<?php
/**
*
*
*
* 相似图片搜索hash的php实现
*/
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 * $this->rate * $this->rate) ? true : false;
}
public function hash($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;
}
}
$instance = ImgHash::getInstance();
$result = $instance->checkIsSimilarImg('gf2.png', 'hjghjgkj.png');
var_dump($result);
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