Re: canvas notes

["Gustavo J. A. M. Carneiro" <gjc inescporto pt>]

On Wed, 2005-09-07 at 16:54 +0200, Alexander Larsson wrote:
> On Mon, 2005-08-15 at 02:38 -0400, Havoc Pennington wrote:
> > Hi,
> > 
> > Been thinking about canvas widgets a little this weekend, thought I'd
> > write down some notes. Some people are doubtless way ahead of me.
> 
> Just dropping a note to say I'm planning to work on this. I've started
> looking at various canvases (well, I know some pretty well already...)
> and thinking about use cases, possible features and implementations
> ideas.

  That's great to hear.

> 
> In my initial thinking about this and talking to various people about it
> i've notived that this is pretty essential for a usable canvas:
> 
> > 4. Widget embedding. Absolutely critical to using the canvas
> >    for real-world UI. The widget embedding can't be broken 
> >    as in GnomeCanvas or it isn't useful; layering and events must work 
> >    properly. Affine transforms probably should work properly, and 
> >    when you think about animations (minimization, etc.) could even be 
> >    useful.
> 
> The obvious way to do this is to get a GtkWidget to render into a pixmap
> and then draw that pixmap translated on the screen (and translate events
> into it).

  I don't understand.  Is there a problem creating a gdk subwindow,
child of the canvas widget window, and putting it at the right
coordinates, effectively sitting on top of the canvas?  Sure, you
wouldn't get transparency (shaped widgets, same problem in the gnome
panel), this way, but that's a limitation we can live with, I suppose?

  Regards.

-- 
Gustavo J. A. M. Carneiro
<gjc inescporto pt> <gustavo users sourceforge net>
The universe is always one step beyond logic.