nl_tokens: Get the RGBA value of a coordinate
pl_tokens: function ( x , y ) { var i = this . _getIndex ( x , y ) ; return { r : this . _png . data [ i + 0 ] , g : this . _png . data [ i + 1 ] , b : this . _png . <mask> [ i + 2 ] , a : this . _png . data [ i + 3 ] } ; }