Re: Is it ok to use (redisplay), or should this be left to the experts?

[Joost Kremers <joostkremers@fastmail.fm>]

On Fri, Jan 11 2019, Eli Zaretskii wrote:
>> It seems that a call to (redisplay) also does the trick, but 
>> I'm 
>> hesitant to add this, because, well, I'm not sure why, exactly, 
>> it's just that I'm not entirely sure when, i.e., in what 
>> circumstances, (redisplay) is meant to be used, what side 
>> effects 
>> to watch out for (in any), etc.
>
> There should be no problem with invoking 'redisplay', it just 
> slows
> down the program a bit, especially if the code in question will 
> or
> might be executed frequently.

It's only called once, when the relevant minor mode is activated 
for the first time, so that shouldn't be an issue.

>  However, sit-for is IMO better, because
> in some use cases you must allow for the window manager to 
> respond to
> the full-screen request and for Emacs to receive a notification 
> from
> the window manager.  And that means waiting for some short time.

An unpredictable amount of time, I guess. Although it's unlikely 
to be very long, if I handle the problem by introducing an 
artificial delay, it would have to be long enough to handle the 
slowest of slow computers. Which might be a noticeable delay, 
which would inconvenience everyone else...

>> So I guess what I'm asking is whether someone can tell me 
>> whether 
>> (redisplay) is the right way to deal with this issue, or 
>> whether 
>> there is a better way. Or perhaps the user is SOL and needs to 
>> do 
>> some local configuration to get things to behave?
>
> I cannot answer this because it isn't clear to me who initiated
> full-screen: the user or the package.  If it's the package, then 
> the
> package should also accommodate these issues, perhaps only when 
> the
> frame size changes significantly.

Yes, it's the package that initiates full-screen. And I suspect 
that in most cases, it will be a significant size-change.

So I'm leaning toward Stefan's proposed solution, which is to use 
`window-size-change-functions'...

Thanks,

-- 
Joost Kremers
Life has its moments