GTK-3 themes: cocoa theme proposal

[Jérôme Lambourg <lambourg adacore com>]

Hello list,

I’m not sure if this is the right list for this email, feel free to blame me (and indicate me where to post 
it) if I’m not in the right place. I thought first to post in on the osx-specific list, but this is a more 
general concern for gtk I think.

I started implementing a native theme for OSX using Cocoa primitives (NSCells mainly, plus other OS-specific 
APIs). To do so, I took the win32 theme example, and so patched the theme directly into gtk itself (plus a 
bit of enhancements to gdk, but that’s ok as this is in the quartz-specific part) to handle so-called 
cssimages for the widgets backgrounds (redirected to drawing primitives of the OS), specific metrics in the 
form of -gtk-quartz-metric as well as colors in the form of -gtk-quartz-color(<parameter>).

In my opinion that’s a lot of hacking directly into gtk, and this does not look right. Are there any plans to 
allow theme engines to perform this kind of customisation ? Something I missed ? Is there a better way to 
allow me to perform those os-specific css-like values that are: color definitions, metrics for widgets, fonts 
name and size, and widgets background images ?

Thanks in advance for your comments.
Kind regards,
- Jerome