<?php
/**
* Zend Framework (http://framework.zend.com/)
*
* @link http://github.com/zendframework/zf2 for the canonical source repository
* @copyright Copyright (c) 2005-2014 Zend Technologies USA Inc. (http://www.zend.com)
* @license http://framework.zend.com/license/new-bsd New BSD License
*/
namespace Zend\Captcha;
use DirectoryIterator;
use Zend\Stdlib\ErrorHandler;
/**
* Image-based captcha element
*
* Generates image displaying random word
*/
class Image extends AbstractWord
{
/**
* Directory for generated images
*
* @var string
*/
protected $imgDir = "public/images/captcha/";
/**
* URL for accessing images
*
* @var string
*/
protected $imgUrl = "/images/captcha/";
/**
* Image's alt tag content
*
* @var string
*/
protected $imgAlt = "";
/**
* Image suffix (including dot)
*
* @var string
*/
protected $suffix = ".png";
/**
* Image width
*
* @var int
*/
protected $width = 200;
/**
* Image height
*
* @var int
*/
protected $height = 50;
/**
* Font size
*
* @var int
*/
protected $fsize = 24;
/**
* Image font file
*
* @var string
*/
protected $font;
/**
* Image to use as starting point
* Default is blank image. If provided, should be PNG image.
*
* @var string
*/
protected $startImage;
/**
* How frequently to execute garbage collection
*
* @var int
*/
protected $gcFreq = 10;
/**
* How long to keep generated images
*
* @var int
*/
protected $expiration = 600;
/**
* Number of noise dots on image
* Used twice - before and after transform
*
* @var int
*/
protected $dotNoiseLevel = 100;
/**
* Number of noise lines on image
* Used twice - before and after transform
*
* @var int
*/
protected $lineNoiseLevel = 5;
/**
* Constructor
*
* @param array|\Traversable $options
* @throws Exception\ExtensionNotLoadedException
*/
public function __construct($options = null)
{
if (!extension_loaded("gd")) {
throw new Exception\ExtensionNotLoadedException("Image CAPTCHA requires GD extension");
}
if (!function_exists("imagepng")) {
throw new Exception\ExtensionNotLoadedException("Image CAPTCHA requires PNG support");
}
if (!function_exists("imageftbbox")) {
throw new Exception\ExtensionNotLoadedException("Image CAPTCHA requires FT fonts support");
}
parent::__construct($options);
}
/**
* @return string
*/
public function getImgAlt()
{
return $this->imgAlt;
}
/**
* @return string
*/
public function getStartImage()
{
return $this->startImage;
}
/**
* @return int
*/
public function getDotNoiseLevel()
{
return $this->dotNoiseLevel;
}
/**
* @return int
*/
public function getLineNoiseLevel()
{
return $this->lineNoiseLevel;
}
/**
* Get captcha expiration
*
* @return int
*/
public function getExpiration()
{
return $this->expiration;
}
/**
* Get garbage collection frequency
*
* @return int
*/
public function getGcFreq()
{
return $this->gcFreq;
}
/**
* Get font to use when generating captcha
*
* @return string
*/
public function getFont()
{
return $this->font;
}
/**
* Get font size
*
* @return int
*/
public function getFontSize()
{
return $this->fsize;
}
/**
* Get captcha image height
*
* @return int
*/
public function getHeight()
{
return $this->height;
}
/**
* Get captcha image directory
*
* @return string
*/
public function getImgDir()
{
return $this->imgDir;
}
/**
* Get captcha image base URL
*
* @return string
*/
public function getImgUrl()
{
return $this->imgUrl;
}
/**
* Get captcha image file suffix
*
* @return string
*/
public function getSuffix()
{
return $this->suffix;
}
/**
* Get captcha image width
*
* @return int
*/
public function getWidth()
{
return $this->width;
}
/**
* @param string $startImage
* @return Image
*/
public function setStartImage($startImage)
{
$this->startImage = $startImage;
return $this;
}
/**
* @param int $dotNoiseLevel
* @return Image
*/
public function setDotNoiseLevel($dotNoiseLevel)
{
$this->dotNoiseLevel = $dotNoiseLevel;
return $this;
}
/**
* @param int $lineNoiseLevel
* @return Image
*/
public function setLineNoiseLevel($lineNoiseLevel)
{
$this->lineNoiseLevel = $lineNoiseLevel;
return $this;
}
/**
* Set captcha expiration
*
* @param int $expiration
* @return Image
*/
public function setExpiration($expiration)
{
$this->expiration = $expiration;
return $this;
}
/**
* Set garbage collection frequency
*
* @param int $gcFreq
* @return Image
*/
public function setGcFreq($gcFreq)
{
$this->gcFreq = $gcFreq;
return $this;
}
/**
* Set captcha font
*
* @param string $font
* @return Image
*/
public function setFont($font)
{
$this->font = $font;
return $this;
}
/**
* Set captcha font size
*
* @param int $fsize
* @return Image
*/
public function setFontSize($fsize)
{
$this->fsize = $fsize;
return $this;
}
/**
* Set captcha image height
*
* @param int $height
* @return Image
*/
public function setHeight($height)
{
$this->height = $height;
return $this;
}
/**
* Set captcha image storage directory
*
* @param string $imgDir
* @return Image
*/
public function setImgDir($imgDir)
{
$this->imgDir = rtrim($imgDir, "/\\") . '/';
return $this;
}
/**
* Set captcha image base URL
*
* @param string $imgUrl
* @return Image
*/
public function setImgUrl($imgUrl)
{
$this->imgUrl = rtrim($imgUrl, "/\\") . '/';
return $this;
}
/**
* @param string $imgAlt
* @return Image
*/
public function setImgAlt($imgAlt)
{
$this->imgAlt = $imgAlt;
return $this;
}
/**
* Set captcha image filename suffix
*
* @param string $suffix
* @return Image
*/
public function setSuffix($suffix)
{
$this->suffix = $suffix;
return $this;
}
/**
* Set captcha image width
*
* @param int $width
* @return Image
*/
public function setWidth($width)
{
$this->width = $width;
return $this;
}
/**
* Generate random frequency
*
* @return float
*/
protected function randomFreq()
{
return mt_rand(700000, 1000000) / 15000000;
}
/**
* Generate random phase
*
* @return float
*/
protected function randomPhase()
{
// random phase from 0 to pi
return mt_rand(0, 3141592) / 1000000;
}
/**
* Generate random character size
*
* @return int
*/
protected function randomSize()
{
return mt_rand(300, 700) / 100;
}
/**
* Generate captcha
*
* @return string captcha ID
*/
public function generate()
{
$id = parent::generate();
$tries = 5;
// If there's already such file, try creating a new ID
while ($tries-- && file_exists($this->getImgDir() . $id . $this->getSuffix())) {
$id = $this->generateRandomId();
$this->setId($id);
}
$this->generateImage($id, $this->getWord());
if (mt_rand(1, $this->getGcFreq()) == 1) {
$this->gc();
}
return $id;
}
/**
* Generate image captcha
*
* Override this function if you want different image generator
* Wave transform from http://www.captcha.ru/captchas/multiwave/
*
* @param string $id Captcha ID
* @param string $word Captcha word
* @throws Exception\NoFontProvidedException if no font was set
* @throws Exception\ImageNotLoadableException if start image cannot be loaded
*/
protected function generateImage($id, $word)
{
$font = $this->getFont();
if (empty($font)) {
throw new Exception\NoFontProvidedException('Image CAPTCHA requires font');
}
$w = $this->getWidth();
$h = $this->getHeight();
$fsize = $this->getFontSize();
$imgFile = $this->getImgDir() . $id . $this->getSuffix();
if (empty($this->startImage)) {
$img = imagecreatetruecolor($w, $h);
} else {
// Potential error is change to exception
ErrorHandler::start();
$img = imagecreatefrompng($this->startImage);
$error = ErrorHandler::stop();
if (!$img || $error) {
throw new Exception\ImageNotLoadableException(
"Can not load start image '{$this->startImage}'", 0, $error
);
}
$w = imagesx($img);
$h = imagesy($img);
}
$textColor = imagecolorallocate($img, 0, 0, 0);
$bgColor = imagecolorallocate($img, 255, 255, 255);
imagefilledrectangle($img, 0, 0, $w-1, $h-1, $bgColor);
$textbox = imageftbbox($fsize, 0, $font, $word);
$x = ($w - ($textbox[2] - $textbox[0])) / 2;
$y = ($h - ($textbox[7] - $textbox[1])) / 2;
imagefttext($img, $fsize, 0, $x, $y, $textColor, $font, $word);
// generate noise
for ($i=0; $i < $this->dotNoiseLevel; $i++) {
imagefilledellipse($img, mt_rand(0, $w), mt_rand(0, $h), 2, 2, $textColor);
}
for ($i=0; $i < $this->lineNoiseLevel; $i++) {
imageline($img, mt_rand(0, $w), mt_rand(0, $h), mt_rand(0, $w), mt_rand(0, $h), $textColor);
}
// transformed image
$img2 = imagecreatetruecolor($w, $h);
$bgColor = imagecolorallocate($img2, 255, 255, 255);
imagefilledrectangle($img2, 0, 0, $w-1, $h-1, $bgColor);
// apply wave transforms
$freq1 = $this->randomFreq();
$freq2 = $this->randomFreq();
$freq3 = $this->randomFreq();
$freq4 = $this->randomFreq();
$ph1 = $this->randomPhase();
$ph2 = $this->randomPhase();
$ph3 = $this->randomPhase();
$ph4 = $this->randomPhase();
$szx = $this->randomSize();
$szy = $this->randomSize();
for ($x = 0; $x < $w; $x++) {
for ($y = 0; $y < $h; $y++) {
$sx = $x + (sin($x*$freq1 + $ph1) + sin($y*$freq3 + $ph3)) * $szx;
$sy = $y + (sin($x*$freq2 + $ph2) + sin($y*$freq4 + $ph4)) * $szy;
if ($sx < 0 || $sy < 0 || $sx >= $w - 1 || $sy >= $h - 1) {
continue;
} else {
$color = (imagecolorat($img, $sx, $sy) >> 16) & 0xFF;
$colorX = (imagecolorat($img, $sx + 1, $sy) >> 16) & 0xFF;
$colorY = (imagecolorat($img, $sx, $sy + 1) >> 16) & 0xFF;
$colorXY = (imagecolorat($img, $sx + 1, $sy + 1) >> 16) & 0xFF;
}
if ($color == 255 && $colorX == 255 && $colorY == 255 && $colorXY == 255) {
// ignore background
continue;
} elseif ($color == 0 && $colorX == 0 && $colorY == 0 && $colorXY == 0) {
// transfer inside of the image as-is
$newcolor = 0;
} else {
// do antialiasing for border items
$fracX = $sx - floor($sx);
$fracY = $sy - floor($sy);
$fracX1 = 1 - $fracX;
$fracY1 = 1 - $fracY;
$newcolor = $color * $fracX1 * $fracY1
+ $colorX * $fracX * $fracY1
+ $colorY * $fracX1 * $fracY
+ $colorXY * $fracX * $fracY;
}
imagesetpixel($img2, $x, $y, imagecolorallocate($img2, $newcolor, $newcolor, $newcolor));
}
}
// generate noise
for ($i=0; $i<$this->dotNoiseLevel; $i++) {
imagefilledellipse($img2, mt_rand(0, $w), mt_rand(0, $h), 2, 2, $textColor);
}
for ($i=0; $i<$this->lineNoiseLevel; $i++) {
imageline($img2, mt_rand(0, $w), mt_rand(0, $h), mt_rand(0, $w), mt_rand(0, $h), $textColor);
}
imagepng($img2, $imgFile);
imagedestroy($img);
imagedestroy($img2);
}
/**
* Remove old files from image directory
*
*/
protected function gc()
{
$expire = time() - $this->getExpiration();
$imgdir = $this->getImgDir();
if (!$imgdir || strlen($imgdir) < 2) {
// safety guard
return;
}
$suffixLength = strlen($this->suffix);
foreach (new DirectoryIterator($imgdir) as $file) {
if (!$file->isDot() && !$file->isDir()) {
if (file_exists($file->getPathname()) && $file->getMTime() < $expire) {
// only deletes files ending with $this->suffix
if (substr($file->getFilename(), -($suffixLength)) == $this->suffix) {
unlink($file->getPathname());
}
}
}
}
}
/**
* Get helper name used to render captcha
*
* @return string
*/
public function getHelperName()
{
return 'captcha/image';
}
}