Improve Table Of Content

@@ -8,6 +8,7 @@
 - Typo: rename "litteral" with "literal"
 - Fix tabs and other spaces placeholder
 - Prevent modifying the document once saved
+- Improve Table Of Content
 
 ## 3.7.4
 

@@ -58,7 +58,7 @@ class PdfOutline extends PdfObjectDict {
     this.color,
     this.destMode = PdfOutlineMode.fitPage,
     this.style = PdfOutlineStyle.normal,
-    String? page,
+    PdfPage? page,
   })  : assert(anchor == null || (dest == null && rect == null)),
         _page = page,
         super(pdfDocument);
@@ -76,12 +76,20 @@ class PdfOutline extends PdfObjectDict {
   PdfPage? dest;
 
   /// Page number
-  String? get page =>
-      _page ??
-      (dest != null
-          ? (pdfDocument.pdfPageList.pages.indexOf(dest!) + 1).toString()
-          : null);
-  final String? _page;
+  String? get page {
+    final int? num;
+    if (_page != null) {
+      num = pdfDocument.pdfPageList.pages.indexOf(_page!);
+    } else if (dest != null) {
+      num = pdfDocument.pdfPageList.pages.indexOf(dest!);
+    } else {
+      num = null;
+    }
+
+    return num == null ? null : (num + 1).toString();
+  }
+
+  final PdfPage? _page;
 
   /// The region on the destination page
   final PdfRect? rect;

@@ -59,8 +59,8 @@ class Anchor extends SingleChildWidget {
 
     if (description != null) {
       final rb = mat.transform3(Vector3(box!.right, box!.top, 0));
-      final ibox = PdfRect.fromLTRB(lt.x, lt.y, rb.x, rb.y);
-      PdfAnnot(context.page, PdfAnnotText(rect: ibox, content: description!));
+      final iBox = PdfRect.fromLTRB(lt.x, lt.y, rb.x, rb.y);
+      PdfAnnot(context.page, PdfAnnotText(rect: iBox, content: description!));
     }
   }
 }
@@ -622,7 +622,7 @@ class Outline extends Anchor {
       anchor: name,
       color: color,
       style: style,
-      page: context.pageLabel,
+      page: context.page,
     )..effectiveLevel = level;
 
     final root = context.document.outline;

@@ -151,7 +151,7 @@ class TableOfContent extends StatelessWidget {
                   thickness: 0.2,
                 )),
                 SizedBox(width: 8),
-                Text('${c.page}'),
+                DelayedWidget(build: (_) => Text('${c.page}')),
               ],
             ),
           ),

@@ -380,3 +380,37 @@ class InheritedWidget extends SingleChildWidget {
     paintChild(_context!);
   }
 }
+
+class DelayedWidget extends SingleChildWidget {
+  DelayedWidget({required this.build}) : super();
+
+  final BuildCallback build;
+
+  @override
+  Widget? get child => _child;
+
+  Widget? _child;
+
+  @override
+  void layout(Context context, BoxConstraints constraints,
+      {bool parentUsesSize = false}) {
+    _child = build(context);
+    super.layout(context, constraints);
+  }
+
+  void delayedPaint(Context context) {
+    _child = build(context);
+    child!.layout(
+      context,
+      BoxConstraints.tight(box!.size),
+      parentUsesSize: false,
+    );
+    paintChild(context);
+  }
+
+  @override
+  void paint(Context context) {
+    delayedPaint(context);
+    super.paint(context);
+  }
+}

@@ -48,6 +48,7 @@ import 'widget_table_test.dart' as widget_table;
 import 'widget_test.dart' as widget;
 import 'widget_text_test.dart' as widget_text;
 import 'widget_theme_test.dart' as widget_theme;
+import 'widget_toc_test.dart' as widget_toc;
 import 'widget_watermark_test.dart' as widget_watermark;
 import 'widget_wrap_test.dart' as widget_wrap;
 
@@ -83,6 +84,7 @@ void main() {
   widget_table.main();
   widget_text.main();
   widget_theme.main();
+  widget_toc.main();
   widget_watermark.main();
   widget_wrap.main();
   widget.main();

+/*
+ * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import 'dart:io';
+import 'dart:math';
+
+import 'package:pdf/widgets.dart';
+import 'package:test/test.dart';
+
+late Document pdf;
+
+void main() {
+  setUpAll(() {
+    Document.debug = true;
+    pdf = Document();
+  });
+
+  test('Pdf Widgets TableOfContent', () {
+    pdf.addPage(
+      Page(
+        build: (context) =>
+            Center(child: Text('Document', style: Theme.of(context).header0)),
+      ),
+    );
+
+    pdf.addPage(
+      MultiPage(
+        footer: (c) => Padding(
+            padding: const EdgeInsets.only(top: 20),
+            child: Align(
+                alignment: Alignment.centerRight, child: Text(c.pageLabel))),
+        build: (context) => [
+          ...Iterable<Widget>.generate(40, (index) {
+            final level = (sin(index / 5) * 6).abs().toInt();
+            return Column(
+              children: [
+                Header(
+                  child: Text('Hello $index level $level'),
+                  text: 'Hello $index',
+                  level: level,
+                ),
+                Lorem(length: 60),
+              ],
+            );
+          }),
+        ],
+      ),
+    );
+
+    pdf.addPage(
+      MultiPage(
+        footer: (c) => Padding(
+            padding: const EdgeInsets.only(top: 20),
+            child: Align(
+                alignment: Alignment.centerRight, child: Text(c.pageLabel))),
+        build: (context) => [
+          Center(
+              child:
+                  Text('Table of content', style: Theme.of(context).header0)),
+          SizedBox(height: 20),
+          TableOfContent(),
+        ],
+      ),
+      index: 1,
+    );
+  });
+
+  tearDownAll(() async {
+    final file = File('widgets-toc.pdf');
+    await file.writeAsBytes(await pdf.save());
+  });
+}