Hi Andreas,

Andreas Neumann <[EMAIL PROTECTED]> wrote on 04/19/2006 01:56:25 
AM:

> >>have the opacity attribute set. I am pretty sure that PDF also 
supports 
> >>real transparency. Are you planning to support real transparency in 
PDF 
> >>output in the future?

> > If you are only using fill or stroke you should
> > map the opacity attribute to fill-opacity or stroke-opacity it will be
> > much more efficient in either case[...]

> sounds like a good approach. Currently, I only need fill opacity. But I 
> set the attribute on the group. Does that matter? Would it be more 
> efficient to set it on the individual elements instead of the group?

   The short answer is that no setting the property on individual
elements is not more efficient. 

   The big difference comes between using 'fill-opacity' and 'opacity'. 
You need to be aware that in some cases the rendering result can be 
quite different.  If a group with 'opacity="0.5"' has two overlapping 
rectangles the  overlap region will have the same opacity as the 
non-overlap regions of the rectangles.  However a group with 
'fill-opacity="0.5"' and the same two rectangles will have 75% 
opacity in the overlap region (the first rectangle will block 50% the 
second will block 50% of what's left).

   Also I realized that the interface we use to draw to PDF does
not allow us to easily specify the group opacity case so even if
PDF does support it (which the more I think about it, it probably
does) it would be quite difficult for us to generate...


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