function __construct()
{
parent::__construct();
$this->zIndex = 1000;
$this->imageMapAreas = array();
$this->descendents = array();
$this->parent = null;
}
/**
* So that memory is deallocated correctly, go through and remove all the
* references to other objects. The PHP GC doesn't deal with circular
* references, so this stops the memory usage from ballooning up.
*/
function cleanUp()
{
parent::cleanUp();
$all_layers = array_keys($this->seen_zlayers);
foreach ($all_layers as $z) {
$this->seen_zlayers[$z] = null;
}
foreach ($this->links as $link) {
$link->cleanUp();
unset($link);
}
foreach ($this->nodes as $node) {
// destroy all the images we created, to prevent memory leaks
$node->cleanUp();
unset($node);
}
// Clear up the other random hashes of information
$this->dsinfocache = null;
$this->colourtable = null;
$this->usage_stats = null;
$this->scales = null;
}
