Re: Ideas for a new GTK+ theming

["Robert Staudinger" <robert staudinger gmail com>]

Hi Hagen,

On Mon, Oct 6, 2008 at 5:45 PM, Hagen Schink <hagen schink st ovgu de> wrote:

[...]

> Engine API:
> - -----------
>
> At the moment the designer can only modify as much details of a theme as the engine provides. That is why I propose a more data driven approach based on SVG. It is standardized and there are a lot of sophisticated tools to create and modify SVG files. It also offers the possibility for the modification via CSS [2]. Even animation would be possible [3].
>
> With librsvg a powerful library exists but it has to become more powerful if it should be usable for theming. I've spoken with the developer, he said he lacks time so it would be on others to provide patches.


As I told you on IRC, what you are proposing here is very well
possible on top of the current engine API. However, it is important
not to confuse the issues at hand, just because the SVG standard
mentions animations that does not mean it's easily possible with
librsvg and/or fitting the way how gtk deals with widgets.

Also, just starting to write an engine you will have to do a
considerable amount of footwork to get where all the other engines are
already.

What about a more ambitious "reseach project" approach? You could for
example try to render an entire GtkWindow with all its children using
generated SVG in webkit or gecko. That would give you the ability to
actually do animations and you could apply all kinds SVG filters
across widget bounds to achieve effects.

Start with implementing proxy classes for GtkWindow, GtkHBox and
GtkButton that produce the SVG,  keep the SVG representation in sync
with the gtk widget and propagate events. Once you have left behind
the constraints of the gtk drawing model it should be way easier to
prototype new theming approaches, like loading SVG images to represent
a GtkButton.

- Rob