Alpha (transparency) transitions are going wrong

[eonj]

Above image is pie chart example with 'transparent' stop.

The shorthand 'transparent' is translated to rgba(0, 0, 0, 0) via getComputedStyle so the gradient comes from transparent-black to gold. This kind of problem is reported in early implementations of linear/radial gradient and fixed following the spec.

Above image shows the almost-right answer. The gradient-right way to process transparency transition, using alpha-premultiplied space, is described in W3C TR css3-images and tech refs.