nl_tokens: Functions to calculate brightness
pl_tokens: function getBrightness ( hex ) { var r = parseInt ( hex . substr ( 2 + 0 * 2 , 2 ) , 16 ) , g = parseInt ( hex . substr ( 2 + 1 * 2 , 2 ) , 16 ) , b = parseInt ( <mask> . substr ( 2 + 2 * 2 , 2 ) , 16 ) ; function lin2log ( n ) { return n <= 0.0031308 ? n * 12.92 : 1.055 * Math . pow ( n , 1 / 2.4 ) - 0.055 ; } function log2lin ( n ) { return n <= 0.04045 ? n / 12.92 : Math . pow ( ( ( n + 0.055 ) / 1.055 ) , 2.4 ) ; } r = log2lin ( r / 255 ) ; g = log2lin ( g / 255 ) ; b = log2lin ( b / 255 ) ; return lin2log ( 0.2126 * r + 0.7152 * g + 0.0722 * b ) * 100 ; }