Created
November 30, 2012 03:50
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<?php | |
/** | |
* | |
* 相似图片æœç´¢hashçš„php实现 | |
* @author welefen | |
* | |
*/ | |
class Imghash{ | |
private static $_instance = null; | |
public $rate = 2; | |
public static function getInstance(){ | |
if (self::$_instance === null){ | |
self::$_instance = new self(); | |
} | |
return self::$_instance; | |
} | |
public function run($file){ | |
if (!function_exists('imagecreatetruecolor')){ | |
throw new Exception('must load gd lib', 1); | |
} | |
$isString = false; | |
if (is_string($file)){ | |
$file = array($file); | |
$isString = true; | |
} | |
$result = array(); | |
foreach ($file as $f){ | |
$result[] = $this->hash($f); | |
} | |
return $isString ? $result[0] : $result; | |
} | |
public function checkIsSimilarImg($imgHash, $otherImgHash){ | |
if (file_exists($imgHash) && file_exists($otherImgHash)){ | |
$imgHash = $this->run($imgHash); | |
$otherImgHash = $this->run($otherImgHash); | |
} | |
if (strlen($imgHash) !== strlen($otherImgHash)) return false; | |
$count = 0; | |
$len = strlen($imgHash); | |
for($i=0;$i<$len;$i++){ | |
if ($imgHash{$i} !== $otherImgHash{$i}){ | |
$count++; | |
} | |
} | |
return $count <= (5 * $rate * $rate) ? true : false; | |
} | |
public function hash($file){ | |
if (!file_exists($file)){ | |
return false; | |
} | |
$height = 8 * $this->rate; | |
$width = 8 * $this->rate; | |
$img = imagecreatetruecolor($width, $height); | |
list($w, $h) = getimagesize($file); | |
$source = $this->createImg($file); | |
imagecopyresampled($img, $source, 0, 0, 0, 0, $width, $height, $w, $h); | |
$value = $this->getHashValue($img); | |
imagedestroy($img); | |
return $value; | |
} | |
public function getHashValue($img){ | |
$width = imagesx($img); | |
$height = imagesy($img); | |
$total = 0; | |
$array = array(); | |
for ($y=0;$y<$height;$y++){ | |
for ($x=0;$x<$width;$x++){ | |
$gray = ( imagecolorat($img, $x, $y) >> 8 ) & 0xFF; | |
if (!is_array($array[$y])){ | |
$array[$y] = array(); | |
} | |
$array[$y][$x] = $gray; | |
$total += $gray; | |
} | |
} | |
$average = intval($total / (64 * $this->rate * $this->rate)); | |
$result = ''; | |
for ($y=0;$y<$height;$y++){ | |
for ($x=0;$x<$width;$x++){ | |
if ($array[$y][$x] >= $average){ | |
$result .= '1'; | |
}else{ | |
$result .= '0'; | |
} | |
} | |
} | |
return $result; | |
} | |
public function createImg($file){ | |
$ext = $this->getFileExt($file); | |
if ($ext === 'jpeg') $ext = 'jpg'; | |
$img = null; | |
switch ($ext){ | |
case 'png' : $img = imagecreatefrompng($file);break; | |
case 'jpg' : $img = imagecreatefromjpeg($file);break; | |
case 'gif' : $img = imagecreatefromgif($file); | |
} | |
return $img; | |
} | |
public function getFileExt($file){ | |
$infos = explode('.', $file); | |
$ext = strtolower($infos[count($infos) - 1]); | |
return $ext; | |
} | |
} |
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