From 206767161c01f18e9aeac53dca66e138017c1fdc Mon Sep 17 00:00:00 2001
From: Maik Wild <mail@maikwild.de>
Date: Fri, 30 Jan 2026 11:43:02 +0200
Subject: [PATCH 1/2] Introduce TextScaler test to reproduce #174828

---
 .../test/painting/text_scaler_test.dart       | 72 +++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/packages/flutter/test/painting/text_scaler_test.dart b/packages/flutter/test/painting/text_scaler_test.dart
index 8d9a1046bda35..fdea871d6dde4 100644
--- a/packages/flutter/test/painting/text_scaler_test.dart
+++ b/packages/flutter/test/painting/text_scaler_test.dart
@@ -57,5 +57,77 @@ void main() {
       expect(scaler1, scaler3);
       expect(scaler1, isNot(scaler2));
     });
+
+    testWidgets('Reclamping', (WidgetTester tester) async {
+      final TextScaler defaultScaler = MediaQueryData.fromView(tester.view).textScaler;
+
+      // Does not raise maxScale > minScale
+      final TextScaler scaler1 = defaultScaler.clamp(minScaleFactor: 1, maxScaleFactor: 1.5);
+      final TextScaler scaler2 = scaler1.clamp(minScaleFactor: 0.5, maxScaleFactor: 1);
+      expect(scaler2, TextScaler.noScaling);
+
+      // No overlap, first scaler < second scaler. uses new minScale of last clamp
+      final TextScaler scaler3 = defaultScaler.clamp(minScaleFactor: 1, maxScaleFactor: 2);
+      final TextScaler scaler4 = scaler3.clamp(minScaleFactor: 3, maxScaleFactor: 4);
+      expect(scaler4, const TextScaler.linear(3));
+
+      // No overlap, first scaler > second scaler. uses new maxScale of last clamp
+      final TextScaler scaler5 = defaultScaler.clamp(minScaleFactor: 5, maxScaleFactor: 6);
+      final TextScaler scaler6 = scaler5.clamp(minScaleFactor: 3, maxScaleFactor: 4);
+      expect(scaler6, const TextScaler.linear(4));
+
+      // Overlap, combine clamps
+      final TextScaler scaler7 = defaultScaler.clamp(minScaleFactor: 1, maxScaleFactor: 3);
+      final TextScaler scaler8 = scaler7.clamp(minScaleFactor: 2, maxScaleFactor: 4);
+      expect(scaler8, defaultScaler.clamp(minScaleFactor: 2, maxScaleFactor: 3));
+    });
+  });
+
+  testWidgets('ClampedScaler asserts', (WidgetTester tester) async {
+    final TextScaler defaultScaler = MediaQueryData.fromView(tester.view).textScaler;
+    final TextScaler clampedScaler = defaultScaler.clamp(minScaleFactor: 1, maxScaleFactor: 5);
+    expect(
+      () => clampedScaler.clamp(minScaleFactor: 3, maxScaleFactor: 2),
+      throwsA(
+        isA<AssertionError>().having(
+          (AssertionError error) => error.toString(),
+          'message',
+          contains('maxScaleFactor >= minScaleFactor'),
+        ),
+      ),
+    );
+
+    expect(
+      () => clampedScaler.clamp(minScaleFactor: 3, maxScaleFactor: double.nan),
+      throwsA(
+        isA<AssertionError>().having(
+          (AssertionError error) => error.toString(),
+          'message',
+          contains('maxScaleFactor >= minScaleFactor'),
+        ),
+      ),
+    );
+
+    expect(
+      () => clampedScaler.clamp(minScaleFactor: -1, maxScaleFactor: 2),
+      throwsA(
+        isA<AssertionError>().having(
+          (AssertionError error) => error.toString(),
+          'message',
+          contains('minScaleFactor >= 0'),
+        ),
+      ),
+    );
+
+    expect(
+      () => clampedScaler.clamp(minScaleFactor: double.infinity),
+      throwsA(
+        isA<AssertionError>().having(
+          (AssertionError error) => error.toString(),
+          'message',
+          contains('minScaleFactor.isFinite'),
+        ),
+      ),
+    );
   });
 }

From 93a455f039fe1cdbd0130bb8304f94129100b954 Mon Sep 17 00:00:00 2001
From: Maik Wild <mail@maikwild.de>
Date: Thu, 19 Feb 2026 23:03:22 +0100
Subject: [PATCH 2/2] ClampedTextScaler: Fix error when applying multiple
 clamps

This fixes #174828
---
 .../flutter/lib/src/painting/text_scaler.dart    | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/packages/flutter/lib/src/painting/text_scaler.dart b/packages/flutter/lib/src/painting/text_scaler.dart
index 6b537c753eb41..8cfc00b18f6f1 100644
--- a/packages/flutter/lib/src/painting/text_scaler.dart
+++ b/packages/flutter/lib/src/painting/text_scaler.dart
@@ -132,9 +132,19 @@ final class _ClampedTextScaler implements TextScaler {
 
   @override
   TextScaler clamp({double minScaleFactor = 0, double maxScaleFactor = double.infinity}) {
-    return minScaleFactor == maxScaleFactor
-        ? _LinearTextScaler(minScaleFactor)
-        : _ClampedTextScaler(scaler, max(minScaleFactor, minScale), min(maxScaleFactor, maxScale));
+    assert(maxScaleFactor >= minScaleFactor);
+    assert(!maxScaleFactor.isNaN);
+    assert(minScaleFactor.isFinite);
+    assert(minScaleFactor >= 0);
+
+    final double newMinScale = max(minScale, minScaleFactor);
+    final double newMaxScale = min(maxScale, maxScaleFactor);
+
+    if (newMaxScale <= newMinScale) {
+      // Ranges don't overlap or collapse to a single point.
+      return TextScaler.linear(clampDouble(minScale, minScaleFactor, maxScaleFactor));
+    }
+    return _ClampedTextScaler(scaler, newMinScale, newMaxScale);
   }
 
   @override