Mail Archives: geda-user/2016/09/19/12:08:00
On Mon, 19 Sep 2016, Dave McGuire (mcguire AT neurotica DOT com) [via geda-user AT delorie DOT com] wrote:
> For my own use, though, while I'm following pcb-rnd development with
> interest, the loss of transparency was a show-stopper for me. I realize
> you don't want to deal with OpenGL (which is definitely the best way to
> do this), but isn't there a practical way to implement transparency
> without it?
I see the following options:
I think gtk/gdk doesn't offer out-of-the-box usable opacity/transparency
with software render. This suggest we'd need to do something like "render
everthing manually in memory using transparency, then copy the result into
a gdk pixmap at the end". Sounds like a lot of work and slow code at the
end. Unless I missed something looking at the APIs, this just wouldn't
work.
The short term solution would be resurrecting the opengl code (through
contribution or donation).
I don't plan migration to gtk3, so my long term plan is an sdl2 based HID,
that will survive a gtk2 phase-out (I won't remove the gtk HID, but
distros will stop delivering the required libraries sooner or later). As a
side effect sdl2 has support for alpha channel both with and without
opengl so it would be much easier to solve there. I plan to have optional
transparency in the sdl HID. I don't know how good the opengl support in
sdl2 is, but it might also solve the gl problem. There's no ETA on this
project yet, it's a rathr big chunk. But as cschem needs a GUI too, and it
will definitely be sdl2 too, it will happen sooner or later.
Regards,
Igor2
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