[Lazarus] Alpha transparency on GTK2 widgetset

Kostas Michalopoulos badsectoracula at gmail.com
Sat Jan 4 14:00:56 CET 2014


I have a problem with the GTK2 widgetset: it doesn't seem to support
alpha channel. I'm using TLazIntfImage and related classes/objects
(TRawImage) to load and display images (converting from/to custom
bitmap structure to "native" structures so i can use them with canvas
for drawing, adding them to imagelists for use with icon views, tree
views, comboboxes, menus, etc). This works fine in Win32 and from a
quick test it seems to work in Qt4 too, but for the latter i'd like to
avoid it since i'm not using a Qt-based desktop myself and i prefer
GTK+. Also i would like to avoid the qt4pas dependency.

By looking around the bugtracker it seems that other people encounter
the same issue - some bugreports are old, like Graeme's one about
missing transparency from 2012.

What is the problem with (full) transparency in GTK2? Is anyone working on this?


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