feat: reduce boilerplate for top-level inherited data

pdf/lib/src/widgets/multi_page.dart

@@ -161,6 +161,7 @@ class MultiPage extends Page {
     PageOrientation? orientation,
     EdgeInsetsGeometry? margin,
     TextDirection? textDirection,
+    List<Inherited>? inherited,
   })  : _buildList = build,
         assert(maxPages > 0),
         super(
@@ -171,6 +172,7 @@ class MultiPage extends Page {
           theme: theme,
           orientation: orientation,
           textDirection: textDirection,
+          inherited: inherited,
         );
 
   final BuildListCallback _buildList;
@@ -247,6 +249,7 @@ class MultiPage extends Page {
       calculatedTheme,
       if (pageTheme.textDirection != null)
         InheritedDirectionality(pageTheme.textDirection),
+      ...inherited,
     ]);
     final children = _buildList(baseContext);
     WidgetContext? widgetContext;

pdf/lib/src/widgets/page.dart

@@ -43,6 +43,7 @@ class Page {
     EdgeInsetsGeometry? margin,
     bool clip = false,
     TextDirection? textDirection,
+    List<Inherited>? inherited,
   })  : assert(
             pageTheme == null ||
                 (pageFormat == null &&
@@ -61,6 +62,7 @@ class Page {
               clip: clip,
               textDirection: textDirection,
             ),
+        inherited = inherited ?? <Inherited>[],
         _build = build;
 
   final PageTheme pageTheme;
@@ -81,6 +83,8 @@ class Page {
 
   EdgeInsets? get resolvedMargin => margin?.resolve(pageTheme.textDirection);
 
+  final List<Inherited> inherited;
+
   @protected
   void debugPaint(Context context) {
     final _margin = resolvedMargin!;
@@ -133,6 +137,7 @@ class Page {
       calculatedTheme,
       if (pageTheme.textDirection != null)
         InheritedDirectionality(pageTheme.textDirection),
+      ...inherited,
     ]);
 
     Widget? background;

pdf/test/inherited_test.dart

@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2025, Kamil Szczęk <kamil@szczek.dev>
+ *
+ * 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 'package:pdf/pdf.dart';
+import 'package:pdf/widgets.dart';
+import 'package:test/test.dart';
+
+class Locale extends Inherited {
+  Locale({required this.languageCode});
+
+  final String languageCode;
+
+  static String of(final Context context) {
+    return context.dependsOn<Locale>()!.languageCode;
+  }
+}
+
+class ColorScheme extends Inherited {
+  ColorScheme({
+    required this.primary,
+    required this.secondary,
+  });
+
+  final PdfColor primary;
+  final PdfColor secondary;
+
+  static ColorScheme of(final Context context) {
+    return context.dependsOn<ColorScheme>()!;
+  }
+}
+
+class Greeting extends StatelessWidget {
+  @override
+  Widget build(final Context context) {
+    final languageCode = Locale.of(context);
+    final colorScheme = ColorScheme.of(context);
+    return Text(
+      languageCode == 'pl' ? 'Witaj' : 'Welcome',
+      style: TextStyle(
+        color: colorScheme.primary,
+        background: BoxDecoration(color: colorScheme.secondary),
+      ),
+      textAlign: TextAlign.center,
+    );
+  }
+}
+
+void main() {
+  late Document pdf;
+
+  setUpAll(() {
+    Document.debug = true;
+    RichText.debug = true;
+    pdf = Document();
+  });
+
+  test('Page should pass inherited data down the widget tree', () {
+    pdf.addPage(
+      Page(
+        inherited: <Inherited>[
+          Locale(languageCode: 'en'),
+          ColorScheme(primary: PdfColors.red, secondary: PdfColors.yellow),
+        ],
+        build: (final Context context) => Column(
+          mainAxisAlignment: MainAxisAlignment.center,
+          crossAxisAlignment: CrossAxisAlignment.stretch,
+          children: <Widget>[
+            Greeting(),
+            InheritedWidget(
+              inherited: ColorScheme(
+                primary: PdfColors.green,
+                secondary: PdfColors.black,
+              ),
+              build: (final Context context) => Greeting(),
+            ),
+            InheritedWidget(
+              inherited: Locale(languageCode: 'pl'),
+              build: (final Context context) => Greeting(),
+            ),
+          ],
+        ),
+      ),
+    );
+  });
+
+  test('MultiPage should pass inherited data down the widget tree', () {
+    pdf.addPage(
+      MultiPage(
+        crossAxisAlignment: CrossAxisAlignment.center,
+        inherited: <Inherited>[
+          Locale(languageCode: 'en'),
+          ColorScheme(primary: PdfColors.red, secondary: PdfColors.yellow),
+        ],
+        build: (final Context context) => <Widget>[
+          Greeting(),
+          InheritedWidget(
+            inherited: ColorScheme(
+              primary: PdfColors.green,
+              secondary: PdfColors.black,
+            ),
+            build: (final Context context) => Greeting(),
+          ),
+          InheritedWidget(
+            inherited: Locale(languageCode: 'pl'),
+            build: (final Context context) => Greeting(),
+          ),
+        ],
+      ),
+    );
+  });
+
+  tearDownAll(() async {
+    final file = File('inherited.pdf');
+    await file.writeAsBytes(await pdf.save());
+  });
+}