SVG angular gradient

There's no standard support to do angular (conical) gradients.

But see http://wiki.inkscape.org/wiki/index.php/Advanced_Gradients#Conical_gradient for some approximation methods (source code not included, though). Examples on that link do not work.

...10 years later...

CSS now supports conical gradients, although browser support is mixed at the time of writing this.

You could apply a <clipPath /> to a <foreignObject /> whose contents use a CSS conical gradient to achieve the desired effect.

https://codepen.io/eastonium/pen/abOpdEm