PHP生成验证码图片

分类：PHP 发布时间：2019-06-06 09:02:00

``` session_start(); getCode(4,60,20); function getCode($num,$w,$h) { $code = ""; for ($i = 0; $i < $num; $i++) { $code .= rand(0, 9); } //4位验证码也能够用rand(1000,9999)直接生成 //将生成的验证码写入session，备验证时用 $_SESSION["helloweba_num"] = $code; //创建图片，定义颜色值 header("Content-type: image/PNG"); $im = imagecreate($w, $h); $black = imagecolorallocate($im, 0, 0, 0); $gray = imagecolorallocate($im, 200, 200, 200); //填充背景 imagefill($im, 0, 0, $gray); //画边框 imagerectangle($im, 0, 0, $w-1, $h-1, $black); //随机绘制两条虚线，起干扰作用 $style = array ($black,$black,$black,$black,$black, $gray,$gray,$gray,$gray,$gray ); imagesetstyle($im, $style); $y1 = rand(0, $h); $y2 = rand(0, $h); $y3 = rand(0, $h); $y4 = rand(0, $h); imageline($im, 0, $y1, $w, $y3, IMG_COLOR_STYLED); imageline($im, 0, $y2, $w, $y4, IMG_COLOR_STYLED); //在画布上随机生成大量黑点，起干扰作用; for ($i = 0; $i < 80; $i++) { imagesetpixel($im, rand(0, $w), rand(0, $h), $black); } //将数字随机显示在画布上,字符的水平间距和位置都按一定波动范围随机生成 $strx = rand(3, $w-12*$num); $stry = rand(3, $h/2); imagestring($im,5,$strx,$stry,$code,$black); //for ($i = 0; $i < $num; $i++) { // $strpos = rand(1, 6); // imagestring($im, 5, $strx, $strpos, substr($code, $i, 1), $black); // $strx += rand(8, 12); // } imagepng($im);//输出图片 imagedestroy($im);//释放图片所占内存 // 如果是laravel框架 // return response('', 200, [ // 'Content-Type' => 'image/png', // ]); } ```