Re: [Gtk2hs-users] Changing font options

[Axel S. <Axe...@en...>]

On Fri, 2009-01-30 at 14:20 +0100, Peter Verswyvelen wrote:
> I'm trying to change the FontOptions in a PangoContext using
> 
> Graphics.UI.Gtk.Cairo.cairoContextSetFontOptions:: PangoContext ->
> FontOptions -> IO ()
> 
> However, all the FontOptions stuff is inside the Render monad.

Yes, it seems that this is unnecessary. We could probably generalise the
types to be MonadIO m => ... -> m (). This way, the functions would be
backwards compatible.

> Therefore it seems I first need a surface before I can actually change
> anything in the FontOptions, although clearly the FontOptions have
> nothing to do with surfaces?

A surface has a default FontOptions structure, but that's about it. So,
yes the FontOptions structure is totally separate.

> So I could create a dummy image surface for doing this, but this feels a bit...
> 
> So is it possible to run the Render monad *without* a surface? Or do
> the FontOptions functions need a surface? If they don't, then maybe
> these functions don't belong in the Render monad?

The latter.

> Also, it seems the FontOptions have no effect on the "toy API"
> textPath function.
> 
> Since I only need the toy API functionality, is it possible to make
> the font options apply to the "toy API" too?

I think this is due to our incomplete binding. What we're missing seems
to be the function "cairo_set_font_options" which would be called
setFontOptions in Haskell. We have setFontMatrix, but we lack the
anything to actually apply the font options again.

These changes won't be big, but I don't know if its too late to into the
release. Pete?

Axel.