Improve PdfPreview widget

 # Changelog
 # Changelog
 
 
-## 5.2.2
+## 5.3.0
 
 
 - Fix raster crash on all OS.
 - Fix raster crash on all OS.
+- Improve PdfPreview widget
 
 
 ## 5.2.1
 ## 5.2.1
 
 

@@ -16,7 +16,8 @@
 
 
 export 'src/asset_utils.dart';
 export 'src/asset_utils.dart';
 export 'src/callback.dart';
 export 'src/callback.dart';
-export 'src/pdf_preview.dart';
+export 'src/preview/pdf_preview.dart';
+export 'src/preview/pdf_preview_action.dart';
 export 'src/printer.dart';
 export 'src/printer.dart';
 export 'src/printing.dart';
 export 'src/printing.dart';
 export 'src/printing_info.dart';
 export 'src/printing_info.dart';

+/*
+ * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
+ *
+ * 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:async';
 import 'dart:async';
 import 'dart:math';
 import 'dart:math';
-import 'dart:typed_data';
 
 
 import 'package:flutter/foundation.dart';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/material.dart';
 import 'package:pdf/pdf.dart';
 import 'package:pdf/pdf.dart';
 import 'package:pdf/widgets.dart' as pw;
 import 'package:pdf/widgets.dart' as pw;
 
 
-import 'callback.dart';
-import 'printing.dart';
-import 'printing_info.dart';
-import 'raster.dart';
+import '../callback.dart';
+import '../printing.dart';
+import '../printing_info.dart';
+import 'pdf_preview_action.dart';
+import 'pdf_preview_raster.dart';
 
 
 /// Flutter widget that uses the rasterized pdf pages to display a document.
 /// Flutter widget that uses the rasterized pdf pages to display a document.
 class PdfPreview extends StatefulWidget {
 class PdfPreview extends StatefulWidget {
@@ -25,7 +41,7 @@ class PdfPreview extends StatefulWidget {
     this.canChangePageFormat = true,
     this.canChangePageFormat = true,
     this.canChangeOrientation = true,
     this.canChangeOrientation = true,
     this.actions,
     this.actions,
-    this.pageFormats,
+    this.pageFormats = _defaultPageFormats,
     this.onError,
     this.onError,
     this.onPrinted,
     this.onPrinted,
     this.onPrintError,
     this.onPrintError,
@@ -44,6 +60,11 @@ class PdfPreview extends StatefulWidget {
     this.shouldRepaint = false,
     this.shouldRepaint = false,
   }) : super(key: key);
   }) : super(key: key);
 
 
+  static const _defaultPageFormats = <String, PdfPageFormat>{
+    'A4': PdfPageFormat.a4,
+    'Letter': PdfPageFormat.letter,
+  };
+
   /// Called when a pdf document is needed
   /// Called when a pdf document is needed
   final LayoutCallback build;
   final LayoutCallback build;
 
 
@@ -72,10 +93,10 @@ class PdfPreview extends StatefulWidget {
   final List<PdfPreviewAction>? actions;
   final List<PdfPreviewAction>? actions;
 
 
   /// List of page formats the user can choose
   /// List of page formats the user can choose
-  final Map<String, PdfPageFormat>? pageFormats;
+  final Map<String, PdfPageFormat> pageFormats;
 
 
   /// Widget to display if the PDF document cannot be displayed
   /// Widget to display if the PDF document cannot be displayed
-  final Widget Function(BuildContext context)? onError;
+  final Widget Function(BuildContext context, Object error)? onError;
 
 
   /// Called if the user prints the pdf document
   /// Called if the user prints the pdf document
   final void Function(BuildContext context)? onPrinted;
   final void Function(BuildContext context)? onPrinted;
@@ -129,22 +150,40 @@ class PdfPreview extends StatefulWidget {
   _PdfPreviewState createState() => _PdfPreviewState();
   _PdfPreviewState createState() => _PdfPreviewState();
 }
 }
 
 
-class _PdfPreviewState extends State<PdfPreview> {
+class _PdfPreviewState extends State<PdfPreview> with PdfPreviewRaster {
   final GlobalKey<State<StatefulWidget>> shareWidget = GlobalKey();
   final GlobalKey<State<StatefulWidget>> shareWidget = GlobalKey();
   final GlobalKey<State<StatefulWidget>> listView = GlobalKey();
   final GlobalKey<State<StatefulWidget>> listView = GlobalKey();
 
 
-  final List<_PdfPreviewPage> pages = <_PdfPreviewPage>[];
+  PdfPageFormat? _pageFormat;
 
 
-  late PdfPageFormat pageFormat;
+  String get localPageFormat {
+    final locale = WidgetsBinding.instance!.window.locale;
+    // ignore: unnecessary_cast
+    final cc = (locale as Locale?)?.countryCode ?? 'US';
 
 
-  bool? horizontal;
+    if (cc == 'US' || cc == 'CA' || cc == 'MX') {
+      return 'Letter';
+    }
+    return 'A4';
+  }
 
 
-  PrintingInfo info = PrintingInfo.unavailable;
-  bool infoLoaded = false;
+  @override
+  PdfPageFormat get pageFormat {
+    _pageFormat ??= widget.initialPageFormat == null
+        ? widget.pageFormats[localPageFormat]
+        : _pageFormat = widget.initialPageFormat!;
+
+    if (!widget.pageFormats.containsValue(_pageFormat)) {
+      _pageFormat = widget.initialPageFormat ??
+          (widget.pageFormats.isNotEmpty
+              ? widget.pageFormats.values.first
+              : PdfPreview._defaultPageFormats[localPageFormat]);
+    }
 
 
-  double dpi = 10;
+    return _pageFormat!;
+  }
 
 
-  Object? error;
+  bool infoLoaded = false;
 
 
   int? preview;
   int? preview;
 
 
@@ -158,125 +197,7 @@ class _PdfPreviewState extends State<PdfPreview> {
 
 
   Timer? previewUpdate;
   Timer? previewUpdate;
 
 
-  var _rastering = false;
-
-  static const defaultPageFormats = <String, PdfPageFormat>{
-    'A4': PdfPageFormat.a4,
-    'Letter': PdfPageFormat.letter,
-  };
-
-  PdfPageFormat get computedPageFormat => horizontal != null
-      ? (horizontal! ? pageFormat.landscape : pageFormat.portrait)
-      : pageFormat;
-
-  Future<void> _raster() async {
-    if (_rastering) {
-      return;
-    }
-    _rastering = true;
-
-    Uint8List _doc;
-
-    if (!info.canRaster) {
-      assert(() {
-        if (kIsWeb) {
-          FlutterError.reportError(FlutterErrorDetails(
-            exception: Exception(
-                'Unable to find the `pdf.js` library.\nPlease follow the installation instructions at https://github.com/DavBfr/dart_pdf/tree/master/printing#installing'),
-            library: 'printing',
-            context: ErrorDescription('while rendering a PDF'),
-          ));
-        }
-
-        return true;
-      }());
-
-      _rastering = false;
-      return;
-    }
-
-    try {
-      _doc = await widget.build(computedPageFormat);
-    } catch (exception, stack) {
-      InformationCollector? collector;
-
-      assert(() {
-        collector = () sync* {
-          yield StringProperty('PageFormat', computedPageFormat.toString());
-        };
-        return true;
-      }());
-
-      FlutterError.reportError(FlutterErrorDetails(
-        exception: exception,
-        stack: stack,
-        library: 'printing',
-        context: ErrorDescription('while generating a PDF'),
-        informationCollector: collector,
-      ));
-      error = exception;
-      _rastering = false;
-      return;
-    }
-
-    if (error != null) {
-      setState(() {
-        error = null;
-      });
-    }
-
-    try {
-      var pageNum = 0;
-      await for (final PdfRaster page in Printing.raster(
-        _doc,
-        dpi: dpi,
-        pages: widget.pages,
-      )) {
-        if (!mounted) {
-          _rastering = false;
-          return;
-        }
-        setState(() {
-          if (pages.length <= pageNum) {
-            pages.add(_PdfPreviewPage(
-              page: page,
-              pdfPreviewPageDecoration: widget.pdfPreviewPageDecoration,
-              pageMargin: widget.previewPageMargin,
-            ));
-          } else {
-            pages[pageNum] = _PdfPreviewPage(
-              page: page,
-              pdfPreviewPageDecoration: widget.pdfPreviewPageDecoration,
-              pageMargin: widget.previewPageMargin,
-            );
-          }
-        });
-
-        pageNum++;
-        pages.removeRange(pageNum, pages.length);
-      }
-    } catch (exception, stack) {
-      InformationCollector? collector;
-
-      assert(() {
-        collector = () sync* {
-          yield StringProperty('PageFormat', computedPageFormat.toString());
-        };
-        return true;
-      }());
-
-      FlutterError.reportError(FlutterErrorDetails(
-        exception: exception,
-        stack: stack,
-        library: 'printing',
-        context: ErrorDescription('while generating a PDF'),
-        informationCollector: collector,
-      ));
-      error = exception;
-    }
-
-    _rastering = false;
-  }
+  static const _errorMessage = 'Unable to display the document';
 
 
   @override
   @override
   void initState() {
   void initState() {
@@ -286,17 +207,17 @@ class _PdfPreviewState extends State<PdfPreview> {
       final cc = (locale as Locale?)?.countryCode ?? 'US';
       final cc = (locale as Locale?)?.countryCode ?? 'US';
 
 
       if (cc == 'US' || cc == 'CA' || cc == 'MX') {
       if (cc == 'US' || cc == 'CA' || cc == 'MX') {
-        pageFormat = PdfPageFormat.letter;
+        _pageFormat = PdfPageFormat.letter;
       } else {
       } else {
-        pageFormat = PdfPageFormat.a4;
+        _pageFormat = PdfPageFormat.a4;
       }
       }
     } else {
     } else {
-      pageFormat = widget.initialPageFormat!;
+      _pageFormat = widget.initialPageFormat!;
     }
     }
 
 
-    final _pageFormats = widget.pageFormats ?? defaultPageFormats;
+    final _pageFormats = widget.pageFormats;
     if (!_pageFormats.containsValue(pageFormat)) {
     if (!_pageFormats.containsValue(pageFormat)) {
-      pageFormat = _pageFormats.values.first;
+      _pageFormat = _pageFormats.values.first;
     }
     }
 
 
     super.initState();
     super.initState();
@@ -310,16 +231,19 @@ class _PdfPreviewState extends State<PdfPreview> {
 
 
   @override
   @override
   void reassemble() {
   void reassemble() {
-    _raster();
+    raster();
     super.reassemble();
     super.reassemble();
   }
   }
 
 
   @override
   @override
   void didUpdateWidget(covariant PdfPreview oldWidget) {
   void didUpdateWidget(covariant PdfPreview oldWidget) {
-    if (oldWidget.build != widget.build || widget.shouldRepaint) {
+    if (oldWidget.build != widget.build ||
+        widget.shouldRepaint ||
+        widget.pageFormats != oldWidget.pageFormats) {
       preview = null;
       preview = null;
       updatePosition = null;
       updatePosition = null;
-      _raster();
+
+      raster();
     }
     }
     super.didUpdateWidget(oldWidget);
     super.didUpdateWidget(oldWidget);
   }
   }
@@ -327,54 +251,35 @@ class _PdfPreviewState extends State<PdfPreview> {
   @override
   @override
   void didChangeDependencies() {
   void didChangeDependencies() {
     if (!infoLoaded) {
     if (!infoLoaded) {
+      infoLoaded = true;
       Printing.info().then((PrintingInfo _info) {
       Printing.info().then((PrintingInfo _info) {
         setState(() {
         setState(() {
-          infoLoaded = true;
           info = _info;
           info = _info;
+          raster();
         });
         });
       });
       });
     }
     }
 
 
-    previewUpdate?.cancel();
-    previewUpdate = Timer(const Duration(seconds: 1), () {
-      final mq = MediaQuery.of(context);
-      dpi = (min(mq.size.width - 16, widget.maxPageWidth ?? double.infinity)) *
-          mq.devicePixelRatio /
-          computedPageFormat.width *
-          72;
-
-      _raster();
-    });
+    raster();
     super.didChangeDependencies();
     super.didChangeDependencies();
   }
   }
 
 
-  Widget _showError() {
+  Widget _showError(Object error) {
     if (widget.onError != null) {
     if (widget.onError != null) {
-      return widget.onError!(context);
+      return widget.onError!(context, error);
     }
     }
 
 
-    return const Center(
-      child: Text(
-        'Unable to display the document',
-        style: TextStyle(
-          fontSize: 20,
-        ),
-      ),
-    );
+    return ErrorWidget(error);
   }
   }
 
 
   Widget _createPreview() {
   Widget _createPreview() {
     if (error != null) {
     if (error != null) {
-      var content = _showError();
-      assert(() {
-        content = ErrorWidget(error!);
-        return true;
-      }());
-      return content;
+      return _showError(error!);
     }
     }
 
 
-    if (!info.canRaster) {
-      return _showError();
+    final _info = info;
+    if (_info != null && !_info.canRaster) {
+      return _showError(_errorMessage);
     }
     }
 
 
     if (pages.isEmpty) {
     if (pages.isEmpty) {
@@ -454,7 +359,7 @@ class _PdfPreviewState extends State<PdfPreview> {
 
 
     final actions = <Widget>[];
     final actions = <Widget>[];
 
 
-    if (widget.allowPrinting && info.canPrint) {
+    if (widget.allowPrinting && info?.canPrint == true) {
       actions.add(
       actions.add(
         IconButton(
         IconButton(
           icon: const Icon(Icons.print),
           icon: const Icon(Icons.print),
@@ -463,7 +368,7 @@ class _PdfPreviewState extends State<PdfPreview> {
       );
       );
     }
     }
 
 
-    if (widget.allowSharing && info.canShare) {
+    if (widget.allowSharing && info?.canShare == true) {
       actions.add(
       actions.add(
         IconButton(
         IconButton(
           key: shareWidget,
           key: shareWidget,
@@ -474,8 +379,7 @@ class _PdfPreviewState extends State<PdfPreview> {
     }
     }
 
 
     if (widget.canChangePageFormat) {
     if (widget.canChangePageFormat) {
-      final _pageFormats = widget.pageFormats ?? defaultPageFormats;
-      final keys = _pageFormats.keys.toList();
+      final keys = widget.pageFormats.keys.toList();
       actions.add(
       actions.add(
         DropdownButton<PdfPageFormat>(
         DropdownButton<PdfPageFormat>(
           dropdownColor: theme.primaryColor,
           dropdownColor: theme.primaryColor,
@@ -485,21 +389,21 @@ class _PdfPreviewState extends State<PdfPreview> {
           ),
           ),
           value: pageFormat,
           value: pageFormat,
           items: List<DropdownMenuItem<PdfPageFormat>>.generate(
           items: List<DropdownMenuItem<PdfPageFormat>>.generate(
-            _pageFormats.length,
+            widget.pageFormats.length,
             (int index) {
             (int index) {
               final key = keys[index];
               final key = keys[index];
-              final val = _pageFormats[key];
+              final val = widget.pageFormats[key];
               return DropdownMenuItem<PdfPageFormat>(
               return DropdownMenuItem<PdfPageFormat>(
                 value: val,
                 value: val,
                 child: Text(key, style: TextStyle(color: iconColor)),
                 child: Text(key, style: TextStyle(color: iconColor)),
               );
               );
             },
             },
           ),
           ),
-          onChanged: (PdfPageFormat? _pageFormat) {
+          onChanged: (PdfPageFormat? pageFormat) {
             setState(() {
             setState(() {
-              if (_pageFormat != null) {
-                pageFormat = _pageFormat;
-                _raster();
+              if (pageFormat != null) {
+                _pageFormat = pageFormat;
+                raster();
               }
               }
             });
             });
           },
           },
@@ -520,7 +424,7 @@ class _PdfPreviewState extends State<PdfPreview> {
             onPressed: (int index) {
             onPressed: (int index) {
               setState(() {
               setState(() {
                 horizontal = index == 1;
                 horizontal = index == 1;
-                _raster();
+                raster();
               });
               });
             },
             },
             isSelected: <bool>[horizontal == false, horizontal == true],
             isSelected: <bool>[horizontal == false, horizontal == true],
@@ -561,7 +465,7 @@ class _PdfPreviewState extends State<PdfPreview> {
               setState(
               setState(
                 () {
                 () {
                   pw.Document.debug = value;
                   pw.Document.debug = value;
-                  _raster();
+                  raster();
                 },
                 },
               );
               );
             },
             },
@@ -624,9 +528,26 @@ class _PdfPreviewState extends State<PdfPreview> {
       if (result && widget.onPrinted != null) {
       if (result && widget.onPrinted != null) {
         widget.onPrinted!(context);
         widget.onPrinted!(context);
       }
       }
-    } catch (e) {
+    } catch (exception, stack) {
+      InformationCollector? collector;
+
+      assert(() {
+        collector = () sync* {
+          yield StringProperty('PageFormat', computedPageFormat.toString());
+        };
+        return true;
+      }());
+
+      FlutterError.reportError(FlutterErrorDetails(
+        exception: exception,
+        stack: stack,
+        library: 'printing',
+        context: ErrorDescription('while printing a PDF'),
+        informationCollector: collector,
+      ));
+
       if (widget.onPrintError != null) {
       if (widget.onPrintError != null) {
-        widget.onPrintError!(context, e);
+        widget.onPrintError!(context, exception);
       }
       }
     }
     }
   }
   }
@@ -656,76 +577,3 @@ class _PdfPreviewState extends State<PdfPreview> {
     }
     }
   }
   }
 }
 }
-
-class _PdfPreviewPage extends StatelessWidget {
-  const _PdfPreviewPage({
-    Key? key,
-    this.page,
-    this.pdfPreviewPageDecoration,
-    this.pageMargin,
-  }) : super(key: key);
-
-  final PdfRaster? page;
-  final Decoration? pdfPreviewPageDecoration;
-  final EdgeInsets? pageMargin;
-
-  @override
-  Widget build(BuildContext context) {
-    final im = PdfRasterImage(page!);
-    final scrollbarTrack = Theme.of(context)
-            .scrollbarTheme
-            .thickness
-            ?.resolve({MaterialState.hovered}) ??
-        12;
-
-    return Container(
-      margin: pageMargin ??
-          EdgeInsets.only(
-            left: 8 + scrollbarTrack,
-            top: 8,
-            right: 8 + scrollbarTrack,
-            bottom: 12,
-          ),
-      decoration: pdfPreviewPageDecoration ??
-          const BoxDecoration(
-            color: Colors.white,
-            boxShadow: <BoxShadow>[
-              BoxShadow(
-                offset: Offset(0, 3),
-                blurRadius: 5,
-                color: Color(0xFF000000),
-              ),
-            ],
-          ),
-      child: AspectRatio(
-        aspectRatio: page!.width / page!.height,
-        child: Image(
-          image: im,
-          fit: BoxFit.cover,
-        ),
-      ),
-    );
-  }
-}
-
-/// Action callback
-typedef OnPdfPreviewActionPressed = void Function(
-  BuildContext context,
-  LayoutCallback build,
-  PdfPageFormat pageFormat,
-);
-
-/// Action to add the the [PdfPreview] widget
-class PdfPreviewAction {
-  /// Represents an icon to add to [PdfPreview]
-  const PdfPreviewAction({
-    required this.icon,
-    required this.onPressed,
-  });
-
-  /// The icon to display
-  final Icon icon;
-
-  /// The callback called when the user tap on the icon
-  final OnPdfPreviewActionPressed? onPressed;
-}

+/*
+ * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
+ *
+ * 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 'package:flutter/material.dart';
+import 'package:pdf/pdf.dart';
+
+import '../callback.dart';
+
+/// Base Action callback
+typedef OnPdfPreviewActionPressed = void Function(
+  BuildContext context,
+  LayoutCallback build,
+  PdfPageFormat pageFormat,
+);
+
+/// Action to add the the [PdfPreview] widget
+class PdfPreviewAction {
+  /// Represents an icon to add to [PdfPreview]
+  const PdfPreviewAction({
+    required this.icon,
+    required this.onPressed,
+  });
+
+  /// The icon to display
+  final Icon icon;
+
+  /// The callback called when the user tap on the icon
+  final OnPdfPreviewActionPressed? onPressed;
+}

+/*
+ * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
+ *
+ * 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 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+
+import '../raster.dart';
+
+/// Represents one PDF page
+class PdfPreviewPage extends StatelessWidget {
+  /// Create a PDF page widget
+  const PdfPreviewPage({
+    Key? key,
+    this.page,
+    this.pdfPreviewPageDecoration,
+    this.pageMargin,
+  }) : super(key: key);
+
+  /// Image representing the content of the page
+  final PdfRaster? page;
+
+  /// Decoration around the page
+  final Decoration? pdfPreviewPageDecoration;
+
+  /// Margin
+  final EdgeInsets? pageMargin;
+
+  @override
+  Widget build(BuildContext context) {
+    final im = PdfRasterImage(page!);
+    final scrollbarTrack = Theme.of(context)
+            .scrollbarTheme
+            .thickness
+            ?.resolve({MaterialState.hovered}) ??
+        12;
+
+    return Container(
+      margin: pageMargin ??
+          EdgeInsets.only(
+            left: 8 + scrollbarTrack,
+            top: 8,
+            right: 8 + scrollbarTrack,
+            bottom: 12,
+          ),
+      decoration: pdfPreviewPageDecoration ??
+          const BoxDecoration(
+            color: Colors.white,
+            boxShadow: <BoxShadow>[
+              BoxShadow(
+                offset: Offset(0, 3),
+                blurRadius: 5,
+                color: Color(0xFF000000),
+              ),
+            ],
+          ),
+      child: AspectRatio(
+        aspectRatio: page!.width / page!.height,
+        child: Image(
+          image: im,
+          fit: BoxFit.cover,
+        ),
+      ),
+    );
+  }
+}

+/*
+ * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
+ *
+ * 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:async';
+import 'dart:math';
+import 'dart:typed_data';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:pdf/pdf.dart';
+
+import '../printing.dart';
+import '../printing_info.dart';
+import '../raster.dart';
+import 'pdf_preview.dart';
+import 'pdf_preview_page.dart';
+
+/// Raster PDF documents
+mixin PdfPreviewRaster on State<PdfPreview> {
+  static const _updateTime = Duration(milliseconds: 300);
+
+  /// Configured page format
+  PdfPageFormat get pageFormat;
+
+  /// Is the print horizontal
+  bool? horizontal;
+
+  /// Resulting pages
+  final List<PdfPreviewPage> pages = <PdfPreviewPage>[];
+
+  /// Printing subsystem information
+  PrintingInfo? info;
+
+  /// Error message
+  Object? error;
+
+  /// Dots per inch
+  double dpi = 10;
+
+  var _rastering = false;
+
+  Timer? _previewUpdate;
+
+  @override
+  void dispose() {
+    _previewUpdate?.cancel();
+    super.dispose();
+  }
+
+  /// Computed page format
+  PdfPageFormat get computedPageFormat => horizontal != null
+      ? (horizontal! ? pageFormat.landscape : pageFormat.portrait)
+      : pageFormat;
+
+  /// Rasterize the document
+  void raster() {
+    _previewUpdate?.cancel();
+    _previewUpdate = Timer(_updateTime, () {
+      final mq = MediaQuery.of(context);
+      dpi = (min(mq.size.width - 16, widget.maxPageWidth ?? double.infinity)) *
+          mq.devicePixelRatio /
+          computedPageFormat.width *
+          72;
+
+      _raster();
+    });
+  }
+
+  Future<void> _raster() async {
+    if (_rastering) {
+      return;
+    }
+    _rastering = true;
+
+    Uint8List _doc;
+
+    final _info = info;
+    if (_info != null && !_info.canRaster) {
+      assert(() {
+        if (kIsWeb) {
+          FlutterError.reportError(FlutterErrorDetails(
+            exception: Exception(
+                'Unable to find the `pdf.js` library.\nPlease follow the installation instructions at https://github.com/DavBfr/dart_pdf/tree/master/printing#installing'),
+            library: 'printing',
+            context: ErrorDescription('while rendering a PDF'),
+          ));
+        }
+
+        return true;
+      }());
+
+      _rastering = false;
+      return;
+    }
+
+    try {
+      _doc = await widget.build(computedPageFormat);
+    } catch (exception, stack) {
+      InformationCollector? collector;
+
+      assert(() {
+        collector = () sync* {
+          yield StringProperty('PageFormat', computedPageFormat.toString());
+        };
+        return true;
+      }());
+
+      FlutterError.reportError(FlutterErrorDetails(
+        exception: exception,
+        stack: stack,
+        library: 'printing',
+        context: ErrorDescription('while generating a PDF'),
+        informationCollector: collector,
+      ));
+      setState(() {
+        error = exception;
+        _rastering = false;
+      });
+      return;
+    }
+
+    if (error != null) {
+      setState(() {
+        error = null;
+      });
+    }
+
+    try {
+      var pageNum = 0;
+      await for (final PdfRaster page in Printing.raster(
+        _doc,
+        dpi: dpi,
+        pages: widget.pages,
+      )) {
+        if (!mounted) {
+          _rastering = false;
+          return;
+        }
+        setState(() {
+          if (pages.length <= pageNum) {
+            pages.add(PdfPreviewPage(
+              page: page,
+              pdfPreviewPageDecoration: widget.pdfPreviewPageDecoration,
+              pageMargin: widget.previewPageMargin,
+            ));
+          } else {
+            pages[pageNum] = PdfPreviewPage(
+              page: page,
+              pdfPreviewPageDecoration: widget.pdfPreviewPageDecoration,
+              pageMargin: widget.previewPageMargin,
+            );
+          }
+        });
+
+        pageNum++;
+      }
+
+      pages.removeRange(pageNum, pages.length);
+    } catch (exception, stack) {
+      InformationCollector? collector;
+
+      assert(() {
+        collector = () sync* {
+          yield StringProperty('PageFormat', computedPageFormat.toString());
+        };
+        return true;
+      }());
+
+      FlutterError.reportError(FlutterErrorDetails(
+        exception: exception,
+        stack: stack,
+        library: 'printing',
+        context: ErrorDescription('while rastering a PDF'),
+        informationCollector: collector,
+      ));
+
+      setState(() {
+        error = exception;
+      });
+    }
+
+    _rastering = false;
+  }
+}

@@ -7,7 +7,7 @@ description: >
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/printing
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/printing
 repository: https://github.com/DavBfr/dart_pdf
 repository: https://github.com/DavBfr/dart_pdf
 issue_tracker: https://github.com/DavBfr/dart_pdf/issues
 issue_tracker: https://github.com/DavBfr/dart_pdf/issues
-version: 5.2.2
+version: 5.3.0
 
 
 environment:
 environment:
   sdk: ">=2.12.0-0 <3.0.0"
   sdk: ">=2.12.0-0 <3.0.0"

@@ -347,7 +347,7 @@ void PrintJob::rasterPdf(std::vector<uint8_t> data,
 
 
   FPDF_DestroyLibrary();
   FPDF_DestroyLibrary();
 
 
-  printing->onPageRasterEnd(this, nullptr);
+  printing->onPageRasterEnd(this, "");
 }
 }
 
 
 std::map<std::string, bool> PrintJob::printingInfo() {
 std::map<std::string, bool> PrintJob::printingInfo() {

@@ -44,7 +44,7 @@ void Printing::onPageRasterized(std::vector<uint8_t> data,
           })));
           })));
 }
 }
 
 
-void Printing::onPageRasterEnd(PrintJob* job, const char* error) {
+void Printing::onPageRasterEnd(PrintJob* job, const std::string error) {
   auto map = flutter::EncodableMap{
   auto map = flutter::EncodableMap{
       {flutter::EncodableValue("job"), flutter::EncodableValue(job->id())},
       {flutter::EncodableValue("job"), flutter::EncodableValue(job->id())},
   };
   };

@@ -40,7 +40,7 @@ class Printing {
                         int height,
                         int height,
                         PrintJob* job);
                         PrintJob* job);
 
 
-  void onPageRasterEnd(PrintJob* job, const char* error);
+  void onPageRasterEnd(PrintJob* job, const std::string error);
 
 
   void onLayout(PrintJob* job,
   void onLayout(PrintJob* job,
                 double pageWidth,
                 double pageWidth,
@@ -50,7 +50,9 @@ class Printing {
                 double marginRight,
                 double marginRight,
                 double marginBottom);
                 double marginBottom);
 
 
-  void Printing::onCompleted(PrintJob* job, bool completed, std::string error);
+  void Printing::onCompleted(PrintJob* job,
+                             bool completed,
+                             const std::string error);
 };
 };
 
 
 }  // namespace nfet
 }  // namespace nfet