diff --git a/pdf/lib/src/widgets/chart/bar_chart.dart b/pdf/lib/src/widgets/chart/bar_chart.dart
index a0c824ba..ff9f858c 100644
--- a/pdf/lib/src/widgets/chart/bar_chart.dart
+++ b/pdf/lib/src/widgets/chart/bar_chart.dart
@@ -17,7 +17,6 @@
 import '../../../pdf.dart';
 import '../flex.dart';
 import '../geometry.dart';
-import '../page.dart';
 import '../widget.dart';
 import 'chart.dart';
 import 'grid_cartesian.dart';
@@ -39,7 +38,7 @@ class BarDataSet<T extends PointChartValue> extends PointDataSet<T> {
     PdfColor? pointColor,
     double pointSize = 3,
     bool drawPoints = false,
-    BuildCallback? shape,
+    LegendBuildCallback? shape,
     Widget Function(Context context, T value)? buildValue,
     ValuePosition valuePosition = ValuePosition.auto,
   })  : drawBorder = drawBorder ?? borderColor != null && color != borderColor,
diff --git a/pdf/lib/src/widgets/chart/line_chart.dart b/pdf/lib/src/widgets/chart/line_chart.dart
index 7ce27cc6..a470ace7 100644
--- a/pdf/lib/src/widgets/chart/line_chart.dart
+++ b/pdf/lib/src/widgets/chart/line_chart.dart
@@ -16,7 +16,6 @@
 
 import '../../../pdf.dart';
 import '../geometry.dart';
-import '../page.dart';
 import '../widget.dart';
 import 'chart.dart';
 import 'grid_cartesian.dart';
@@ -38,7 +37,7 @@ class LineDataSet<T extends PointChartValue> extends PointDataSet<T> {
     this.drawLine = true,
     this.lineColor,
     bool drawPoints = true,
-    BuildCallback? shape,
+    LegendBuildCallback? shape,
     Widget Function(Context context, T value)? buildValue,
     ValuePosition valuePosition = ValuePosition.auto,
     this.drawSurface = false,
diff --git a/pdf/lib/src/widgets/chart/point_chart.dart b/pdf/lib/src/widgets/chart/point_chart.dart
index c4ca4bbe..4572c346 100644
--- a/pdf/lib/src/widgets/chart/point_chart.dart
+++ b/pdf/lib/src/widgets/chart/point_chart.dart
@@ -17,12 +17,13 @@
 import '../../../pdf.dart';
 import '../basic.dart';
 import '../geometry.dart';
-import '../page.dart';
 import '../widget.dart';
 import 'chart.dart';
 
 enum ValuePosition { left, top, right, bottom, auto }
 
+typedef LegendBuildCallback = Widget Function(Context context);
+
 class PointChartValue extends ChartValue {
   const PointChartValue(this.x, this.y);
   final double x;
@@ -56,7 +57,7 @@ class PointDataSet<T extends PointChartValue> extends Dataset {
 
   final double pointSize;
 
-  final BuildCallback? shape;
+  final LegendBuildCallback? shape;
 
   final Widget Function(Context context, T value)? buildValue;
 
@@ -94,7 +95,7 @@ class PointDataSet<T extends PointChartValue> extends Dataset {
   }
 
   @override
-  void paintForeground(Context context) {
+  Future<void> paintForeground(Context context) async {
     super.paintForeground(context);
 
     if (data.isEmpty) {
@@ -120,7 +121,7 @@ class PointDataSet<T extends PointChartValue> extends Dataset {
           Widget.draw(
             SizedBox.square(
               dimension: pointSize * 2,
-              child: shape!(context),
+              child: await shape!(context),
             ),
             offset: p,
             alignment: Alignment.center,
diff --git a/pdf/lib/src/widgets/multi_page.dart b/pdf/lib/src/widgets/multi_page.dart
index 04b85771..0ae82de1 100644
--- a/pdf/lib/src/widgets/multi_page.dart
+++ b/pdf/lib/src/widgets/multi_page.dart
@@ -216,7 +216,8 @@ class MultiPage extends Page {
   }
 
   @override
-  void generate(Document document, {bool insert = true, int? index}) {
+  Future<void> generate(Document document,
+      {bool insert = true, int? index}) async {
     assert(pageFormat.width > 0 && pageFormat.width < double.infinity);
     assert(pageFormat.height > 0 && pageFormat.height < double.infinity);
 
@@ -248,7 +249,7 @@ class MultiPage extends Page {
       if (pageTheme.textDirection != null)
         InheritedDirectionality(pageTheme.textDirection),
     ]);
-    final children = _buildList(baseContext);
+    final children = await _buildList(baseContext);
     WidgetContext? widgetContext;
 
     while (_index < children.length) {
@@ -300,7 +301,7 @@ class MultiPage extends Page {
         ));
 
         if (header != null) {
-          final headerWidget = header!(context);
+          final headerWidget = await header!(context);
 
           headerWidget.layout(context, constraints, parentUsesSize: false);
           assert(headerWidget.box != null);
@@ -308,7 +309,7 @@ class MultiPage extends Page {
         }
 
         if (footer != null) {
-          final footerWidget = footer!(context);
+          final footerWidget = await footer!(context);
 
           footerWidget.layout(context, constraints, parentUsesSize: false);
           assert(footerWidget.box != null);
@@ -395,7 +396,7 @@ class MultiPage extends Page {
   }
 
   @override
-  void postProcess(Document document) {
+  Future<void> postProcess(Document document) async {
     final _margin = resolvedMargin!;
     final _mustRotate = mustRotate;
     final pageHeight = _mustRotate ? pageFormat.width : pageFormat.height;
@@ -412,7 +413,7 @@ class MultiPage extends Page {
           _mustRotate ? pageHeightMargin - _margin.left : _margin.bottom;
 
       if (pageTheme.buildBackground != null) {
-        final child = pageTheme.buildBackground!(page.context);
+        final child = await pageTheme.buildBackground!(page.context);
 
         child.layout(page.context, page.fullConstraints, parentUsesSize: false);
         assert(child.box != null);
@@ -444,7 +445,7 @@ class MultiPage extends Page {
       }
 
       if (header != null) {
-        final headerWidget = header!(page.context);
+        final headerWidget = await header!(page.context);
         headerWidget.layout(page.context, page.constraints,
             parentUsesSize: false);
         assert(headerWidget.box != null);
@@ -457,7 +458,7 @@ class MultiPage extends Page {
       }
 
       if (footer != null) {
-        final footerWidget = footer!(page.context);
+        final footerWidget = await footer!(page.context);
         footerWidget.layout(page.context, page.constraints,
             parentUsesSize: false);
         assert(footerWidget.box != null);
@@ -580,7 +581,7 @@ class MultiPage extends Page {
       }
 
       if (pageTheme.buildForeground != null) {
-        final child = pageTheme.buildForeground!(page.context);
+        final child = await pageTheme.buildForeground!(page.context);
 
         child.layout(page.context, page.fullConstraints, parentUsesSize: false);
         assert(child.box != null);
diff --git a/pdf/lib/src/widgets/page.dart b/pdf/lib/src/widgets/page.dart
index 7b34184e..5532760f 100644
--- a/pdf/lib/src/widgets/page.dart
+++ b/pdf/lib/src/widgets/page.dart
@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 
+import 'dart:async';
 import 'dart:math' as math;
 
 import 'package:meta/meta.dart';
@@ -28,8 +29,8 @@ import 'text_style.dart';
 import 'theme.dart';
 import 'widget.dart';
 
-typedef BuildCallback = Widget Function(Context context);
-typedef BuildListCallback = List<Widget> Function(Context context);
+typedef BuildCallback = FutureOr<Widget> Function(Context context);
+typedef BuildListCallback = FutureOr<List<Widget>> Function(Context context);
 
 enum PageOrientation { natural, landscape, portrait }
 
@@ -112,7 +113,7 @@ class Page {
     }
   }
 
-  void postProcess(Document document) {
+  Future<void> postProcess(Document document) async {
     final canvas = _pdfPage!.getGraphics();
     canvas.reset();
     final _margin = resolvedMargin;
@@ -139,7 +140,7 @@ class Page {
     Widget? content;
     Widget? foreground;
 
-    content = _build(context);
+    content = await _build(context);
 
     final size = layout(content, context, constraints);
 
@@ -156,12 +157,12 @@ class Page {
     }
 
     if (pageTheme.buildBackground != null) {
-      background = pageTheme.buildBackground!(context);
+      background = await pageTheme.buildBackground!(context);
       layout(background, context, constraints);
     }
 
     if (pageTheme.buildForeground != null) {
-      foreground = pageTheme.buildForeground!(context);
+      foreground = await pageTheme.buildForeground!(context);
       layout(foreground, context, constraints);
     }
 
diff --git a/pdf/lib/src/widgets/widget.dart b/pdf/lib/src/widgets/widget.dart
index 0751ac68..63b7d4e9 100644
--- a/pdf/lib/src/widgets/widget.dart
+++ b/pdf/lib/src/widgets/widget.dart
@@ -368,10 +368,13 @@ class InheritedWidget extends SingleChildWidget {
   Widget? _child;
 
   @override
-  void layout(Context context, BoxConstraints constraints,
-      {bool parentUsesSize = false}) {
+  void layout(
+    Context context,
+    BoxConstraints constraints, {
+    bool parentUsesSize = false,
+  }) async {
     _context = inherited != null ? context.inheritFrom(inherited!) : context;
-    _child = build!(_context!);
+    _child = await build!(_context!);
     super.layout(_context!, constraints);
   }
 
@@ -394,14 +397,17 @@ class DelayedWidget extends SingleChildWidget {
   Widget? _child;
 
   @override
-  void layout(Context context, BoxConstraints constraints,
-      {bool parentUsesSize = false}) {
-    _child = build(context);
+  Future<void> layout(
+    Context context,
+    BoxConstraints constraints, {
+    bool parentUsesSize = false,
+  }) async {
+    _child = await build(context);
     super.layout(context, constraints);
   }
 
-  void delayedPaint(Context context) {
-    _child = build(context);
+  Future<void> delayedPaint(Context context) async {
+    _child = await build(context);
     child!.layout(
       context,
       BoxConstraints.tight(box!.size),