[svg2] radialGradient @fr constraints

Some issues regarding the added 'fr' attribute on radialGradient:

a) Should 'fr' be allowed to be negative? (this is disallowed in  
<canvas>). What should happen if it is?
b) Should we still keep the constraint[1] to move the focal point inside  
the other circle? <canvas> doesn't do this. What the spec currently  
defines means some kinds of conical gradients aren't possible to do with  
<radialGradient>.
c) Related to b): the case where the focal point is outside the other  
circle, but the focal radius makes the two circles intersect, how should  
that be handled?

Proposal:
a) disallow negative values for 'fr', and let these cases fallback to the  
lacuna value '0%'.
b) remove the constraint and handle it the same as in <canvas>, noting  
that this may break some existing content. If we do this way it doesn't  
matter how the two circles are positioned relative to one another, so it  
addresses c) as well.


[1] https://svgwg.org/svg2-draft/pservers.html#RadialGradientNotes
-- 
Erik Dahlstrom, Core Technology Developer, Opera Software
Co-Chair, W3C SVG Working Group
Personal blog: http://my.opera.com/macdev_ed

Received on Wednesday, 29 August 2012 08:33:16 UTC