var SVGScreen = function(xsize,ysize)
{
	this.XSIZE = xsize;
	this.YSIZE = ysize;
	this.CX = xsize/2;
	this.CY = ysize/2;
}

SVGScreen.prototype.radians = function(deg)
{
  return deg/180*Math.PI;
}

SVGScreen.prototype.setCircle = function(cx,cy,r)
{
  this.CIRCLEX = cx;
  this.CIRCLEY = cy;
  this.CIRCLER = r;
}

SVGScreen.prototype.setLineStyle = function(width,color)
{
  this.WIDTH = width;
  this.COLOR = color;
}


SVGScreen.prototype.getHeadSVG =  function(){
	return '<svg width="'+ this.XSIZE +'" height="' + this.YSIZE
	+'" xmlns="http://www.w3.org/2000/svg">';
}

SVGScreen.prototype.getTailSVG =  function(){
	return '</svg>';
}

SVGScreen.prototype.getScrPointAry =  function(x,y){
//    return [ ((this.CX-x)+"").substring(0,10), ((this.CY-y)+"").substring(0,10) ];
    return [ ((x)+"").substring(0,10), ((y)+"").substring(0,10) ];
}

SVGScreen.prototype.getXYZ = function(lamda,fai,L0,B0,P){
  var cosB0 = Math.cos( this.radians( B0 ) );
  var sinB0 = Math.sin( this.radians( B0 ) );
  var cosP = Math.cos( this.radians( P ) );
  var sinP = Math.sin( this.radians( P ) );
  var L,M,N;
  var LD,MD,ND;
  var x, y, z;

  L = Math.cos( this.radians( fai ) ) * Math.cos( this.radians(lamda-L0));
  M = Math.cos( this.radians( fai ) ) * Math.sin( this.radians(lamda-L0));
  N = Math.sin( this.radians( fai ) );

  LD = cosB0  * L + sinB0 * N;
  MD = M;
  ND = -sinB0 * L + cosB0 * N;

  x = LD;
  y = cosP * MD - sinP * ND;
  z = sinP * MD + cosP * ND;
  
  return [x,y,z];
}

SVGScreen.prototype.outLine = function(point){
  var drawPos = this.getScrPointAry( 
		point[0][1]*this.CIRCLER+this.CIRCLEX, -point[0][2]*this.CIRCLER+this.CIRCLEY
  );
  
  
  var retStr = '<path d='
         +'"M ' + drawPos[0]
         +" "   + drawPos[1];

  for(i=0;i<point.length;i++){
	  drawPos = this.getScrPointAry( 
	  		point[i][1]*this.CIRCLER+this.CIRCLEX, -point[i][2]*this.CIRCLER+this.CIRCLEY
 	  );
      if( point[i][0] > 0 ){
	      retStr += 
		    ' L ' + drawPos[0] +" "  + drawPos[1];
	  } else {
	      retStr += 
		    ' M ' + drawPos[0] +" "  + drawPos[1];
	  }
  }
  retStr += ' " stroke-width="'+this.WIDTH+'" fill="none" stroke="'+this.COLOR+'" />\n';
  return retStr;
}

SVGScreen.prototype.drawCircles = function(L0,B0,P){
//  L0 = document.getElementById("L0").value-0;
//  B0 = document.getElementById("B0").value-0;
//  P = document.getElementById("P").value-0;

  var svgHtml = "";

  var point;
  var lamda = 0;
  var fai   = 0;
  
  for(fai=-90;fai<=90;fai+=10){
    point = new Array();
    for(lamda=0;lamda<=360;lamda+=2){
      point[lamda/2] = this.getXYZ(lamda,fai,L0,B0,P);
    }
      svgHtml += this.outLine(point);
  }

  for(lamda=0;lamda<=360;lamda+=10){
    point = new Array();
    for(fai=-90;fai<=90;fai+=2){
      point[(fai+90)/2] = this.getXYZ(lamda,fai,L0,B0,P);
    }
    svgHtml += this.outLine(point);
  }

  return svgHtml;
}

SVGScreen.prototype.getCircle = function(point){
	var pflag = false;
	var a1,b1,a2,b2;
	var  ret = new Array();
	
	var xc1 = ( point[1].x - point[0].x )/2.0 + point[0].x ;
	var yc1 = ( point[1].y - point[0].y )/2.0 + point[0].y ;
	var xc2 = ( point[2].x - point[1].x )/2.0 + point[1].x ;
	var yc2 = ( point[2].y - point[1].y )/2.0 + point[1].y ;
	
	if( point[0].y != point[1].y ){
		a1 = ( point[1].x - point[0].x ) / ( point[0].y - point[1].y ) ;
		b1 = yc1 - a1 * xc1;
	} else {
		ret[0] = xc1;
		pflag = true;
	}
	
	if( point[1].y != point[2].y ){
		a2 = ( point[2].x - point[1].x ) / ( point[1].y - point[2].y ) ;
		b2 = yc2 - a2 * xc2;
	} else {
		ret[0] = xc2;
		a2 = a1;
		b2 = b1;
		pflag = true;
	
	}
	
	if( !pflag ){
		ret[0] = (b2-b1)/(a1-a2);
	}
	

	ret[1] = a2 * ret[0] + b2;
	ret[2] = Math.sqrt(  (point[0].x - ret[0])*(point[0].x - ret[0])
	      			    +(point[0].y - ret[1])*(point[0].y - ret[1]) ); 
					  
	return ret;
}

SVGScreen.prototype.outputCircle=function(){
	return '<circle cx="'+ this.CIRCLEX +'" cy="' + this.CIRCLEY 
	+'" r="'+ this.CIRCLER +'"  '
	+'stroke-width="'+this.WIDTH+'" fill="none" stroke="'+this.COLOR+'" />\n';

}