Re: Exposing cairo based implementation of CSS as an API in GTK+/gtkmm

[Samik Ganguly <sganguly87 gmail com>]

Hello Emmanuele,
    sorry for the wrong mailing list and thanks for the reply. I've 
went ahead and searched further for any news on this scene-graph API and 
found your blog entry on 
it(https://www.bassi.io/articles/2014/07/29/guadec-2014-gsk/). Looks 
like this process has been going on for 2 years now, which is good 
because I guess we'll be able to use it soon :) I was looking at Qt API 
too and looks like they have a scene graph implementation in place now. 
But I'm sticking to gtkmm and cairo for now and keeping things ready to 
be ported to GSK soon.
Regards,
Samik Ganguly

On Thursday 30 June 2016 09:18 PM, Emmanuele Bassi wrote:
> Hi;
>
> On 25 June 2016 at 12:45, Samik Ganguly <sganguly87 gmail com> wrote:
> > Hello Gtk+ developers,
> if you're trying to reach the GTK+ developers you're using the wrong
> mailing list; you want to use gtk-devel-list. I've added the list to
> the Cc:
>
> >      Gtk+ implements various CSS3 functionality so that widgets can be styled
> > with CSS. As far as I understand these effects are implemented with cairo
> > drawing API. Is there any chance to expose some of the effects such as
> > blurred shadow, transitions etc. as generic functions in Gtk+ API so that
> > they can be used without CSS?
> No, there are no plans.
>
> The CSS-based drawing is heavily tied to the state defined by the CSS
> machinery, and that section of the API is private (for good reasons,
> given the speed with which it's been changing and it's supposed to
> change in the future).
>
> > For example, if someone is doing some custom drawing with cairo on Gtk+ such
> > as non rectangular widgets, curves with shadow etc. then they can take
> > advantages of such API instead having to implement those effects with cairo
> > themselves. For rectangular widgets StyleProvider's draw_background,
> > draw_frame methods can be used to specify such effects in CSS, but for
> > others I'm guessing they're probably not suitable.
> The overall plan is to make widgets more lightweight and easier to
> compose — similar to "<div>" elements in HTML. The idea is that if you
> want something that draws with CSS semantics, you will be able to use
> widgets.
>
> Additionally, the plan is to add a Clutter-like scene graph that sits
> below GTK, for UIs that do not rely on complex widget semantics (like
> media player UIs or games).
>
> Ciao,
>   Emmanuele.