Re: Aborting display. Is this possible?

[Michael Welsh Duggan <mwd@cert.org>]

Alan Mackenzie <acm@muc.de> writes:

> On Mon, Oct 20, 2014 at 10:24:54PM +0300, Eli Zaretskii wrote:
>> > Date: Mon, 20 Oct 2014 18:57:57 +0000
>> > From: Alan Mackenzie <acm@muc.de>
>> > Cc: emacs-devel@gnu.org
>> >
>> > So, how about the following strategy: when the (new) variable
>> > `face-instead-of-fontifying' is bound to a face, AND the input queue is
>> > non-empty (or, perhaps, very non-empty), the appropriate subroutine of
>> > window-scroll should deem characters without a `face' (or `fontified' ?)
>> > property to have face `face-instead-of-fontifying'.
>
>> > This should empty the input queue pretty quickly, enabling a current
>> > buffer portion to get displayed frequently enough.
>
>> This would mean we will sometimes wind up in the wrong place after
>> scroll.  IOW, you are sacrificing correctness on behalf of some
>> (questionable for now) speedup.
>
> I'd posit that the absolute correctness isn't all that important after an
> auto-repeating PageDown.  For an individual PageDown keystroke, the
> fontification and scrolling would be done accurately as now.

Please be careful.  If you were to change things such that C-v might
scroll heuristically instead of "correctly", please make sure this
behavior is controlled by a configuration value.  When I am trying to
recreate cc-mode problems in order to make bug reports, it is very
important that I can recreate the problem exactly.  It would be very
strange if C-v run manually ended up in a different location than C-v in
a macro, for example.

-- 
Michael Welsh Duggan
(mwd@cert.org)