Add label to edges about arbor HOT 2 OPEN

      var label = edge.data.label ? $.trim(edge.data.label) : '';
      if (label != '' && ctx){
        mid_x = (tail.x+head.x)/2;
        mid_y = (tail.y+head.y)/2;
        ctx.save();
            ctx.font = "1.1em Arial";
            ctx.textAlign = "center";
            ctx.lineWidth = 4;
            ctx.strokeStyle = 'rgba(255,255,255,1)';
            ctx.strokeText(label, mid_x, mid_y);
            ctx.fillStyle = "black";
            ctx.fillText(label, mid_x, mid_y);
        ctx.restore();
      }