More Line methods.

src/main/java/pythagoras/f/AbstractLine.java

@@ -43,6 +43,46 @@ public abstract class AbstractLine implements ILine
         return new Point(getX2(), getY2());
     }
 
+    @Override // from interface ILine
+    public float pointLineDistSq (float px, float py) {
+        return Geometry.pointLineDistSq(px, py, getX1(), getY1(), getX2(), getY2());
+    }
+
+    @Override // from interface ILine
+    public float pointLineDistSq (IPoint p) {
+        return Geometry.pointLineDistSq(p.getX(), p.getY(), getX1(), getY1(), getX2(), getY2());
+    }
+
+    @Override // from interface ILine
+    public float pointLineDist (float px, float py) {
+        return Geometry.pointLineDist(px, py, getX1(), getY1(), getX2(), getY2());
+    }
+
+    @Override // from interface ILine
+    public float pointLineDist (IPoint p) {
+        return Geometry.pointLineDist(p.getX(), p.getY(), getX1(), getY1(), getX2(), getY2());
+    }
+
+    @Override // from interface ILine
+    public float pointSegDistSq (float px, float py) {
+        return Geometry.pointSegDistSq(px, py, getX1(), getY1(), getX2(), getY2());
+    }
+
+    @Override // from interface ILine
+    public float pointSegDistSq (IPoint p) {
+        return Geometry.pointSegDistSq(p.getX(), p.getY(), getX1(), getY1(), getX2(), getY2());
+    }
+
+    @Override // from interface ILine
+    public float pointSegDist (float px, float py) {
+        return Geometry.pointSegDist(px, py, getX1(), getY1(), getX2(), getY2());
+    }
+
+    @Override // from interface ILine
+    public float pointSegDist (IPoint p) {
+        return Geometry.pointSegDist(p.getX(), p.getY(), getX1(), getY1(), getX2(), getY2());
+    }
+
     @Override // from interface ILine
     public Line clone () {
         return new Line(getX1(), getY1(), getX2(), getY2());

src/main/java/pythagoras/f/Geometry.java

@@ -80,6 +80,64 @@ public class Geometry
             || linesIntersect(rr, ry, rx, rb, x1, y1, x2, y2);
     }
 
+    /**
+     * Returns the square of the distance from the specified point to the specified line.
+     */
+    public static float pointLineDistSq (float px, float py,
+                                         float x1, float y1, float x2, float y2) {
+        x2 -= x1;
+        y2 -= y1;
+        px -= x1;
+        py -= y1;
+        float s = px * y2 - py * x2;
+        return (s * s) / (x2 * x2 + y2 * y2);
+    }
+
+    /**
+     * Returns the distance from the specified point to the specified line.
+     */
+    public static float pointLineDist (float px, float py, float x1, float y1, float x2, float y2) {
+        return (float)Math.sqrt(pointLineDistSq(px, py, x1, y1, x2, y2));
+    }
+
+    /**
+     * Returns the square of the distance between the specified point and the specified line
+     * segment.
+     */
+    public static float pointSegDistSq (float px, float py,
+                                        float x1, float y1, float x2, float y2) {
+        // A = (x2 - x1, y2 - y1)
+        // P = (px - x1, py - y1)
+        x2 -= x1; // A = (x2, y2)
+        y2 -= y1;
+        px -= x1; // P = (px, py)
+        py -= y1;
+        float dist;
+        if (px * x2 + py * y2 <= 0.0) { // P*A
+            dist = px * px + py * py;
+        } else {
+            px = x2 - px; // P = A - P = (x2 - px, y2 - py)
+            py = y2 - py;
+            if (px * x2 + py * y2 <= 0.0) { // P*A
+                dist = px * px + py * py;
+            } else {
+                dist = px * y2 - py * x2;
+                dist = dist * dist / (x2 * x2 + y2 * y2); // pxA/|A|
+            }
+        }
+        if (dist < 0) {
+            dist = 0;
+        }
+        return dist;
+    }
+
+    /**
+     * Returns the distance between the specified point and the specified line segment.
+     */
+    public static float pointSegDist (float px, float py, float x1, float y1, float x2, float y2) {
+        return (float)Math.sqrt(pointSegDistSq(px, py, x1, y1, x2, y2));
+    }
+
     /**
      * Returns a string describing the supplied point, of the form <code>+x+y</code>,
      * <code>+x-y</code>, <code>-x-y</code>, etc.

src/main/java/pythagoras/f/ILine.java

@@ -52,6 +52,48 @@ public interface ILine extends IShape, Cloneable
      */
     Point getP2 ();
 
+    /**
+     * Returns the square of the distance from the specified point to the line defined by this line
+     * segment.
+     */
+    float pointLineDistSq (float px, float py);
+
+    /**
+     * Returns the square of the distance from the supplied point to the line defined by this line
+     * segment.
+     */
+    float pointLineDistSq (IPoint p);
+
+    /**
+     * Returns the distance from the specified point to the line defined by this line segment.
+     */
+    float pointLineDist (float px, float py);
+
+    /**
+     * Returns the distance from the supplied point to the line defined by this line segment.
+     */
+    float pointLineDist (IPoint p);
+
+    /**
+     * Returns the square of the distance from the specified point this line segment.
+     */
+    float pointSegDistSq (float px, float py);
+
+    /**
+     * Returns the square of the distance from the supplied point this line segment.
+     */
+    float pointSegDistSq (IPoint p);
+
+    /**
+     * Returns the distance from the specified point this line segment.
+     */
+    float pointSegDist (float px, float py);
+
+    /**
+     * Returns the distance from the supplied point this line segment.
+     */
+    float pointSegDist (IPoint p);
+
     /**
      * Returns a mutable copy of this line.
      */