[Urwid] Creating a border around a widget

[Sébastien Pierre]

Ian Ward a écrit :

>> It seems like Filler does not implement the `rows` method... is it on
>> purpose ?
> 
> Yes, Filler is a box widget whose purpose is to add lines above and/or 
> below a flow widget so that it "fills" the area provided to the Filler 
> widget.  Since it is a box widget it needs to be told how many rows it 
> has -- it can't have a rows() function.

It would be great to make this clearer... because it is quite unnatural 
that a widget found in 'top-level widgets' (Filler, in this case) does 
not implement the 'widgets' interface.

I think it would be simpler to say : if a class does not implement the 
widget interface, it is not a widget. And then Filler would not be a 
widget. So maybe there is a need for an intermediate interface ?

> As of 0.9.5 you can use Pile widgets as either box widgets or flow 
> widgets.  This is a widget similar to the new "LineBox" class in 
> graphics.py, which you could use for a border:
> 
> class Border(urwid.WidgetWrap):
>         def __init__(self, w):
>                 # Define the border characters
>                 tline = bline = urwid.Divider("B")
>                 lline = rline = urwid.SolidFill("B")
>                 tlcorner = urwid.Text("B")
>         trcorner = blcorner = brcorner = tlcorner
> 
>                 top = Columns([ ('fixed', 1, tlcorner),
>                         tline, ('fixed', 1, trcorner) ])
>                 middle = Columns( [('fixed', 1, lline),
>                         w, ('fixed', 1, rline)], box_columns = [0,2],
>                         focus_column = 1)
>                 bottom = Columns([ ('fixed', 1, blcorner),
>                         bline, ('fixed', 1, brcorner) ])
>                 pile = Pile([('flow',top),middle,('flow',bottom)],
>                         focus_item = 1)
>                 WidgetWrap.__init__(self, pile)


This is great !
Would you consider including it in the next release of URWID ?

> I have tried to document the widget interface definition:
> http://excess.org/urwid/reference.html#Widget_interface_definition

I find it hard to get the hierarchy of classes in the documentation.

> A global container interface would allow a generic render function to 
> walk the tree of widgets. That could really improve the error messages 
> when the wrong type of widget is used, and in reporting exactly which 
> widget failed. That is high on my list of priorities, but it might break 
> backwards compatibility.

This would be really helpful, as I personnaly would like to 
iterate/manipulate the content of containers using a uniform interface 
(instead of having to care about each particular case).

I can't wait to see this implemented :)

Thanks,

  -- Sébastien