Re: cell word wrapping

["Kevin C. Krinke" <kckrinke opendoorsoftware com>]

On Thu, 2005-01-20 at 00:17 -0500, muppet wrote:
> On Jan 19, 2005, at 11:17 PM, Kevin C. Krinke wrote:
> 
> > Is there a way to set a Gtk2::CellRendererText to word-wrap it's 
> > contents?
> 
> Put newlines in the text strings.
> 
> *cough*

*chokes on a cough*

> > I've been trying with Gtk2::Pango::Layouts but can't figure out how to 
> > apply them to a cellrenderer.
> 
> GtkCellRendererText creates and initializes a new PangoLayout every 
> time it needs to calculate the size of a cell or draw a cell.  It's 
> also private, so you can't get a handle to it.
> 
> Create your own cell renderer and you can do whatever you want with 
> your layouts.

This is actually what I was asking about... I'm trying to make a simple
Gtk2::CellRendererWrapText but am finding that my brain is breaking down
somewhere along the way. Perhaps I need to learn more about using the
PangoLayout in general before attempting to do this.

>   If you let the renderer wrap, then you'll need some 
> "interesting" logic for choosing a size when the column is in autosize 
> mode.

Note taken.

>   My memory may be fuzzy, but i seem to recall learning while 
> writing Mup::CellRendererMultiline in Gtk2/examples/customrenderer.pl 
> that there are deficiencies in the TreeView design that make it 
> impossible to write a cellrenderer that can change size while editing.  
> (I wanted to have a Mac Aqua-style multi-line editable cell in 
> Torsten's odot...)

I don't need the cells to be editable at all, in fact, a read-only
situation would be a bonus in this case.

> > I've also run into the problem of not being able to find any practical 
> > help regarding Gtk2::Pango::AttrList. I can get an AttrList from 
> > $cell->get_property( 'attributes' ) but what can I do with it? If I 
> > try any methods on it I get the "can't call method on an undefined 
> > value" even though a Dumper() reveals a blessed Gtk2::Pango::AttrList.
> 
> It would appear that you have stumbled into one of the back corners of 
> the API that we don't have bound.  A PangoAttrList is what Pango markup 
> gets parsed into; it's a collection object for PangoAttrs, and, well, 
> we never bound it, probably because it seemed pretty esoteric.

Well, as far as I can tell this is how it could be used to wrap text as
a TreeView column_type from the Simple::List:

[code]
add_column_type
 Gtk2::Ex::Simple::List
  ( 'wrap_text',
    type     => 'Glib::Scalar',
    renderer => 'Gtk2::CellRendererText',
    attr     => sub {
                  my ( $treecol, $cell, $model, $iter, $col_num ) = @_;
                  my $info = $model->get( $iter, $col_num );
                  my $pal = new
                             Gtk2::Pango::AttrList
                              ( 'wrap-mode' => 'word' );
                  $cell->set_property( attributes => $pal );
                  $cell->set( markup => $info );
                }
  );
[/code]

However I may be mistaken on this usage of course and without being able
to test it I'm not sure whether Gtk2::Pango::AttrList is even useful.

> If you find you need this, we'll get it on the todo list.  If the job 
> isn't too big and we can get it tested quickly, we may be able to make 
> an API freeze break.  Otherwise, it will have to wait for 1.10x.  :-(

If my thinking in how to use it (as in the above example) is correct
then I'd say it is necessary. Seems it's a must-have for when you want
to change the "attributes" of a Gtk2::Label or Gtk2::CellRendererText
via the set_property() method inherited from Glib::Object.

I won't ask for it to be done ASAP but done sometime in the future would
be good. At the very least a note in Gtk2::Label and
Gtk2::CellRendererText that it doesn't exist would be helpful.

-- 
Kevin C. Krinke <kckrinke opendoorsoftware com>
Open Door Software Inc.