DomPDF: Image not readable or empty

Question

For some reason, DomPDF won\'t render an image included in the html that is being parsed:

Answer 1

For our use case we had to convert all the images on the page to base64 since the pdf should be usable offline. Our code lives inside a controller class but you can modify that to your needs.

Here's the code:

    /**
     * Convert images to Base64 so it's included in the PDF.
     *
     * @param $html  Full html render of the page.
     */
    public function convertReportImagesToURI($html): string
    {
        $doc = new DOMDocument();
        libxml_use_internal_errors(true);
        $doc->loadHTML($html);
        $tags = $doc->getElementsByTagName('img');
        $imgArr = array();

        // Iterate over all image tags.
        foreach ($tags as $tag) {
            // Get the src attribute.
            $imgSrc = $tag->getAttribute('src');

            // Convert to base64.
            $base64src = self::getImageDataURI($imgSrc);
            $tag->setAttribute('src', $base64src);
        }
        return $doc->saveHTML();
    }

    /**
     * This does the actual encoding.
     */
    public static function getImageDataURI($image, $mime = ''): string
    {
        // Director::absoluteURL('/') gets the base url of the site.
        // We had to remove the leading slash of the image hence the use of substr.
        // If your images have absolute urls you will need to modify this.
        $imageLocation = Director::absoluteURL('/') . substr($image, 1);
        // Get the image location. remove leading slash on image url.
        return 'data:' . self::get_image_mime_type($imageLocation) . ';base64,' . base64_encode(file_get_contents($imageLocation));
    }

    /**
     * https://stackoverflow.com/a/45054843
     * @param $image_path
     * @return string
     */
    public static function get_image_mime_type($image_path): string
    {
        $mimes  = array(
            IMAGETYPE_GIF => "image/gif",
            IMAGETYPE_JPEG => "image/jpg",
            IMAGETYPE_PNG => "image/png",
            IMAGETYPE_SWF => "image/swf",
            IMAGETYPE_PSD => "image/psd",
            IMAGETYPE_BMP => "image/bmp",
            IMAGETYPE_TIFF_II => "image/tiff",
            IMAGETYPE_TIFF_MM => "image/tiff",
            IMAGETYPE_JPC => "image/jpc",
            IMAGETYPE_JP2 => "image/jp2",
            IMAGETYPE_JPX => "image/jpx",
            IMAGETYPE_JB2 => "image/jb2",
            IMAGETYPE_SWC => "image/swc",
            IMAGETYPE_IFF => "image/iff",
            IMAGETYPE_WBMP => "image/wbmp",
            IMAGETYPE_XBM => "image/xbm",
            IMAGETYPE_ICO => "image/ico");

        if (($image_type = exif_imagetype($image_path))
            && (array_key_exists($image_type, $mimes))) {
            return $mimes[$image_type];
        } else {
            return '';
        }
    }