在业务中，有时候需要动态的调整颜色，在处理动态内容时，确定颜色是浅色还是深色非常方便。 我们可以通过颜色计算出HSP值，并用HSP来确定颜色是浅色还是深色。

function lightOrDark(color) {
    // Variables for red, green, blue values, and hsp
    var r, g, b, hsp;

    // Check the format of the color, HEX or RGB?
    if (color.match(/^rgb/)) {

        // If RGB --> store the red, green, blue values in separate variables
        color = color.match(/^rgba?\((\d+),\s*(\d+),\s*(\d+)(?:,\s*(\d+(?:\.\d+)?))?\)$/);
        
        r = color[1];
        g = color[2];
        b = color[3];
    } 
    else {
        
        // If hex --> Convert it to RGB: http://gist.github.com/983661
        color = +("0x" + color.slice(1).replace( 
        color.length < 5 && /./g, '$&$&'));

        r = color >> 16;
        g = color >> 8 & 255;
        b = color & 255;
    }
    
    // HSP (Highly Sensitive Poo) equation from http://alienryderflex.com/hsp.html
    hsp = Math.sqrt(
    0.299 * (r * r) +
    0.587 * (g * g) +
    0.114 * (b * b)
    );

    // Using the HSP value, determine whether the color is light or dark
    if (hsp>127.5) {

        return 'light';
    } 
    else {

        return 'dark';
    }
}

参考

• https://gist.github.com/krabs-github/ec56e4f1c12cddf86ae9c551aa9d9e04
• http://alienryderflex.com/hsp.html