Added Point.subtract, for creating a vector from endpoints.

src/main/java/pythagoras/d/AbstractPoint.java

@@ -52,6 +52,21 @@ public abstract class AbstractPoint implements IPoint
         return result.set(x() + x, y() + y);
     }
 
+    @Override // from IPoint
+    public Vector subtract (double x, double y) {
+        return subtract(x, y, new Vector());
+    }
+
+    @Override
+    public Vector subtract (double x, double y, Vector result) {
+        return result.set(x() - x, y() - y);
+    }
+
+    @Override
+    public Vector subtract (IPoint other, Vector result) {
+        return subtract(other.x(), other.y(), result);
+    }
+
     @Override // from IPoint
     public Point rotate (double angle) {
         return rotate(angle, new Point());

src/main/java/pythagoras/d/IPoint.java

@@ -43,6 +43,18 @@ public interface IPoint extends Cloneable
      * @return a reference to the result, for chaining. */
     Point add (double x, double y, Point result);
 
+    /** Subtracts the supplied point from {@code this}.
+     * @return a new vector containing the result. */
+    Vector subtract (double x, double y);
+
+    /** Subtracts the supplied point from {@code this} and stores the result in {@code result}.
+     * @return a reference to the result, for chaining. */
+    Vector subtract (double x, double y, Vector result);
+
+    /** Subtracts the supplied point from {@code this} and stores the result in {@code result}.
+     * @return a reference to the result, for chaining. */
+    Vector subtract (IPoint other, Vector result);
+
     /** Rotates this point around the origin by the specified angle.
      * @return a new point containing the result. */
     Point rotate (double angle);

src/main/java/pythagoras/f/AbstractPoint.java

@@ -52,6 +52,21 @@ public abstract class AbstractPoint implements IPoint
         return result.set(x() + x, y() + y);
     }
 
+    @Override // from IPoint
+    public Vector subtract (float x, float y) {
+        return subtract(x, y, new Vector());
+    }
+
+    @Override
+    public Vector subtract (float x, float y, Vector result) {
+        return result.set(x() - x, y() - y);
+    }
+
+    @Override
+    public Vector subtract (IPoint other, Vector result) {
+        return subtract(other.x(), other.y(), result);
+    }
+
     @Override // from IPoint
     public Point rotate (float angle) {
         return rotate(angle, new Point());

src/main/java/pythagoras/f/IPoint.java

@@ -43,6 +43,18 @@ public interface IPoint extends Cloneable
      * @return a reference to the result, for chaining. */
     Point add (float x, float y, Point result);
 
+    /** Subtracts the supplied point from {@code this}.
+     * @return a new vector containing the result. */
+    Vector subtract (float x, float y);
+
+    /** Subtracts the supplied point from {@code this} and stores the result in {@code result}.
+     * @return a reference to the result, for chaining. */
+    Vector subtract (float x, float y, Vector result);
+
+    /** Subtracts the supplied point from {@code this} and stores the result in {@code result}.
+     * @return a reference to the result, for chaining. */
+    Vector subtract (IPoint other, Vector result);
+
     /** Rotates this point around the origin by the specified angle.
      * @return a new point containing the result. */
     Point rotate (float angle);