Fix pana linting notices

+# 1.3.1
+* Fix pana linting notices
+
 # 1.3.0
 * Add a Flutter like widget system
 

+# 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.
+
+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
+    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 # not yet tested
+    # - 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
+    - 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
+    - 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_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_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_locals
+    - prefer_foreach
+    # - prefer_function_declarations_over_variables # not yet tested
+    - prefer_generic_function_type_aliases
+    - prefer_initializing_formals
+    # - 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_single_quotes
+    - prefer_typing_uninitialized_variables
+    - prefer_void_to_null
+    # - 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_constructors_first
+    - sort_pub_dependencies
+    - sort_unnamed_constructors_first
+    - super_goes_last
+    - 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
+    # - 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

@@ -42,7 +42,7 @@ class PdfCatalog extends PdfObject {
     params["/Pages"] = pdfPageList.ref();
 
     // the Outlines object
-    if (outlines != null && outlines.outlines.length > 0) {
+    if (outlines != null && outlines.outlines.isNotEmpty) {
       params["/Outlines"] = outlines.ref();
     }
 

@@ -56,7 +56,7 @@ class PdfFont extends PdfObject {
   PdfRect stringBounds(String s) {
     var chars = latin1.encode(s);
 
-    if (chars.length == 0) return const PdfRect(0.0, 0.0, 0.0, 0.0);
+    if (chars.isEmpty) return const PdfRect(0.0, 0.0, 0.0, 0.0);
 
     var n = 0;
     var c = chars[n];

@@ -44,16 +44,16 @@ class PdfFormXObject extends PdfXObject {
     final resources = Map<String, PdfStream>();
 
     // fonts
-    if (fonts.length > 0) {
+    if (fonts.isNotEmpty) {
       resources["/Font"] = PdfStream()..putObjectDictionary(fonts);
     }
 
     // Now the XObjects
-    if (xobjects.length > 0) {
+    if (xobjects.isNotEmpty) {
       resources["/XObject"] = PdfStream()..putObjectDictionary(xobjects);
     }
 
-    if (resources.length > 0) {
+    if (resources.isNotEmpty) {
       params["/Resources"] = PdfStream.dictionary(resources);
     }
   }

@@ -32,7 +32,7 @@ class PdfGraphics {
   PdfGraphics(this.page, this.buf);
 
   PdfFont get defaultFont {
-    if (page.pdfDocument.fonts.length == 0) {
+    if (page.pdfDocument.fonts.isEmpty) {
       PdfFont.helvetica(page.pdfDocument);
     }
 
@@ -460,7 +460,7 @@ class PdfGraphics {
           case 'S': // smooth cubic bézier, absolute
             while (points.length >= 4) {
               PdfPoint c1;
-              if ('cCsS'.indexOf(lastAction) >= 0) {
+              if ('cCsS'.contains(lastAction)) {
                 c1 = PdfPoint(lastPoint.x + (lastPoint.x - lastControl.x),
                     lastPoint.y + (lastPoint.y - lastControl.y));
               } else {
@@ -493,7 +493,7 @@ class PdfGraphics {
           case 's': // smooth cubic bézier, relative
             while (points.length >= 4) {
               PdfPoint c1;
-              if ('cCsS'.indexOf(lastAction) >= 0) {
+              if ('cCsS'.contains(lastAction)) {
                 c1 = PdfPoint(lastPoint.x + (lastPoint.x - lastControl.x),
                     lastPoint.y + (lastPoint.y - lastControl.y));
               } else {

@@ -70,7 +70,7 @@ class PdfObject {
   }
 
   void _writeContent(PdfStream os) {
-    if (params.length > 0) {
+    if (params.isNotEmpty) {
       os.putDictionary(params);
       os.putString("\n");
     }

@@ -122,7 +122,7 @@ class PdfOutline extends PdfObject {
     }
 
     // These only valid if we have children
-    if (outlines.length > 0) {
+    if (outlines.isNotEmpty) {
       // the number of the first outline in list
       params["/First"] = outlines[0].ref();
 

@@ -91,7 +91,7 @@ class PdfPage extends PdfObject {
 //        }
 
     // the /Contents pages object
-    if (contents.length > 0) {
+    if (contents.isNotEmpty) {
       if (contents.length == 1) {
         params["/Contents"] = contents[0].ref();
       } else {
@@ -104,12 +104,12 @@ class PdfPage extends PdfObject {
     final resources = Map<String, PdfStream>();
 
     // fonts
-    if (fonts.length > 0) {
+    if (fonts.isNotEmpty) {
       resources["/Font"] = PdfStream()..putObjectDictionary(fonts);
     }
 
     // Now the XObjects
-    if (xObjects.length > 0) {
+    if (xObjects.isNotEmpty) {
       resources["/XObject"] = PdfStream()..putObjectDictionary(xObjects);
     }
 
@@ -121,7 +121,7 @@ class PdfPage extends PdfObject {
     }
 
     // The /Annots object
-    if (annotations.length > 0) {
+    if (annotations.isNotEmpty) {
       params["/Annots"] = PdfStream()..putObjectArray(annotations);
     }
   }

@@ -2,7 +2,7 @@ name: pdf
 author: David PHAM-VAN <dev.nfet.net@gmail.com>
 description: A pdf producer for Dart. It can create pdf files for both web or flutter.
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/pdf
-version: 1.3.0
+version: 1.3.1
 
 environment:
   sdk: ">=1.8.0 <3.0.0"

+# 1.3.1
+* Fix pana linting notices
+
 # 1.3.0
 * Add a Flutter like widget system
 

+# 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.
+
+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
+    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 # not yet tested
+    # - 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
+    - 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
+    - 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_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_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_locals
+    - prefer_foreach
+    # - prefer_function_declarations_over_variables # not yet tested
+    - prefer_generic_function_type_aliases
+    - prefer_initializing_formals
+    # - 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_single_quotes
+    - prefer_typing_uninitialized_variables
+    - prefer_void_to_null
+    # - 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_constructors_first
+    - sort_pub_dependencies
+    - sort_unnamed_constructors_first
+    - super_goes_last
+    - 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
+    # - 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

@@ -2,7 +2,7 @@ name: printing
 author: David PHAM-VAN <dev.nfet.net@gmail.com>
 description: Plugin that allows Flutter apps to generate and print documents to android or ios compatible printers
 homepage: https://github.com/DavBfr/dart_pdf/tree/master/printing
-version: 1.3.0
+version: 1.3.1
 
 environment:
   sdk: ">=1.19.0 <3.0.0"