstrom <quanstro@quanstro.net>]

> I can confirm that the problem happens with a plan9 terminal and the
> vera.ttf font running as a guest OS in VMware workstation 5.5, I'd
> thought it was an oddity of my setup.
> 
> > However this doesn't happen in acme window, it happens only to the
> > terminal window.
> 
> > Any hints how to avoid this?

you need an updated rio/libframe/devdraw.  the problem is that libframe
used to do an alpha draw on top of the current screen image.
with a subpixel antialiased font, there are many pixels with 
an alpha channel between 0 and 0xff, so drawing a character
on top of itself will result in these pixels becoming darker.
so when you deselect a window and reselect it (causing the text
to be redrawn grey and then black), the old algorithm would
cause pixels with an alpha channel between 0 and 0xff to become
darker, making the text look pretty blocky.

this was fixed may 15, 2006, i believe.  i use a subpixel antialiased font.
(/n/sources/contrib/quanstro/antialias.tar /lib/font/bit/cyberbit/mod14.font)

by the way, i don't think acme ever had this problem.

- erik