getTangentForOffset method
Computes the position of the current contour at the given offset, and the angle of the path at that point.
For example, calling this method with a distance of 1.41 for a line from 0.0,0.0 to 2.0,2.0 would give a point 1.0,1.0 and the angle 45 degrees (but in radians).
Returns null if the contour has zero length.
The distance is clamped to the length of the current contour.
Implementation
Tangent getTangentForOffset(double distance) {
return _measure.getTangentForOffset(contourIndex, distance);
}