[sugar] sugar system font in cairo

[Erik Blankinship]

Thanks, that sample code is very helpful for making the transition from
cairo text rendering to cairo+pango text rendering.

Are there python examples for pango font metrics?
When just using cairo's font rendering, I would make calls such as
x_bearing, y_bearing, width, height, x_advance, y_advance = ctx.text_extents(
"how do i measure this in pango?" )

How do I measure these attributes in pango?

Thanks
Erik

On 11/9/06, Behdad Esfahbod <besfahbo at redhat.com> wrote:
>
> On Mon, 2006-11-06 at 21:08 -0500, Erik Blankinship wrote:
> > Thanks for the warning about cairo's font rendering.
> >
> > Could you please send a reference to how to use pangocairo with
> > pycairo?  I think that would be helpful for everyone on this list who
> > might use text in their application.
>
> Attaching a complete test case.  If you can find your way in the
> example, the better, otherwise some explanation follows that may be
> helpful mapping the C APIs to the pygtk ones.
>
>
> In the C API, there are three objects of interest:
>
>   cairo_t
>   PangoContext
>   PangoLayout
>
> You can get a cairo_t for your widget using
>
>         gdk_cairo_create (widget->window)
>
> You can also get a PangoContext using
>
>         gtk_widget_get_pango_context (widget)
>
> You can create a PangoLayout either using a PangoContext:
>
>         pango_layout_new (pangocontext)
>
> or get it directly from the widget:
>
>         gtk_widget_create_pango_layout (widget)
>
> There's also a third way, which is to create one using a cairo_t:
>
>         pango_cairo_create_layout (cr)
>
>
> Of these, you should avoid the last one if possible, because that
> doesn't derive font and other properties from the widget style.
>
>
> In pygtk, there is a convenience class hierarchy that doesn't really map
> to the C api, so it's worth mentioning to reduce confusion:
>
> There is the cairo.Context object which is a cairo_t.
>
> Then there is a pangocairo.CairoContext object which is a descendant of
> cairo.Context, with additional methods mapping to the functions like
> pango_cairo_create_layout() and pango_cairo_show_layout()...  It
> actually makes sense, since those are functions taking a cairo_t as
> their first argument, so they can be thought of as extended cairo_t
> methods.
>
> Then there is gtk.gdk.CairoContext that derives from
> pangocairo.CairoContext and extends that with some gdk methods, namely
> set_source_color and set_source_pixbuf.  Those too map to gkd_cairo_*()
> functions that take a cairo_t as their first argument.
>
> Now the cool part is that widget.window.cairo_create () returns a
> gtk.gdk.CairoContext, so you can do a show_layout() on it directly,
> without having to create a pangocairo.CairoContext out of it.
>
> The only thing to note is to not use the widget.window.cairo_create ()
> context to create a PangoLayout directly (create_layout()) and use
> widget.get_pango_context() instead, for reasons stated above.
>
> behdad
>
>
> > Erik
> >
> > On 11/6/06, Behdad Esfahbod < besfahbo at redhat.com> wrote:
> >         On Fri, 2006-11-03 at 17:27 -0500, Erik Blankinship wrote:
> >         > Hello
> >         >
> >         > If I want to use the system font in my cairo context, where
> >         do I find
> >         > the font file to load in?
> >
> >         NEVER EVER use cairo's text rendering capabilities to render
> >         any text.
> >         Not in olpc at least.  Use pangocairo ALL THE TIME.
> >
> >         And for families, like others suggested, use "sans-serif",
> >         "serif", and
> >         "monospace".
> >
> >
> >         > Thanks,
> >         > Erik
> >
> >         --
> >         behdad
> >         http://behdad.org/
> >
> >
> >
> --
> behdad
> http://behdad.org/
>
>
>
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