app/config/dompdf.php

<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Settings
    |--------------------------------------------------------------------------
    |
    | Set some default values. It is possible to add all defines that can be set
    | in dompdf_config.inc.php. You can also override the entire config file.
    |
    */
    'show_warnings' => false,   // Throw an Exception on warnings from dompdf

    'public_path' => null,  // Override the public path if needed

    /*
     * Dejavu Sans font is missing glyphs for converted entities, turn it off if you need to show € and £.
     */
    'convert_entities' => true,

    'options' => [
        /**
         * The location of the DOMPDF font directory
         *
         * The location of the directory where DOMPDF will store fonts and font metrics
         * Note: This directory must exist and be writable by the webserver process.
         * *Please note the trailing slash.*
         *
         * Notes regarding fonts:
         * Additional .afm font metrics can be added by executing load_font.php from command line.
         *
         * Only the original "Base 14 fonts" are present on all pdf viewers. Additional fonts must
         * be embedded in the pdf file or the PDF may not display correctly. This can significantly
         * increase file size unless font subsetting is enabled. Before embedding a font please
         * review your rights under the font license.
         *
         * Any font specification in the source HTML is translated to the closest font available
         * in the font directory.
         *
         * The pdf standard "Base 14 fonts" are:
         * Courier, Courier-Bold, Courier-BoldOblique, Courier-Oblique,
         * Helvetica, Helvetica-Bold, Helvetica-BoldOblique, Helvetica-Oblique,
         * Times-Roman, Times-Bold, Times-BoldItalic, Times-Italic,
         * Symbol, ZapfDingbats.
         */
        'font_dir' => storage_path('fonts'), // advised by dompdf (https://github.com/dompdf/dompdf/pull/782)

        /**
         * The location of the DOMPDF font cache directory
         *
         * This directory contains the cached font metrics for the fonts used by DOMPDF.
         * This directory can be the same as DOMPDF_FONT_DIR
         *
         * Note: This directory must exist and be writable by the webserver process.
         */
        'font_cache' => storage_path('fonts'),

        /**
         * The location of a temporary directory.
         *
         * The directory specified must be writeable by the webserver process.
         * The temporary directory is required to download remote images and when
         * using the PDFLib back end.
         */
        'temp_dir' => sys_get_temp_dir(),

        /**
         * ==== IMPORTANT ====
         *
         * dompdf's "chroot": Prevents dompdf from accessing system files or other
         * files on the webserver.  All local files opened by dompdf must be in a
         * subdirectory of this directory.  DO NOT set it to '/' since this could
         * allow an attacker to use dompdf to read any files on the server.  This
         * should be an absolute path.
         * This is only checked on command line call by dompdf.php, but not by
         * direct class use like:
         * $dompdf = new DOMPDF();  $dompdf->load_html($htmldata); $dompdf->render(); $pdfdata = $dompdf->output();
         */
        'chroot' => realpath(base_path()),

        /**
         * Protocol whitelist
         *
         * Protocols and PHP wrappers allowed in URIs, and the validation rules
         * that determine if a resouce may be loaded. Full support is not guaranteed
         * for the protocols/wrappers specified
         * by this array.
         *
         * @var array
         */
        'allowed_protocols' => [
            'file://' => ['rules' => []],
            'http://' => ['rules' => []],
            'https://' => ['rules' => []],
        ],

        /**
         * Operational artifact (log files, temporary files) path validation
         */
        'artifactPathValidation' => null,

        /**
         * @var string
         */
        'log_output_file' => null,

        /**
         * Whether to enable font subsetting or not.
         */
        'enable_font_subsetting' => false,

        /**
         * The PDF rendering backend to use
         *
         * Valid settings are 'PDFLib', 'CPDF' (the bundled R&OS PDF class), 'GD' and
         * 'auto'. 'auto' will look for PDFLib and use it if found, or if not it will
         * fall back on CPDF. 'GD' renders PDFs to graphic files.
         * {@link * Canvas_Factory} ultimately determines which rendering class to
         * instantiate based on this setting.
         *
         * Both PDFLib & CPDF rendering backends provide sufficient rendering
         * capabilities for dompdf, however additional features (e.g. object,
         * image and font support, etc.) differ between backends.  Please see
         * {@link PDFLib_Adapter} for more information on the PDFLib backend
         * and {@link CPDF_Adapter} and lib/class.pdf.php for more information
         * on CPDF. Also see the documentation for each backend at the links
         * below.
         *
         * The GD rendering backend is a little different than PDFLib and
         * CPDF. Several features of CPDF and PDFLib are not supported or do
         * not make any sense when creating image files.  For example,
         * multiple pages are not supported, nor are PDF 'objects'.  Have a
         * look at {@link GD_Adapter} for more information.  GD support is
         * experimental, so use it at your own risk.
         *
         * @link http://www.pdflib.com
         * @link http://www.ros.co.nz/pdf
         * @link http://www.php.net/image
         */
        'pdf_backend' => 'CPDF',

        /**
         * html target media view which should be rendered into pdf.
         * List of types and parsing rules for future extensions:
         * http://www.w3.org/TR/REC-html40/types.html
         *   screen, tty, tv, projection, handheld, print, braille, aural, all
         * Note: aural is deprecated in CSS 2.1 because it is replaced by speech in CSS 3.
         * Note, even though the generated pdf file is intended for print output,
         * the desired content might be different (e.g. screen or projection view of html file).
         * Therefore allow specification of content here.
         */
        'default_media_type' => 'screen',

        /**
         * The default paper size.
         *
         * North America standard is "letter"; other countries generally "a4"
         *
         * @see CPDF_Adapter::PAPER_SIZES for valid sizes ('letter', 'legal', 'A4', etc.)
         */
        'default_paper_size' => 'a4',

        /**
         * The default paper orientation.
         *
         * The orientation of the page (portrait or landscape).
         *
         * @var string
         */
        'default_paper_orientation' => 'portrait',

        /**
         * The default font family
         *
         * Used if no suitable fonts can be found. This must exist in the font folder.
         *
         * @var string
         */
        'default_font' => 'serif',

        /**
         * Image DPI setting
         *
         * This setting determines the default DPI setting for images and fonts.  The
         * DPI may be overridden for inline images by explictly setting the
         * image's width & height style attributes (i.e. if the image's native
         * width is 600 pixels and you specify the image's width as 72 points,
         * the image will have a DPI of 600 in the rendered PDF.  The DPI of
         * background images can not be overridden and is controlled entirely
         * via this parameter.
         *
         * For the purposes of DOMPDF, pixels per inch (PPI) = dots per inch (DPI).
         * If a size in html is given as px (or without unit as image size),
         * this tells the corresponding size in pt.
         * This adjusts the relative sizes to be similar to the rendering of the
         * html page in a reference browser.
         *
         * In pdf, always 1 pt = 1/72 inch
         *
         * Rendering resolution of various browsers in px per inch:
         * Windows Firefox and Internet Explorer:
         *   SystemControl->Display properties->FontResolution: Default:96, largefonts:120, custom:?
         * Linux Firefox:
         *   about:config *resolution: Default:96
         *   (xorg screen dimension in mm and Desktop font dpi settings are ignored)
         *
         * Take care about extra font/image zoom factor of browser.
         *
         * In images, <img> size in pixel attribute, img css style, are overriding
         * the real image dimension in px for rendering.
         *
         * @var int
         */
        'dpi' => 96,

        /**
         * Enable embedded PHP
         *
         * If this setting is set to true then DOMPDF will automatically evaluate embedded PHP contained
         * within <script type="text/php"> ... </script> tags.
         *
         * ==== IMPORTANT ==== Enabling this for documents you do not trust (e.g. arbitrary remote html pages)
         * is a security risk.
         * Embedded scripts are run with the same level of system access available to dompdf.
         * Set this option to false (recommended) if you wish to process untrusted documents.
         * This setting may increase the risk of system exploit.
         * Do not change this settings without understanding the consequences.
         * Additional documentation is available on the dompdf wiki at:
         * https://github.com/dompdf/dompdf/wiki
         *
         * @var bool
         */
        'enable_php' => false,

        /**
         * Rnable inline JavaScript
         *
         * If this setting is set to true then DOMPDF will automatically insert JavaScript code contained
         * within <script type="text/javascript"> ... </script> tags as written into the PDF.
         * NOTE: This is PDF-based JavaScript to be executed by the PDF viewer,
         * not browser-based JavaScript executed by Dompdf.
         *
         * @var bool
         */
        'enable_javascript' => true,

        /**
         * Enable remote file access
         *
         *  If this setting is set to true, DOMPDF will access remote sites for
         *  images and CSS files as required.
         *
         *  ==== IMPORTANT ====
         *  This can be a security risk, in particular in combination with isPhpEnabled and
         *  allowing remote html code to be passed to $dompdf = new DOMPDF(); $dompdf->load_html(...);
         *  This allows anonymous users to download legally doubtful internet content which on
         *  tracing back appears to being downloaded by your server, or allows malicious php code
         *  in remote html pages to be executed by your server with your account privileges.
         *
         *  This setting may increase the risk of system exploit. Do not change
         *  this settings without understanding the consequences. Additional
         *  documentation is available on the dompdf wiki at:
         *  https://github.com/dompdf/dompdf/wiki
         *
         * @var bool
         */
        'enable_remote' => false,

        /**
         * List of allowed remote hosts
         *
         * Each value of the array must be a valid hostname.
         *
         * This will be used to filter which resources can be loaded in combination with
         * isRemoteEnabled. If enable_remote is FALSE, then this will have no effect.
         *
         * Leave to NULL to allow any remote host.
         *
         * @var array|null
         */
        'allowed_remote_hosts' => null,

        /**
         * A ratio applied to the fonts height to be more like browsers' line height
         */
        'font_height_ratio' => 1.1,

        /**
         * Use the HTML5 Lib parser
         *
         * @deprecated This feature is now always on in dompdf 2.x
         *
         * @var bool
         */
        'enable_html5_parser' => true,
    ],

];