// EShapes.js
//
// Based on an idea, and some lines of code, by "thetoy" 
//
//   This Javascript is provided by Mike Williams
//   Community Church Javascript Team
//   http://www.bisphamchurch.org.uk/   
//   http://econym.org.uk/gmap/
//
//   This work is licenced under a Creative Commons Licence
//   http://creativecommons.org/licenses/by/2.0/uk/
//
// Version 0.0 04/Apr/2008 Not quite finished yet
// Version 1.0 10/Apr/2008 Initial release

  GPolyline.Shape = function(point,r1,r2,r3,r4,rotation,vertexCount,  colour,weight,opacity,opts,tilt) {
    var rot = -rotation*Math.PI/180;
    var points = [];
    var latConv = point.distanceFrom(new GLatLng(point.lat()+0.1,point.lng()))*10;
    var lngConv = point.distanceFrom(new GLatLng(point.lat(),point.lng()+0.1))*10;
    var step = (360/vertexCount)||10;

    var flop = -1;
    if (tilt) {
      var I1=180/vertexCount;
    } else {
      var  I1=0;
    }
    for(var i=I1; i<=360.001+I1; i+=step) {
      var r1a = flop?r1:r3;
      var r2a = flop?r2:r4;
      flop = -1-flop;
      var y = r1a * Math.cos(i * Math.PI/180);
      var x = r2a * Math.sin(i * Math.PI/180);
      var lng = (x*Math.cos(rot)-y*Math.sin(rot))/lngConv;
      var lat = (y*Math.cos(rot)+x*Math.sin(rot))/latConv;

      points.push(new GLatLng(point.lat()+lat,point.lng()+lng));
    }
    return (new GPolyline(points,colour,weight,opacity,opts))
  }

  GPolyline.Circle = function(point,radius,colour,weight,opacity,opts) {
    return GPolyline.Shape(point,radius,radius,radius,radius,0,100,colour,weight,opacity,opts)
  }

  GPolyline.RegularPoly = function(point,radius,vertexCount,rotation,colour,weight,opacity,opts) {
    rotation = rotation||0;
    var tilt = !(vertexCount&1);
    return GPolyline.Shape(point,radius,radius,radius,radius,rotation,vertexCount,colour,weight,opacity,opts,tilt)
  }

  GPolyline.Star = function(point,r1,r2,points,rotation,colour,weight,opacity,opts) {
    rotation = rotation||0;
    return GPolyline.Shape(point,r1,r1,r2,r2,rotation,points*2,colour,weight,opacity,opts)
  }

  GPolyline.Ellipse = function(point,r1,r2,rotation,colour,weight,opacity,opts) {
    rotation = rotation||0;
    return GPolyline.Shape(point,r1,r2,r1,r2,rotation,100,colour,weight,opacity,opts)
  }




  GPolygon.Shape = function(point,r1,r2,r3,r4,rotation,vertexCount,  strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts,tilt) {
    var rot = -rotation*Math.PI/180;
    var points = [];
    var latConv = point.distanceFrom(new GLatLng(point.lat()+0.1,point.lng()))*10;
    var lngConv = point.distanceFrom(new GLatLng(point.lat(),point.lng()+0.1))*10;
    var step = (360/vertexCount)||10;

    var flop = -1;
    if (tilt) {
      var I1=180/vertexCount;
    } else {
      var  I1=0;
    }
    for(var i=I1; i<=360.001+I1; i+=step) {
      var r1a = flop?r1:r3;
      var r2a = flop?r2:r4;
      flop = -1-flop;
      var y = r1a * Math.cos(i * Math.PI/180);
      var x = r2a * Math.sin(i * Math.PI/180);
      var lng = (x*Math.cos(rot)-y*Math.sin(rot))/lngConv;
      var lat = (y*Math.cos(rot)+x*Math.sin(rot))/latConv;

      points.push(new GLatLng(point.lat()+lat,point.lng()+lng));
    }
    return (new GPolygon(points,strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts))
  }

  GPolygon.Circle = function(point,radius,strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts) {
    return GPolygon.Shape(point,radius,radius,radius,radius,0,100,strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts)
  }

  GPolygon.RegularPoly = function(point,radius,vertexCount,rotation,strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts) {
    rotation = rotation||0;
    var tilt = !(vertexCount&1);
    return GPolygon.Shape(point,radius,radius,radius,radius,rotation,vertexCount,strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts,tilt)
  }

  GPolygon.Star = function(point,r1,r2,points,rotation,strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts) {
    rotation = rotation||0;
    return GPolygon.Shape(point,r1,r1,r2,r2,rotation,points*2,strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts)
  }

  GPolygon.Ellipse = function(point,r1,r2,rotation,strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts) {
    rotation = rotation||0;
    return GPolygon.Shape(point,r1,r2,r1,r2,rotation,100,strokeColour,strokeWeight,Strokepacity,fillColour,fillOpacity,opts)
  }




  function EOffset(point,easting,northing) {
    var latConv = point.distanceFrom(new GLatLng(point.lat()+0.1,point.lng()))*10;
    var lngConv = point.distanceFrom(new GLatLng(point.lat(),point.lng()+0.1))*10;
    return new GLatLng(point.lat()+northing/latConv,point.lng()+easting/lngConv)      
  }

  function EOffsetBearing(point,dist,bearing) {
    var latConv = point.distanceFrom(new GLatLng(point.lat()+0.1,point.lng()))*10;
    var lngConv = point.distanceFrom(new GLatLng(point.lat(),point.lng()+0.1))*10;
    var lat=dist * Math.cos(bearing * Math.PI/180)/latConv;
    var lng=dist * Math.sin(bearing * Math.PI/180)/lngConv; 
    return new GLatLng(point.lat()+lat,point.lng()+lng)      
  }