博客

class ImagesList {

    private $rate = 3;

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 $this->getBin2hex($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 $ext;
}
public function getBin2hex($str,$len = '4'){
    $string = '';
    $time = ceil(strlen($str)/$len);
    for($i=0;$i<$time;$i++){
        $start = $i*4;
        $string .= dechex(bindec(substr($str,$start,$len)));
    }
    return $string;
}
}