The previous method of subtracting slightly from the radius introduces
distortion where smaller circles are disproportionately reduced. For example,
subtracting 1px from the radius scales a circle of radius 5px by 0.64x, while a
circle of radius 50px is only reduced by 0.96x.

By incorporating padding into the layout algorithm, the leaf circles’ area is
still proportional to the associated value. Due to the scale-independent nature
of the layout, the specified padding value is only approximate.