Import already defined form

@@ -6,6 +6,8 @@
 - Fix Color.toHex()
 - Improve Annotations placement
 - Improve documentation strings
+- Improve verbose output
+- Import already defined form
 
 ## 3.9.0
 

@@ -114,6 +114,10 @@ class PdfNum extends PdfDataType {
     return false;
   }
 
+  PdfNum operator |(PdfNum other) {
+    return PdfNum(value.toInt() | other.value.toInt());
+  }
+
   @override
   int get hashCode => value.hashCode;
 }

@@ -123,17 +123,13 @@ class PdfCatalog extends PdfObjectDict {
     }
 
     if (widgets.isNotEmpty) {
-      params['/AcroForm'] = PdfDict({
-        '/SigFlags': PdfNum(pdfDocument.sign?.flagsValue ?? 0),
-        '/Fields': PdfArray.fromObjects(widgets),
-      });
-
-      // final acroForm = (params['/AcroForm'] ??= PdfDict()) as PdfDict;
-      // acroForm['/SigFlags'] = PdfNum(pdfDocument.sign?.flagsValue ?? 0);
-      // final fields = (acroForm['/Fields'] ??= PdfArray()) as PdfArray;
-      // for (final w in widgets) {
-      //   fields.add(w.ref());
-      // }
+      final acroForm = (params['/AcroForm'] ??= PdfDict()) as PdfDict;
+      acroForm['/SigFlags'] = PdfNum(pdfDocument.sign?.flagsValue ?? 0) |
+          (acroForm['/SigFlags'] as PdfNum? ?? const PdfNum(0));
+      final fields = (acroForm['/Fields'] ??= PdfArray()) as PdfArray;
+      for (final w in widgets) {
+        fields.add(w.ref());
+      }
     }
   }
 }