Re: Emacs Mac port

[YAMAMOTO Mitsuharu]

>>>>> On Wed, 17 Apr 2013 07:08:25 +0200, Jan Djärv <address@hidden> said:

> 17 apr 2013 kl. 01:52 skrev YAMAMOTO Mitsuharu <address@hidden>:
>> 
>> My proof-of-concept cairo port was primarily intended for the printing
>> support, not for screen drawing (though it does both).
>> 
>> http://lists.gnu.org/archive/html/emacs-devel/2009-04/msg00390.html
>> 
>> Screen drawing in the cairo port is not so efficient for several
>> reasons.  To make it more efficient, one would need some modest
>> modifications to the current drawing model in Emacs.
>> 
>> 1. Don't draw during redisplay, but mark the updated area dirty so
>> the upcoming exposure event can trigger the actual redraw for the
>> area to be updated.
>> 2. Restrict the actual drawings to those in response to exposure
>> events.  This is the standard way in GTK+ and Cocoa.  That would
>> make double-buffering straightforward in GTK+ builds.

> Double buffering in the Gtk+ is not turned off because of the expose
> handler, but because Gtk+ can not double buffer text/images not
> drawn with Gtk/Gdk primitives, and Emacs uses X primitives.  So
> changing the way expose handler works does absolutely nothing to
> make Gtk+ double buffering easier.

That would be correct in itself.  But my description above is in the
context of cairo.  The cairo context passed via the expose handler is
automatically double-buffered.

                                     YAMAMOTO Mitsuharu
                                address@hidden