Force Flutter 3.7

@@ -333,7 +333,7 @@ class MultiPage extends Page {
               'You probably need a SpanningWidget or use a single page layout');
         }
 
-        final span = child as SpanningWidget;
+        final span = child;
 
         if (savedContext != null) {
           // Restore saved context

@@ -9,7 +9,7 @@ screenshots:
 version: 3.9.0
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
+  sdk: ">=2.18.0 <3.0.0"
 
 dependencies:
   archive: ^3.1.0

@@ -317,10 +317,10 @@ class PrintingPlugin extends PrintingPlatform {
           js.context['document'].createElement('canvas');
 
       final context = canvas.getContext('2d') as html.CanvasRenderingContext2D?;
-      final _pages =
+      final computedPages =
           pages ?? Iterable<int>.generate(numPages, (index) => index);
 
-      for (final pageIndex in _pages) {
+      for (final pageIndex in computedPages) {
         final page =
             await promiseToFuture<PdfJsPage>(doc.getPage(pageIndex + 1));
         try {

@@ -237,14 +237,14 @@ class PdfPageFormatAction extends StatelessWidget {
     final theme = Theme.of(context);
     final iconColor = theme.primaryIconTheme.color ?? Colors.white;
     final data = PdfPreviewController.listen(context);
-    final _pageFormats = <String, PdfPageFormat>{...pageFormats};
+    final allPageFormats = <String, PdfPageFormat>{...pageFormats};
 
     var format = data.pageFormat;
     final orientation = data.horizontal;
 
-    if (!_pageFormats.values.contains(data.pageFormat)) {
+    if (!allPageFormats.values.contains(data.pageFormat)) {
       var found = false;
-      for (final f in _pageFormats.values) {
+      for (final f in allPageFormats.values) {
         if (format.portrait == f.portrait) {
           format = f;
           found = true;
@@ -252,11 +252,11 @@ class PdfPageFormatAction extends StatelessWidget {
         }
       }
       if (!found) {
-        _pageFormats['---'] = format;
+        allPageFormats['---'] = format;
       }
     }
 
-    final keys = _pageFormats.keys.toList()..sort();
+    final keys = allPageFormats.keys.toList()..sort();
 
     return DropdownButton<PdfPageFormat>(
       dropdownColor: theme.primaryColor,
@@ -266,10 +266,10 @@ class PdfPageFormatAction extends StatelessWidget {
       ),
       value: format,
       items: List<DropdownMenuItem<PdfPageFormat>>.generate(
-        _pageFormats.length,
+        allPageFormats.length,
         (int index) {
           final key = keys[index];
-          final val = _pageFormats[key]!;
+          final val = allPageFormats[key]!;
           return DropdownMenuItem<PdfPageFormat>(
             value: val,
             child: Text(key, style: TextStyle(color: iconColor)),

@@ -67,12 +67,9 @@ class PdfPreviewData extends ChangeNotifier {
   PdfPageFormat get actualPageFormat => _onComputeActualPageFormat();
 
   String get localPageFormat {
-    // Flutter 3 workaround
-    // ignore: omit_local_variable_types
-    final WidgetsBinding? wbi = WidgetsBinding.instance;
-    final locale = wbi!.window.locale;
-    // ignore: unnecessary_cast
-    final cc = (locale as Locale?)?.countryCode ?? 'US';
+    final wbi = WidgetsBinding.instance;
+    final locale = wbi.window.locale;
+    final cc = locale.countryCode ?? 'US';
 
     if (cc == 'US' || cc == 'CA' || cc == 'MX') {
       return 'Letter';

@@ -157,9 +157,9 @@ class PdfPreviewCustomState extends State<PdfPreviewCustom>
   void didChangeDependencies() {
     if (!infoLoaded) {
       infoLoaded = true;
-      Printing.info().then((PrintingInfo _info) {
+      Printing.info().then((PrintingInfo printingInfo) {
         setState(() {
-          info = _info;
+          info = printingInfo;
           raster();
         });
       });
@@ -182,8 +182,8 @@ class PdfPreviewCustomState extends State<PdfPreviewCustom>
       return _showError(error!);
     }
 
-    final _info = info;
-    if (_info != null && !_info.canRaster) {
+    final printingInfo = info;
+    if (printingInfo != null && !printingInfo.canRaster) {
       return _showError(_errorMessage);
     }
 

@@ -228,10 +228,10 @@ class PdfPreview extends StatefulWidget {
   final CustomPdfPagesBuilder? _pagesBuilder;
 
   @override
-  _PdfPreviewState createState() => _PdfPreviewState();
+  PdfPreviewState createState() => PdfPreviewState();
 }
 
-class _PdfPreviewState extends State<PdfPreview> {
+class PdfPreviewState extends State<PdfPreview> {
   final previewWidget = GlobalKey<PdfPreviewCustomState>();
   late PdfPreviewData previewData;
 
@@ -305,9 +305,9 @@ class _PdfPreviewState extends State<PdfPreview> {
   void didChangeDependencies() {
     if (!infoLoaded) {
       infoLoaded = true;
-      Printing.info().then((PrintingInfo _info) {
+      Printing.info().then((PrintingInfo printingInfo) {
         setState(() {
-          info = _info;
+          info = printingInfo;
         });
       });
     }

@@ -100,10 +100,10 @@ mixin PdfPreviewRaster on State<PdfPreviewCustom> {
     }
     _rastering = true;
 
-    Uint8List _doc;
+    Uint8List doc;
 
-    final _info = info;
-    if (_info != null && !_info.canRaster) {
+    final printingInfo = info;
+    if (printingInfo != null && !printingInfo.canRaster) {
       assert(() {
         if (kIsWeb) {
           FlutterError.reportError(FlutterErrorDetails(
@@ -122,7 +122,7 @@ mixin PdfPreviewRaster on State<PdfPreviewCustom> {
     }
 
     try {
-      _doc = await widget.build(pageFormat);
+      doc = await widget.build(pageFormat);
     } catch (exception, stack) {
       InformationCollector? collector;
 
@@ -159,7 +159,7 @@ mixin PdfPreviewRaster on State<PdfPreviewCustom> {
     try {
       var pageNum = 0;
       await for (final PdfRaster page in Printing.raster(
-        _doc,
+        doc,
         dpi: dpi,
         pages: widget.pages,
       )) {

@@ -74,9 +74,9 @@ mixin Printing {
     Rect? bounds,
     String? title,
   }) async {
-    final _info = await info();
+    final printingInfo = await info();
 
-    if (_info.canListPrinters) {
+    if (printingInfo.canListPrinters) {
       final printers = await listPrinters();
       printers.sort((a, b) {
         if (a.isDefault) {
@@ -88,6 +88,7 @@ mixin Printing {
         return a.name.compareTo(b.name);
       });
 
+      // ignore: use_build_context_synchronously
       return await showDialog<Printer>(
         context: context,
         builder: (context) => SimpleDialog(

@@ -144,31 +144,32 @@ class WidgetWrapper extends pw.ImageProvider {
       child: widget,
     );
 
-    final _properties = DiagnosticPropertiesBuilder();
-    widget.debugFillProperties(_properties);
+    final prop = DiagnosticPropertiesBuilder();
+    widget.debugFillProperties(prop);
 
-    if (_properties.properties.isEmpty) {
+    if (prop.properties.isEmpty) {
       throw ErrorDescription('Unable to get the widget properties');
     }
 
-    final _constraints = _properties.properties
+    final computedConstraints = prop.properties
         .whereType<DiagnosticsProperty<BoxConstraints>>()
         .first
         .value;
 
-    if (_constraints == null ||
-        !_constraints.hasBoundedWidth ||
-        !_constraints.hasBoundedWidth) {
+    if (computedConstraints == null ||
+        !computedConstraints.hasBoundedWidth ||
+        !computedConstraints.hasBoundedWidth) {
       throw Exception('Unable to convert an unbounded widget.');
     }
 
-    final _repaintBoundary = RenderRepaintBoundary();
+    final repaintBoundary = RenderRepaintBoundary();
 
     final renderView = RenderView(
       child: RenderPositionedBox(
-          alignment: Alignment.center, child: _repaintBoundary),
+          alignment: Alignment.center, child: repaintBoundary),
       configuration: ViewConfiguration(
-          size: Size(_constraints.maxWidth, _constraints.maxHeight),
+          size:
+              Size(computedConstraints.maxWidth, computedConstraints.maxHeight),
           devicePixelRatio: ui.window.devicePixelRatio),
       window: ui.window,
     );
@@ -177,8 +178,8 @@ class WidgetWrapper extends pw.ImageProvider {
     renderView.prepareInitialFrame();
 
     final buildOwner = BuildOwner(focusManager: FocusManager());
-    final _rootElement = RenderObjectToWidgetAdapter<RenderBox>(
-      container: _repaintBoundary,
+    final rootElement = RenderObjectToWidgetAdapter<RenderBox>(
+      container: repaintBoundary,
       child: Directionality(
         textDirection: TextDirection.ltr,
         child: IntrinsicHeight(child: IntrinsicWidth(child: widget)),
@@ -186,7 +187,7 @@ class WidgetWrapper extends pw.ImageProvider {
     ).attachToRenderTree(buildOwner);
 
     buildOwner
-      ..buildScope(_rootElement)
+      ..buildScope(rootElement)
       ..finalizeTree();
 
     pipelineOwner
@@ -194,7 +195,7 @@ class WidgetWrapper extends pw.ImageProvider {
       ..flushCompositingBits()
       ..flushPaint();
 
-    final image = await _repaintBoundary.toImage(pixelRatio: pixelRatio);
+    final image = await repaintBoundary.toImage(pixelRatio: pixelRatio);
     final bytes = await image.toByteData(format: ui.ImageByteFormat.rawRgba);
     if (bytes == null) {
       throw Exception('Unable to read image data');

@@ -12,8 +12,8 @@ screenshots:
 version: 5.10.0
 
 environment:
-  sdk: ">=2.12.0 <3.0.0"
-  flutter: ">=1.16.0"
+  sdk: ">=2.18.0 <3.0.0"
+  flutter: ">=3.7.0"
 
 dependencies:
   ffi: ">=1.1.0 <3.0.0"
@@ -22,17 +22,17 @@ dependencies:
   flutter_web_plugins:
     sdk: flutter
   http: ^0.13.0
-  image: ^4.0.0
+  image: ^4.0.02
   js: ^0.6.3
   meta: ">=1.3.0 <2.0.0"
   pdf: ^3.9.0
-  plugin_platform_interface: ^2.0.0
+  plugin_platform_interface: ^2.1.0
 
 dev_dependencies:
-  flutter_lints: ^1.0.4
+  flutter_lints: ^2.0.1
   flutter_test:
     sdk: flutter
-  mockito: ^5.0.0
+  mockito: ^5.3.2
 
 dependency_overrides:
   pdf: