Convert HTML to PNG in PHP

$presentation = new Presentation();
try {
    $slides = $presentation->getSlides();
    $slides->removeAt(0);

    $htmlContent = file_get_contents("input.html");
    $slides->addFromHtml($htmlContent);

    $slideCount = java_values($slides->size());
    for ($slideIndex = 0; $slideIndex < $slideCount; $slideIndex++) {
        $slide = $slides->get_Item($slideIndex);
        $slideImage = $slide->getImage(1, 1);

        try {
            $filePath = "slide_" . ($slideIndex + 1) . ".png";
            $slideImage->save($filePath, ImageFormat::Png);
        } finally {
            $slideImage->dispose();
        }
    }
} finally {
    $presentation->dispose();
}