重叠曲线的布尔运算

Description/Steps to reproduce The subtract operation improperly includes portions of overlapping curves. # Link to reproduction test-case Here is a failing sketch This appears to break in all prior versions as well. Possible hint for the solution: You will notice that the overlapping curve is divvied up in perfectly non-overlapping segments between the two "parent" shapes. When the radii of the circles are the same, the segments are equal in size, but when the radii of one of the circles changes, the sizing becomes inconsistent.