Re: Subclassing Gtk2::CellRenderer

[Bjarne Steinsbø <bosteins broadpark no>]

Thanks a lot, muppet.  You're confirming my most pessimistic 
suspicions.  I took at quick look at the xs code (and even some gtk+ 
code) and I'm now starting to get a glimmer of understanding (and 
appreciation) of the magic that goes on to make the perl interface work 
so well as it does.

Still, wouldn't it be nice to be able to do anything you can do in C in 
perl as well?  Not necessarily making it simple to do in perl, but at 
least possible?  Some additional magic during code generation, maybe?  
Exposing in special-purpose perl classes what you're doing your best to 
hide in the normal case?

muppet wrote:

> On Wednesday, October 1, 2003, at 10:50 AM, Bjarne Steinsbø wrote:
>
> > A method invocation in GObject is just a signal, right?  So I should 
> > override the proper signal name in order to let my own routine handle 
> > this method.
>
>
> i wish it was just that simple.

Yepp, that's where I went wrong, allright.  Reality is never as simple 
as you think it is after just a few days exposure to a new 
system/job/API/whatever...

> now to be perfectly honest, the render method would be called a *lot*, 
> so they probably assume that you'd have to be insane to want to 
> implement that in a non-c or c++ language.  given that i can't see a 
> way to attach a widget to the treeview and you'll probably wind up 
> rendering something that looks like an optionmenu by hand, i can't say 
> that i really fault them for that assumption.

An optionmenu shouldn't really be that hard to render in the normal 
case, it's just a string and a pixmap.  It's the editing phase that's 
complicated.  But I see your point.  The elegant way to extend the 
treeview would be to allow widgets in the cells, much like a gnome 
canvas or (just saw this in the docs, really neat!) in a Combo.  And 
yes, it would hurt performance, which is probably one of the reasons 
they didn't put it in.

> if you don't mind having a little bit of extra XS for your custom 
> cellrenderer, i think you can pull it off a little more easily by 
> mixing C and perl.

Since it's not simple to do, I'll probably implement the functionality 
some other way, at least initially.  Probably a popup when the user 
clicks in a column of a certain type.  I'll probably sub-class the 
widget and hide it down there, so that I can come back and change the 
implementation at a later stage, if and when I want to do it properly.

Bjarne

P.S. I think I stumbled across a typo in the xs documentation for Glib.  
Please see attached diff.
*** /usr/src/Gtk2-perl/Glib-1.00rc3/GType.xs    Fri Sep 26 01:26:32 2003
--- GType.xs    Thu Oct  2 12:55:29 2003
***************
*** 453,455 ****
  
! =item GType gperl_type_from_package (GType gtype)
  
--- 453,455 ----
  
! =item GType gperl_package_from_type (GType gtype)