Due an internal scale of the brush size done by grease pencil
draw tool (this scale factor cannot be removed), the size of the
radial control is not equal to the actual stroke thickness and
this makes the radial size displayed useless.
This patch adds a new property that allows to pass the
path of the tool path and this value is used to apply
the correct scale to the radial size.
Reviewed By: mendio, frogstomp, pepeland, brecht
Differential Revision: https://developer.blender.org/D16866
0fb12a9c2e