added a CHANGELOG

fixed the bug where binary ops throw NullPointerException when the result is empty
added an overloaded contains(x, y)

CHANGELOG

@@ -0,0 +1,3 @@
+rev 17:
+ - fixed the binary shape ops for when the result is null (thanks to ekene ijeoma for spotting it)
+ - added a RShape.contains(float x, float y)

Makefile

@@ -1,5 +1,5 @@
 
-GEOMERATIVE_VERSION=16
+GEOMERATIVE_VERSION=18
 
 JAVAC_ARGS=-source 1.3 -target 1.1
 CLASSPATH=external/batikfont.jar:"$(PROCESSING_PATH)/lib/core.jar":"$(PROCESSING_PATH)/libraries/xml/library/xml.jar"

src/geomerative/RG.java

@@ -80,7 +80,7 @@ public static class NoPathInitializedException extends NullPointerException{
     private static final long serialVersionUID = -3710605630786298673L;
 
     NoPathInitializedException(){
-      super("Must initialize a path by calling RG.beginGroup(), RG.beginShape() or RG.beginPath() first.");
+      super("Must initialize a path by calling RG.beginShape() or RG.beginPath() first.");
     }
   }
 
@@ -270,6 +270,18 @@ protected static PApplet parent(){
   public static RShape diff(RShape a, RShape b){
     return a.diff(b);
   }
+
+  public static RShape union(RShape a, RShape b){
+    return a.union(b);
+  }
+
+  public static RShape intersection(RShape a, RShape b){
+    return a.intersection(b);
+  }
+
+  public static RShape xor(RShape a, RShape b){
+    return a.xor(b);
+  }
 
 
   public static void ignoreStyles(){

src/geomerative/RShape.java

@@ -436,7 +436,11 @@ public RShape toShape(){
    * @related diff ( )
    */
   public RShape intersection( RShape p ){
-    return RClip.intersection( p.toPolygon(), this.toPolygon() ).toShape();
+    RPolygon result = RClip.intersection( p.toPolygon(), this.toPolygon() );
+
+    if (result == null) return null;
+
+    return result.toShape();
   }
 
   /**
@@ -449,7 +453,11 @@ public RShape intersection( RShape p ){
    * @related diff ( )
    */
   public RShape union( RShape p ){
-    return RClip.union( p.toPolygon(), this.toPolygon() ).toShape();
+    RPolygon result = RClip.union( p.toPolygon(), this.toPolygon() );
+
+    if (result == null) return null;
+
+    return result.toShape();
   }
 
   /**
@@ -462,7 +470,12 @@ public RShape union( RShape p ){
    * @related diff ( )
    */
   public RShape xor( RShape p ){
-    return RClip.xor( p.toPolygon(), this.toPolygon() ).toShape();
+    RPolygon result = RClip.xor( p.toPolygon(), this.toPolygon() );
+
+    if (result == null) return null;
+
+    return result.toShape();
+
   }
 
   /**
@@ -475,7 +488,11 @@ public RShape xor( RShape p ){
    * @related intersection ( )
    */	
   public RShape diff( RShape p ){
-    return RClip.diff( this.toPolygon(), p.toPolygon() ).toShape();
+    RPolygon result = RClip.diff( p.toPolygon(), this.toPolygon() );
+
+    if (result == null) return null;
+
+    return result.toShape();
   }
 
   /**
@@ -600,6 +617,16 @@ public RPoint getTangent(float t){
     }
   }
 
+  /**
+   * Use this to return a specific tangent on the curve.  It returns true if the point passed as a parameter is inside the shape.  Implementation taken from: http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
+   * @param float x, the X coordinate of the point for which to test containement.
+   * @param float y, the Y coordinate of the point for which to test containement.
+   * @return bool, true if the point is in the path.
+   * */
+  public boolean contains(float x, float y){
+    return contains(new RPoint(x, y));
+  }
+
   /**
    * Use this to return a specific tangent on the curve.  It returns true if the point passed as a parameter is inside the shape.  Implementation taken from: http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html
    * @param RPoint p, the point for which to test containement..