Weighted points in density

[Ben Adams]

It would be great to add an option for entering weighted points in the density function. I think it would just be a matter of having a weight function that passes in the weights for each data point and adjusting line 35 accordingly:

    values0[xi + yi * n] = values0[xi + yi * n] + weight(d, i, data);

default could be 1.

[Mike Bostock]

Fixed in #29; released in 1.3.0.

[Ben Adams]

thanks!