Re: porting to Wayland

[Daiki Ueno <ueno@gnu.org>]

Hi Jan,

Thanks for the comment.  Glad to hear from the right person.

Jan Djärv <jan.h.d@swipnet.se> writes:

> I have updated the YAMAMOTO Mitsuharu patch:
> http://lists.gnu.org/archive/html/emacs-devel/2009-04/msg00390.html

I missed it, thanks for the pointer.

> It does not add another window system, rather expands the xterm.c code.
> I was expecting that Gtk3+ and Cairo together would let us re-enable
> double buffering in Gtk and thus get that for free.  Unfortunately
> this did not work, as Gtk needs to do its drawing in the event loop,
> like the NS port needs to do as mentioned in #17124.

Yeah, it would be ideal that the single stack (Gtk3+ and Cairo) supports
all the underlying display system.

> I will probably check this in if I get round to writing all those
> ChangeLog entries and fix the image things.  There is actually not
> much user benefit from using Cairo, except Mitsuharus printing
> extension.  For Wayland, there is XWayland.

> Using Cairo is actually slower than using X, sometimes visible
> so. Making Cairo draw the same way we draw in X may be a suboptimal
> way to use Cairo.

However, on Wayland, I feel rendering through XWayland rather slower
than using Cairo directly.  Even the 'M-x butterfly' animation is not
very smooth (few glyphs are visible before being cleared).  Maybe I
should have measured the speed before coding.

Anyway, my intention was to understand more about the redisplay stuff,
not to propose code for merge, so I'm already rewarded :-)

Regards,
-- 
Daiki Ueno