Re: [Pythoncard-users] XRC file support in PythonCard

[Kevin A. <al...@se...>]

On Apr 19, 2006, at 2:34 PM, Winston Wolff wrote:

> Is anybody thinking about integrating XRC files in PythonCard?
>
> Here are my reasons why it would be a good idea:
> 	- Could use a number of GUI builders such as wxGlade.
> 	- PythonCard's resourceEditor has problems including:
> 		- on Mac OS X grow handles don't appear
> 		- on Mac OS X sizes get "stuck" and I can't grow widgets
> 		- Layouts/Sizers are not supported.
>
> I'm thinking about a resource loader in PythonCard that would load  
> an .XRC file (XML file written out by wxGlade or XRCed) and then do  
> the regular PythonCard magic for binding events to widgets.
>
> The great thing about PythonCard is how it links up widgets and  
> handlers automatically, saving great amounts of time and  
> simplifying your code.  Probably when it was first written,  
> wxPython GUI editors were not very good, or didn't exist.  But now  
> they are better than PythonCard's resourceEditor.  Let's leverage  
> other's work on GUI editors, and take the good part from PythonCard.
>
> Would anybody use this?  Would I be allowed to add it to the  
> sourceforge repository?  Any other technical issues?
>
> -Winston

If all you really want is the auto-event binding that would be  
relatively easy to separate from the rest of PythonCard. It could  
even be done so that there isn't a central dispatcher if you don't  
care about event tracing. What you would do is iterate over the  
widgets after the XRC has been loaded. Dabo might be another tool to  
look at.

There isn't a one-to-one match between the standard  wxWidgets/ 
wxPython widget attributes so at a minimum PythonCard would probably  
need a custom XRC loader and some attributes that can be set in the  
resourceEditor. For example, a wxButton in an XRC file normally has  
the following possible attributes: XML ID, label, default, pos, size,  
and style. In addition, it has the style attributes: fg, bg, font,  
enabled, focused, hidden, tooltip. For the most part the names are  
just different than what is used for PythonCard so that is proably a  
simple translation. "XML ID" could be treated as the PythonCard  
"name" attribute which is crucial for event binding. The "command"  
attribute has no equivalent in XRC.

Having PythonCard be able to support XRC files for resources that  
follow some specific guidelines such as using XML ID as the "name"  
probably wouldn't be that hard, though you might lose support for  
some PythonCard attributes and/or wxWidget attributes that PythonCard  
doesn't currently recognize. A module that was able to load the XRC  
files directly would be preferable, but a conversion tool would avoid  
requiring modification of the framework itself. If the framework has  
to deal with it I suspect you would need to "walk" the layout after  
it is loaded and translate between wxPython attributes and PythonCard  
ones, doing GetXXX() method calls in most cases.

What is much more complicated and unlikely to happen is having the  
resourceEditor be able to read and write generic XRC files. That  
would be something to tackle after just being able to load was  
implemented.

ka