From d2bebff7368bba6fab4f5238a39c47dcb47e6bfc Mon Sep 17 00:00:00 2001
From: Tim Conkling <tconkling@gmail.com>
Date: Fri, 16 Dec 2011 12:35:25 -0800
Subject: [PATCH] Functions for computing the distance between a Point and a
 Rectangle

---
 src/main/java/pythagoras/f/Rectangles.java    | 35 +++++++++++++++++++
 src/test/java/pythagoras/f/RectangleTest.java | 22 ++++++++++++
 2 files changed, 57 insertions(+)
 create mode 100644 src/test/java/pythagoras/f/RectangleTest.java

diff --git a/src/main/java/pythagoras/f/Rectangles.java b/src/main/java/pythagoras/f/Rectangles.java
index 982ed5d..c1e54c0 100644
--- a/src/main/java/pythagoras/f/Rectangles.java
+++ b/src/main/java/pythagoras/f/Rectangles.java
@@ -30,4 +30,39 @@ public class Rectangles
         float y2 = Math.max(src1.maxY(), src2.maxY());
         dst.setBounds(x1, y1, x2 - x1, y2 - y1);
     }
+    
+    /**
+     * Computes the Point on the rectangle that's closest to the given point, writing
+     the result int {@code out}
+     */
+    public static Point closestInteriorPoint (IRectangle r, IPoint p, Point out)
+    {
+        out.set(MathUtil.clamp(p.x(), r.minX(), r.maxX()),
+                MathUtil.clamp(p.y(), r.minY(), r.maxY()));
+        return out;
+    }
+
+    /**
+     * Computes the Point on the rectangle that's closest to the given point
+     */
+    public static Point closestInteriorPoint (IRectangle r, IPoint p)  {
+        return closestInteriorPoint(r, p, new Point());
+    }
+
+    /**
+     * Returns the squared Euclidean distance between the given point and the nearest point on the
+     * given rectangle.
+     */
+    public static float pointRectDistanceSq (IRectangle r, IPoint p) {
+        Point p2 = closestInteriorPoint(r, p);
+        return Points.distanceSq(p.x(), p.y(), p2.x, p2.y);
+    }
+
+    /**
+     * Returns the Euclidean distance between the given point and the nearest point on the
+     * given rectangle.
+     */
+    public static float pointRectDistance (IRectangle r, IPoint p) {
+        return FloatMath.sqrt(pointRectDistanceSq(r, p));
+    }
 }
diff --git a/src/test/java/pythagoras/f/RectangleTest.java b/src/test/java/pythagoras/f/RectangleTest.java
new file mode 100644
index 0000000..9051351
--- /dev/null
+++ b/src/test/java/pythagoras/f/RectangleTest.java
@@ -0,0 +1,22 @@
+//
+// Pythagoras - a collection of geometry classes
+// http://github.com/samskivert/pythagoras
+
+package pythagoras.f;
+
+import org.junit.*;
+import static org.junit.Assert.*;
+
+public class RectangleTest
+{
+    @Test public void testPointRectDistance () {
+        testPointRectDistance(0, new Rectangle(0, 0, 10, 10), new Point(0, 0)); // edge
+        testPointRectDistance(0, new Rectangle(0, 0, 10, 10), new Point(5, 5)); // interior
+        testPointRectDistance(5, new Rectangle(0, 0, 10, 10), new Point(5, 15)); // exterior
+    }
+
+    protected void testPointRectDistance (float expected, IRectangle r, Point p) {
+        assertEquals(expected, Rectangles.pointRectDistance(r, p), MathUtil.EPSILON);
+    }
+
+}