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Re: Emacs and Gnome Canvas

From: Jan Djärv
Subject: Re: Emacs and Gnome Canvas
Date: Thu, 15 Jul 2010 10:48:12 +0200
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Eli Zaretskii skrev 2010-07-15 10.38:
Date: Thu, 15 Jul 2010 09:46:36 +0200
From: Jan Djärv<address@hidden>
CC: Óscar Fuentes<address@hidden>,

   . Canvas redisplay is caused by requests from the application to
     update some "canvas item" when the underlying application's objects
     are modified; these requests are then served when GTK+ idle
     handlers are run.  Emacs display engine works differently: changes
     that require redisplay are not considered until redisplay is
     entered; the "requests" to update the display are implicitly
     recorded in the buffers and in the various related data structures
     (text properties and overlays, display strings, etc.), but not
     explicitly translated to display terms until redisplay time, and as
     an inherent part of redisplay itself.  These two very different
     models will need to be reconciled in some reasonably efficient way.

The changes that require redisplay would have to notify the Canvas that things
changed.  I think this style is more efficient.

What do you mean by "changes that require redisplay"?  Suppose a
character was inserted or deleted -- would that need to notify the


 How about an arbitrary mouse move?

If it resulted in a different highlightning of a link, yes.

        Jan D.

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