Apply Desktop specs for Tooltip (#68681)

packages/flutter/lib/src/material/tooltip.dart

@@ -170,10 +170,8 @@ class Tooltip extends StatefulWidget {
 }
 
 class _TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
-  static const double _defaultTooltipHeight = 32.0;
   static const double _defaultVerticalOffset = 24.0;
   static const bool _defaultPreferBelow = true;
-  static const EdgeInsetsGeometry _defaultPadding = EdgeInsets.symmetric(horizontal: 16.0);
   static const EdgeInsetsGeometry _defaultMargin = EdgeInsets.all(0.0);
   static const Duration _fadeInDuration = Duration(milliseconds: 150);
   static const Duration _fadeOutDuration = Duration(milliseconds: 75);
@@ -215,6 +213,43 @@ class _TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
     GestureBinding.instance!.pointerRouter.addGlobalRoute(_handlePointerEvent);
   }
 
+  // https://material.io/components/tooltips#specs
+  double _getDefaultTooltipHeight() {
+    final ThemeData theme = Theme.of(context)!;
+    switch (theme.platform) {
+      case TargetPlatform.macOS:
+      case TargetPlatform.linux:
+      case TargetPlatform.windows:
+        return 24.0;
+      default:
+        return 32.0;
+    }
+  }
+
+  EdgeInsets _getDefaultPadding() {
+    final ThemeData theme = Theme.of(context)!;
+    switch (theme.platform) {
+      case TargetPlatform.macOS:
+      case TargetPlatform.linux:
+      case TargetPlatform.windows:
+        return const EdgeInsets.symmetric(horizontal: 8.0);
+      default:
+        return const EdgeInsets.symmetric(horizontal: 16.0);
+    }
+  }
+
+  double _getDefaultFontSize() {
+    final ThemeData theme = Theme.of(context)!;
+    switch (theme.platform) {
+      case TargetPlatform.macOS:
+      case TargetPlatform.linux:
+      case TargetPlatform.windows:
+        return 10.0;
+      default:
+        return 14.0;
+    }
+  }
+
   // Forces a rebuild if a mouse has been added or removed.
   void _handleMouseTrackerChange() {
     if (!mounted) {
@@ -375,6 +410,7 @@ class _TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
     if (theme.brightness == Brightness.dark) {
       defaultTextStyle = theme.textTheme.bodyText2!.copyWith(
         color: Colors.black,
+        fontSize: _getDefaultFontSize(),
       );
       defaultDecoration = BoxDecoration(
         color: Colors.white.withOpacity(0.9),
@@ -383,6 +419,7 @@ class _TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
     } else {
       defaultTextStyle = theme.textTheme.bodyText2!.copyWith(
         color: Colors.white,
+        fontSize: _getDefaultFontSize(),
       );
       defaultDecoration = BoxDecoration(
         color: Colors.grey[700]!.withOpacity(0.9),
@@ -390,8 +427,8 @@ class _TooltipState extends State<Tooltip> with SingleTickerProviderStateMixin {
       );
     }
 
-    height = widget.height ?? tooltipTheme.height ?? _defaultTooltipHeight;
+    height = widget.height ?? tooltipTheme.height ?? _getDefaultTooltipHeight();
-    padding = widget.padding ?? tooltipTheme.padding ?? _defaultPadding;
+    padding = widget.padding ?? tooltipTheme.padding ?? _getDefaultPadding();
     margin = widget.margin ?? tooltipTheme.margin ?? _defaultMargin;
     verticalOffset = widget.verticalOffset ?? tooltipTheme.verticalOffset ?? _defaultVerticalOffset;
     preferBelow = widget.preferBelow ?? tooltipTheme.preferBelow ?? _defaultPreferBelow;

packages/flutter/test/material/tooltip_test.dart

@@ -741,6 +741,38 @@ void main() {
     ));
   });
 
+  testWidgets('Tooltip default size, shape, and color test for Desktop', (WidgetTester tester) async {
+    // Regressing test for https://github.com/flutter/flutter/issues/68601
+    final GlobalKey key = GlobalKey();
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Tooltip(
+          key: key,
+          message: tooltipText,
+          child: const SizedBox(
+            width: 0.0,
+            height: 0.0,
+          ),
+        ),
+      ),
+    );
+    (key.currentState as dynamic).ensureTooltipVisible();
+    await tester.pump(const Duration(seconds: 2)); // faded in, show timer started (and at 0.0)
+
+    final RenderParagraph tooltipRenderParagraph = tester.renderObject<RenderParagraph>(find.text(tooltipText));
+    expect(tooltipRenderParagraph.textSize.height, equals(10.0));
+
+    final RenderBox tip = tester.renderObject(
+      _findTooltipContainer(tooltipText),
+    );
+    expect(tip.size.height, equals(24.0));
+    expect(tip.size.width, equals(46.0));
+    expect(tip, paints..rrect(
+      rrect: RRect.fromRectAndRadius(tip.paintBounds, const Radius.circular(4.0)),
+      color: const Color(0xe6616161),
+    ));
+  }, variant: const TargetPlatformVariant(<TargetPlatform>{TargetPlatform.macOS, TargetPlatform.linux, TargetPlatform.windows}));
+
   testWidgets('Can tooltip decoration be customized', (WidgetTester tester) async {
     final GlobalKey key = GlobalKey();
     const Decoration customDecoration = ShapeDecoration(