给定这个函数,我想用随机颜色生成器替换颜色。

document.overlay = GPolyline.fromEncoded({
    color: "#0000FF",
    weight: 10,
    points: encoded_points,
    zoomFactor: 32,
    levels: encoded_levels,
    numLevels: 4
});

我该怎么做呢?


当前回答

创建一个基于任意随机值的唯一颜色

    selectColor(numberOrString) {
      if (typeof numberOrString === "string") {
        // convert string to number
        numberOrString = numberOrString.toLowerCase().split('').reduce(function (a, b) {
          a = ((a << 5) - a) + b.charCodeAt(0); // explained here: https://stackoverflow.com/a/7616484/112731
          return a & a
        }, 0);
      }
      const hue = numberOrString * 137.508; // use golden angle approximation
      return `hsl(${hue},50%,75%)`;
    }

其他回答

function randomColor(format = 'hex') {
    const rnd = Math.random().toString(16).slice(-6);
    if (format === 'hex') {
        return '#' + rnd;
    }
    if (format === 'rgb') {
        const [r, g, b] = rnd.match(/.{2}/g).map(c=>parseInt(c, 16));
        return `rgb(${r}, ${g}, ${b})`;
    }
}
'#'+Math.random().toString(16).slice(-3) // three-numbers format aka #f3c
'#'+Math.random().toString(16).slice(-6) // six-number format aka #abc123

我喜欢这个:'#' + (Math.random().toString(16) + "000000").substring(2,8)

Use:

function random_color(format)
{
    var rint = Math.round(0xffffff * Math.random());
    switch(format)
    {
        case 'hex':
            return ('#0' + rint.toString(16)).replace(/^#0([0-9a-f]{6})$/i, '#$1');
            break;

        case 'rgb':
            return 'rgb(' + (rint >> 16) + ',' + (rint >> 8 & 255) + ',' + (rint & 255) + ')';
            break;

        default:
            return rint;
            break;
    }
}

升级版:

function random_color( format ){
  var rint = Math.floor( 0x100000000 * Math.random());
  switch( format ){
    case 'hex':
      return '#' + ('00000'   + rint.toString(16)).slice(-6).toUpperCase();
    case 'hexa':
      return '#' + ('0000000' + rint.toString(16)).slice(-8).toUpperCase();
    case 'rgb':
      return 'rgb('  + (rint & 255) + ',' + (rint >> 8 & 255) + ',' + (rint >> 16 & 255) + ')';
    case 'rgba':
      return 'rgba(' + (rint & 255) + ',' + (rint >> 8 & 255) + ',' + (rint >> 16 & 255) + ',' + (rint >> 24 & 255)/255 + ')';
    default:
      return rint;
  }
}

所以,虽然这里所有的答案都很好,但我想对输出有更多的控制。例如,我想防止任何接近白色的阴影,同时确保我得到明亮的充满活力的颜色,而不是水洗阴影。

function generateColor(ranges) {
            if (!ranges) {
                ranges = [
                    [150,256],
                    [0, 190],
                    [0, 30]
                ];
            }
            var g = function() {
                //select random range and remove
                var range = ranges.splice(Math.floor(Math.random()*ranges.length), 1)[0];
                //pick a random number from within the range
                return Math.floor(Math.random() * (range[1] - range[0])) + range[0];
            }
            return "rgb(" + g() + "," + g() + "," + g() +")";
        };

所以现在我可以指定3个任意范围来选择rgb值。你可以不带参数调用它,得到我的默认设置,它通常会生成一个非常鲜艳的颜色,有明显的主色调,或者你可以提供你自己的范围数组。