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diff --git a/src/geometry.cpp b/src/geometry.cpp
index b52ff7e..95d12c6 100644
--- a/src/geometry.cpp
+++ b/src/geometry.cpp
@@ -39,6 +39,29 @@ double Geometry::ParameterOfLineAndPoint(Point tail, Point head, Point point)
 }
 
 
+double Geometry::DistanceToLineFromPoint(Point tail, Point head, Point point)
+{
+	// Interpretation: given a line in the form x = a + tu, where u is the
+	// unit vector of the line, a is the tail and t is a parameter which
+	// describes the line, the distance of a point p to the line is given by:
+	// || (a - p) - ((a - p) . u) u ||
+	// We go an extra step: we set the sign to reflect which side of the line
+	// it's on (+ == to the left if head points away from you, - == to the
+	// right)
+	Vector line(tail, head);
+	Vector u = line.Unit();
+	Vector a_p = tail - point;
+	Vector dist = a_p - (u * (a_p).Dot(u));
+
+	double angle = Vector::Angle(tail, point) - line.Angle();
+
+	if (angle < 0)
+		angle += TAU;
+
+	return dist.Magnitude() * (angle < HALF_TAU ? +1.0 : -1.0);
+}
+
+
 Point Geometry::MirrorPointAroundLine(Point point, Point tail, Point head)
 {
 	// Get the vector of the intersection of the line and the normal on the
@@ -341,6 +364,13 @@ Point Geometry::GetPointForParameter(Object * obj, double t)
 }
 
 
+Point Geometry::Midpoint(Line * line)
+{
+	return Point((line->p[0].x + line->p[1].x) / 2.0,
+		(line->p[0].y + line->p[1].y) / 2.0);
+}
+
+
 /*
 How to find the tangent of a point off a circle: