for ($i = 0, $num_layers = $im->getNumberImages(); $i < $num_layers; ++$i) {
$im->setImageIndex($i);         //this
    $im->setIteratorIndex($i);      //or this is kinda redundant
    $pagedata=$im->getImagePage();
    //print("x,y: " + $pagedata["x"].", ".$pagedata["y"]."<br/>\n");
    //print("w,h: " + $pagedata["width"].", ".$pagedata["height"]."<br/>\n");
 
    foreach($im->getImageProperties("*") as $k => $v) print("$k: $v<br/>\n"); 
 
    //export layer
    //$im->writeImage('layer_' . $i . '.png'); //导出所有图层到单独的png文件
}
