area VEX function
Computes the shading area of the variable.
Contexts: cop, displace, fog, light, photon, shadow, surface

float area(vector )
Computes the shading area of the variable. This is typically used to get a representation of the area being shaded in terms of pixels.
You can specify optional parameters to control the computation.
Computes the area of the current pixel, which will not be 1 if the UV coordinates are transformed. The optional parameter “extrapolate” controls whether to do derivative extrapolation at the edges.