code: function(size) {
          OpenLayers.Renderer.prototype.setSize.apply(this, arguments);
          
          // setting width and height on all roots to avoid flicker which we
          // would get with 100% width and height on child roots
          var roots = [
              this.rendererRoot,
              this.root,
              this.vectorRoot,
              this.textRoot
          ];
          var w = this.size.w + "px";
          var h = this.size.h + "px";
          var root;
          for(var i=0, len=roots.length; i<len; ++i) {
              root = roots[i];
              root.style.width = w;
              root.style.height = h;
          }
      }
docs: Method: setSize
  Set the size of the drawing surface
  
  Parameters:
  size - {<OpenLayers.Size>} the size of the drawing surface