Canvas, drag & drop, widget items

[Jose Diago <Jose Diago ircam fr>]

Hello all.

This question is about the gtk-canvas in GTK 1.x (almost the same as the 
gnome-canvas, I think).

I'm using the canvas to place some icons on it and to do some drawing 
and drag&drop operations (I draw lines and rectangles). The icons are 
actually a pixmap inside an eventbox, the eventbox is packed inside a 
vbox, and the vbox is placed inside a gtk_canvas_group to put it in the 
canvas.

Ok, so now I need to drag&drop the icons within the same window and from 
one window to another,  that works fine (drag-begin and drag-motion 
connected to the eventbox, drag-drop connected to the canvas), but then 
I need to drag an icon and drop it over another icon (like when in a 
file manager you want to drop a file inside a folder), that's where the 
trouble shows up.

To do the later operation I have drag-begin and drag-motion connected to 
the eventbox and drag-drop connected to the other event box, the signals 
work fine and I have no problem with them, but in the drag-drop handler 
function I'm calling gtk_object_destroy on the dragged GTK_OBJECT(canvas 
group) which contains the vbox->eventbox->pixmap and that destroys and 
erases the source icon (the desired effect) but also erases the pixmap 
in the target eventbox (actually it only erases the part of the target 
pixmap covered by the source icon). Shouldn't the canvas take care of 
the redrawing? and even if it doesn't I cannot get the pixmap redrawed 
by calling functions like gnome_canvas_update_now, 
gnome_canvas_request_redraw, etc.

Another problem I'm getting in my app, is that I cannot drop over icons 
that where drawed in the canvas after the source icon was drawed, so for 
instance, if I create and draw an icon for a file (in the file manager 
example) and after that I create and draw an icon for a folder then the 
folder's icon is always in top of the file icon and there's no way to 
perform the drop over it. I cannot use the canvas functions like 
gnome_canvas_item_raise_to_top because that doesn't works with widgets 
inside the canvas.

Thanks,
Jose Diago.