[Etoys] Sugar Nav bar problems

[Yoshiki Ohshima]

  Bert,

> Just built a new RPM, image version 1276. This includes the new nav  
> bar in Sugar look, Scott's blueprint canvas, and the implicit self  
> tiles.

  Thank you!

> The problem is that as soon as the sugar nav bar is enabled, there is  
> a pause every second. The tiny car moves some steps, then stops,  
> moves, stops. This is only visible on the XO, my desktop is too fast.  
> Disabling the flap cures this.

  Ouch.  

> MessageTally indicates that undoButtonAppearance is the culprit. It  
> rebuilds the undo icon every second, which apparently is not a cheap  
> operation. Maybe using an 8-bit bitmap with a colormap would be more  
> efficient? To get really fancy we'd even need to support two colors  
> plus alpha, because the original icons have a fill color, stroke  
> color, and transparency info.

  Since the other apps don't show different buttons when they are
disabled, we don't have to do that.  Just Graying (cheaply) is ok.
I'll make that modification.

> Also, on the XO the navbar looks tiny, I think each button must be  
> 75x75 px.

  Yes.  There was some confusion about the size among Abe-san and me.
I'll try to hook up the SVG stuff and FFI interface to Cairo by
Kawamura-san to prerender these icons from SVG file.

-- Yoshiki