Fix dispose state issue

 # Changelog
 
+## 5.7.2
+
+- Fix dispose state issue
+
 ## 5.7.1
 
 - Update Google Fonts, fixes documentation issues

@@ -237,7 +237,26 @@ class PdfPageFormatAction extends StatelessWidget {
     final theme = Theme.of(context);
     final iconColor = theme.primaryIconTheme.color ?? Colors.white;
     final data = PdfPreviewController.listen(context);
-    final keys = pageFormats.keys.toList();
+    final _pageFormats = <String, PdfPageFormat>{...pageFormats};
+
+    var format = data.pageFormat;
+    final orientation = data.horizontal;
+
+    if (!_pageFormats.values.contains(data.pageFormat)) {
+      var found = false;
+      for (final f in _pageFormats.values) {
+        if (format.portrait == f.portrait) {
+          format = f;
+          found = true;
+          break;
+        }
+      }
+      if (!found) {
+        _pageFormats['---'] = format;
+      }
+    }
+
+    final keys = _pageFormats.keys.toList()..sort();
 
     return DropdownButton<PdfPageFormat>(
       dropdownColor: theme.primaryColor,
@@ -245,12 +264,12 @@ class PdfPageFormatAction extends StatelessWidget {
         Icons.arrow_drop_down,
         color: iconColor,
       ),
-      value: data.pageFormat,
+      value: format,
       items: List<DropdownMenuItem<PdfPageFormat>>.generate(
-        pageFormats.length,
+        _pageFormats.length,
         (int index) {
           final key = keys[index];
-          final val = pageFormats[key];
+          final val = _pageFormats[key]!;
           return DropdownMenuItem<PdfPageFormat>(
             value: val,
             child: Text(key, style: TextStyle(color: iconColor)),
@@ -259,7 +278,8 @@ class PdfPageFormatAction extends StatelessWidget {
       ),
       onChanged: (PdfPageFormat? pageFormat) {
         if (pageFormat != null) {
-          data.pageFormat = pageFormat;
+          data.pageFormat =
+              orientation ? pageFormat.landscape : pageFormat.portrait;
         }
       },
     );

@@ -19,41 +19,52 @@ import 'package:pdf/pdf.dart';
 
 import '../callback.dart';
 
-mixin PdfPreviewData implements ChangeNotifier {
-  // PdfPreviewData(this.build);
+typedef ComputePageFormat = PdfPageFormat Function();
+
+class PdfPreviewData extends ChangeNotifier {
+  PdfPreviewData({
+    PdfPageFormat? initialPageFormat,
+    required this.buildDocument,
+    required Map<String, PdfPageFormat> pageFormats,
+    required ComputePageFormat onComputeActualPageFormat,
+  })  : assert(pageFormats.isNotEmpty),
+        _onComputeActualPageFormat = onComputeActualPageFormat {
+    _pageFormat = initialPageFormat ??
+        (pageFormats[localPageFormat] ?? pageFormats.values.first);
+  }
 
-  LayoutCallback get buildDocument;
+  late PdfPageFormat _pageFormat;
 
-  PdfPageFormat? _pageFormat;
+  final LayoutCallback buildDocument;
 
-  PdfPageFormat get initialPageFormat;
+  final ComputePageFormat _onComputeActualPageFormat;
 
-  PdfPageFormat get pageFormat => _pageFormat ?? initialPageFormat;
+  PdfPageFormat get pageFormat => _pageFormat;
 
   set pageFormat(PdfPageFormat value) {
-    if (_pageFormat == value) {
-      return;
-    }
+    if (_pageFormat != value) {
       _pageFormat = value;
       notifyListeners();
     }
-
-  bool? _horizontal;
+  }
 
   /// Is the print horizontal
-  bool get horizontal => _horizontal ?? pageFormat.width > pageFormat.height;
+  bool get horizontal => _pageFormat.width > _pageFormat.height;
 
   set horizontal(bool value) {
-    if (_horizontal == value) {
-      return;
-    }
-    _horizontal = value;
+    final format = value ? _pageFormat.landscape : _pageFormat.portrait;
+    if (format != _pageFormat) {
+      _pageFormat = format;
       notifyListeners();
     }
+  }
 
   /// Computed page format
-  PdfPageFormat get computedPageFormat =>
-      horizontal ? pageFormat.landscape : pageFormat.portrait;
+  @Deprecated('Use pageFormat instead')
+  PdfPageFormat get computedPageFormat => _pageFormat;
+
+  /// The page format of the document
+  PdfPageFormat get actualPageFormat => _onComputeActualPageFormat();
 
   String get localPageFormat {
     final locale = WidgetsBinding.instance!.window.locale;
@@ -65,8 +76,6 @@ mixin PdfPreviewData implements ChangeNotifier {
     }
     return 'A4';
   }
-
-  PdfPageFormat get actualPageFormat => pageFormat;
 }
 
 class PdfPreviewController extends InheritedNotifier {

@@ -158,41 +158,17 @@ class PdfPreview extends StatefulWidget {
   _PdfPreviewState createState() => _PdfPreviewState();
 }
 
-class _PdfPreviewState extends State<PdfPreview>
-    with PdfPreviewData, ChangeNotifier {
+class _PdfPreviewState extends State<PdfPreview> {
   final previewWidget = GlobalKey<PdfPreviewCustomState>();
+  late PdfPreviewData previewData;
 
   /// Printing subsystem information
   PrintingInfo? info;
-  var infoLoaded = false;
-
-  @override
-  LayoutCallback get buildDocument => widget.build;
-
-  @override
-  PdfPageFormat get initialPageFormat =>
-      widget.initialPageFormat ??
-      (widget.pageFormats.isNotEmpty
-          ? (widget.pageFormats[localPageFormat] ??
-              widget.pageFormats.values.first)
-          : (PdfPreview._defaultPageFormats[localPageFormat]) ??
-              PdfPreview._defaultPageFormats.values.first);
-
-  @override
-  PdfPageFormat get pageFormat {
-    var _pageFormat = super.pageFormat;
-
-    if (!widget.pageFormats.containsValue(_pageFormat)) {
-      _pageFormat = initialPageFormat;
-      pageFormat = _pageFormat;
-    }
 
-    return _pageFormat;
-  }
+  var infoLoaded = false;
 
-  @override
-  PdfPageFormat get actualPageFormat {
-    var format = pageFormat;
+  PdfPageFormat computeActualPageFormat() {
+    var format = previewData.pageFormat;
     final pages = previewWidget.currentState?.pages ?? const [];
     final dpi = previewWidget.currentState?.dpi ?? 72;
 
@@ -209,7 +185,16 @@ class _PdfPreviewState extends State<PdfPreview>
 
   @override
   void initState() {
-    addListener(() {
+    previewData = PdfPreviewData(
+      buildDocument: widget.build,
+      pageFormats: widget.pageFormats.isNotEmpty
+          ? widget.pageFormats
+          : PdfPreview._defaultPageFormats,
+      initialPageFormat: widget.initialPageFormat,
+      onComputeActualPageFormat: computeActualPageFormat,
+    );
+
+    previewData.addListener(() {
       if (mounted) {
         setState(() {});
       }
@@ -219,10 +204,24 @@ class _PdfPreviewState extends State<PdfPreview>
   }
 
   @override
+  void dispose() {
+    previewData.dispose();
+    super.dispose();
+  }
+
+  @override
   void didUpdateWidget(covariant PdfPreview oldWidget) {
     if (oldWidget.build != widget.build ||
         widget.shouldRepaint ||
         widget.pageFormats != oldWidget.pageFormats) {
+      previewData = PdfPreviewData(
+        buildDocument: widget.build,
+        pageFormats: widget.pageFormats.isNotEmpty
+            ? widget.pageFormats
+            : PdfPreview._defaultPageFormats,
+        initialPageFormat: previewData.pageFormat,
+        onComputeActualPageFormat: computeActualPageFormat,
+      );
       setState(() {});
     }
     super.didUpdateWidget(oldWidget);
@@ -301,7 +300,7 @@ class _PdfPreviewState extends State<PdfPreview>
     }());
 
     return PdfPreviewController(
-      data: this,
+      data: previewData,
       child: Column(
         mainAxisAlignment: MainAxisAlignment.center,
         children: <Widget>[
@@ -313,7 +312,7 @@ class _PdfPreviewState extends State<PdfPreview>
               maxPageWidth: widget.maxPageWidth,
               onError: widget.onError,
               padding: widget.padding,
-              pageFormat: computedPageFormat,
+              pageFormat: previewData.pageFormat,
               pages: widget.pages,
               pdfPreviewPageDecoration: widget.pdfPreviewPageDecoration,
               previewPageMargin: widget.previewPageMargin,

@@ -6,7 +6,7 @@ description: >
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/printing
 repository: https://github.com/DavBfr/dart_pdf
 issue_tracker: https://github.com/DavBfr/dart_pdf/issues
-version: 5.7.1
+version: 5.7.2
 
 environment:
   sdk: ">=2.12.0 <3.0.0"