Re: [gsl-dev] GTK+ v FLTK

[Havoc Pennington <hp redhat com>]

On Sun, Apr 27, 2003 at 01:04:40AM -0700, Edward Peterlin wrote:
>  E.g., it is possible for code to request "hey you, draw 
> a button with the following label here" and (alebit with a little 
> better architecting) it draws the button in whatever underlying 
> mechanism it wants, be it through a native widget, native bitmap draw 
> requests (current approach in Neo), or the existing VCL abstraction.  

Right, this is how an emulating toolkit would normally match the
target platform visually; all of WinXP and OSX and GTK+ and Qt 
provide "draw the button" type of functionality, and you call their
drawing code.

Basically, it's just "themes"

This is only look though, not feel. And doesn't cover widget-spanning
aspects of look as you'd find in UI guidelines.

GTK's mechanism for feel is a thing called a style property, which is
just a setting that modifies behavior. One thing one could do to
improve platform emulation for GTK would be to go around adding more
such properties to let widgets be more closely tuned to a specific
platform.
 
I'd expect if you improve VCL's emulating properties, you'd want a
similar mechanism.

> There is absolutely NO reason we need to move to GTK or ANY OTHER 
> "cross-platform" toolkit for the sheer purpose of drawing buttons in 
> the appearance of a specific platform and widget set.  

However, it's probably easier to draw the buttons using the GTK theme
if you link to and use the GTK core when on unix. i.e. use GTK rather
than Xlib. Well, basically you *have* to do that to some extent, 
GTK can't draw to a plain Display*, it needs a GdkDisplay*.

Havoc