[Lazarus] Canvas cannot draw properly if has an alpha channel?

zeljko zeljko at holobit.net
Wed Apr 25 20:01:01 CEST 2018

On 25.04.2018 16:30, Anthony Walter via Lazarus wrote:
> I am trying to paint controls, so I need to eventually Canvas.Draw() to 
> get a graphic onto a control. I've been working on creating a fully 
> featured web browser for Lazarus and have been looking at the underlying 
> widgetset interface code.
> Gtk3, which my project currently works great on, uses the now required 
> Cairo system for painting Gtk widgets. I've already had to patch the 
> Gtk3 LCL interface section quite a bit to fix errors and I'll submit 
> those changes when I publish my project.

That would be nice.

> However, the LCL Gtk2 widgetset is stuck using the Gdk system for 
> drawing, even though that was deprecated early on in the Gtk2 lifetime 
> and Cairo has been recommend for a decade or more. I would like to 
> submit a patch for Gtk2 replacing Gdk with Cairo, but using a swtich 
> setting that could be changed at runtime.

+1, maybe add Gtk2UseCairo as default.

.... paths are also welcome, afair win32,qt and gtk2/3 supports paths 
and it can be implemented inside widgetsets.


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