PeachDrawing.Core
PeachDrawing.Core.ColorGlyphs.RadialColorGlyphPaint
RadialColorGlyphPaint.FocalRadius Property
The radius of the circle around Focal that the first stop fills, in target units (0 is a point). With a nonzero value
the gradient is the two-circle gradient from that circle to the outer one.
public double FocalRadius { get; init; }