bug#20189: 25.0.50; Feature request: Alternative split-window-sensibly functions

[martin rudalics <rudalics@gmx.at>]

 >> Then how comes you "eventually end up with three side-by-side windows
 >> each of size 86x82"?
 >
 > No, I don't end up with that.  If I had the split function I imagined,
 > then I would end up with that configuration.  So that's the goal I want
 > to achieve but for which I have no solution.

I see.  I thought there was some black magic involved when I read your
first post ;-)

 >> By default you should get one window with 135 columns and two windows
 >> with 67 columns, approximately.
 >
 > Indeed, that's what I get with C-x 3 C-x 3 starting from a single window
 > of size 269x82 and the default value of `window-combination-resize' and
 > `window-combination-limit'.
 >
 > With
 >
 >    (setq window-combination-resize t
 >          window-combination-limit nil)
 >
 > two consecutive C-x 3 starting from the big single window results in
 > three side-by-side *balanced* windows, each being 86x82 large.  That's
 > actually what I wanted.  However, I'd like that this splitting behavior
 > was the default for `display-buffer'.  But that fails because after the
 > first horizontal split, `window-splittable-p' says that both horizontal
 > windows aren't horizontally splittable anymore because they are narrower
 > than `split-width-threshold'.

If you set `split-width-threshold' to zero and `split-height-threshold'
to nil you should get the behavior you want.

 > I've come up with a solution which seems to fit my preferences quite
 > nicely although it's probably quite hackish and ignores possible
 > contracts that might exist for dedicated windows, fixed-size windows,
 > side windows and what else there might be.

You should be able to simplify your code by using idioms from the below.

(defun th/split-window-sensibly (_window)
   (let ((root (frame-root-window))
	(window-combination-resize 'resize))
     (cond
      ((>= (/ (window-total-width root) (window-combinations root t)) 80)
       (split-window (window-last-child root) nil 'right))
      ((>= (/ (window-total-height root) (window-combinations root)) 40)
       (split-window (window-last-child root) nil 'below))
      (t
       (split-window-sensibly window)))))

martin