neyric/wireit

YUI.add("leftsquarearrow-wire", function(Y){

/**
 * Square type of arrows for representing loops (but not restricted to) in CFG
 * @class LeftSquareArrow
 * @extends Wire
 * @constructor
 * @param  {WireIt.Terminal}    terminal1   Source terminal
 * @param  {WireIt.Terminal}    terminal2   Target terminal
 * @param  {HTMLElement} parentEl    Container of the CANVAS tag
 * @param  {Obj}                options      Wire configuration (see options property)
 */
Y.LeftSquareArrow = function( terminal1, terminal2, parentEl, options) {
    Y.LeftSquareArrow.superclass.constructor.call(this, terminal1, terminal2, parentEl, options);
};

Y.extend(Y.LeftSquareArrow, Y.Wire, {
    
    /** 
    * @attribute xtype
    * @description String representing this class for exporting as JSON
    * @default "WireIt.LeftSquareArrow"
    * @type String
    */
   xtype: "Y.LeftSquareArrow",

    /**
    * Drawing method
    */
   draw: function() {    

       // Get the positions of the terminals
       var p1 = this.terminal1.getXY();
       var p2 = this.terminal2.getXY();

       var distance=Math.sqrt(Math.pow(p1[0]-p2[0],2)+Math.pow(p1[1]-p2[1],2));

        var d = 7; // arrow width/2

       var redim = d + distance*0.5; //we have to make the canvas a little bigger because of arrows

       var margin=[4+redim,4+redim];

       var min=[ Math.min(p1[0],p2[0])-margin[0],
        Math.min(p1[1],p2[1])-margin[1]];

       var max=[ Math.max(p1[0],p2[0])+margin[0],
        Math.max(p1[1],p2[1])+margin[1]];

       // Redimensionnement du canvas
       var lw=Math.abs(max[0]-min[0])+redim;
       var lh=Math.abs(max[1]-min[1])+redim;

       p1[0]=p1[0]-min[0];
       p1[1]=p1[1]-min[1];
       p2[0]=p2[0]-min[0];
       p2[1]=p2[1]-min[1];

       this.SetCanvasRegion(min[0],min[1],lw,lh);

       var ctxt=this.getContext();

        //      (e1) .------> * (p1)
        //               |
        //              |
        //            |
        //      (e2) .-------* (p2)

        var e1 = this.terminal1.getXY();
        var e2 = this.terminal2.getXY();
         e1[0] = p1[0] - distance/4 + 5;      // Change the x coordinate; y remains same
        e1[1] = p1[1];
        e2[0] = p2[0] - distance/4 + 5;
        e2[1] = p2[1];

      // Draw the border
      ctxt.lineCap=this.bordercap;
      ctxt.strokeStyle=this.bordercolor;
      ctxt.lineWidth=this.width+this.borderwidth*2;
      ctxt.beginPath();
      ctxt.moveTo(p1[0], p1[1]);          
          ctxt.lineTo(e1[0], e1[1]);
          ctxt.lineTo(e2[0], e2[1]);
      ctxt.lineTo(p2[0], p2[1]);    
      ctxt.stroke();

      // Draw the inner bezier curve
      ctxt.lineCap=this.cap;
      ctxt.strokeStyle=this.color;
      ctxt.lineWidth=this.width;
      ctxt.beginPath();
      ctxt.moveTo(p1[0],p1[1]);
          ctxt.lineTo(e1[0], e1[1]);
          ctxt.lineTo(e2[0], e2[1]);
      ctxt.lineTo(p2[0], p2[1]);    
      ctxt.stroke();

      /* start drawing arrows */
       var t1 = e2;
       var t2 = p2;

       var z = [0,0]; //point on the wire with constant distance (dlug) from terminal2
       var dlug = 20; //arrow length
       var t = (distance === 0) ? 0 : 1-(dlug/distance);
       z[0] = Math.abs( t1[0] +  t*(t2[0]-t1[0]) );
       z[1] = Math.abs( t1[1] + t*(t2[1]-t1[1]) );    

       //line which connects the terminals: y=ax+b
       var W = t1[0] - t2[0];
       var Wa = t1[1] - t2[1];
       var Wb = t1[0]*t2[1] - t1[1]*t2[0];
       if (W !== 0) {
           a = Wa/W;
           b = Wb/W;
       }
       else {
           a = 0;
       }

       //line perpendicular to the main line: y = aProst*x + b
       if (a === 0) {
           aProst = 0;
       }
       else {
           aProst = -1/a;
       }
       bProst = z[1] - aProst*z[0]; //point z lays on this line

       //we have to calculate coordinates of 2 points, which lay on perpendicular line and have the same distance (d) from point z
       var A = 1 + Math.pow(aProst,2);
       var B = 2*aProst*bProst - 2*z[0] - 2*z[1]*aProst;
       var C = -2*z[1]*bProst + Math.pow(z[0],2) + Math.pow(z[1],2) - Math.pow(d,2) + Math.pow(bProst,2);
       var delta = Math.pow(B,2) - 4*A*C;

       if (delta < 0) { return; }

       var x1 = (-B + Math.sqrt(delta)) / (2*A);
       var x2 = (-B - Math.sqrt(delta)) / (2*A);    
       var y1 = aProst*x1 + bProst;
       var y2 = aProst*x2 + bProst;

       if(t1[1] == t2[1]) {
             var o = (t1[0] > t2[0]) ? 1 : -1;
             x1 = t2[0]+o*dlug;
             x2 = x1;
             y1 -= d;
             y2 += d;
       }       

       //triangle fill
       ctxt.fillStyle = this.color;
       ctxt.beginPath();
       ctxt.moveTo(t2[0],t2[1]);
       ctxt.lineTo(x1,y1);
       ctxt.lineTo(x2,y2);
       ctxt.fill();

       //triangle border    
       ctxt.strokeStyle = this.bordercolor;
       ctxt.lineWidth = this.borderwidth;
       ctxt.beginPath();
       ctxt.moveTo(t2[0],t2[1]);
       ctxt.lineTo(x1,y1);
       ctxt.lineTo(x2,y2);
       ctxt.lineTo(t2[0],t2[1]);
       ctxt.stroke();
   }

});

}, '0.7.0',{
  requires: ['wire']
});