40 lines
1.1 KiB
JavaScript
40 lines
1.1 KiB
JavaScript
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/**
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* Get luminance from a HEX color.
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*
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* @since Twenty Twenty-One 1.0
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*
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* @param {string} hex - The hex color.
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*
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* @return {number} - Returns the luminance, number between 0 and 255.
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*/
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function twentytwentyoneGetHexLum( hex ) { // jshint ignore:line
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var rgb = twentytwentyoneGetRgbFromHex( hex );
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return Math.round( ( 0.2126 * rgb.r ) + ( 0.7152 * rgb.g ) + ( 0.0722 * rgb.b ) );
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}
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/**
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* Get RGB from HEX.
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*
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* @since Twenty Twenty-One 1.0
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*
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* @param {string} hex - The hex color.
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*
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* @return {Object} - Returns an object {r, g, b}
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*/
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function twentytwentyoneGetRgbFromHex( hex ) {
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var shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i,
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result;
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// Expand shorthand form (e.g. "03F") to full form (e.g. "0033FF").
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hex = hex.replace( shorthandRegex, function( m, r, g, b ) {
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return r.toString() + r.toString() + g.toString() + g.toString() + b.toString() + b.toString();
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} );
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result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec( hex );
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return result ? {
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r: parseInt( result[1], 16 ),
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g: parseInt( result[2], 16 ),
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b: parseInt( result[3], 16 )
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} : null;
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}
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