Passthrough SpanningWidget on SingleChildWidget and StatelessWidget

@@ -26,8 +26,8 @@ Future<Uint8List> generateDocument(
   final doc = pw.Document(pageMode: PdfPageMode.outlines);
 
   doc.addPage(pw.MultiPage(
-      pageFormat:
-          PdfPageFormat.letter.copyWith(marginBottom: 1.5 * PdfPageFormat.cm),
+      pageFormat: format.copyWith(marginBottom: 1.5 * PdfPageFormat.cm),
+      orientation: pw.PageOrientation.portrait,
       crossAxisAlignment: pw.CrossAxisAlignment.start,
       header: (pw.Context context) {
         if (context.pageNumber == 1) {

@@ -10,6 +10,7 @@
 - ImageProvider.resolve returns non-null object
 - Fix textScalingFactor with lineSpacing
 - Implement SpanningWidget on RichText
+- Passthrough SpanningWidget on SingleChildWidget and StatelessWidget
 
 ## 3.2.0
 

@@ -133,12 +133,13 @@ class Header extends StatelessWidget {
 }
 
 class Paragraph extends StatelessWidget {
-  Paragraph(
-      {this.text,
+  Paragraph({
+    this.text,
     this.textAlign = TextAlign.justify,
     this.style,
     this.margin = const EdgeInsets.only(bottom: 5.0 * PdfPageFormat.mm),
-      this.padding});
+    this.padding,
+  });
 
   final String? text;
 
@@ -159,6 +160,7 @@ class Paragraph extends StatelessWidget {
         text!,
         textAlign: textAlign,
         style: style ?? Theme.of(context).paragraphStyle,
+        overflow: TextOverflow.span,
       ),
     );
   }

@@ -81,7 +81,7 @@ class _FlexContext extends WidgetContext {
   String toString() => '$runtimeType first:$firstChild last:$lastChild';
 }
 
-class Flex extends MultiChildWidget implements SpanningWidget {
+class Flex extends MultiChildWidget with SpanningWidget {
   Flex({
     required this.direction,
     this.mainAxisAlignment = MainAxisAlignment.start,

@@ -53,7 +53,7 @@ class _GridViewContext extends WidgetContext {
       '$runtimeType first:$firstChild last:$lastChild size:${childCrossAxis}x$childMainAxis';
 }
 
-class GridView extends MultiChildWidget implements SpanningWidget {
+class GridView extends MultiChildWidget with SpanningWidget {
   GridView(
       {this.direction = Axis.vertical,
       this.padding = EdgeInsets.zero,

@@ -37,7 +37,7 @@ abstract class WidgetContext {
   void apply(covariant WidgetContext other);
 }
 
-abstract class SpanningWidget extends Widget {
+mixin SpanningWidget on Widget {
   bool get canSpan;
 
   bool get hasMoreWidgets;
@@ -46,7 +46,7 @@ abstract class SpanningWidget extends Widget {
   @protected
   WidgetContext saveContext();
 
-  /// Aplpy the context for next layout
+  /// Apply the context for next layout
   @protected
   void restoreContext(covariant WidgetContext context);
 }
@@ -230,10 +230,6 @@ class MultiPage extends Page {
 
     while (_index < children.length) {
       final child = children[_index];
-      var canSpan = false;
-      if (child is SpanningWidget) {
-        canSpan = child.canSpan;
-      }
 
       assert(() {
         // Detect too big widgets
@@ -292,7 +288,7 @@ class MultiPage extends Page {
       }
 
       // If we are processing a multi-page widget, we restore its context
-      if (widgetContext != null && canSpan && child is SpanningWidget) {
+      if (widgetContext != null && child is SpanningWidget) {
         child.restoreContext(widgetContext);
         widgetContext = null;
       }
@@ -300,6 +296,8 @@ class MultiPage extends Page {
       child.layout(context, constraints, parentUsesSize: false);
       assert(child.box != null);
 
+      final canSpan = child is SpanningWidget && child.canSpan;
+
       // What to do if the widget is too big for the page?
       if (offsetStart! - child.box!.height < offsetEnd) {
         // If it is not a multi-page widget and its height
@@ -475,7 +473,8 @@ class MultiPage extends Page {
         final flex = child is Flexible ? child.flex : 0;
         final fit = child is Flexible ? child.fit : FlexFit.loose;
         if (flex > 0) {
-          assert(child is! SpanningWidget);
+          assert(child is! SpanningWidget || child.canSpan == false,
+              'Cannot have a spanning widget flexible');
           final maxChildExtent = child == lastFlexChild
               ? (freeSpace - allocatedFlexSpace)
               : spacePerFlex * flex;

@@ -24,7 +24,7 @@ import 'geometry.dart';
 import 'multi_page.dart';
 import 'widget.dart';
 
-class Partition implements SpanningWidget {
+class Partition extends Widget with SpanningWidget {
   Partition({
     required this.child,
     this.width,
@@ -59,6 +59,7 @@ class Partition implements SpanningWidget {
 
   @override
   void paint(Context context) {
+    super.paint(context);
     child.paint(context);
   }
 
@@ -102,7 +103,7 @@ class _PartitionsContext extends WidgetContext {
   }
 }
 
-class Partitions extends Widget implements SpanningWidget {
+class Partitions extends Widget with SpanningWidget {
   Partitions({
     required this.children,
     this.mainAxisSize = MainAxisSize.max,

@@ -236,7 +236,7 @@ typedef OnCellDecoration = BoxDecoration Function(
     int index, dynamic data, int rowNum);
 
 /// A widget that uses the table layout algorithm for its children.
-class Table extends Widget implements SpanningWidget {
+class Table extends Widget with SpanningWidget {
   Table({
     this.children = const <TableRow>[],
     this.border,

@@ -575,7 +575,7 @@ class _RichTextContext extends WidgetContext {
       '$runtimeType Offset: $startOffset -> $endOffset  Span: $spanStart -> $spanEnd';
 }
 
-class RichText extends Widget implements SpanningWidget {
+class RichText extends Widget with SpanningWidget {
   RichText({
     required this.text,
     this.textAlign,

@@ -19,6 +19,7 @@ import 'dart:math' as math;
 
 import 'package:meta/meta.dart';
 import 'package:pdf/pdf.dart';
+import 'package:pdf/widgets.dart';
 import 'package:vector_math/vector_math_64.dart';
 
 import 'document.dart';
@@ -210,7 +211,7 @@ abstract class Widget {
   }
 }
 
-abstract class StatelessWidget extends Widget {
+abstract class StatelessWidget extends Widget with SpanningWidget {
   StatelessWidget() : super();
 
   Widget? _child;
@@ -246,9 +247,33 @@ abstract class StatelessWidget extends Widget {
 
   @protected
   Widget build(Context context);
+
+  @override
+  bool get canSpan =>
+      _child is SpanningWidget && (_child as SpanningWidget).canSpan;
+
+  @override
+  bool get hasMoreWidgets =>
+      _child is SpanningWidget && (_child as SpanningWidget).hasMoreWidgets;
+
+  @override
+  void restoreContext(covariant WidgetContext context) {
+    if (_child is SpanningWidget) {
+      (_child as SpanningWidget).restoreContext(context);
+    }
+  }
+
+  @override
+  WidgetContext saveContext() {
+    if (_child is SpanningWidget) {
+      return (_child as SpanningWidget).saveContext();
+    }
+
+    throw UnimplementedError();
+  }
 }
 
-abstract class SingleChildWidget extends Widget {
+abstract class SingleChildWidget extends Widget with SpanningWidget {
   SingleChildWidget({this.child}) : super();
 
   final Widget? child;
@@ -277,6 +302,30 @@ abstract class SingleChildWidget extends Widget {
       context.canvas.restoreContext();
     }
   }
+
+  @override
+  bool get canSpan =>
+      child is SpanningWidget && (child as SpanningWidget).canSpan;
+
+  @override
+  bool get hasMoreWidgets =>
+      child is SpanningWidget && (child as SpanningWidget).hasMoreWidgets;
+
+  @override
+  void restoreContext(covariant WidgetContext context) {
+    if (child is SpanningWidget) {
+      (child as SpanningWidget).restoreContext(context);
+    }
+  }
+
+  @override
+  WidgetContext saveContext() {
+    if (child is SpanningWidget) {
+      return (child as SpanningWidget).saveContext();
+    }
+
+    throw UnimplementedError();
+  }
 }
 
 abstract class MultiChildWidget extends Widget {
@@ -285,8 +334,8 @@ abstract class MultiChildWidget extends Widget {
   final List<Widget> children;
 }
 
-class InheritedWidget extends Widget {
-  InheritedWidget({this.build, this.inherited});
+class InheritedWidget extends SingleChildWidget {
+  InheritedWidget({this.build, this.inherited}) : super();
 
   final BuildCallback? build;
 
@@ -294,6 +343,9 @@ class InheritedWidget extends Widget {
 
   Context? _context;
 
+  @override
+  Widget? get child => _child;
+
   Widget? _child;
 
   @override
@@ -301,29 +353,13 @@ class InheritedWidget extends Widget {
       {bool parentUsesSize = false}) {
     _context = inherited != null ? context.inheritFrom(inherited!) : context;
     _child = build!(_context!);
-
-    if (_child != null) {
-      _child!.layout(_context!, constraints, parentUsesSize: parentUsesSize);
-      assert(_child!.box != null);
-      box = _child!.box;
-    } else {
-      box = PdfRect.fromPoints(PdfPoint.zero, constraints.smallest);
-    }
+    super.layout(_context!, constraints);
   }
 
   @override
   void paint(Context context) {
     assert(_context != null);
     super.paint(_context!);
-
-    if (_child != null) {
-      final mat = Matrix4.identity();
-      mat.translate(box!.x, box!.y);
-      context.canvas
-        ..saveContext()
-        ..setTransform(mat);
-      _child!.paint(_context!);
-      context.canvas.restoreContext();
-    }
+    paintChild(_context!);
   }
 }

@@ -67,7 +67,7 @@ class _WrapContext extends WidgetContext {
 }
 
 /// A widget that displays its children in multiple horizontal or vertical runs.
-class Wrap extends MultiChildWidget implements SpanningWidget {
+class Wrap extends MultiChildWidget with SpanningWidget {
   /// Creates a wrap layout.
 
   Wrap({