Re: frame title is not updated often enough

[Colin Marquardt]

Richard Stallman <rms@gnu.org> writes:

>     However, with Emacs 21, the window title updates only every once in a
>     while (e.g., not while I type, but if there is some bigger re-display
>     going on).
>
> The frame title is updated only in special situations as an efficiency
> measure; the mode line too.  Emacs has special code to recognize it
> should update the mode line more often when the column number is
> shown, and also to optimize when the column number is unchanged.  We
> could do something similar for the frame title, but do you really want
> to update the frame title after most Emacs commands?  I am sure it is
> slower to update the frame title than the mode line.
>
> What was your reason for putting it in the frame title instead
> of the mode line?

Well, the mode line is getting more clobbered the more minor modes
are active. Sure, I could change the mode line format, but the frame
title does not have this problem at all. With a different mode line
format, adaptations might even be necessary over time as I install
new packages. Also, a non-standard mode line format makes it a bit
harder to orient oneself on other people's Emacsen.

How about adding that special code for the frame title also, and warn
the user (in the docstring) about a possible slowdown if
frame-title-format has dynamically changing values? I could probably
live with a slight slowdown.

In any case, the docstring for frame-title-format should mention that
it is lazily updated, patch attached (against the released 21.1).
Should the same be done for e.g. icon-title-format?

In the end, we might even want to have a multi-line mode line...

Cheers,
   Colin

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