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Re: Side effects in `tooltip-show'
From: |
Eli Zaretskii |
Subject: |
Re: Side effects in `tooltip-show' |
Date: |
Mon, 17 Jan 2022 14:41:49 +0200 |
> From: Po Lu <luangruo@yahoo.com>
> Date: Mon, 17 Jan 2022 09:30:16 +0800
>
> I'd like to install a fix for a regression in the release branch: since
> `equal-including-properties' is used in Emac 28 to compare tooltip
> strings with their previous values, this branch in tooltip-show-help is
> never reached:
>
> ((equal-including-properties previous-help msg)
> ;; Same help as before (but possibly the mouse has moved).
> ;; Keep what we have.
> )
>
> Because tooltip-show mutates the text properties of any string passed to
> it. This causes a lot of flicker when the mouse is moved around.
>
> The fix is to copy the string passed to `tooltip-show' before modifying
> its text properties, like this:
I'm not happy about consing a new string each time we have a help-echo
event. That'd definitely increase the GC pressure, which is
undesirable.
How about using 'equal' to compare the strings instead? What are the
chances that two help-echo strings of 2 different tooltips will
compare equal without the properties, but not with the properties?
Re: Side effects in `tooltip-show', Pankaj Jangid, 2022/01/18