public void LineAlgorithmsIntersectsTest()
{
// coinciding lines
Coordinate firstLineStart = new Coordinate(1, 1);
Coordinate firstLineEnd = new Coordinate(4, 1);
Coordinate secondLineStart = new Coordinate(1, 1);
Coordinate secondLineEnd = new Coordinate(4, 1);
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
// parallel lines
firstLineStart = new Coordinate(1.3, 1.3);
firstLineEnd = new Coordinate(1.3, 4.3);
secondLineStart = new Coordinate(2.3, 1.3);
secondLineEnd = new Coordinate(2.3, 4.3);
Assert.IsFalse(LineAlgorithms.Intersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
// intersecting lines
firstLineStart = new Coordinate(1, 1);
firstLineEnd = new Coordinate(1, 4);
secondLineStart = new Coordinate(4, 2);
secondLineEnd = new Coordinate(0, 2);
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1, 1);
firstLineEnd = new Coordinate(4, 4);
secondLineStart = new Coordinate(1, 4);
secondLineEnd = new Coordinate(4, 1);
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(2, 2);
firstLineEnd = new Coordinate(2, 8);
secondLineStart = new Coordinate(2, 5);
secondLineEnd = new Coordinate(2, 10);
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(2, 2);
firstLineEnd = new Coordinate(2, 8);
secondLineStart = new Coordinate(2, 1);
secondLineEnd = new Coordinate(2, 8);
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(7, 7);
firstLineEnd = new Coordinate(7, 7);
secondLineStart = new Coordinate(7, 7);
secondLineEnd = new Coordinate(7, 7);
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
// not intersecting lines
firstLineStart = new Coordinate(2, 2);
firstLineEnd = new Coordinate(2, 8);
secondLineStart = new Coordinate(2.1, 1);
secondLineEnd = new Coordinate(10, 8);
Assert.IsFalse(LineAlgorithms.Intersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(2, 2);
firstLineEnd = new Coordinate(2, 8);
secondLineStart = new Coordinate(1, 8.001);
secondLineEnd = new Coordinate(10, 8.001);
Assert.IsFalse(LineAlgorithms.Intersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
// internally intersecting lines
firstLineStart = new Coordinate(1, 4);
firstLineEnd = new Coordinate(4, 1);
secondLineStart = new Coordinate(3, 2);
secondLineEnd = new Coordinate(2, 3);
Assert.IsTrue(LineAlgorithms.InternalIntersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1, 4);
firstLineEnd = new Coordinate(4, 1);
secondLineStart = new Coordinate(3, 2);
secondLineEnd = new Coordinate(3, 2);
Assert.IsTrue(LineAlgorithms.InternalIntersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1, 4);
firstLineEnd = new Coordinate(4, 1);
secondLineStart = new Coordinate(1, 2);
secondLineEnd = new Coordinate(200, 3);
Assert.IsTrue(LineAlgorithms.InternalIntersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1, 4);
firstLineEnd = new Coordinate(4, 1);
secondLineStart = new Coordinate(1, 2);
secondLineEnd = new Coordinate(200, 3);
Assert.IsTrue(LineAlgorithms.InternalIntersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
// not internally intersecting lines
firstLineStart = new Coordinate(0, 0);
firstLineEnd = new Coordinate(0, 1000.33);
secondLineStart = new Coordinate(1000.33, 200);
secondLineEnd = new Coordinate(0, 0);
Assert.IsFalse(LineAlgorithms.InternalIntersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
firstLineStart = new Coordinate(1, 1);
firstLineEnd = new Coordinate(100, 1);
secondLineStart = new Coordinate(1, 4);
secondLineEnd = new Coordinate(1, 1);
Assert.IsFalse(LineAlgorithms.InternalIntersects(firstLineStart, firstLineEnd, secondLineStart, secondLineEnd));
// intersecting infinite lines
firstLineStart = new Coordinate(2, 5);
CoordinateVector firstVector = new CoordinateVector(0, 1);
secondLineStart = new Coordinate(2, 4);
CoordinateVector secondVector = new CoordinateVector(4, 0);
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstVector, secondLineStart, secondVector));
firstLineStart = new Coordinate(2, 4);
firstVector = new CoordinateVector(-3, 1);
secondLineStart = new Coordinate(5, 3);
secondVector = new CoordinateVector(-3, 1);
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstVector, secondLineStart, secondVector));
firstLineStart = new Coordinate(1, 1);
firstVector = new CoordinateVector(0, 1);
secondLineStart = new Coordinate(1, 1);
secondVector = new CoordinateVector(1, 0);
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstVector, secondLineStart, secondVector));
firstLineStart = new Coordinate(1, 1);
firstVector = new CoordinateVector(0, 1);
secondLineStart = new Coordinate(2, 2);
secondVector = new CoordinateVector(0, 1);
Assert.IsTrue(LineAlgorithms.IsParallel(firstLineStart, firstVector, secondLineStart, secondVector));
Assert.IsTrue(LineAlgorithms.Intersects(firstLineStart, firstVector, secondLineStart, secondVector));
}