Varying opacity of a thick spline orthogonally to the spline direction

Questions
,
1

I need opacity diminishing from the center of a thick spline orthogonally to the spline direction (tangent). I could come up only with piling up a few semi-opaque splines with decreasing width on the top of each other. Is there a simpler solution or just better alternative solution with a nice visual? Here is my code

Manipulate[
 Graphics[{White, Opacity[g], CapForm["Round"], AbsoluteThickness[#], 
     BSplineCurve[pts]} & /@ Table[i^s, {i, 1, 10 s^2}], 
  PlotRange -> 1.3, Background -> Black]
 , {{s, 1.3, "width"}, .5, 1.7}
 , {{g, .15, "glow"}, .01, .5}
 , {{pts, {{0.8, 0.8}, {-1, 0}, {0, -1}, {1, 0}, {-0.5, 0.5}}}, 
  Locator, LocatorAutoCreate -> True, 
  Appearance -> Style["o", 40, Red]},
 FrameMargins -> 0]

415×479 24.5 KB

2

I don’t have a better solution, but that’s a cool effect.

Chris