[LIBART] Rendering Gradients

[Catherine Daly CMIS CSIRO AU]

Hi,

I am trying to use Libart to render linear and radial gradients but am
having some problems understanding the structures: ArtGradientRadial and
ArtGradientLinear.

In ArtGradientLinear what do the values a, b and c represent and how can you
determine them from the gradients end points?

In ArtGradientLinear what is the affine matrix and given the centre and
radius of the gradient circle how can you calculate the affine matrix?

I am quite stuck on this problem so any suggestions would be much
appreciated.

Thanks in advance.

Catherine.