getRelativeOffset method
Converts an absolute offset within this widget to a relative offset about the shoulder joint.
Implementation
Offset getRelativeOffset(Size size, Offset absolute) {
final length = min(size.width / 4, size.height / 2);
final radius = length * totalArmLength;
final x = (absolute.dx - size.width / 2 - gripperLength) / radius;
final y = (size.height - absolute.dy) / radius;
return Offset(x, y);
}