复制代码代码如下:php 0.99,// 白色概率1 => 0.01,);// Requires the GD Library header("Content-type: image/png");$im = imagecreatetruecolor(256, 256) or die("Cannot Initialize new GD image stream");$white = imagecolorallocate($im, 255, 255, 255);$start = microtime(true);for ($y=0; $yfor ($x=0; $xif (random($setting) === 1) {imagesetpixel($im, $x, $y, $white);}}}$time = microtime(true) - $start;header("X-Exec-Time: ".$time);imagepng($im);imagedestroy($im);/*** 全概率计算** @param array $p array('a'=>0.5,'b'=>0.2,'c'=>0.4)* @return string 返回上面数组的key* @author Lukin*/function random($ps){static $arr = array(); $key = md5(serialize($ps));if (!isset($arr[$key])) {$max = array_sum($ps);foreach ($ps as $k=>$v) {$v = $v / $max * 10000;for ($i=0; $i}}return $arr[$key][mt_rand(0,count($arr[$key])-1)];}?>黑点出现概率99%，白点出现概率1%，测试结果：
