calculate the offset for the two beziers that make the sandwich
for the slur
*/
- Real alpha = (curve.control_[3] - curve.control_[0]).arg ();
+ Offset dir = (curve.control_[3] - curve.control_[0]).direction ();
Bezier back = curve;
- Offset perp = curvethick * complex_exp (Offset (0, alpha + M_PI / 2)) * 0.5;
+ Offset perp = 0.5 * curvethick * Offset (-dir[Y_AXIS], dir[X_AXIS]);
back.control_[1] += perp;
back.control_[2] += perp;