Improve code documentation

@@ -5,6 +5,7 @@
 - Add PdfPreview Widget
 - Implement Printing.raster() on Flutter Web
 - Fix Swift 5 deprecated function
+- Improve code documentation
 
 ## 3.3.1
 

-# Specify analysis options.
-#
-# Until there are meta linter rules, each desired lint must be explicitly enabled.
-# See: https://github.com/dart-lang/linter/issues/288
-#
-# For a list of lints, see: http://dart-lang.github.io/linter/lints/
-# See the configuration guide for more
-# https://github.com/dart-lang/sdk/tree/master/pkg/analyzer#configuring-the-analyzer
-#
-# There are other similar analysis options files in the flutter repos,
-# which should be kept in sync with this file:
-#
-#   - analysis_options.yaml (this file)
-#   - packages/flutter/lib/analysis_options_user.yaml
-#   - https://github.com/flutter/plugins/blob/master/analysis_options.yaml
-#   - https://github.com/flutter/engine/blob/master/analysis_options.yaml
-#
-# This file contains the analysis options used by Flutter tools, such as IntelliJ,
-# Android Studio, and the `flutter analyze` command.
+include: package:pedantic/analysis_options.yaml
 
 analyzer:
   strong-mode:
     implicit-dynamic: false
   errors:
-    # treat missing required parameters as a warning (not a hint)
     missing_required_param: warning
-    # treat missing returns as a warning (not a hint)
     missing_return: warning
-    # allow having TODOs in the code
+    public_member_api_docs: warning
     todo: ignore
-    # Ignore analyzer hints for updating pubspecs when using Future or
-    # Stream and not importing dart:async
-    # Please see https://github.com/flutter/flutter/pull/24528 for details.
-    sdk_version_async_exported_from_core: ignore
-  exclude:
-    - "bin/cache/**"
-    # the following two are relative to the stocks example and the flutter package respectively
-    # see https://github.com/dart-lang/sdk/issues/28463
-    - "lib/i18n/stock_messages_*.dart"
-    - "lib/src/http/**"
 
 linter:
   rules:
-    # these rules are documented on and in the same order as
-    # the Dart Lint rules page to make maintenance easier
-    # https://github.com/dart-lang/linter/blob/master/example/all.yaml
-    - always_declare_return_types
     - always_put_control_body_on_new_line
-    # - always_put_required_named_parameters_first # we prefer having parameters in the same order as fields https://github.com/flutter/flutter/issues/10219
-    - always_require_non_null_named_parameters
-    - always_specify_types
-    - annotate_overrides
-    # - avoid_annotating_with_dynamic # conflicts with always_specify_types
     - avoid_as
     - avoid_bool_literals_in_conditional_expressions
-    # - avoid_catches_without_on_clauses # we do this commonly
-    # - avoid_catching_errors # we do this commonly
     - avoid_classes_with_only_static_members
-    # - avoid_double_and_int_checks # only useful when targeting JS runtime
-    - avoid_empty_else
     - avoid_field_initializers_in_const_classes
     - avoid_function_literals_in_foreach_calls
-    # - avoid_implementing_value_types # not yet tested
-    - avoid_init_to_null
-    # - avoid_js_rounded_ints # only useful when targeting JS runtime
-    - avoid_null_checks_in_equality_operators
-    # - avoid_positional_boolean_parameters # not yet tested
-    # - avoid_private_typedef_functions # we prefer having typedef (discussion in https://github.com/flutter/flutter/pull/16356)
-    - avoid_relative_lib_imports
     - avoid_renaming_method_parameters
-    - avoid_return_types_on_setters
-    # - avoid_returning_null # there are plenty of valid reasons to return null
-    # - avoid_returning_null_for_future # not yet tested
     - avoid_returning_null_for_void
-    # - avoid_returning_this # there are plenty of valid reasons to return this
-    # - avoid_setters_without_getters # not yet tested
-    # - avoid_shadowing_type_parameters # not yet tested
-    # - avoid_single_cascade_in_expression_statements # not yet tested
     - avoid_slow_async_io
-    - avoid_types_as_parameter_names
-    # - avoid_types_on_closure_parameters # conflicts with always_specify_types
     - avoid_unused_constructor_parameters
     - avoid_void_async
     - await_only_futures
     - camel_case_types
     - cancel_subscriptions
-    # - cascade_invocations # not yet tested
-    # - close_sinks # not reliable enough
-    # - comment_references # blocked on https://github.com/flutter/flutter/issues/20765
-    # - constant_identifier_names # needs an opt-out https://github.com/dart-lang/linter/issues/204
     - control_flow_in_finally
-    # - curly_braces_in_flow_control_structures # not yet tested
-    # - diagnostic_describe_all_properties # not yet tested
     - directives_ordering
-    - empty_catches
-    - empty_constructor_bodies
     - empty_statements
-    # - file_names # not yet tested
     - flutter_style_todos
     - hash_and_equals
     - implementation_imports
-    # - invariant_booleans # too many false positives: https://github.com/dart-lang/linter/issues/811
     - iterable_contains_unrelated_type
-    # - join_return_with_assignment # not yet tested
-    - library_names
-    - library_prefixes
-    # - lines_longer_than_80_chars # not yet tested
     - list_remove_unrelated_type
-    # - literal_only_boolean_expressions # too many false positives: https://github.com/dart-lang/sdk/issues/34181
     - no_adjacent_strings_in_list
-    - no_duplicate_case_values
     - non_constant_identifier_names
-    # - null_closures  # not yet tested
-    # - omit_local_variable_types # opposite of always_specify_types
-    # - one_member_abstracts # too many false positives
-    # - only_throw_errors # https://github.com/flutter/flutter/issues/5792
+    - omit_local_variable_types
     - overridden_fields
     - package_api_docs
     - package_names
     - package_prefixed_library_names
-    # - parameter_assignments # we do this commonly
-    - prefer_adjacent_string_concatenation
     - prefer_asserts_in_initializer_lists
-    # - prefer_asserts_with_message # not yet tested
-    - prefer_collection_literals
-    - prefer_conditional_assignment
     - prefer_const_constructors
     - prefer_const_constructors_in_immutables
     - prefer_const_declarations
     - prefer_const_literals_to_create_immutables
-    # - prefer_constructors_over_static_methods # not yet tested
-    - prefer_contains
-    # - prefer_double_quotes # opposite of prefer_single_quotes
-    - prefer_equal_for_default_values
-    # - prefer_expression_function_bodies # conflicts with https://github.com/flutter/flutter/wiki/Style-guide-for-Flutter-repo#consider-using--for-short-functions-and-methods
-    - prefer_final_fields
-    # - prefer_final_in_for_each # not yet tested
     - prefer_final_locals
-    # - prefer_for_elements_to_map_fromIterable # not yet tested
     - prefer_foreach
-    # - prefer_function_declarations_over_variables # not yet tested
-    - prefer_generic_function_type_aliases
     - prefer_if_elements_to_conditional_expressions
-    - prefer_if_null_operators
     - prefer_initializing_formals
     - prefer_inlined_adds
-    # - prefer_int_literals # not yet tested
-    # - prefer_interpolation_to_compose_strings # not yet tested
-    - prefer_is_empty
-    - prefer_is_not_empty
-    - prefer_iterable_whereType
-    # - prefer_mixin # https://github.com/dart-lang/language/issues/32
-    # - prefer_null_aware_operators # disable until NNBD, see https://github.com/flutter/flutter/pull/32711#issuecomment-492930932
-    - prefer_single_quotes
-    - prefer_spread_collections
     - prefer_typing_uninitialized_variables
     - prefer_void_to_null
-    # - provide_deprecation_message # not yet tested
-    # - public_member_api_docs # enabled on a case-by-case basis; see e.g. packages/analysis_options.yaml
-    - recursive_getters
-    - slash_for_doc_comments
-    # - sort_child_properties_last # not yet tested
+    - public_member_api_docs
     - sort_constructors_first
     - sort_pub_dependencies
     - sort_unnamed_constructors_first
     - test_types_in_equals
     - throw_in_finally
-    # - type_annotate_public_apis # subset of always_specify_types
-    - type_init_formals
-    # - unawaited_futures # too many false positives
-    # - unnecessary_await_in_return # not yet tested
     - unnecessary_brace_in_string_interps
-    - unnecessary_const
     - unnecessary_getters_setters
-    # - unnecessary_lambdas # has false positives: https://github.com/dart-lang/linter/issues/498
-    - unnecessary_new
     - unnecessary_null_aware_assignments
-    - unnecessary_null_in_if_null_operators
     - unnecessary_overrides
     - unnecessary_parenthesis
     - unnecessary_statements
-    - unnecessary_this
-    - unrelated_type_equality_checks
-    # - unsafe_html # not yet tested
     - use_full_hex_values_for_flutter_colors
-    # - use_function_type_syntax_for_parameters # not yet tested
-    - use_rethrow_when_possible
-    # - use_setters_to_change_properties # not yet tested
-    # - use_string_buffers # has false positives: https://github.com/dart-lang/sdk/issues/34182
-    # - use_to_and_as_if_applicable # has false positives, so we prefer to catch this by code-review
-    - valid_regexps
-    # - void_checks # not yet tested

@@ -15,7 +15,6 @@
  */
 
 import 'dart:async';
-import 'dart:typed_data';
 import 'dart:ui' as ui;
 
 import 'package:flutter/rendering.dart';
@@ -28,8 +27,7 @@ import 'package:pdf/widgets.dart';
 /// into a [PdfImage] instance
 Future<PdfImage> pdfImageFromImage(
     {@required PdfDocument pdf, @required ui.Image image}) async {
-  final ByteData bytes =
-      await image.toByteData(format: ui.ImageByteFormat.rawRgba);
+  final bytes = await image.toByteData(format: ui.ImageByteFormat.rawRgba);
 
   return PdfImage(pdf,
       image: bytes.buffer.asUint8List(),
@@ -44,14 +42,12 @@ Future<PdfImage> pdfImageFromImageProvider(
     @required ImageProvider image,
     ImageConfiguration configuration,
     ImageErrorListener onError}) async {
-  final Completer<PdfImage> completer = Completer<PdfImage>();
-  final ImageStream stream =
-      image.resolve(configuration ?? ImageConfiguration.empty);
+  final completer = Completer<PdfImage>();
+  final stream = image.resolve(configuration ?? ImageConfiguration.empty);
 
   ImageStreamListener listener;
   listener = ImageStreamListener((ImageInfo image, bool sync) async {
-    final PdfImage result =
-        await pdfImageFromImage(pdf: pdf, image: image.image);
+    final result = await pdfImageFromImage(pdf: pdf, image: image.image);
     if (!completer.isCompleted) {
       completer.complete(result);
     }
@@ -75,6 +71,6 @@ Future<PdfImage> pdfImageFromImageProvider(
 /// Loads a font from an asset bundle key. If used multiple times with the same font name,
 /// it will be included multiple times in the pdf file
 Future<TtfFont> fontFromAssetBundle(String key, AssetBundle bundle) async {
-  final ByteData data = await bundle.load(key);
+  final data = await bundle.load(key);
   return TtfFont(data);
 }

@@ -32,6 +32,7 @@ const MethodChannel _channel = MethodChannel('net.nfet.printing');
 
 /// An implementation of [PrintingPlatform] that uses method channels.
 class MethodChannelPrinting extends PrintingPlatform {
+  /// Create a [PrintingPlatform] object for method channels.
   MethodChannelPrinting() : super() {
     _channel.setMethodCallHandler(_handleMethod);
   }
@@ -43,8 +44,8 @@ class MethodChannelPrinting extends PrintingPlatform {
   static Future<dynamic> _handleMethod(MethodCall call) async {
     switch (call.method) {
       case 'onLayout':
-        final PrintJob job = _printJobs[call.arguments['job']];
-        final PdfPageFormat format = PdfPageFormat(
+        final job = _printJobs[call.arguments['job']];
+        final format = PdfPageFormat(
           call.arguments['width'],
           call.arguments['height'],
           marginLeft: call.arguments['marginLeft'],
@@ -53,7 +54,7 @@ class MethodChannelPrinting extends PrintingPlatform {
           marginBottom: call.arguments['marginBottom'],
         );
 
-        final Uint8List bytes = await job.onLayout(format);
+        final bytes = await job.onLayout(format);
 
         if (bytes == null) {
           throw 'onLayout returned null';
@@ -64,7 +65,7 @@ class MethodChannelPrinting extends PrintingPlatform {
       case 'onCompleted':
         final bool completed = call.arguments['completed'];
         final String error = call.arguments['error'];
-        final PrintJob job = _printJobs[call.arguments['job']];
+        final job = _printJobs[call.arguments['job']];
         if (completed == false && error != null) {
           job.onCompleted.completeError(error);
         } else {
@@ -72,16 +73,16 @@ class MethodChannelPrinting extends PrintingPlatform {
         }
         break;
       case 'onHtmlRendered':
-        final PrintJob job = _printJobs[call.arguments['job']];
+        final job = _printJobs[call.arguments['job']];
         job.onHtmlRendered.complete(call.arguments['doc']);
         break;
       case 'onHtmlError':
-        final PrintJob job = _printJobs[call.arguments['job']];
+        final job = _printJobs[call.arguments['job']];
         job.onHtmlRendered.completeError(call.arguments['error']);
         break;
       case 'onPageRasterized':
-        final PrintJob job = _printJobs[call.arguments['job']];
-        final PdfRaster raster = PdfRaster(
+        final job = _printJobs[call.arguments['job']];
+        final raster = PdfRaster(
           call.arguments['width'],
           call.arguments['height'],
           call.arguments['image'],
@@ -89,7 +90,7 @@ class MethodChannelPrinting extends PrintingPlatform {
         job.onPageRasterized.add(raster);
         break;
       case 'onPageRasterEnd':
-        final PrintJob job = _printJobs[call.arguments['job']];
+        final job = _printJobs[call.arguments['job']];
         job.onPageRasterized.close();
         _printJobs.remove(job.index);
         break;
@@ -126,12 +127,12 @@ class MethodChannelPrinting extends PrintingPlatform {
     String name,
     PdfPageFormat format,
   ) async {
-    final PrintJob job = _newPrintJob(PrintJob(
+    final job = _newPrintJob(PrintJob(
       onCompleted: Completer<bool>(),
       onLayout: onLayout,
     ));
 
-    final Map<String, dynamic> params = <String, dynamic>{
+    final params = <String, dynamic>{
       'name': name,
       'job': job.index,
       'width': format.width,
@@ -152,14 +153,14 @@ class MethodChannelPrinting extends PrintingPlatform {
 
   @override
   Future<Printer> pickPrinter(Rect bounds) async {
-    final Map<String, dynamic> params = <String, dynamic>{
+    final params = <String, dynamic>{
       'x': bounds.left,
       'y': bounds.top,
       'w': bounds.width,
       'h': bounds.height,
     };
-    final Map<dynamic, dynamic> printer = await _channel
-        .invokeMethod<Map<dynamic, dynamic>>('pickPrinter', params);
+    final printer = await _channel.invokeMethod<Map<dynamic, dynamic>>(
+        'pickPrinter', params);
     if (printer == null) {
       return null;
     }
@@ -178,23 +179,23 @@ class MethodChannelPrinting extends PrintingPlatform {
     String name,
     PdfPageFormat format,
   ) async {
-    final PrintJob job = _newPrintJob(PrintJob(
+    final job = _newPrintJob(PrintJob(
       onCompleted: Completer<bool>(),
     ));
 
-    final Uint8List bytes = await onLayout(format);
+    final bytes = await onLayout(format);
     if (bytes == null) {
       return false;
     }
 
-    final Map<String, dynamic> params = <String, dynamic>{
+    final params = <String, dynamic>{
       'name': name,
       'printer': printer.url,
       'doc': Uint8List.fromList(bytes),
       'job': job.index,
     };
     await _channel.invokeMethod<int>('directPrintPdf', params);
-    final bool result = await job.onCompleted.future;
+    final result = await job.onCompleted.future;
     _printJobs.remove(job.index);
     return result;
   }
@@ -205,7 +206,7 @@ class MethodChannelPrinting extends PrintingPlatform {
     String filename,
     Rect bounds,
   ) async {
-    final Map<String, dynamic> params = <String, dynamic>{
+    final params = <String, dynamic>{
       'doc': Uint8List.fromList(bytes),
       'name': filename,
       'x': bounds.left,
@@ -219,11 +220,11 @@ class MethodChannelPrinting extends PrintingPlatform {
   @override
   Future<Uint8List> convertHtml(
       String html, String baseUrl, PdfPageFormat format) async {
-    final PrintJob job = _newPrintJob(PrintJob(
+    final job = _newPrintJob(PrintJob(
       onHtmlRendered: Completer<Uint8List>(),
     ));
 
-    final Map<String, dynamic> params = <String, dynamic>{
+    final params = <String, dynamic>{
       'html': html,
       'baseUrl': baseUrl,
       'width': format.width,
@@ -236,7 +237,7 @@ class MethodChannelPrinting extends PrintingPlatform {
     };
 
     await _channel.invokeMethod<void>('convertHtml', params);
-    final Uint8List result = await job.onHtmlRendered.future;
+    final result = await job.onHtmlRendered.future;
     _printJobs.remove(job.index);
     return result;
   }
@@ -247,11 +248,11 @@ class MethodChannelPrinting extends PrintingPlatform {
     List<int> pages,
     double dpi,
   ) {
-    final PrintJob job = _newPrintJob(PrintJob(
+    final job = _newPrintJob(PrintJob(
       onPageRasterized: StreamController<PdfRaster>(),
     ));
 
-    final Map<String, dynamic> params = <String, dynamic>{
+    final params = <String, dynamic>{
       'doc': Uint8List.fromList(document),
       'pages': pages,
       'scale': dpi / PdfPageFormat.inch,

@@ -10,7 +10,9 @@ import 'printing.dart';
 import 'printing_info.dart';
 import 'raster.dart';
 
+/// Flutter widget that uses the rasterized pdf pages to display a document.
 class PdfPreview extends StatefulWidget {
+  /// Show a pdf document built on demand
   const PdfPreview({
     Key key,
     @required this.build,
@@ -26,26 +28,37 @@ class PdfPreview extends StatefulWidget {
     this.onShared,
   }) : super(key: key);
 
+  /// Called when a pdf document is needed
   final LayoutCallback build;
 
+  /// Pdf page format asked for the first display
   final PdfPageFormat initialPageFormat;
 
+  /// Add a button to print the pdf document
   final bool allowPrinting;
 
+  /// Add a button to share the pdf document
   final bool allowSharing;
 
+  /// Maximum width of the pdf document on screen
   final double maxPageWidth;
 
+  /// Add a drop-down menu to choose the page format
   final bool canChangePageFormat;
 
+  /// Additionnal actions to add to the widget
   final List<PdfPreviewAction> actions;
 
+  /// List of page formats the user can choose
   final Map<String, PdfPageFormat> pageFormats;
 
+  /// Called if an error creating the Pdf occured
   final Widget Function(BuildContext context) onError;
 
+  /// Called if the user prints the pdf document
   final void Function(BuildContext context) onPrinted;
 
+  /// Called if the user shares the pdf document
   final void Function(BuildContext context) onShared;
 
   @override
@@ -93,7 +106,7 @@ class _PdfPreviewState extends State<PdfPreview> {
       });
     }
 
-    int pageNum = 0;
+    var pageNum = 0;
     await for (final PdfRaster page in Printing.raster(_doc, dpi: dpi)) {
       setState(() {
         if (pages.length <= pageNum) {
@@ -111,9 +124,9 @@ class _PdfPreviewState extends State<PdfPreview> {
 
   @override
   void initState() {
-    final Locale locale =
+    final locale =
         WidgetsBinding.instance.window.locale ?? const Locale('en', 'US');
-    final String cc = locale.countryCode;
+    final cc = locale.countryCode;
     if (cc == 'US' || cc == 'CA' || cc == 'MX') {
       pageFormat = widget.initialPageFormat ?? PdfPageFormat.letter;
     } else {
@@ -150,7 +163,7 @@ class _PdfPreviewState extends State<PdfPreview> {
       });
     }
 
-    final MediaQueryData mq = MediaQuery.of(context);
+    final mq = MediaQuery.of(context);
     dpi = (min(mq.size.width - 16, widget.maxPageWidth ?? double.infinity)) *
         mq.devicePixelRatio /
         pageFormat.width *
@@ -177,7 +190,7 @@ class _PdfPreviewState extends State<PdfPreview> {
 
   Widget _createPreview() {
     if (error != null) {
-      Widget content = _showError();
+      var content = _showError();
       assert(() {
         print(error);
         content = ErrorWidget(error);
@@ -204,7 +217,7 @@ class _PdfPreviewState extends State<PdfPreview> {
 
   @override
   Widget build(BuildContext context) {
-    final ThemeData theme = Theme.of(context);
+    final theme = Theme.of(context);
 
     final Widget scrollView = Container(
       decoration: BoxDecoration(
@@ -224,7 +237,7 @@ class _PdfPreviewState extends State<PdfPreview> {
       ),
     );
 
-    final List<Widget> actions = <Widget>[];
+    final actions = <Widget>[];
 
     if (widget.allowPrinting && info.canPrint) {
       actions.add(
@@ -248,9 +261,8 @@ class _PdfPreviewState extends State<PdfPreview> {
     }
 
     if (widget.canChangePageFormat) {
-      final Map<String, PdfPageFormat> _pageFormats =
-          widget.pageFormats ?? defaultPageFormats;
-      final List<String> keys = _pageFormats.keys.toList();
+      final _pageFormats = widget.pageFormats ?? defaultPageFormats;
+      final keys = _pageFormats.keys.toList();
       actions.add(
         DropdownButton<PdfPageFormat>(
           icon: Icon(
@@ -261,8 +273,8 @@ class _PdfPreviewState extends State<PdfPreview> {
           items: List<DropdownMenuItem<PdfPageFormat>>.generate(
             _pageFormats.length,
             (int index) {
-              final String key = keys[index];
-              final PdfPageFormat val = _pageFormats[key];
+              final key = keys[index];
+              final val = _pageFormats[key];
               return DropdownMenuItem<PdfPageFormat>(
                 child: Text(key),
                 value: val,
@@ -280,7 +292,7 @@ class _PdfPreviewState extends State<PdfPreview> {
     }
 
     if (widget.actions != null) {
-      for (final PdfPreviewAction action in widget.actions) {
+      for (final action in widget.actions) {
         actions.add(
           IconButton(
             icon: action.icon,
@@ -338,7 +350,7 @@ class _PdfPreviewState extends State<PdfPreview> {
   }
 
   Future<void> _print() async {
-    final bool result = await Printing.layoutPdf(onLayout: widget.build);
+    final result = await Printing.layoutPdf(onLayout: widget.build);
 
     if (result && widget.onPrinted != null) {
       widget.onPrinted(context);
@@ -349,14 +361,14 @@ class _PdfPreviewState extends State<PdfPreview> {
     // Calculate the widget center for iPad sharing popup position
     final RenderBox referenceBox =
         shareWidget.currentContext.findRenderObject();
-    final Offset topLeft =
+    final topLeft =
         referenceBox.localToGlobal(referenceBox.paintBounds.topLeft);
-    final Offset bottomRight =
+    final bottomRight =
         referenceBox.localToGlobal(referenceBox.paintBounds.bottomRight);
-    final Rect bounds = Rect.fromPoints(topLeft, bottomRight);
+    final bounds = Rect.fromPoints(topLeft, bottomRight);
 
-    final Uint8List bytes = await widget.build(pageFormat);
-    final bool result = await Printing.sharePdf(bytes: bytes, bounds: bounds);
+    final bytes = await widget.build(pageFormat);
+    final result = await Printing.sharePdf(bytes: bytes, bounds: bounds);
 
     if (result && widget.onShared != null) {
       widget.onShared(context);
@@ -374,7 +386,7 @@ class _PdfPreviewPage extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final PdfRasterImage im = PdfRasterImage(page);
+    final im = PdfRasterImage(page);
 
     return Container(
       margin: const EdgeInsets.only(
@@ -410,12 +422,17 @@ typedef OnPdfPreviewActionPressed = void Function(
   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,
   }) : assert(icon != null);
 
+  /// 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.
+ */
+
+/// ignore_for_file: public_member_api_docs
+
 @JS()
 library pdf.js;
 

@@ -20,7 +20,9 @@ import 'dart:typed_data';
 import 'callback.dart';
 import 'raster.dart';
 
+/// Represents a print job to communicate with the platform implementation
 class PrintJob {
+  /// Create a print job
   PrintJob({
     this.onLayout,
     this.onHtmlRendered,
@@ -28,10 +30,18 @@ class PrintJob {
     this.onPageRasterized,
   });
 
+  /// Callback used when calling Printing.layoutPdf()
   final LayoutCallback onLayout;
+
+  /// Callback used when calling Printing.convertHtml()
   final Completer<Uint8List> onHtmlRendered;
+
+  /// Future triggered when the job is done
   final Completer<bool> onCompleted;
+
+  /// Stream of rasterized pages
   final StreamController<PdfRaster> onPageRasterized;
 
+  /// The Job number
   int index;
 }

@@ -36,6 +36,7 @@ import 'callback.dart';
 import 'interface.dart';
 import 'printing_info.dart';
 
+/// Print plugin targetting Flutter on the Web
 class PrintingPlugin extends PrintingPlatform {
   /// Registers this class as the default instance of [PrintingPlugin].
   static void registerWith(Registrar registrar) {
@@ -66,35 +67,34 @@ class PrintingPlugin extends PrintingPlatform {
     String name,
     PdfPageFormat format,
   ) async {
-    final Uint8List result = await onLayout(format);
+    final result = await onLayout(format);
 
     if (result == null || result.isEmpty) {
       return false;
     }
 
-    final bool isChrome = js.context['chrome'] != null;
-    final bool isSafari = js.context['safari'] != null;
+    final isChrome = js.context['chrome'] != null;
+    final isSafari = js.context['safari'] != null;
     // Maybe Firefox 75 will support iframe printing
     // https://bugzilla.mozilla.org/show_bug.cgi?id=911444
 
     if (!isChrome && !isSafari) {
-      final String pr = 'data:application/pdf;base64,${base64.encode(result)}';
+      final pr = 'data:application/pdf;base64,${base64.encode(result)}';
       final html.Window win = js.context['window'];
       win.open(pr, name);
 
       return true;
     }
 
-    final Completer<bool> completer = Completer<bool>();
-    final html.Blob pdfFile = html.Blob(
+    final completer = Completer<bool>();
+    final pdfFile = html.Blob(
       <Uint8List>[Uint8List.fromList(result)],
       'application/pdf',
     );
-    final String pdfUrl = html.Url.createObjectUrl(pdfFile);
+    final pdfUrl = html.Url.createObjectUrl(pdfFile);
     final html.HtmlDocument doc = js.context['document'];
 
-    final html.Element frame =
-        doc.getElementById(_frameId) ?? doc.createElement('iframe');
+    final frame = doc.getElementById(_frameId) ?? doc.createElement('iframe');
     frame.setAttribute(
       'style',
       'visibility: hidden; height: 0; width: 0; position: absolute;',
@@ -126,11 +126,11 @@ class PrintingPlugin extends PrintingPlatform {
     String filename,
     Rect bounds,
   ) async {
-    final html.Blob pdfFile = html.Blob(
+    final pdfFile = html.Blob(
       <Uint8List>[Uint8List.fromList(bytes)],
       'application/pdf',
     );
-    final String pdfUrl = html.Url.createObjectUrl(pdfFile);
+    final pdfUrl = html.Url.createObjectUrl(pdfFile);
     final html.HtmlDocument doc = js.context['document'];
     final html.AnchorElement link = doc.createElement('a');
     link.href = pdfUrl;
@@ -171,23 +171,23 @@ class PrintingPlugin extends PrintingPlatform {
     List<int> pages,
     double dpi,
   ) async* {
-    final PdfJsDocLoader t = PdfJs.getDocument(Settings()..data = document);
+    final t = PdfJs.getDocument(Settings()..data = document);
 
-    final PdfJsDoc d = await promiseToFuture(t.promise);
-    final int numPages = d.numPages;
+    final d = await promiseToFuture<PdfJsDoc>(t.promise);
+    final numPages = d.numPages;
 
     final html.CanvasElement canvas =
         js.context['document'].createElement('canvas');
     final html.CanvasRenderingContext2D context = canvas.getContext('2d');
 
-    for (int i = 0; i < numPages; i++) {
-      final PdfJsPage page = await promiseToFuture(d.getPage(i + 1));
-      final PdfJsViewport viewport = page.getViewport(Settings()..scale = 1.5);
+    for (var i = 0; i < numPages; i++) {
+      final page = await promiseToFuture<PdfJsPage>(d.getPage(i + 1));
+      final viewport = page.getViewport(Settings()..scale = 1.5);
 
       canvas.height = viewport.height.toInt();
       canvas.width = viewport.width.toInt();
 
-      final Settings renderContext = Settings()
+      final renderContext = Settings()
         ..canvasContext = context
         ..viewport = viewport;
 
@@ -197,10 +197,10 @@ class PrintingPlugin extends PrintingPlatform {
       // context.getImageData(0, 0, canvas.width, canvas.height).data;
 
       // Convert the image to PNG
-      final Completer<void> completer = Completer<void>();
-      final html.Blob blob = await canvas.toBlob();
-      final BytesBuilder data = BytesBuilder();
-      final html.FileReader r = FileReader();
+      final completer = Completer<void>();
+      final blob = await canvas.toBlob();
+      final data = BytesBuilder();
+      final r = FileReader();
       r.readAsArrayBuffer(blob);
       r.onLoadEnd.listen(
         (ProgressEvent e) {
@@ -233,7 +233,7 @@ class _WebPdfRaster extends PdfRaster {
   @override
   Uint8List get pixels {
     if (_pixels == null) {
-      final im.Image img = asImage();
+      final img = asImage();
       _pixels = img.data.buffer.asUint8List();
     }
 
@@ -242,7 +242,7 @@ class _WebPdfRaster extends PdfRaster {
 
   @override
   Future<Image> toImage() {
-    final Completer<Image> comp = Completer<Image>();
+    final comp = Completer<Image>();
     decodeImageFromPixels(
       png,
       width,

@@ -44,7 +44,7 @@ class PdfRaster {
 
   /// Decode RGBA raw image to dart:ui Image
   Future<ui.Image> toImage() {
-    final Completer<ui.Image> comp = Completer<ui.Image>();
+    final comp = Completer<ui.Image>();
     ui.decodeImageFromPixels(
       pixels,
       width,
@@ -57,9 +57,8 @@ class PdfRaster {
 
   /// Convert to a PNG image
   Future<Uint8List> toPng() async {
-    final ui.Image image = await toImage();
-    final ByteData data =
-        await image.toByteData(format: ui.ImageByteFormat.png);
+    final image = await toImage();
+    final data = await image.toByteData(format: ui.ImageByteFormat.png);
     return data.buffer.asUint8List();
   }
 
@@ -78,7 +77,7 @@ class PdfRasterImage extends ImageProvider<PdfRaster> {
   final PdfRaster raster;
 
   Future<ImageInfo> _loadAsync() async {
-    final ui.Image uiImage = await raster.toImage();
+    final uiImage = await raster.toImage();
     return ImageInfo(image: uiImage, scale: 1);
   }
 

@@ -15,7 +15,6 @@
  */
 
 import 'dart:async';
-import 'dart:typed_data';
 import 'dart:ui' as ui;
 
 import 'package:flutter/material.dart';
@@ -35,10 +34,9 @@ Future<PdfImage> wrapWidget(
 
   final RenderRepaintBoundary wrappedWidget =
       key.currentContext.findRenderObject();
-  final ui.Image image = await wrappedWidget.toImage(pixelRatio: pixelRatio);
-  final ByteData byteData =
-      await image.toByteData(format: ui.ImageByteFormat.rawRgba);
-  final Uint8List imageData = byteData.buffer.asUint8List();
+  final image = await wrappedWidget.toImage(pixelRatio: pixelRatio);
+  final byteData = await image.toByteData(format: ui.ImageByteFormat.rawRgba);
+  final imageData = byteData.buffer.asUint8List();
   return PdfImage(document,
       image: imageData, width: image.width, height: image.height);
 }

@@ -15,12 +15,10 @@
  */
 
 import 'dart:io';
-import 'dart:typed_data';
 
 import 'package:flutter/services.dart';
 import 'package:flutter/widgets.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:pdf/pdf.dart';
 import 'package:pdf/widgets.dart' as pw;
 import 'package:printing/printing.dart';
 
@@ -28,9 +26,8 @@ pw.Document doc;
 pw.Font ttf;
 
 void main() {
-  final String path =
-      Directory.current.path.split('/').last == 'test' ? '..' : '.';
-  const MethodChannel channel = MethodChannel('net.nfet.printing');
+  final path = Directory.current.path.split('/').last == 'test' ? '..' : '.';
+  const channel = MethodChannel('net.nfet.printing');
   TestWidgetsFlutterBinding.ensureInitialized();
 
   setUp(() {
@@ -49,7 +46,7 @@ void main() {
   });
 
   test('pdfImageFromImageProvider(FileImage)', () async {
-    final PdfImage image = await pdfImageFromImageProvider(
+    final image = await pdfImageFromImageProvider(
         pdf: doc.document, image: FileImage(File('$path/example.png')));
 
     doc.addPage(
@@ -66,14 +63,13 @@ void main() {
   setUpAll(() {
     pw.Document.debug = true;
     pw.RichText.debug = true;
-    final Uint8List fontData =
-        File('$path/../pdf/open-sans.ttf').readAsBytesSync();
+    final fontData = File('$path/../pdf/open-sans.ttf').readAsBytesSync();
     ttf = pw.Font.ttf(fontData.buffer.asByteData());
     doc = pw.Document();
   });
 
   tearDownAll(() {
-    final File file = File('printing.pdf');
+    final file = File('printing.pdf');
     file.writeAsBytesSync(doc.save());
   });
 }

@@ -23,7 +23,7 @@ void main() {
   });
 
   test('PrintingInfo', () async {
-    const PrintingInfo info = PrintingInfo.unavailable;
+    const info = PrintingInfo.unavailable;
     expect(info.canConvertHtml, false);
     expect(info.directPrint, false);
     expect(info.dynamicLayout, false);
@@ -36,7 +36,7 @@ void main() {
   });
 
   test('PrintingInfo.fromMap', () async {
-    final PrintingInfo info = PrintingInfo.fromMap(
+    final info = PrintingInfo.fromMap(
       <dynamic, dynamic>{
         'canPrint': true,
       },

@@ -26,12 +26,12 @@ import 'package:printing/src/interface.dart';
 void main() {
   setUp(() {
     TestWidgetsFlutterBinding.ensureInitialized();
-    final MockPrinting mock = MockPrinting();
+    final mock = MockPrinting();
     PrintingPlatform.instance = mock;
   });
 
   test('info', () async {
-    final PrintingInfo info = await Printing.info();
+    final info = await Printing.info();
     expect(info, null);
   });
 

@@ -27,7 +27,7 @@ void main() {
   });
 
   test('PdfRaster', () async {
-    final PdfRaster raster =
+    final raster =
         PdfRaster(10, 10, Uint8List.fromList(List<int>.filled(10 * 10 * 4, 0)));
     expect(raster.toString(), 'Image 10x10 400 bytes');
     expect(await raster.toImage(), isA<ui.Image>());
@@ -35,7 +35,7 @@ void main() {
   });
 
   testWidgets('PdfRasterImage', (WidgetTester tester) async {
-    final PdfRaster raster =
+    final raster =
         PdfRaster(10, 10, Uint8List.fromList(List<int>.filled(10 * 10 * 4, 0)));
 
     await tester.pumpWidget(Image(image: PdfRasterImage(raster)));