engine-flutter-autoroll
diff --git a/‎packages/flutter/lib/src/material/tabs.dart‎
Lines changed: 26 additions & 38 deletions b/‎packages/flutter/lib/src/material/tabs.dart‎
Lines changed: 26 additions & 38 deletions
@@ -586,10 +586,27 @@ class _IndicatorPainter extends CustomPainter {
     _painter ??= indicator.createBoxPainter(markNeedsPaint);
 
     final double value = controller.animation!.value;
+    final int to =
+        controller.indexIsChanging
+            ? controller.index
+            : switch (textDirection) {
+              TextDirection.ltr => value.ceil(),
+              TextDirection.rtl => value.floor(),
+            }.clamp(0, maxTabIndex);
+    final int from =
+        controller.indexIsChanging
+            ? controller.previousIndex
+            : switch (textDirection) {
+              TextDirection.ltr => (to - 1),
+              TextDirection.rtl => (to + 1),
+            }.clamp(0, maxTabIndex);
+    final Rect toRect = indicatorRect(size, to);
+    final Rect fromRect = indicatorRect(size, from);
+    _currentRect = Rect.lerp(fromRect, toRect, (value - from).abs());
 
     _currentRect = switch (indicatorAnimation) {
-      TabIndicatorAnimation.linear => _applyLinearEffect(size: size, value: value),
-      TabIndicatorAnimation.elastic => _applyElasticEffect(size: size, value: value),
+      TabIndicatorAnimation.linear => _currentRect,
+      TabIndicatorAnimation.elastic => _applyElasticEffect(fromRect, toRect, _currentRect!),
     };
 
     assert(_currentRect != null);
@@ -611,17 +628,6 @@ class _IndicatorPainter extends CustomPainter {
     _painter!.paint(canvas, _currentRect!.topLeft, configuration);
   }
 
-  /// Applies the linear effect to the indicator.
-  Rect? _applyLinearEffect({required Size size, required double value}) {
-    final double index = controller.index.toDouble();
-    final bool ltr = index > value;
-    final int from = (ltr ? value.floor() : value.ceil()).clamp(0, maxTabIndex);
-    final int to = (ltr ? from + 1 : from - 1).clamp(0, maxTabIndex);
-    final Rect fromRect = indicatorRect(size, from);
-    final Rect toRect = indicatorRect(size, to);
-    return Rect.lerp(fromRect, toRect, (value - from).abs());
-  }
-
   // Ease out sine (decelerating).
   double decelerateInterpolation(double fraction) {
     return math.sin((fraction * math.pi) / 2.0);
@@ -633,38 +639,20 @@ class _IndicatorPainter extends CustomPainter {
   }
 
   /// Applies the elastic effect to the indicator.
-  Rect? _applyElasticEffect({required Size size, required double value}) {
-    final double index = controller.index.toDouble();
-    double progressLeft = (index - value).abs();
-
-    final int to =
-        progressLeft == 0.0 || !controller.indexIsChanging
-            ? switch (textDirection) {
-              TextDirection.ltr => value.ceil(),
-              TextDirection.rtl => value.floor(),
-            }.clamp(0, maxTabIndex)
-            : controller.index;
-    final int from =
-        progressLeft == 0.0 || !controller.indexIsChanging
-            ? switch (textDirection) {
-              TextDirection.ltr => (to - 1),
-              TextDirection.rtl => (to + 1),
-            }.clamp(0, maxTabIndex)
-            : controller.previousIndex;
-    final Rect toRect = indicatorRect(size, to);
-    final Rect fromRect = indicatorRect(size, from);
-    final Rect rect = Rect.lerp(fromRect, toRect, (value - from).abs())!;
-
+  Rect _applyElasticEffect(Rect fromRect, Rect toRect, Rect currentRect) {
     // If the tab animation is completed, there is no need to stretch the indicator
     // This only works for the tab change animation via tab index, not when
     // dragging a [TabBarView], but it's still ok, to avoid unnecessary calculations.
     if (controller.animation!.isCompleted) {
-      return rect;
+      return currentRect;
     }
 
+    final double index = controller.index.toDouble();
+    final double value = controller.animation!.value;
     final double tabChangeProgress;
 
     if (controller.indexIsChanging) {
+      double progressLeft = (index - value).abs();
       final int tabsDelta = (controller.index - controller.previousIndex).abs();
       if (tabsDelta != 0) {
         progressLeft /= tabsDelta;
@@ -676,7 +664,7 @@ class _IndicatorPainter extends CustomPainter {
 
     // If the animation has finished, there is no need to apply the stretch effect.
     if (tabChangeProgress == 1.0) {
-      return rect;
+      return currentRect;
     }
 
     final double leftFraction;
@@ -713,7 +701,7 @@ class _IndicatorPainter extends CustomPainter {
       };
     }
 
-    return Rect.fromLTRB(lerpRectLeft, rect.top, lerpRectRight, rect.bottom);
+    return Rect.fromLTRB(lerpRectLeft, currentRect.top, lerpRectRight, currentRect.bottom);
   }
 
   @override