fix(ui): draw the split button's divider on every surface

apps/design_system_gallery/lib/components/buttons/split_button.dart

@@ -17,20 +17,12 @@ import 'package:widgetbook_annotation/widgetbook_annotation.dart' as widgetbook;
 Widget buildStreamSplitButtonPlayground(BuildContext context) {
   final icons = context.streamIcons;
 
-  final style = context.knobs.object.dropdown(
-    label: 'Style',
-    options: StreamButtonStyle.values,
-    initialOption: StreamButtonStyle.secondary,
+  final variant = context.knobs.object.dropdown(
+    label: 'Variant',
+    options: StreamSplitButtonVariant.values,
+    initialOption: StreamSplitButtonVariant.regular,
     labelBuilder: (option) => option.name,
-    description: 'Split button visual style variant.',
-  );
-
-  final type = context.knobs.object.dropdown(
-    label: 'Type',
-    options: StreamButtonType.values,
-    initialOption: StreamButtonType.solid,
-    labelBuilder: (option) => option.name,
-    description: 'Split button type variant. Outline draws one border around both halves.',
+    description: 'Split button color scheme variant.',
   );
 
   final caretUp = context.knobs.boolean(
@@ -59,13 +51,12 @@ Widget buildStreamSplitButtonPlayground(BuildContext context) {
     child: _MaybeBadged(
       showErrorBadge: showErrorBadge,
       child: StreamSplitButton.icon(
-        icon: Icon(icons.voiceFill),
+        leadingIcon: Icon(icons.voiceFill),
         trailingIcon: Icon(caretUp ? icons.caretUp : icons.caretDown),
-        style: style,
-        type: type,
-        tooltip: 'Mute',
+        variant: variant,
+        leadingTooltip: 'Mute',
         trailingTooltip: 'Audio settings',
-        onPressed: leadingEnabled ? () {} : null,
+        onLeadingPressed: leadingEnabled ? () {} : null,
         onTrailingPressed: trailingEnabled ? () {} : null,
       ),
     ),
@@ -94,7 +85,7 @@ Widget buildStreamSplitButtonShowcase(BuildContext context) {
         crossAxisAlignment: CrossAxisAlignment.start,
         spacing: spacing.xl,
         children: const [
-          _StyleTypeMatrixSection(),
+          _VariantSection(),
           _DisabledSection(),
           _CallControlSection(),
         ],
@@ -103,37 +94,35 @@ Widget buildStreamSplitButtonShowcase(BuildContext context) {
   );
 }
 
-class _StyleTypeMatrixSection extends StatelessWidget {
-  const _StyleTypeMatrixSection();
+class _VariantSection extends StatelessWidget {
+  const _VariantSection();
 
   @override
   Widget build(BuildContext context) {
     final icons = context.streamIcons;
     final spacing = context.streamSpacing;
 
     return _ExampleCard(
-      title: 'Style × type',
+      title: 'Variants',
       description: 'The surface resolves from the same button style the halves use, so the two never drift apart.',
       child: Column(
         crossAxisAlignment: CrossAxisAlignment.start,
         spacing: spacing.md,
         children: [
-          for (final style in StreamButtonStyle.values)
+          for (final variant in StreamSplitButtonVariant.values)
             Row(
               spacing: spacing.md,
               children: [
-                SizedBox(width: 88, child: Text(style.name)),
-                for (final type in StreamButtonType.values)
-                  StreamSplitButton.icon(
-                    icon: Icon(icons.voiceFill),
-                    trailingIcon: Icon(icons.caretDown),
-                    style: style,
-                    type: type,
-                    tooltip: 'Mute',
-                    trailingTooltip: 'Audio settings',
-                    onPressed: () {},
-                    onTrailingPressed: () {},
-                  ),
+                SizedBox(width: 88, child: Text(variant.name)),
+                StreamSplitButton.icon(
+                  leadingIcon: Icon(icons.voiceFill),
+                  trailingIcon: Icon(icons.caretDown),
+                  variant: variant,
+                  leadingTooltip: 'Mute',
+                  trailingTooltip: 'Audio settings',
+                  onLeadingPressed: () {},
+                  onTrailingPressed: () {},
+                ),
               ],
             ),
         ],
@@ -165,10 +154,9 @@ class _DisabledSection extends StatelessWidget {
               spacing: spacing.xs,
               children: [
                 StreamSplitButton.icon(
-                  icon: Icon(icons.voiceFill),
+                  leadingIcon: Icon(icons.voiceFill),
                   trailingIcon: Icon(icons.caretDown),
-                  style: StreamButtonStyle.secondary,
-                  onPressed: leading ? () {} : null,
+                  onLeadingPressed: leading ? () {} : null,
                   onTrailingPressed: trailing ? () {} : null,
                 ),
                 Text(label),
@@ -204,12 +192,12 @@ class _CallControlSectionState extends State<_CallControlSection> {
         child: _MaybeBadged(
           showErrorBadge: true,
           child: StreamSplitButton.icon(
-            icon: Icon(_isMuted ? icons.voiceOffFill : icons.voiceFill),
+            leadingIcon: Icon(_isMuted ? icons.voiceOffFill : icons.voiceFill),
             trailingIcon: Icon(_isSettingsOpen ? icons.caretUp : icons.caretDown),
-            style: _isMuted ? StreamButtonStyle.destructive : StreamButtonStyle.secondary,
-            tooltip: _isMuted ? 'Unmute' : 'Mute',
+            variant: _isMuted ? StreamSplitButtonVariant.destructive : StreamSplitButtonVariant.regular,
+            leadingTooltip: _isMuted ? 'Unmute' : 'Mute',
             trailingTooltip: 'Audio settings',
-            onPressed: () => setState(() => _isMuted = !_isMuted),
+            onLeadingPressed: () => setState(() => _isMuted = !_isMuted),
             onTrailingPressed: () => setState(() => _isSettingsOpen = !_isSettingsOpen),
           ),
         ),

packages/stream_core_flutter/CHANGELOG.md

@@ -4,7 +4,10 @@
 
 - Added `StreamColorScheme.backgroundOverlayDarkStrong`, the design system's `background/core/overlay-dark-strong` token. A heavier version of `backgroundOverlayDark`, for content that has to stay legible on top of arbitrary imagery or video.
 - Added `StreamReactions.onReactionLongPressed`, reporting the long-pressed `StreamReactionsItem` — or `null` for the cluster/overflow chip. When null, the chips register no long-press gesture, leaving it to an ancestor.
-- Added `StreamSplitButton`.
+- Added `StreamSplitButton`, in the two variants the design covers —
+  `StreamSplitButtonVariant.regular` and `.destructive`. Each variant carries
+  its own `StreamSplitButtonStyle` on `StreamSplitButtonThemeData`, so the two
+  can be themed independently.
 - Refreshed the icon set from the design tokens and added 44 icons, including a
   filled variant for many existing icons: `blurFill`, `boltFill`,
   `cameraFlipFill`, `captionFill`, `caretDown`, `caretUp`, `copyFill`,