Re: multiple-item drag-and-drop

[muppet <scott asofyet org>]

On Aug 29, 2007, at 7:32 AM, Jeffrey Ratcliffe wrote:

> But I still don't understand how to determine the height of the header
> row of a Simple::List.


/me pokes at gtktreeview.c for a few minutes.


I would presume that while you are dragging a row from the tree view,  
you are getting events from a grab of the pointer in the treeview's  
bin_window.  The bin_window is the GdkWindow of the scrollable part  
of the widget, which is anchored at a y coordinate of TREE_VIEW_HEIGHT 
(treeview).

In theory, then,  header height = widget allocation height - bin  
window drawable height.  The drag-motion callback doesn't give you an  
event, so you'd have to capture this value in the button-press-event  
that starts the drag, as, i'm thinking, that button-press-event will  
happen with $event->window == treeview->private->bin_window.


   # when the user clicks, store the current header height, in case  
this
   # click starts a drag.
   $treeview->signal_connect (button_press_event => sub {
       my ($widget, $event) = @_;
       my (undef, $bin_window_height) = $event->window->get_size;
       $widget->{header_height} = $widget->allocation->height -  
$bin_window_height;
       return FALSE;
   });


I can't help thinking there ought to be a way to get it to work  
without knowing this stuff, but i have never messed with it, so it's  
just conjecture.  :-/


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