code: function(mtx) {
  		
              if (mtx && typeof mtx == "object" && mtx.mtx) mtx = mtx.mtx;
              if (!mtx) return new Point(this.x,this.y);
  			
              var point = svg.createSVGPoint();
              point.x = this.x;
              point.y = this.y;
              point = point.matrixTransform(mtx);
  			
              return new this.constructor(point.x,point.y);
          }
docs: Applique une matrice de transformation
  @param mtx instance de JSYG.Matrix (ou SVGMatrix)
  @returns nouvelle instance