Re: gtk_widget_queue_draw_area much slower in gtk3 than gtk3

[Stefan Salewski <mail ssalewski de>]

On Sun, 2015-03-29 at 22:16 -0700, dmg wrote:
> Hi there,
>
> I am one of the developers of xournal.

Hello,

if I understand correctly, your problem is, that shapes drawn on screen
are not smooth.

I can remember a related thread, see

https://mail.gnome.org/archives/gtk-list/2014-August/thread.html

where the problem seems to be more the low rate of input events. It may
well be related to your task, because with input events only every 12 ms
it is hard to draw smooth shapes. I have never further investigated this
task, because it does not really concerns my application currently. (I
was only concerned about smooth moving objects, but for moving we are
always limited by 60 Hz screen refresh rate, so input events every 12 ms
is OK. But I would really like being able doing smooth free hand
drawing) It is interesting that you observed a difference in behaviour
to GTK2.

In case that you should not get an answer from a smart developer soon,
it may really help making a minimal example for your observation,
preferable in plain C, and maybe send the question to gtk-list too. You
may start with the GTK3 scribble window from
https://developer.gnome.org/gtk3/3.0/gtk-getting-started.html
maybe modify it that it draws plain points or thin line segments.

Obviously this problem my depend on hardware and OS strongly!