Re: New balance-windows

[Pascal Bourguignon]

"Ehud Karni" <ehud@unix.mvs.co.il> writes:
>> Well, I can arrive at
>>
>> -------------------------
>> |           |X          |
>> |           |           |
>> |           |           | configuration
>> -------------------------      0
>> |           |           |
>> |           |           |
>> |           |           |
>> -------------------------
>>
>> with enlarge-window from either
>>
>> -------------------------
>> |           |X          |
>> |           |           |
>> |           |-----------| configuration
>> ------------|           |     1
>> |           |           |
>> |           |           |
>> |           |           |
>> -------------------------
>>
>> or
>>
>> -------------------------
>> |            |X         |
>> |            |          | configuration
>> |            |          |      2
>> -------------------------
>> |           |           |
>> |           |           |
>> |           |           |
>> -------------------------
>>
>> If I now do another enlarge-window, I would be surprised if the
>> direction of enlargement would suddenly change.
>
> The direction of enlargement (vertical or horizontal) is given by
> the user, how could that be changed by the split tree.

Look at the problem from the other side!  

Why the user could not start from configuration 1 above, enlarge
window X to reach configuration 0, and then enlarge window X in the
other direction to reach configuration 1?

The only reason it's not possible is because emacs cast it in C
firmware, instead of leaving it up to user emacs lisp code.

If the split tree was available, one could easily swap some split
nodes without changing the window leaves, to change the direction and
enable that.

For example in this configuration:

+---+---+
| 1 | 3 |
+---+---+
| 2 | 4 |
+---+---+

we would have a split tree such as: (H (V 1 2) (V 3 4)) 
if the user clicked on 1|3 separation to move it horizontally, we
could change the split tree to: (V (H 1 3) (H 2 4))

+----+--+
| 1  |3 |
+---++--+
| 2 | 4 |
+---+---+



On the other hand, perhaps we need to add something to this split tree
idea, to alloww the emacs user interface easily let the use move the +
in the middle in any direction, to let the user go from configuration
0 to this in one click-and-drag:

+-+-----+
|1|  3  |
+-+-----+
| |     |
|2|  4  |
| |     |
+-+-----+

in addition to allowing indiscriminate horizontal or vertical window
resizing.


> As I said this is only a technical difficulty. I know Emacs behave
> this way, but this is because of the design of Emacs.
>
> I expect that when we have configuration 0 (even if we got there going
> through configuration 2 and not from 1), and we do enlarge-window
> (on window with X) we'll get:
>
>  -------------------------
>  |           |X          |
>  |           |           |
>  |           |           | expectation
>  ------------|           |
>  |           |-----------|
>  |           |           |
>  |           |           |
>  -------------------------
>
> And the way Emacs works is to move the whole border like this:
>
>  -------------------------
>  |           |X          |
>  |           |           |
>  |           |           | current behavior
>  |           |           |
>  ------------------------|
>  |           |           |
>  |           |           |
>  -------------------------


-- 
__Pascal Bourguignon__                     http://www.informatimago.com/
-----BEGIN GEEK CODE BLOCK-----
Version: 3.12
GCS d? s++:++ a+ C+++ UL++++ P--- L+++ E+++ W++ N+++ o-- K- w--- 
O- M++ V PS PE++ Y++ PGP t+ 5+ X++ R !tv b+++ DI++++ D++ 
G e+++ h+ r-- z? 
------END GEEK CODE BLOCK------