Reorder MultiPage paint operations

@@ -4,6 +4,7 @@
 
 - Fix Align debug painting
 - Fix GridView when empty
+- Reorder MultiPage paint operations
 
 ## 1.4.1
 
@@ -94,7 +95,7 @@
 
 ## 1.3.16
 
-- Add better debugPaint on Align Widget
+- Add better debug painting on Align Widget
 - Fix Transform placement when Alignment and Origin are Null
 - Add Transform.rotateBox constructor
 - Add Wrap Widget
@@ -126,7 +127,7 @@
 ## 1.3.10
 
 - Deprecate the document argument in Printing.sharePdf()
-- Add default value to alpha in PdfColor variants
+- Add a default value to alpha in PdfColor variants
 - Fix Table Widget
 - Add Flexible and Spacer Widgets
 
@@ -186,7 +187,7 @@
 - Fix dart lint warnings
 - Improve font bounds calculation
 - Add RichText Widget
-- Fix MultiPage max height
+- Fix MultiPage max-height
 - Add Stack Widget
 - Update Readme
 
@@ -196,13 +197,13 @@
 
 ## 1.3.0
 
-- Add a Flutter like widget system
+- Add a Flutter-like Widget system
 
 ## 1.2.0
 
 - Change license to Apache 2.0
 - Improve PdfRect
-- Add support for CMYK, HSL anf HSV colors
+- Add support for CMYK, HSL and HSV colors
 - Implement rounded rect
 
 ## 1.1.1
@@ -225,7 +226,7 @@
 - Implement drawShape
 - Add support for Jpeg images
 - Fix numeric conversions in graphic operations
-- Add unicode support for annotations and info block
+- Add Unicode support for annotations and info block
 - Add Flutter example
 
 ## 1.0.8
@@ -258,7 +259,7 @@
 
 ## 1.0.2
 
-- Update sdk support for 2.0.0
+- Update SDK support for 2.0.0
 
 ## 1.0.1
 

@@ -59,14 +59,19 @@ class Document {
 
   final List<Page> _pages = <Page>[];
 
+  bool _paint = false;
+
   void addPage(Page page) {
     page.generate(this);
     _pages.add(page);
   }
 
   List<int> save() {
-    for (Page page in _pages) {
-      page.postProcess(this);
+    if (!_paint) {
+      for (Page page in _pages) {
+        page.postProcess(this);
+      }
+      _paint = true;
     }
     return document.save();
   }

@@ -26,8 +26,27 @@ class _GridViewContext extends WidgetContext {
   double childMainAxis;
 
   @override
+  void apply(WidgetContext other) {
+    if (other is _GridViewContext) {
+      firstChild = other.firstChild;
+      lastChild = other.lastChild;
+      childCrossAxis = other.childCrossAxis;
+      childMainAxis = other.childMainAxis;
+    }
+  }
+
+  @override
+  WidgetContext clone() {
+    return _GridViewContext()
+      ..firstChild = firstChild
+      ..lastChild = lastChild
+      ..childCrossAxis = childCrossAxis
+      ..childMainAxis = childMainAxis;
+  }
+
+  @override
   String toString() =>
-      'GridViewContext first:$firstChild last:$lastChild size:${childCrossAxis}x$childMainAxis';
+      '$runtimeType first:$firstChild last:$lastChild size:${childCrossAxis}x$childMainAxis';
 }
 
 class GridView extends MultiChildWidget implements SpanningWidget {

@@ -18,14 +18,20 @@
 
 part of widget;
 
-class WidgetContext {}
+abstract class WidgetContext {
+  WidgetContext clone();
+
+  void apply(WidgetContext other);
+}
 
 abstract class SpanningWidget extends Widget {
   bool get canSpan => false;
 
+  /// Get unmodified mutable context object
   @protected
   WidgetContext saveContext();
 
+  /// Aplpy the context for next layout
   @protected
   void restoreContext(WidgetContext context);
 }
@@ -38,17 +44,37 @@ class NewPage extends Widget {
   }
 }
 
+@immutable
+class _MultiPageWidget {
+  const _MultiPageWidget({
+    @required this.child,
+    @required this.x,
+    @required this.y,
+    @required this.constraints,
+    @required this.widgetContext,
+  });
+
+  final Widget child;
+  final double x;
+  final double y;
+  final BoxConstraints constraints;
+  final WidgetContext widgetContext;
+}
+
+@immutable
 class _MultiPageInstance {
-  const _MultiPageInstance(
-      {@required this.context,
-      @required this.constraints,
-      @required this.fullConstraints,
-      @required this.offsetStart});
+  _MultiPageInstance({
+    @required this.context,
+    @required this.constraints,
+    @required this.fullConstraints,
+    @required this.offsetStart,
+  });
 
   final Context context;
   final BoxConstraints constraints;
   final BoxConstraints fullConstraints;
   final double offsetStart;
+  final List<_MultiPageWidget> widgets = <_MultiPageWidget>[];
 }
 
 class MultiPage extends Page {
@@ -168,16 +194,6 @@ class MultiPage extends Page {
           return true;
         }());
 
-        if (pageTheme.buildBackground != null) {
-          final Widget child = pageTheme.buildBackground(context);
-          if (child != null) {
-            child.layout(context, fullConstraints, parentUsesSize: false);
-            assert(child.box != null);
-            _paintChild(context, child, _margin.left, _margin.bottom,
-                pageFormat.height);
-          }
-        }
-
         offsetStart = pageHeight -
             (_mustRotate ? pageHeightMargin - margin.bottom : _margin.top);
         offsetEnd =
@@ -238,17 +254,23 @@ class MultiPage extends Page {
 
         final SpanningWidget span = child;
 
-        child.layout(
-            context, constraints.copyWith(maxHeight: offsetStart - offsetEnd),
-            parentUsesSize: false);
+        final BoxConstraints localConstraints =
+            constraints.copyWith(maxHeight: offsetStart - offsetEnd);
+        child.layout(context, localConstraints, parentUsesSize: false);
         assert(child.box != null);
-        _paintChild(context, child, _margin.left,
-            offsetStart - child.box.height, pageFormat.height);
+        widgetContext = span.saveContext();
+        _pages.last.widgets.add(
+          _MultiPageWidget(
+            child: child,
+            x: _margin.left,
+            y: offsetStart - child.box.height,
+            constraints: localConstraints,
+            widgetContext: widgetContext?.clone(),
+          ),
+        );
 
         // Has it finished spanning?
-        if (span.canSpan) {
-          widgetContext = span.saveContext();
-        } else {
+        if (!span.canSpan) {
           sameCount = 0;
           index++;
         }
@@ -258,8 +280,17 @@ class MultiPage extends Page {
         continue;
       }
 
-      _paintChild(context, child, _margin.left, offsetStart - child.box.height,
-          pageFormat.height);
+      _pages.last.widgets.add(
+        _MultiPageWidget(
+          child: child,
+          x: _margin.left,
+          y: offsetStart - child.box.height,
+          constraints: constraints,
+          widgetContext:
+              child is SpanningWidget ? child.saveContext().clone() : null,
+        ),
+      );
+
       offsetStart -= child.box.height;
       sameCount = 0;
       index++;
@@ -271,6 +302,29 @@ class MultiPage extends Page {
     final EdgeInsets _margin = margin;
 
     for (_MultiPageInstance page in _pages) {
+      if (pageTheme.buildBackground != null) {
+        final Widget child = pageTheme.buildBackground(page.context);
+        if (child != null) {
+          child.layout(page.context, page.fullConstraints,
+              parentUsesSize: false);
+          assert(child.box != null);
+          _paintChild(page.context, child, _margin.left, _margin.bottom,
+              pageFormat.height);
+        }
+      }
+
+      for (_MultiPageWidget widget in page.widgets) {
+        final Widget child = widget.child;
+        if (child is SpanningWidget) {
+          final WidgetContext context = child.saveContext();
+          context.apply(widget.widgetContext);
+        }
+        child.layout(page.context, widget.constraints, parentUsesSize: false);
+        assert(child.box != null);
+        _paintChild(
+            page.context, widget.child, widget.x, widget.y, pageFormat.height);
+      }
+
       if (header != null) {
         final Widget headerWidget = header(page.context);
         if (headerWidget != null) {

@@ -84,6 +84,24 @@ class TableBorder extends BoxBorder {
 class _TableContext extends WidgetContext {
   int firstLine = 0;
   int lastLine = 0;
+
+  @override
+  void apply(WidgetContext other) {
+    if (other is _TableContext) {
+      firstLine = other.firstLine;
+      lastLine = other.lastLine;
+    }
+  }
+
+  @override
+  WidgetContext clone() {
+    return _TableContext()
+      ..firstLine = firstLine
+      ..lastLine = lastLine;
+  }
+
+  @override
+  String toString() => '$runtimeType firstLine: $firstLine lastLine: $lastLine';
 }
 
 class _ColumnLayout {
@@ -215,7 +233,7 @@ class Table extends Widget implements SpanningWidget {
   final List<double> _widths = <double>[];
   final List<double> _heights = <double>[];
 
-  _TableContext _context = _TableContext();
+  final _TableContext _context = _TableContext();
 
   final TableColumnWidth defaultColumnWidth;
   final Map<int, TableColumnWidth> columnWidths;
@@ -227,7 +245,7 @@ class Table extends Widget implements SpanningWidget {
 
   @override
   void restoreContext(WidgetContext context) {
-    _context = context;
+    _context.apply(context);
     _context.firstLine = _context.lastLine;
   }
 

@@ -44,7 +44,22 @@ class _WrapContext extends WidgetContext {
   int lastChild = 0;
 
   @override
-  String toString() => 'WrapContext first:$firstChild last:$lastChild';
+  void apply(WidgetContext other) {
+    if (other is _WrapContext) {
+      firstChild = other.firstChild;
+      lastChild = other.lastChild;
+    }
+  }
+
+  @override
+  WidgetContext clone() {
+    return _WrapContext()
+      ..firstChild = firstChild
+      ..lastChild = lastChild;
+  }
+
+  @override
+  String toString() => '$runtimeType first:$firstChild last:$lastChild';
 }
 
 /// A widget that displays its children in multiple horizontal or vertical runs.

@@ -18,15 +18,19 @@
 
 import 'dart:io';
 
+import 'package:pdf/pdf.dart';
 import 'package:pdf/widgets.dart';
 import 'package:test/test.dart';
 
+Document pdf;
+PageTheme pageTheme;
+
 void main() {
-  test('Pdf Widgets Watermark', () {
+  setUpAll(() {
     Document.debug = true;
-    final Document pdf = Document();
+    pdf = Document();
 
-    final PageTheme pageTheme = PageTheme(
+    pageTheme = PageTheme(
       buildBackground: (Context context) => FullPage(
         ignoreMargins: true,
         child: Watermark.text('DRAFT'),
@@ -40,7 +44,9 @@ void main() {
         ),
       ),
     );
+  });
 
+  test('Pdf Widgets Watermark Page', () {
     pdf.addPage(
       Page(
         pageTheme: pageTheme,
@@ -51,7 +57,9 @@ void main() {
         ),
       ),
     );
+  });
 
+  test('Pdf Widgets Watermark MultiPage', () {
     pdf.addPage(
       MultiPage(
         pageTheme: pageTheme,
@@ -63,7 +71,38 @@ void main() {
         ),
       ),
     );
+  });
+
+  test('Pdf Widgets Watermark Page Count', () async {
+    final PageTheme pageTheme = PageTheme(
+      buildBackground: (Context context) =>
+          (context.pageNumber == context.pagesCount)
+              ? Align(
+                  alignment: Alignment.topRight,
+                  child: SizedBox(
+                      width: 200,
+                      height: 200,
+                      child: PdfLogo(color: PdfColors.blue200)),
+                )
+              : Container(),
+    );
+
+    pdf.addPage(
+      MultiPage(
+        pageTheme: pageTheme,
+        build: (Context context) => <Widget>[
+          Wrap(
+            children: List<Widget>.generate(
+              670,
+              (_) => Text('Hello World '),
+            ),
+          ),
+        ],
+      ),
+    );
+  });
 
+  tearDownAll(() {
     final File file = File('widgets-watermark.pdf');
     file.writeAsBytesSync(pdf.save());
   });

+widgets-monopage.pdf
\ No newline at end of file

+widgets-multipage.pdf
\ No newline at end of file