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【JavaScript】颜色选择器

颜色空间RGB与HSV(HSL)的转换

从 HSV 到 RGB 的转换

类似的，给定在 HSV 中 (h, s, v) 值定义的一个颜色，带有如上的 h，和分别表示饱和度和明度的 s 和 v 变化于 0 到 1 之间，在 RGB 空间中对应的 (r, g, b) 三原色可以计算为：

$h_i equiv leftlfloor frac{h}{60} ight floor pmod{6}$

$f = frac{h}{60} - h_i$

$p = v imes (1 - s) \,$

$q = v imes (1 - f imes s) \,$

$t = v imes (1 - (1 - f) imes s) \,$

对于每个颜色向量 (r, g, b),

$(r, g, b) = egin{cases}(v, t, p), & mbox{if } h_i = 0 \(q, v, p), & mbox{if } h_i = 1 \(p, v, t), & mbox{if } h_i = 2 \(p, q, v), & mbox{if } h_i = 3 \(t, p, v), & mbox{if } h_i = 4 \(v, p, q), & mbox{if } h_i = 5 \end{cases}$

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>Untitled Document</title>
</head>
<body>
<script type="text/JavaScript">
<!--
var colorPicker = function(idStr){
 this.colorPool = ["#000000","#993300","#333300","#003300","#003366","#000080","#333399","#333333","#800000","#FF6600","#808000","#008000","#008080","#0000FF","#666699","#808080","#FF0000","#FF9900","#99CC00","#339966","#33CCCC","#3366FF","#800080","#999999","#FF00FF","#FFCC00","#FFFF00","#00FF00","#00FFFF","#00CCFF","#993366","#CCCCCC","#FF99CC","#FFCC99","#FFFF99","#CCFFCC","#CCFFFF","#99CCFF","#CC99FF","#FFFFFF"];
 this.initialize(idStr);
}
colorPicker.prototype = {
 initialize: function(idStr){
  var count=0;
  var html = '';
  var self = this;
  html+= '<table cellspacing="5" cellpadding="0" border="2" bordercolor="#000000" style="cursor:pointer;background:#ECE9D8" mce_style="cursor:pointer;background:#ECE9D8" >';
  // html+= '<tr><td align="center" colspan="8" width="160" height="20" id="currentColor" bgcolor="#ffffff">当前颜色</td></tr>';
  for(i=0;i<5;i++)
  {
   html+= "<tr>";
   for(j=0;j<8;j++)
   {
    html+= '<td align="center" width="20" height="20" style="background:'+ this.colorPool[count]+'" mce_style="background:'+ this.colorPool[count]+'" unselectable="on"> </td>';
    count++;
   }
   html+= "</tr>";
  }
  html+= '</table>';
  this.trigger = document.getElementById(idStr);
  this.div = document.createElement('div');
  this.div.innerHTML = html;
  var tds = this.div.getElementsByTagName('td');
  for(var i=0,l=tds.length;i<l;i++){
   tds[i].onclick = function(){
    self.setColor(this.style.backgroundColor);
   }
  }
  this.div.id = 'myColorPicker';
  this.trigger.parentNode.appendChild(this.div);
  this.div.style.position = 'absolute';
  this.div.style.left = this.trigger.offsetLeft + 'px'
  this.div.style.top = (this.trigger.clientHeight + this.trigger.offsetTop)+ 'px';
  //this.hide();
  this.trigger.onclick = function(){
   if(self.div.style.display == 'none'){
    self.show();
    return false;
   }else{
    self.hide();
    return false;
   }
  }
 },
 setColor : function(c){
  this.hide();
  document.getElementById('demo').style.backgroundColor = c //proEditor.setColor(c); //自己定义函数决定setColor的功能
 },
 hide : function(){
  this.div.style.display = 'none'
 },
 show : function(){
  this.div.style.display = 'block'
 }
}
// -->
</script>
<div >
<a href="#" mce_href="#" onclick="initColorPicker();return false" id="demo" style="position:absolute;left:200px">颜色选择</a>
</div>
<script type="text/javascript">
<!--
function initColorPicker(){
 picker = new colorPicker('demo');
}
// -->
</script>
</body>
</html>

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原文地址：https://www.cnblogs.com/yujihang/p/6956424.html