Re: canvas notes

[Alexander Larsson <alexl redhat com>]

On Thu, 2005-09-08 at 17:05 +0100, Gustavo J. A. M. Carneiro wrote:

> > 
> > 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?

You don't get layering right, and no transformations. The widgets won't
be in the canvas, just sort of stick on top of it. For many cool uses of
a canvas this just isn't good enough.

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 Alexander Larsson                                            Red Hat, Inc 
                   alexl redhat com    alla lysator liu se 
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