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Re: Use cases for post-redisplay hooks
From: |
Clément Pit--Claudel |
Subject: |
Re: Use cases for post-redisplay hooks |
Date: |
Thu, 7 Jul 2016 12:08:09 -0400 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.8.0 |
On 2016-07-04 18:50, Keith David Bershatsky wrote:
> The reason I mentioned the `window-scroll-functions` hook was an
> assumption (on my part) that Clément had initially categorized my
> potential usage of the proposed `post-redisplay-hook` as only
> relating to scrolling. I just wanted to clarify / differentiate my
> proposed use case as needing `window-start` and `window-end` each
> command loop.
IIUC then the post-redisplay-hook thing wouldn't work very nicely: in general,
it's going to run more often than once per command loop cycle.
> With respect to the hook running more than once each command loop, it
> is only a problem for me because my calculations are costly time-wise
> (e.g., `vertical-motion'). So, I only want to do it one time each
> command loop.
Would registering a post-command hook and incrementing a counter in there help?
You would then predicate your costly calculations on the value of that counter
having changed since the last time the calculations ran.
Even simpler: in a pre/post-command hook switch a `needs-recalculation' flag to
t, and after completing the calculations (from whichever other hook you're
using for them) switch `needs-recalculation' to nil. If the function doing the
calculations is called when `needs-recalculation' is nil, then can exit
immediately.
Or is there something more complex that I'm missing?
Clément.
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- Re: Use cases for post-redisplay hooks, (continued)
- Re: Use cases for post-redisplay hooks, Eli Zaretskii, 2016/07/04
- Re: Use cases for post-redisplay hooks, Stefan Monnier, 2016/07/04
- Re: Use cases for post-redisplay hooks, Clément Pit--Claudel, 2016/07/10
- Re: Use cases for post-redisplay hooks, Keith David Bershatsky, 2016/07/04
- Re: Use cases for post-redisplay hooks, Keith David Bershatsky, 2016/07/04
- Re: Use cases for post-redisplay hooks, Keith David Bershatsky, 2016/07/05
- Re: Use cases for post-redisplay hooks, Keith David Bershatsky, 2016/07/07
- Re: Use cases for post-redisplay hooks, Keith David Bershatsky, 2016/07/07