fix(dompdf): Relative images are not supported on DomPDF v0.8.0+ (#3172857 by...

fix(dompdf): Relative images are not supported on DomPDF v0.8.0+ (#3172857 by Eduardo Morales Alberti, ron_s, klausi, ShaneOnABike, 4kant)

modules/commerce_billy_pdf/commerce_billy_pdf.module

@@ -229,11 +229,35 @@ function commerce_billy_pdf_commerce_order_view($order, $view_mode) {
       $logo_path = DRUPAL_ROOT . '/' . $logo_path;
     }
     $order->content['invoice_logo'] = array(
-      '#value' => $logo_path,
+      '#value' => _commerce_billy_pdf_base64_image($logo_path),
     );
   }
 }
 
+/**
+ * Convert image path into Base64 image.
+ *
+ * @param string $image_path
+ *   Valid image path to convert.
+ *
+ * @return string
+ *   Base64 image.
+ */
+function _commerce_billy_pdf_base64_image($image_path) {
+  // Check if image exists in local file system.
+  if (file_exists($image_path)) {
+    $image_data = base64_encode(file_get_contents($image_path));
+    $mime_type = mime_content_type($image_path);
+    // Image source format: "data:{mime};base64,{data};"
+    return 'data:' . $mime_type . ';base64,' . $image_data;
+  }
+
+  // If the file cannot be found, post a watchdog message and display no logo.
+  watchdog('commerce_billy_pdf', 'Invoice logo does not exist or cannot be found: %path',
+    array('%path' => $image_path), WATCHDOG_ERROR);
+  return '';
+}
+
 /**
  * Transforms HTML to PDF and outputs it to the browser.
  *