Re: [matplotlib-devel] MEP 27 Backend Refactor (Gcf)

[OceanWolf <jui...@ya...>]

Okay, just about finished WebAgg, but it has raised an interesting 
question about layout...
I started working to standardise using the way we do it on ``Gtk3``, 
i.e. using a pure vertical layout, adding elements from either the top 
or the bottom of the container and setting widgets (i.e. the canvas) as 
expandable.  In my original version of this MEP I used a boolean to 
specify whether to add to the beginning or the end of the window's 
layout.  ``Tk`` gave me the idea to extend past this and use string 
argument of 'top' or 'bottom', no real difference but just to keep it 
flexible for the future.

However now I rethink that strategy having converted Qt and now on 
WebAgg, perhaps we should conform around a Grid layout, by that I mean 
we have the following:

           North
----------------------------
    |                      |
E |                      | W
a |     Centre      |  e
s |                      |  s
t |                       |  t
    |                      |
---------------------------
           South

For now we will just use Centre and South (with the canvas in Centre; 
and Toolbar/statusbar in South), but it also leaves it open for the 
future.  If I recode it like this, I would make each 5 positions a box, 
with the compass points adding elements from the outside inwards which 
keeps the pattern explained above.

What do people think?  I don't feel 100% comfortable for limiting 
ourselves to just one layout, but I can persuade myself that we have to 
decide on something and atm we only have a really adhoc system, so 
definitely an improvement, and should anything happen in the future to 
make us change our mind we can the workaround of using centre as our new 
starting point, or wait for a major release.

Looking forward to getting some feedback on this.