Re: Intelligent stacking of messages in the echo area

[Ihor Radchenko <yantar92@gmail.com>]

> Maybe this is because multi-line messages resize the echo-area window
> every time a new message line is added (when resize-mini-windows is non-nil),
> so height changes of the echo-area window invoke window-configuration-change-hook.

I suspect that it is exactly the case.
However, window-configuration-change-hook is not fired so frequently in
other functions like split-window.
Most likely, it is because window-configuration-change-hook is only
called during redisplay. From its docstring:
"Functions called during redisplay when window configuration has
changed."

I guess that resizing echo-area forcefully calls redisplay and hence
window-configuration-change-hook, thus slowing down command execution.

Best,
Ihor

> Now for the multi-message feature where multi-line messages are
> not an exception but a rule, one way to mitigate it is to use
> a message separator other than a newline, e.g.
>
> (setq multi-message-separator (propertize ";" 'face 'minibuffer-prompt))
>
> In a wide frame, one echo-area line can accommodate several short messages
> without resizing the echo-area window.

This is a workaround, not a solution.
Also, I am using a laptop with small screen and this workaround does not
really work for me (at least for org-capture, which emits fairly long
messages).



Juri Linkov <juri@linkov.net> writes:

>> I was testing the code for a while.
>> There seem to be one irritating (for me) problem with the way
>> set-message-function is implemented.
>> When I run a command changing current buffer and emitting multiple
>> messages, emacs frame is redrawn every time a new message comes out.
>> Specifically, I was running org-capture, which changes windows
>> configuration, switches to different buffer, and emits multiple messages
>> while running. Normally, it runs very fast (the capture template I used
>> does not require any user input), but with multi-message, I can see the
>> frame being redrawn on every new message popping up. Since window
>> configuration is different, full redraw is forced and the whole
>> org-capture runs a lot slower.
>
> Maybe this is because multi-line messages resize the echo-area window
> every time a new message line is added (when resize-mini-windows is non-nil),
> so height changes of the echo-area window invoke window-configuration-change-hook.
>
> It seems the same problem existed for a long time, but had no noticeable effect
> because multi-line messages were rare.
>
> Now for the multi-message feature where multi-line messages are
> not an exception but a rule, one way to mitigate it is to use
> a message separator other than a newline, e.g.
>
> (setq multi-message-separator (propertize ";" 'face 'minibuffer-prompt))
>
> In a wide frame, one echo-area line can accommodate several short messages
> without resizing the echo-area window.

-- 
Ihor Radchenko,
PhD,
Center for Advancing Materials Performance from the Nanoscale (CAMP-nano)
State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an, China
Email: yantar92@gmail.com, ihor_radchenko@alumni.sutd.edu.sg