Re: [OT font resolution -- was Re: [Devel] TrueType font-scaling]

[Owen Taylor]

"Joaquin Cuenca Abela" <address@hidden> writes:

> Owen wrote:
> >
> > Vadim Plessky <address@hidden> writes:
> >
> > > |  OK, I think I need to alias address@hidden to
> > > |  foot-in-mouth-list ;-), seem to always make mistakes when posting
> > > |  here... I (for some reason) thought I was replying to a post
> > > |  about the current Red Hat beta, which does behave as above.
> > > |
> > > |  Most Linux setups will either use the physical screen resolution
> > > |  (for Xft) or a fixed value of 75 or 100dpi (for rendering via the
> > > |  core  X protocol)
> > >
> > > Hi Owen!
> > >
> > > AFAIK several graphics adapters supported under XFree86 (ATI and Matrox,
> in
> > > particular) can auto-detect dpi during initialization / X startup.
> > > So, there is no need to pre-define 96dpi if user has modern graphics
> adapter.
> >
> > A) It's very hard to tell _if_ the resolution was probed successfully,
> [snip]
> > C) Unless padding and graphics scale along with the text, large
> >    changes in the DPI used will destroy layouts.
> 
> Amen.  In AbiWord we hardcoded a resolution of 96dpi to get at least a
> decent resolution, but if in the next redhat, users are going to have an
> easy way to choose the "resolution" that should be used for fonts, I will
> like to know how to read it.
> 
> Are we going to pick the right value if we just leave the dpi parameter
> unspecified in the pattern that we pass to fontconfig?

 - If you aren't using Xft, no.

 - If you are using Xft, then yes, but only if Abiword was started *after*
   the user changed the DPI. (The GNOME control center changes the
   X resources that Xft reads to handle non GTK+/GNOME apps.)

   To get change-on-the-fly behavior, you have to hook up to the 
   gtk-xft-dpi GtkSetting (or directly to the Xft/DPI XSETTING)
   I can provide sample code if you are interested.

Regards,
                                        Owen