From tonalcode: the dot-size core of the halftone renderer.
Halftone core
(defn halftone-cell
"Dot radius for a luminance sample (0.0-1.0)."
[luma max-r]
(* max-r (Math/sqrt (- 1.0 luma))))
(defn halftone-cell
"Dot radius for a luminance sample (0.0-1.0)."
[luma max-r]
(* max-r (Math/sqrt (- 1.0 luma))))