public function captcha()
{
$text = $this->make_rand(4);
session()->put('captcha', strtolower($text));
$im_x = 160;
$im_y = 46;
$im = imagecreatetruecolor($im_x, $im_y);
$text_c = ImageColorAllocate($im, mt_rand(0, 100), mt_rand(0, 100), mt_rand(0, 100));
$tmpC0 = mt_rand(100, 255);
$tmpC1 = mt_rand(100, 255);
$tmpC2 = mt_rand(100, 255);
$buttum_c = ImageColorAllocate($im, $tmpC0, $tmpC1, $tmpC2);
imagefill($im, 16, 13, $buttum_c);
$font = './assets/font/captcha.ttf';
for ($i = 0; $i < strlen($text); $i++) {
$tmp = substr($text, $i, 1);
$array = array(-1, 1);
$p = array_rand($array);
$an = $array[$p] * mt_rand(1, 10);
//角度
$size = 28;
imagettftext($im, $size, $an, 15 + $i * $size, 35, $text_c, $font, $tmp);
}
$distortion_im = imagecreatetruecolor($im_x, $im_y);
imagefill($distortion_im, 16, 13, $buttum_c);
for ($i = 0; $i < $im_x; $i++) {
for ($j = 0; $j < $im_y; $j++) {
$rgb = imagecolorat($im, $i, $j);
if ((int) ($i + 20 + sin($j / $im_y * 2 * M_PI) * 10) <= imagesx($distortion_im) && (int) ($i + 20 + sin($j / $im_y * 2 * M_PI) * 10) >= 0) {
imagesetpixel($distortion_im, (int) ($i + 10 + sin($j / $im_y * 2 * M_PI - M_PI * 0.1) * 4), $j, $rgb);
}
}
}
//加入干扰象素;
$count = 160;
//干扰像素的数量
for ($i = 0; $i < $count; $i++) {
$randcolor = ImageColorallocate($distortion_im, mt_rand(0, 255), mt_rand(0, 255), mt_rand(0, 255));
imagesetpixel($distortion_im, mt_rand() % $im_x, mt_rand() % $im_y, $randcolor);
}
$rand = mt_rand(5, 30);
$rand1 = mt_rand(15, 25);
$rand2 = mt_rand(5, 10);
for ($yy = $rand; $yy <= +$rand + 2; $yy++) {
for ($px = -80; $px <= 80; $px = $px + 0.1) {
$x = $px / $rand1;
if ($x != 0) {
$y = sin($x);
}
$py = $y * $rand2;
imagesetpixel($distortion_im, $px + 80, $py + $yy, $text_c);
}
}
//设置文件头;
Header("Content-type: image/JPEG");
//以PNG格式将图像输出到浏览器或文件;
ImagePNG($distortion_im);
//销毁一图像,释放与image关联的内存;
ImageDestroy($distortion_im);
ImageDestroy($im);
}
