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December 11, 2015 18:43
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Plugin for one-color https://github.com/One-com/one-color. Function calculates perceived brightness of a passed color.
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| function pB (algo) { | |
| var algorithm = algo || 'rec2020'; | |
| var rgb = this.rgb(); | |
| if (algorithm === 'rec2020') { | |
| // https://en.wikipedia.org/wiki/Rec._2020 | |
| return ( (rgb._red * 2627) + (rgb._green * 6780) + (rgb._blue * 593) ) / 10000; | |
| } else if (algorithm === 'w3c') { | |
| // http://www.w3.org/TR/AERT#color-contrast | |
| return ( (rgb._red * 299) + (rgb._green * 587) + (rgb._blue * 114) ) / 1000; | |
| } else if (algorithm === 'nbd') { | |
| // http://www.nbdtech.com/Blog/archive/2008/04/27/Calculating-the-Perceived-Brightness-of-a-Color.aspx | |
| return Math.sqrt( (Math.pow(rgb._red, 2) * .241) + (Math.pow(rgb._green, 2) * .691) + (Math.pow(rgb._blue, 2) * .068) ); | |
| } else if (algorithm === 'rec709') { | |
| // https://en.wikipedia.org/wiki/Relative_luminance ; https://en.wikipedia.org/wiki/Rec._709 | |
| return ( (rgb._red * 241) + (rgb._green * 691) + (rgb._blue * 68) ) / 1000; | |
| } else { | |
| // default rec2020 | |
| return ( (rgb._red * 2627) + (rgb._green * 6780) + (rgb._blue * 593) ) / 10000; | |
| } | |
| } | |
| one.color.installMethod('perceivedBrightness', pB); | |
| //ONECOLOR.installMethod('perceivedBrightness', pB); |
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