simkoG/acme-woocommerce-pdf-invoice-preview.php

## acme-woocommerce-pdf-invoice-preview.php
<?php
defined( 'ABSPATH' ) || exit;

if( is_plugin_active( "woocommerce-pdf-invoice/woocommerce-pdf-invoice.php" ) ) :


  /**
   * Create a custom PDF preview page for the plugin.
   *
   * @since 1.0.0
   * @return void
   */

  function acme_woocommerce_pdf_preview_render() {
    if( !is_admin() || !isset( $_GET['woocommerce_pdf_preview'] ) ) {
      return;
    }

    if( !class_exists( 'WC_send_pdf' ) ){
      include_once WP_PLUGIN_DIR . '/woocommerce-pdf-invoice/classes/class-pdf-send-pdf-class.php';
    }

    global $WC_send_pdf;

    $test_order_id = 9522;

    $pdf_content = $WC_send_pdf->get_woocommerce_invoice_content( wc_get_order( $test_order_id ) );
    $pdf_content_base64 = base64_encode( $pdf_content );
    ?>

    <!DOCTYPE html>
    <html>
      <head>
        <meta charset="<?php echo get_bloginfo( 'charset' ); ?>">

        <title><?php esc_html_e( 'PDF Invoice', 'woocommerce-pdf-invoice' ); ?></title>

        <style>
          body {
            background-color: #f7f7f7;
            overflow: auto;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
          }

          #invoice-preview {
            background: #fff;
            display: block;
            width: 210mm;
            height: 297mm;
            margin: 3rem auto;
            border: 1px solid #ddd;
            box-shadow: 0 10px 20px rgb( 0 0 0 / 10% );
          }
        </style>
      </head>
      <body>

        <iframe id="invoice-preview" src="data:text/html;base64,<?php echo $pdf_content_base64; ?>">
          Iframe is not supported.
        </iframe>

      </body>
    </html>

    <?php
    die;
  }

  add_action( 'admin_init', 'acme_woocommerce_pdf_preview_render' );


endif; // is_plugin_active()
	<?php
	defined( 'ABSPATH' ) \|\| exit;

	if( is_plugin_active( "woocommerce-pdf-invoice/woocommerce-pdf-invoice.php" ) ) :


	/**
	* Create a custom PDF preview page for the plugin.
	*
	* @since 1.0.0
	* @return void
	*/

	function acme_woocommerce_pdf_preview_render() {
	if( !is_admin() \|\| !isset( $_GET['woocommerce_pdf_preview'] ) ) {
	return;
	}

	if( !class_exists( 'WC_send_pdf' ) ){
	include_once WP_PLUGIN_DIR . '/woocommerce-pdf-invoice/classes/class-pdf-send-pdf-class.php';
	}

	global $WC_send_pdf;

	$test_order_id = 9522;

	$pdf_content = $WC_send_pdf->get_woocommerce_invoice_content( wc_get_order( $test_order_id ) );
	$pdf_content_base64 = base64_encode( $pdf_content );
	?>

	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="<?php echo get_bloginfo( 'charset' ); ?>">

	<title><?php esc_html_e( 'PDF Invoice', 'woocommerce-pdf-invoice' ); ?></title>

	<style>
	body {
	background-color: #f7f7f7;
	overflow: auto;
	-webkit-font-smoothing: antialiased;
	-moz-osx-font-smoothing: grayscale;
	}

	#invoice-preview {
	background: #fff;
	display: block;
	width: 210mm;
	height: 297mm;
	margin: 3rem auto;
	border: 1px solid #ddd;
	box-shadow: 0 10px 20px rgb( 0 0 0 / 10% );
	}
	</style>
	</head>
	<body>

	<iframe id="invoice-preview" src="data:text/html;base64,<?php echo $pdf_content_base64; ?>">
	Iframe is not supported.
	</iframe>

	</body>
	</html>

	<?php
	die;
	}

	add_action( 'admin_init', 'acme_woocommerce_pdf_preview_render' );


	endif; // is_plugin_active()