Controller file –<\/p>\n
public function captcha() {\r\n\t\t$this->session->data['captcha'] = substr(sha1(mt_rand()), 17, 6);\r\n\r\n\t\t$image = imagecreatetruecolor(150, 35);\r\n\r\n\t\t$width = imagesx($image);\r\n\t\t$height = imagesy($image);\r\n\r\n\t\t$black = imagecolorallocate($image, 0, 0, 0);\r\n\t\t$white = imagecolorallocate($image, 255, 255, 255);\r\n\t\t$red = imagecolorallocatealpha($image, 255, 0, 0, 75);\r\n\t\t$green = imagecolorallocatealpha($image, 0, 255, 0, 75);\r\n\t\t$blue = imagecolorallocatealpha($image, 0, 0, 255, 75);\r\n\r\n\t\timagefilledrectangle($image, 0, 0, $width, $height, $white);\r\n\t\timagefilledellipse($image, ceil(rand(5, 145)), ceil(rand(0, 35)), 30, 30, $red);\r\n\t\timagefilledellipse($image, ceil(rand(5, 145)), ceil(rand(0, 35)), 30, 30, $green);\r\n\t\timagefilledellipse($image, ceil(rand(5, 145)), ceil(rand(0, 35)), 30, 30, $blue);\r\n\t\timagefilledrectangle($image, 0, 0, $width, 0, $black);\r\n\t\timagefilledrectangle($image, $width - 1, 0, $width - 1, $height - 1, $black);\r\n\t\timagefilledrectangle($image, 0, 0, 0, $height - 1, $black);\r\n\t\timagefilledrectangle($image, 0, $height - 1, $width, $height - 1, $black);\r\n\r\n\t\timagestring($image, 10, intval(($width - (strlen($this->session->data['captcha']) * 9)) \/ 2), intval(($height - 15) \/ 2), $this->session->data['captcha'], $black);\r\n\r\n\t\theader('Content-type: image\/jpeg');\r\n\r\n\t\timagejpeg($image);\r\n\r\n\t\timagedestroy($image);\r\n\t}<\/pre>\nResult –<\/p>\n
![\"\"](\"http:\/\/i.imgur.com\/tlzPzTI.png\")
<\/p>\n","protected":false},"excerpt":{"rendered":"