orientation_xld — Orientation of contours or polygons.
orientation_xld calculates the orientation of
each input contour or polygon. The operator is based on
elliptic_axis_xld. In addition, the contour respectively polygon
point with maximum distance to the center of gravity is calculated. If the
column coordinate of this point is less than the column coordinate
of the center of gravity the value of is added to the
angle. It is assumed that the contours or polygons are closed. If
this is not the case
orientation_xld will artificially close
the contours or polygons.
It should be noted that
orientation_xld only returns useful
results if the contour or polygon encloses a region in the plane. In
particular, the contour or polygon must not intersect itself. This
is particularly important if open contours or polygons are passed
because they are closed automatically, which can produce a
self-intersection. To test whether the contours or polygons
test_self_intersection_xld can be
used. If the contour or polygon intersects itself, useful values
for the orientation can be calculated with
If more than one contour or polygon is passed, the values of the
orientations are stored in a tuple in the same order as the respective
contours or polygons in
Contours or polygons to be examined.
Orientation of the contours or polygons (radians).
- pi < Phi && Phi <= pi
orientation_xld returns the value 2 (H_MSG_TRUE) if the input
is not empty. The behavior in case of empty input (no input contours
available) is set via the operator
If necessary an exception is raised.