Corner is an intersection of line with two points at exactly same location. There are two cases of corner-line intersection: first the line passes out of object, touching corner. In this case line segment should not be started at corner, second: the line goes from outside of object to inside through the angle, in this case line should start at the corner.
Resolution
Corner is an intersection of line with two points at exactly same location. There are two cases of corner-line intersection: first the line passes out of object, touching corner. In this case line segment should not be started at corner, second: the line goes from outside of object to inside through the angle, in this case line should start at the corner.