Widget Overlays

[Matthew Bucknall <matt mattbucknall com>]

Hello!

I'm working on a UI where I would like, at times, to overlay some icons
on top of a window's normal layout when the user performs certain
operations, similar to the way tool tips appear, except I want the user
to be able to click on these icons, or use the window as normal.

I've been looking around for a solution to performing this kind of
layering in GTK, but have not found a decent solution. Some have
suggested using a fixed container to hold everything, adding the icons
last so they appear on top of everything else. The problem with this is,
GTK widgets are not designed to overlap so there is no guarantee that
things won't mess up, and using a fixed container messes up the layout
flow of widgets.

I've considered hovering undecorated 'always above' top-level windows
above my main window, but the icons are not rectangular in shape, so I
need to deal with transparency (I don't know how), and I also need to
control their position relative to the main window with pixel precision
otherwise things are just going to look wonky.

Any suggestions greatly appreciated.

Thanks,
Matt.