[xmonad] Bluetile

[wagnerdm at seas.upenn.edu]

Quoting Gwern Branwen <gwern0 at gmail.com>:

> On Tue, Aug 25, 2009 at 7:09 PM, Jan
> Vornberger<Jan.Vornberger at informatik.uni-oldenburg.de> wrote:
>>> - XMonad.Hooks.WorkspaceByPos
>>>     No idea. What I did notice is that it looks like it could use  
>>> the Maybe monad!
>>
>> WorkspaceByPos is only useful in dual-head setups. If you open a new
>> window it looks at the position where it wants to go and moves it to the
>> correct workspace - as opposed to just assigning it to the active
>> workspace. That's also very helpful when starting up in a dual-head
>> setup. If you already have windows open and then start Bluetile, they
>> are correctly assigned to the two visible workspaces, instead of all
>> being moved onto one workspace.
>
> Hm. The one it 'wants to go' to? You mean some apps detect that there
> are multiple physical screens and choose to go to #2 instead of #1, or
> something? (What apps do this, and why?)

When an X window appears, it has a chance to request a particular  
geometry (size and shape on the screen).  There are lots of good  
reasons for this to happen.  Some apps have a "-geometry" argument on  
the command line, some detect the shape of the screen and try to show  
up in the center of the screen (or the center of one of the screens,  
if their developers are Xinerama-savvy), some request the same  
geometry as when they were closed the last time, and so on.  I assume  
WorkspaceByPos detects which screen an app "wants to go to" by where  
the requested geometry would put it.

With these use cases in mind, it seems useful, and perhaps even a nice  
feature.
~d