private void FindIntersection()

in UWP-Advanced-Inking/UnprocessedInput/UnprocessedInput/MainPage.xaml.cs [214:277]

• 50 lines of code
• 9 McCabe index (conditional complexity)

private void FindIntersection(
	PointF p1, PointF p2, PointF p3, PointF p4,
	out bool lines_intersect, out bool segments_intersect,
	out PointF intersection,
	out PointF close_p1, out PointF close_p2)
{
	// Get the segments' parameters.
	float dx12 = p2.X - p1.X;
	float dy12 = p2.Y - p1.Y;
	float dx34 = p4.X - p3.X;
	float dy34 = p4.Y - p3.Y;

	// Solve for t1 and t2
	float denominator = (dy12 * dx34 - dx12 * dy34);

	float t1 =
		((p1.X - p3.X) * dy34 + (p3.Y - p1.Y) * dx34)
			/ denominator;
	if (float.IsInfinity(t1))
	{
		// The lines are parallel (or close enough to it).
		lines_intersect = false;
		segments_intersect = false;
		intersection = new PointF(float.NaN, float.NaN);
		close_p1 = new PointF(float.NaN, float.NaN);
		close_p2 = new PointF(float.NaN, float.NaN);
		return;
	}
	lines_intersect = true;

	float t2 =
		((p3.X - p1.X) * dy12 + (p1.Y - p3.Y) * dx12)
			/ -denominator;

	// Find the point of intersection.
	intersection = new PointF(p1.X + dx12 * t1, p1.Y + dy12 * t1);

	// The segments intersect if t1 and t2 are between 0 and 1.
	segments_intersect =
		((t1 >= 0) && (t1 <= 1) &&
			(t2 >= 0) && (t2 <= 1));

	// Find the closest points on the segments.
	if (t1 < 0)
	{
		t1 = 0;
	}
	else if (t1 > 1)
	{
		t1 = 1;
	}

	if (t2 < 0)
	{
		t2 = 0;
	}
	else if (t2 > 1)
	{
		t2 = 1;
	}

	close_p1 = new PointF(p1.X + dx12 * t1, p1.Y + dy12 * t1);
	close_p2 = new PointF(p3.X + dx34 * t2, p3.Y + dy34 * t2);
}