Re: GTK+ canvas?

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

On Qui, 2006-08-31 at 11:02 +0100, Bill Haneman wrote:
[...]
> To the extent that this is true, the accessibility requirements are 
> fairly clear - widget-like things inside the canvas must follow the ATK 
> accessibility principles, exposing fairly rich queryable interfaces.  
> Textual content must expose AtkText/AtkEditableText, and onscreen 
> objects must expose AtkComponent (bounds, z-order, position, focus).  
> Also the objects must somehow have a keyboard navigation model so that 
> the canvas can be used without the mouse.

  GooCanvas has some sort of object focus and keyboard navigation.  I
think we need to programmatically activate it somehow, but it's there,
I've seen a demo too.

> 
> If we anticipate using a canvas for something other than plain vector or 
> graphics primitive drawing, then a good deal of thought needs to go in 
> to how the canvas' object model hooks in to ATK.  Even in a simple 
> graphics primitive canvas, we need an object model so that the parts of 
> the resulting drawing can be organized in a hierarchical model and 
> queried for bounds and attributes such as color, 
> names/labels/descriptions, etc.    The need to make a canvas-based 
> application accessible also means that some facility for making the 
> content accessible to blind users needs to be available in the main 
> canvas API (in the manner of web page "alt text", at minimum) so that 
> the application developer can provide the appropriate info when building 
> the app.

  The GooCanvas standard items implement Atk interfaces already.  It
contains a standard 'title' property that I guess fills the role of "alt
text".  And it also contains a "hierarchical model and queried for
bounds and attributes such as color, names/labels/descriptions, etc."

  So I think GooCanvas is well ahead of the competition in terms of gtk+
accessibility support.

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