Re: window-size constraints

[Stefan Monnier <monnier@iro.umontreal.ca>]

>> I think we should go in the direction of "constraints", which would take
>> the form of Elisp functions.  Every configuration change would
>> correspond to adding&removing constraints, and then try and solve the
>> resulting CSP.  Constraints would come with priorities so that in the
>> case the CSP has no solution, we can choose which constraint(s)
>> to break, or alternatively, the satisfaction of a constraint would not be
>> boolean, so the goal would be to try and maximize the satisfaction.

> We'd still have to decide whether and how to honor buffer-local values
> of variables like `window-min-height'

Of course, we have to honor it.  It's already defined as buffer-local.
It should be easy/trivial to support.  At least window-area-factor was
trivial and I see no reason why window-min-height should be any
more difficult.

> or `split-height-threshold'.

I'm not sure I'd want to include display-buffer in this system, tho
I guess it might make sense.

> When the window configuration changes Emacs often tries to preserve
> proportionally the size of non-fixed size windows as faithfully as
> possible.  How would `balance-windows-area' help here?

I'm not referring to the functionality it provides, but to the way it
does it, i.e. to its code.  But it's really not that important: just let
the C code do its thing, hoping it won't mess up majorly (i.e. it won't
delete windows that don't absolutely need to be deleted), and then do
the actual size-choice in Elisp by trying to resolve the CSP.

> Doesn't it try to give all windows the same size?

Yes, except for the window-area-factor detail, but again, this
isn't relevant, really.


        Stefan