We need to be able to identify segment centers

[timlinux]

Problem

Given a line vector layer, we need to identify the segment center of each line in the layer. Segment center is linear layer from the line, as explained in the picture below:

Proposed solution

The algorithm should be something like this

def get_segment_center(line):
    """Return the linear center of a segment.

    We can find the center segment by finding the point that has half distance from start point.

    :param line: A line from a vector layer.
    :type line: QgsLine

    :returns: A linear center of the line.
    :rtype: QgsPoint
    """

Expected outcome

A point in the center segment of the line.