From:  T Rowley <>
Date:  23 Nov 2005 05:33:16 Hong Kong Time

Re: Background color for SVG


On 11/22/05 5:20 AM, Peter Weilbacher wrote:
> The compositing is the problem on OS/2. AFAIU it's not possible to draw 
> directly to the screen in an efficient way. Instead we draw to an 
> offscreen surface and then blit that to the screen. To composite implies
> that we know the background color while painting the offscreen surface.

On all platforms gecko uses doublebuffering, rendering offscreen and 
only showing the user the completed rendered area.  If your os/2 cairo 
backend is working correctly then the composite "just happens" from the 
mozilla SVG point of view.

> Let me take a look at nsSVGOuterSVGFrame, but I guess for now I just 
> query the prefs for the background color and use that to fill the cairo 
> surface.

That's not really a route you want to go down, as it violates the 
specification and means that on os/2 SVG will act differently to all the 
other platforms mozilla runs on.

> For some reason the printing path doesn't work, either. It creates the 
> image surface correctly but nothing appears in the printout (or on the 
> screen if I try to use that for screen display). This is probably 
> connected to the offscreen surface stuff, too. I have to debug that at 
> some point.

Does printing of RGBA images work on os/2?