Re: [spam score 10.00/10.0 -pobox] Newbie seeks advice (mixing text, widgets, images on a scrollable canvas)

[Havoc Pennington <hp redhat com>]

Pascal Haakmat <a haakmat chello nl> writes: 
> I have just one quick question; is it safe to have widgets overlap eachother
> in a GtkLayout container? How about in general? 

It is safe to have child widgets overlap their parent. Having widgets
in a layout or fixed overlap is safe, but the stacking order and
redraw results aren't well-defined.

> (What I'm thinking is to add
> a GtkDrawingArea to the GtkLayout that completely covers the GtkLayout, then
> add GtkEntry widgets in the appropriate places).

But don't do this, it defeats the purpose of the layout. The layout is
an infinite scrolling area. Normal widgets can only be a certain size
(32,000 pixels or so). Also, the layout is doing some funky stuff to
ensure smooth scrolling. Adding a drawing area will mangle that.
Draw directly to the layout, as GnomeCanvas does.

You want to: 

 - set the layout size to the full size of the page being browsed

 - go ahead and add all the child widgets at their appropriate
   positions in layout coordinates (relative to the entire page)

 - when you get an expose event, the area of the expose is 
   in the coordinates of the layout->bin_window GdkWindow. 
   Convert these coordinates to full-page coordinates using 
   layout->xoffset and layout->yoffset which are the logical 
   position of the bin_window in full-page coordinates.
   Then draw that region of the full page.  

Havoc