Add support for irregular transformations to TransformFeature

Give the TransformFeature control an irregular mode where dragging a
handle just extends that side rather than growing the shape symmetrically
about the centre.

lib/OpenLayers/Control/TransformFeature.js

@@ -166,6 +166,12 @@ OpenLayers.Control.TransformFeature = OpenLayers.Class(OpenLayers.Control, {
      */
     dragControl: null,
        
+    /**
+     * APIProperty: irregular
+     * {Boolean}
+     */
+    irregular: false,
+ 
     /**
      * Constructor: OpenLayers.Control.TransformFeature
      * Create a new transform feature control.
@@ -390,6 +396,14 @@ OpenLayers.Control.TransformFeature = OpenLayers.Class(OpenLayers.Control, {
             var dy1 = this.y - centerGeometry.y;
             var dx0 = dx1 - (this.x - oldGeom.x);
             var dy0 = dy1 - (this.y - oldGeom.y);
+            if (control.irregular && !control._setfeature) {
+               dx1 -= (this.x - oldGeom.x) / 2;
+               dy1 -= (this.y - oldGeom.y) / 2;
+               var newCenter = centerGeometry.clone();
+               newCenter.x += Math.abs(dx0) < 0.00001 ? 0 : (this.x - oldGeom.x) / 2;
+               newCenter.y += Math.abs(dy0) < 0.00001 ? 0 : (this.y - oldGeom.y) / 2;
+               control.transformFeature({center: newCenter});
+            }
             this.x = oldX;
             this.y = oldY;
             var scale, ratio = 1;
@@ -410,6 +424,7 @@ OpenLayers.Control.TransformFeature = OpenLayers.Class(OpenLayers.Control, {
 
             control.box.geometry.resize(scale, centerGeometry, ratio);
             control.box.geometry.rotate(control.rotation, centerGeometry);
+            control.box.move(control.feature.geometry.getBounds().getCenterLonLat());
             control.transformFeature({scale: scale, ratio: ratio});
         };