chore: more upgrades for channel_header_theme.dart

* Renamed:
  * title -> titleStyle
  * subtitle -> subtitleStyle
* Added
  * ==
  * hashcode
  * debugFillProperties
  * lerp

packages/stream_chat_flutter/lib/src/channel_header.dart

@@ -169,7 +169,7 @@ class ChannelHeader extends StatelessWidget implements PreferredSizeWidget {
                     title ??
                         ChannelName(
                           textStyle: chatThemeData
-                              .channelTheme.channelHeaderTheme.title,
+                              .channelTheme.channelHeaderTheme.titleStyle,
                         ),
                     const SizedBox(height: 2),
                     subtitle ??
@@ -177,7 +177,7 @@ class ChannelHeader extends StatelessWidget implements PreferredSizeWidget {
                           showTypingIndicator: showTypingIndicator,
                           channel: channel,
                           textStyle: chatThemeData
-                              .channelTheme.channelHeaderTheme.subtitle,
+                              .channelTheme.channelHeaderTheme.subtitleStyle,
                         ),
                   ],
                 ),

packages/stream_chat_flutter/lib/src/channel_info.dart

@@ -64,7 +64,7 @@ class ChannelInfo extends StatelessWidget {
         style: StreamChatTheme.of(context)
             .channelTheme
             .channelHeaderTheme
-            .subtitle,
+            .subtitleStyle,
       );
     } else {
       final userId = StreamChat.of(context).currentUser?.id;

packages/stream_chat_flutter/lib/src/message_list_view.dart

@@ -628,7 +628,7 @@ class _MessageListViewState extends State<MessageListView> {
         child: Text(
           '$replyCount ${replyCount == 1 ? 'Reply' : 'Replies'}',
           textAlign: TextAlign.center,
-          style: _streamTheme.channelTheme.channelHeaderTheme.subtitle,
+          style: _streamTheme.channelTheme.channelHeaderTheme.subtitleStyle,
         ),
       ),
     );

packages/stream_chat_flutter/lib/src/stream_chat_theme.dart

@@ -288,8 +288,8 @@ class StreamChatThemeData {
           ),
         ),
         color: colorTheme.barsBg,
-        title: textTheme.headlineBold,
+        titleStyle: textTheme.headlineBold,
-        subtitle: textTheme.footnote.copyWith(
+        subtitleStyle: textTheme.footnote.copyWith(
           color: const Color(0xff7A7A7A),
         ),
       ),

packages/stream_chat_flutter/lib/src/theme/channel_header_theme.dart

@@ -2,6 +2,7 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:stream_chat_flutter/src/stream_chat_theme.dart';
 import 'package:stream_chat_flutter/src/theme/avatar_theme.dart';
+import 'package:stream_chat_flutter/src/theme/themes.dart';
 
 /// Overrides the default style of [ChannelHeader] descendants.
 ///
@@ -59,17 +60,17 @@ class ChannelHeaderTheme extends InheritedTheme {
 class ChannelHeaderThemeData with Diagnosticable {
   /// Creates a [ChannelHeaderThemeData]
   const ChannelHeaderThemeData({
-    this.title,
+    this.titleStyle,
-    this.subtitle,
+    this.subtitleStyle,
     this.avatarTheme,
     this.color,
   });
 
   /// Theme for title
-  final TextStyle? title;
+  final TextStyle? titleStyle;
 
   /// Theme for subtitle
-  final TextStyle? subtitle;
+  final TextStyle? subtitleStyle;
 
   /// Theme for avatar
   final AvatarThemeData? avatarTheme;
@@ -79,26 +80,70 @@ class ChannelHeaderThemeData with Diagnosticable {
 
   /// Copy with theme
   ChannelHeaderThemeData copyWith({
-    TextStyle? title,
+    TextStyle? titleStyle,
-    TextStyle? subtitle,
+    TextStyle? subtitleStyle,
     AvatarThemeData? avatarTheme,
     Color? color,
   }) =>
       ChannelHeaderThemeData(
-        title: title ?? this.title,
+        titleStyle: titleStyle ?? this.titleStyle,
-        subtitle: subtitle ?? this.subtitle,
+        subtitleStyle: subtitleStyle ?? this.subtitleStyle,
         avatarTheme: avatarTheme ?? this.avatarTheme,
         color: color ?? this.color,
       );
 
+  /// Linearly interpolate between two [ChannelHeaderThemeData].
+  ///
+  /// All the properties must be non-null.
+  ChannelHeaderThemeData lerp(
+    ChannelHeaderThemeData a,
+    ChannelHeaderThemeData b,
+    double t,
+  ) =>
+      ChannelHeaderThemeData(
+        titleStyle: TextStyle.lerp(a.titleStyle, b.titleStyle, t),
+        subtitleStyle: TextStyle.lerp(a.subtitleStyle, b.subtitleStyle, t),
+        avatarTheme:
+            const AvatarThemeData().lerp(a.avatarTheme!, b.avatarTheme!, t),
+        color: Color.lerp(a.color, b.color, t),
+      );
+
   /// Merge with other [ChannelHeaderThemeData]
   ChannelHeaderThemeData merge(ChannelHeaderThemeData? other) {
     if (other == null) return this;
     return copyWith(
-      title: title?.merge(other.title) ?? other.title,
+      titleStyle: titleStyle?.merge(other.titleStyle) ?? other.titleStyle,
-      subtitle: subtitle?.merge(other.subtitle) ?? other.subtitle,
+      subtitleStyle:
+          subtitleStyle?.merge(other.subtitleStyle) ?? other.subtitleStyle,
       avatarTheme: avatarTheme?.merge(other.avatarTheme) ?? other.avatarTheme,
       color: other.color,
     );
   }
+
+  @override
+  bool operator ==(Object other) =>
+      identical(this, other) ||
+      other is ChannelHeaderThemeData &&
+          runtimeType == other.runtimeType &&
+          titleStyle == other.titleStyle &&
+          subtitleStyle == other.subtitleStyle &&
+          avatarTheme == other.avatarTheme &&
+          color == other.color;
+
+  @override
+  int get hashCode =>
+      titleStyle.hashCode ^
+      subtitleStyle.hashCode ^
+      avatarTheme.hashCode ^
+      color.hashCode;
+
+  @override
+  void debugFillProperties(DiagnosticPropertiesBuilder properties) {
+    super.debugFillProperties(properties);
+    properties
+      ..add(DiagnosticsProperty('title', titleStyle))
+      ..add(DiagnosticsProperty('subtitle', subtitleStyle))
+      ..add(DiagnosticsProperty('avatarTheme', avatarTheme))
+      ..add(ColorProperty('color', color));
+  }
 }

packages/stream_chat_flutter/lib/src/theme/gallery_header_theme.dart

@@ -86,7 +86,7 @@ class GalleryHeaderThemeData with Diagnosticable {
 
   /// The [TextStyle] to use for the [GalleryHeader] subtitle text.
   ///
-  /// Defaults to [ChannelPreviewTheme.subtitle].
+  /// Defaults to [ChannelPreviewTheme.subtitleStyle].
   final TextStyle? subtitleTextStyle;
 
   ///

packages/stream_chat_flutter/lib/src/thread_header.dart

@@ -112,12 +112,12 @@ class ThreadHeader extends StatelessWidget implements PreferredSizeWidget {
           children: [
             Text(
               'with ',
-              style: chatThemeData.channelTheme.channelHeaderTheme.subtitle,
+              style: chatThemeData.channelTheme.channelHeaderTheme.subtitleStyle,
             ),
             Flexible(
               child: ChannelName(
                 textStyle:
-                    chatThemeData.channelTheme.channelHeaderTheme.subtitle,
+                    chatThemeData.channelTheme.channelHeaderTheme.subtitleStyle,
               ),
             ),
           ],
@@ -150,14 +150,14 @@ class ThreadHeader extends StatelessWidget implements PreferredSizeWidget {
               title ??
                   Text(
                     'Thread Reply',
-                    style: chatThemeData.channelTheme.channelHeaderTheme.title,
+                    style: chatThemeData.channelTheme.channelHeaderTheme.titleStyle,
                   ),
               const SizedBox(height: 2),
               if (showTypingIndicator)
                 TypingIndicator(
                   alignment: Alignment.center,
                   channel: StreamChannel.of(context).channel,
-                  style: chatThemeData.channelTheme.channelHeaderTheme.subtitle,
+                  style: chatThemeData.channelTheme.channelHeaderTheme.subtitleStyle,
                   parentId: parent.id,
                   alternativeWidget: defaultSubtitle,
                 )