Merge pull request #459 from Leptopoda/feature/dialog_constraints

neon: rework DialogTheme

packages/neon/neon/lib/src/pages/login.dart

@@ -60,7 +60,7 @@ class _LoginPageState extends State<LoginPage> {
       ),
       body: Center(
         child: ConstrainedBox(
-          constraints: Theme.of(context).extension<NeonTheme>()?.tabletLayout ?? const BoxConstraints(),
+          constraints: NeonDialogTheme.of(context).constraints,
           child: Scrollbar(
             interactive: true,
             child: SingleChildScrollView(

packages/neon/neon/lib/src/pages/login_check_account.dart

@@ -56,7 +56,7 @@ class _LoginCheckAccountPageState extends State<LoginCheckAccountPage> {
           child: Padding(
             padding: const EdgeInsets.all(10),
             child: ConstrainedBox(
-              constraints: Theme.of(context).extension<NeonTheme>()?.tabletLayout ?? const BoxConstraints(),
+              constraints: NeonDialogTheme.of(context).constraints,
               child: ResultBuilder.behaviorSubject(
                 stream: bloc.state,
                 builder: (final context, final state) => Column(

packages/neon/neon/lib/src/pages/login_check_server_status.dart

@@ -44,7 +44,7 @@ class _LoginCheckServerStatusPageState extends State<LoginCheckServerStatusPage>
           child: Padding(
             padding: const EdgeInsets.all(10),
             child: ConstrainedBox(
-              constraints: Theme.of(context).extension<NeonTheme>()?.tabletLayout ?? const BoxConstraints(),
+              constraints: NeonDialogTheme.of(context).constraints,
               child: ResultBuilder.behaviorSubject(
                 stream: bloc.state,
                 builder: (final context, final state) => Column(

packages/neon/neon/lib/src/utils/theme.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/material.dart';
 import 'package:meta/meta.dart';
 import 'package:neon/src/utils/hex_color.dart';
+import 'package:neon/src/widgets/dialog.dart';
 import 'package:nextcloud/nextcloud.dart';
 
 @internal
@@ -48,11 +49,7 @@ class AppTheme {
       snackBarTheme: _snackBarTheme,
       dividerTheme: _dividerTheme,
       extensions: [
-        const NeonTheme(
+        const NeonTheme(),
-          tabletLayout: BoxConstraints(
-            maxWidth: 640,
-          ),
-        ),
         ...?appThemes,
       ],
     );
@@ -71,21 +68,27 @@ class AppTheme {
   );
 }
 
+/// Defines the configuration of the overall visual [Theme] for a NeonApp
+/// or a widget subtree within the app.
 @internal
 @immutable
 class NeonTheme extends ThemeExtension<NeonTheme> {
+  /// Create a [NeonTheme] that's used to configure a [Theme].
   const NeonTheme({
-    required this.tabletLayout,
+    this.dialogTheme = const NeonDialogTheme(),
   });
 
-  final BoxConstraints? tabletLayout;
+  /// A theme for customizing the visual properties of [NeonDialog]s.
+  ///
+  /// This is the value returned from [NeonDialogTheme.of].
+  final NeonDialogTheme dialogTheme;
 
   @override
   NeonTheme copyWith({
-    final BoxConstraints? tabletLayout,
+    final NeonDialogTheme? dialogTheme,
   }) =>
       NeonTheme(
-        tabletLayout: tabletLayout ?? this.tabletLayout,
+        dialogTheme: dialogTheme ?? this.dialogTheme,
       );
 
   @override
@@ -94,7 +97,68 @@ class NeonTheme extends ThemeExtension<NeonTheme> {
       return this;
     }
     return NeonTheme(
-      tabletLayout: BoxConstraints.lerp(tabletLayout, other.tabletLayout, t),
+      dialogTheme: NeonDialogTheme.lerp(dialogTheme, other.dialogTheme, t),
     );
   }
 }
+
+/// Defines a theme for [NeonDialog] widgets.
+///
+/// Descendant widgets obtain the current [NeonDialogTheme] object using
+/// `NeonDialogTheme.of(context)`. Instances of [NeonDialogTheme] can be customized with
+/// [NeonDialogTheme.copyWith].
+@immutable
+class NeonDialogTheme {
+  /// Creates a dialog theme that can be used for [NeonTheme.dialogTheme].
+  const NeonDialogTheme({
+    this.constraints = const BoxConstraints(
+      minWidth: 280,
+      maxWidth: 560,
+    ),
+  });
+
+  /// Used to configure the [BoxConstraints] for the [NeonDialog] widget.
+  ///
+  /// This value should also be used on [Dialog.fullscreen] and other similar pages.
+  /// By default it follows the default [m3 dialog specification](https://m3.material.io/components/dialogs/specs).
+  final BoxConstraints constraints;
+
+  /// Creates a copy of this object but with the given fields replaced with the
+  /// new values.
+  NeonDialogTheme copyWith({
+    final BoxConstraints? constraints,
+  }) =>
+      NeonDialogTheme(
+        constraints: constraints ?? this.constraints,
+      );
+
+  /// The data from the closest [NeonDialogTheme] instance given the build context.
+  static NeonDialogTheme of(final BuildContext context) => Theme.of(context).extension<NeonTheme>()!.dialogTheme;
+
+  /// Linearly interpolate between two neon dialog themes.
+  ///
+  /// {@macro dart.ui.shadow.lerp}
+  // ignore: prefer_constructors_over_static_methods
+  static NeonDialogTheme lerp(final NeonDialogTheme a, final NeonDialogTheme b, final double t) {
+    if (identical(a, b)) {
+      return a;
+    }
+    return NeonDialogTheme(
+      constraints: BoxConstraints.lerp(a.constraints, b.constraints, t)!,
+    );
+  }
+
+  @override
+  int get hashCode => constraints.hashCode;
+
+  @override
+  bool operator ==(final Object other) {
+    if (identical(this, other)) {
+      return true;
+    }
+    if (other.runtimeType != runtimeType) {
+      return false;
+    }
+    return other is NeonDialogTheme && other.constraints == constraints;
+  }
+}