/**
* `CompareImagesWith` compares the images at the urls stored in the `$urls`
* property. There are three different "components" that are available to
* interchange, namely, `comparators`, `filters`, and `parsers`.
*/
public function compareImagesWith($comparators = array('md5'), $filters = array(), $parser = 'html')
{
if (count($this->urls) < 2) {
return false;
}
/**
* Parsers are what take an html page and return a set of image URLs.
* For now, we have implimented a simple HTML parser based of of
* PHPs built in DOMdocument. But it wouldn't be a far stretch to
* drop in another module that takes into account JS images, using
* something like PHPJS or P2P5.
*/
$images = array();
foreach ($this->urls as $url) {
$name = '\\ImageMatcher\\Parsers\\' . $parser;
$imgs = @class_exists($name) ? ImageFactory::imagesFromLocationArray($name::parse($url), md5($url)) : array();
foreach ($imgs as $img) {
$images[] = $img;
}
}
$images = $this->runFilters('before_filters', $filters, $images);
/**
* Comparators compare images and create MatchCollection's of MatchPairs,
* which hold the two image objects, as well as a score for their similarity.
*/
$matches = new MatchCollection();
foreach ($comparators as $comparator) {
$name = '\\ImageMatcher\\Comparators\\' . $comparator;
$collection = @class_exists($name) ? $name::compare($images) : new MatchCollection();
$matches->appendCollection($collection);
}
$matches = $this->runFilters('after_filters', $filters, $matches);
return $matches;
}
/**
* The static `compare` method is implimented by all of the Comparators.
* This method takes an array of images and performs the needed calculations
* on them and outputs a MatchCollection object, which will then be appended
* to the global collection.
*/
public static function compare($images)
{
// we operate on arrays of image objects
if (!is_array($images)) {
return false;
}
$hashes = array();
$matches = new MatchCollection();
foreach ($images as $image) {
if ($image instanceof Image) {
$image->hashes['md5'] = !$image->hashes['md5'] ? md5($image->data['raw']) : $image->hashes['md5'];
if (!empty($hashes[$image->hashes['md5']]) && $hashes[$image->hashes['md5']]->page != $image->page) {
$matches->addPair(new MatchPair(array($hashes[$image->hashes['md5']], $image), 'md5', 1));
} else {
$hashes[$image->hashes['md5']] = $image;
}
}
}
return $matches;
}
