Incorrect output

[bobroberts177]

This does not produce the correct visibility in the following situation:

    let point = geo::Point::new(1.53, -0.4);
    let lines = vec![
      Line {
        start: Coordinate { x: 0.0, y: 0.5 },
        end: Coordinate { x: 1.5, y: 0.5 },
      },
      Line {
        start: Coordinate { x: 0.0, y: 0.0 },
        end: Coordinate { x: 0.0, y: 1.0 },
      },
      Line {
        start: Coordinate { x: 1.5, y: 0.5 },
        end: Coordinate { x: 1.5, y: 1.5 },
      },
      Line {
        start: Coordinate { x: 0.5, y: -0.5 },
        end: Coordinate { x: 0.5, y: 0.5 },
      },
      Line {
        start: Coordinate { x: -25.0, y: -25.0 },
        end: Coordinate { x: 25.0, y: -25.0 },
      },
      Line {
        start: Coordinate { x: 25.0, y: -25.0 },
        end: Coordinate { x: 25.0, y: 25.0 },
      },
      Line {
        start: Coordinate { x: 25.0, y: 25.0 },
        end: Coordinate { x: -25.0, y: 25.0 },
      },
      Line {
        start: Coordinate { x: -25.0, y: 25.0 },
        end: Coordinate { x: -25.0, y: -25.0 },
      },
    ];
    let vis = point.visibility(lines.as_slice());

The output is:

Polygon { exterior: LineString([Coordinate { x: 25.0, y: 25.0 }, Coordinate { x: 25.0, y: -25.0 }, Coordinate { x: -25.0, y: -25.0 }, Coordinate { x: -25.0, y: -2.975728155339805 }, Coordinate { x: 0.5, y: -0.5 }, Coordinate { x: 0.5, y: 0.5 }, Coordinate { x: 0.0, y: 1.0 }, Coordinate { x: 0.5464285714285712, y: 0.5000000000000001 }, Coordinate { x: 25.0, y: 25.0 }]), interiors: [] }

This is incorrect. In particular, the Coordinate { x: 0.0, y: 1.0 } should not be visible (the first line blocks it).

It also prints out the following warnings:

[geo_visibility::visibility] ray intersects a line segment iff the line segment is in the state
[geo_visibility::visibility] ray intersects a line segment iff the line segment is in the state
[geo_visibility::visibility] ray intersects a line segment iff the line segment is in the state