[poppler] LCD filtering

[Tobias Wolf]

On Di, 2008-05-13 at 11:27 -0700, Carl Worth wrote:
> On Tue, 13 May 2008 19:54:48 +0200, Albert Astals Cid wrote:
> > A Dimarts 13 Maig 2008, towolf at gmail.com va escriure:
> > > Can we enable FreeType's/Cairo's subpixel rendering mode in Poppler?
> > > Just asking whether that's possible.
> >
> > More info needed.
> >
> > What's that?
> >
> > Should it be always on or configurable by the application?
> >
> > How does one enable it?
> 
> The mode is selectable with:
> 
> 	cairo_font_options_set_antialias (font_options,
> 					  CAIRO_ANTIALIAS_SUBPIXEL);
> 
> But poppler really shouldn't need to be calling this
> explicitly. Instead, cairo should be setting the font options
> automatically so that when cairo renders to an X surface, the subpixel
> settings are enabled by default if the user has configured his system
> to do so, (such as with GNOME or KDE font-rendering preferences).
> 
> Tobias, what kind of surface are you rendering to? And do you have
> your system font settings set to do sub-pixel rendering?

Oh, just a user here (of evince). I have subpixel rendering everywhere
(but Evince) via the premature inclusion in Ubuntu of similar patches
to 

Cairo: http://bugs.freedesktop.org/show_bug.cgi?id=10301
and Fontconfig: http://bugs.freedesktop.org/show_bug.cgi?id=13566

i.e. the new methods FT_LCD_FILTER_*

Poppler seems not to care, and I just stumbled upon a poposed patch at:

Poppler: https://bugs.freedesktop.org/show_bug.cgi?id=3307

It looks like it does what you suggest, Carl, but it also does strange
things like hard-coding the RGB order. I don't know about the caveat
mentioned by the submitter, but the Screenshots look like they do what I
want. The difference is striking.

--Tobias


> -Carl