anchor.diff:    Impress pres = new Impress();
     pres.setupCanvas();
   
  -  // prevent default keydown action when one of supported key is pressed
  -  document.on.keyDown.add((event) {
  -    if (event.keyCode === 9 || (event.keyCode >= 32 && event.keyCode <= 34 ) || (event.keyCode >= 37 && event.keyCode <= 40)) {
  -      event.preventDefault();
  -    }
  -  });
  -
     // trigger impress action (next or prev) on keyup
     document.on.keyUp.add((event) {
       switch (event.keyCode) {
  
positive.code:   
    num getAttribute(Element root, String a, num def) =>
        (root.attributes[a] == null) ?
          def : Math.parseDouble(root.attributes[a]);
    
    Config(Element root)
    {
  
negative.code:   num winScale()
    {
      num hScale = document.window.innerHeight / mCfg.height;
      num wScale = document.window.innerWidth / mCfg.width;
      num scale = Math.min(hScale,wScale);
      scale = Math.min(mCfg.maxScale,scale);
      scale = Math.max(mCfg.minScale,scale);
      return scale;
    }
    
  