JAVASCRIPT亮度功能-降低

Question

我在堆栈上创建了这段代码：

function increase_brightness(hex, percent){
    var r = parseInt(hex.substr(1, 2), 16),
        g = parseInt(hex.substr(3, 2), 16),
        b = parseInt(hex.substr(5, 2), 16);

    return '#' +
       ((0|(1<<8) + r + (256 - r) * percent / 100).toString(16)).substr(1) +
       ((0|(1<<8) + g + (256 - g) * percent / 100).toString(16)).substr(1) +
       ((0|(1<<8) + b + (256 - b) * percent / 100).toString(16)).substr(1);
}

有谁知道如何进行完全逆运算？

函数decreas_brightness(){}我的意思是

Answer 1

您的代码来自JavaScript Calculate brighter colour。根据 cmets 的说法，以下更改应使其亮度降低：

function decrease_brightness(hex, percent){
    var r = parseInt(hex.substr(1, 2), 16),
        g = parseInt(hex.substr(3, 2), 16),
        b = parseInt(hex.substr(5, 2), 16);

   return '#' +
       ((0|(1<<8) + r * (100 - percent) / 100).toString(16)).substr(1) +
       ((0|(1<<8) + g * (100 - percent) / 100).toString(16)).substr(1) +
       ((0|(1<<8) + b * (100 - percent) / 100).toString(16)).substr(1);
}