Re: How to make toolbar with transparent icons

[Owas Lone <hello owaislone org>]

On Sat, Sep 17, 2011 at 2:31 AM,  <kmbruhnk rockwellcollins com> wrote:
> I need to make transparent toolbars and panels that can fade after not
> being interacted with for a certain period of time. The fade level and
> speed must be user configurable and must apply only to the current
> application, not to the whole desktop environment. These toolbars and
> panels must overlay a viewport which is drawn to by a 3rd-party library.
>
> I'm using a theme that imitates Motif with CDE which I created using the
> pixmap engine. I know its slow, but it works well for this application so
> far. Also, I'm using GTK+ 2 with libglade, but am willing to do this part
> without glade if it will work.
>
> I thought I could use transparent button images in the theme and use cairo
> to simply set the alpha level to make them fade. Although I can fade the
> toolbar, the underlying viewport does not show through. I simply get a
> black background in the area that I want to be transparent. Now I'm
> thinking I need an alphachannel-aware theme engine to draw my widgets.
> Murrine might work if I could set the alpha level programmatically,
> instead of setting it in a .h file.


It looks like to me that you'll have to ship your app with a minimal
theme aka style code and read that at runtime and apply to your
widgets.

http://developer.gnome.org/gtk/2.24/GtkStyle.html

If you are using Gtk3, then you need GtkStyleContext.
> Is there a different theme engine that would be better for my application
> that would allow me to set the alpha level dynamically? Or is there
> another, perhaps better, way to superimpose my toolbar on the viewport? Am
> I just missing something obvious?
>
> Thanks in advance,
>
> Kurt M. Bruhnke
> Rockwell-Collins Simulation & Training Solutions
> Email: kmbruhnk rockwellcollins com
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-- 
Owais Lone
hello owaislone org
http://www.owaislone.org