fix: left handle scroll direction on iOS/Android (#1185)

* fix: correct auto-scroll direction for left selection handle drag on iOS

When dragging the left selection handle upward, the proxy rect used for
auto-scroll detection was built with offset & Size(1, edgeOffset), which
extends 220px downward from the selection start. This caused the bottom
of the rect to exceed the viewport bottom, triggering a downward scroll
(showing content below) — the opposite of the intended direction.

Fix by using Rect.fromLTWH(offset.dx, offset.dy - edgeOffset, 1, edgeOffset)
so the proxy rect extends upward, only triggering scroll-up when the
handle approaches the top edge of the viewport.

* chore: update iOS minimum deployment target to 13.0

* test: add auto_scroller proxy rect direction tests

Adds regression tests for the left selection handle auto-scroll bug
where the proxy rect incorrectly extended downward, triggering scroll
in the wrong direction. Verifies the rect extends upward from the
handle offset when direction is AxisDirection.up.

* fix: remove unused import in auto_scroller_test

* chore: code review

example/ios/Flutter/AppFrameworkInfo.plist

@@ -21,6 +21,6 @@
   <key>CFBundleVersion</key>
   <string>1.0</string>
   <key>MinimumOSVersion</key>
-  <string>12.0</string>
+  <string>13.0</string>
 </dict>
 </plist>

example/ios/Podfile

@@ -1,5 +1,5 @@
 # Uncomment this line to define a global platform for your project
-platform :ios, '12.0'
+platform :ios, '13.0'
 
 # CocoaPods analytics sends network stats synchronously affecting flutter build latency.
 ENV['COCOAPODS_DISABLE_STATS'] = 'true'

example/ios/Runner.xcodeproj/project.pbxproj

@@ -342,7 +342,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
 				SUPPORTED_PLATFORMS = iphoneos;
@@ -420,7 +420,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
 				MTL_ENABLE_DEBUG_INFO = YES;
 				ONLY_ACTIVE_ARCH = YES;
 				SDKROOT = iphoneos;
@@ -469,7 +469,7 @@
 				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
 				GCC_WARN_UNUSED_FUNCTION = YES;
 				GCC_WARN_UNUSED_VARIABLE = YES;
-				IPHONEOS_DEPLOYMENT_TARGET = 12.0;
+				IPHONEOS_DEPLOYMENT_TARGET = 13.0;
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = iphoneos;
 				SUPPORTED_PLATFORMS = iphoneos;

example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme

@@ -26,6 +26,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      customLLDBInitFile = "$(SRCROOT)/Flutter/ephemeral/flutter_lldbinit"
       shouldUseLaunchSchemeArgsEnv = "YES">
       <MacroExpansion>
          <BuildableReference
@@ -43,6 +44,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      customLLDBInitFile = "$(SRCROOT)/Flutter/ephemeral/flutter_lldbinit"
       launchStyle = "0"
       useCustomWorkingDirectory = "NO"
       ignoresPersistentStateOnLaunch = "NO"

lib/src/editor/editor_component/service/scroll/auto_scroller.dart

@@ -45,7 +45,7 @@ class AutoScroller extends EdgeDraggingAutoScroller
     lastDirection = direction;
     if (direction != null && direction == AxisDirection.up) {
       return startAutoScrollIfNecessary(
-        offset & Size(1, edgeOffset),
+        Rect.fromLTWH(offset.dx, offset.dy - edgeOffset, 1, edgeOffset),
         duration: duration,
       );
     }

test/editor/editor_component/service/auto_scroller_test.dart

@@ -1,38 +1,135 @@
+import 'package:appflowy_editor/src/editor/editor_component/service/scroll/auto_scroller.dart';
+import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 
-// @LucasXu0 refactor this test
+/// Captures the rect passed to [startAutoScrollIfNecessary] without triggering
+/// real scrolling, so we can assert on the proxy rect computation.
+class _CapturingAutoScroller extends AutoScroller {
+  _CapturingAutoScroller(super.scrollable);
+
+  Rect? capturedRect;
+
+  @override
+  void startAutoScrollIfNecessary(Rect dragTarget, {Duration? duration}) {
+    capturedRect = dragTarget;
+    // intentionally do not call super — we only want the rect
+  }
+}
 
 void main() {
-  group('AutoScroller', () {
+  group('AutoScroller.startAutoScroll', () {
-    testWidgets('can render', (tester) async {
+    late ScrollableState scrollableState;
-      // late AutoScroller scroller;
 
-      // await tester.buildAndPump(
+    setUp(() async {});
-      //   AutoScrollableWidget(
-      //     scrollController: ScrollController(),
-      //     builder: (context, autoScroller) {
-      //       scroller = autoScroller;
 
-      //       return const SizedBox(width: 600, height: 600);
+    /// Builds a minimal scrollable so we can obtain a real [ScrollableState].
-      //     },
+    Future<void> buildScrollable(WidgetTester tester) async {
-      //   ),
+      await tester.pumpWidget(
-      // );
+        const MaterialApp(
+          home: SingleChildScrollView(
+            child: SizedBox(height: 2000),
+          ),
+        ),
+      );
+      await tester.pumpAndSettle();
+      scrollableState =
+          tester.state<ScrollableState>(find.byType(Scrollable).first);
+    }
 
-      // await tester.pumpAndSettle();
+    // Regression test for:
+    // When dragging the left selection handle upward on iOS/Android, the screen
+    // was scrolling DOWN (showing content below) instead of UP (showing content
+    // above). The root cause was that the proxy rect used for auto-scroll
+    // detection extended 220px DOWNWARD from the selection start, so when the
+    // handle was in the lower portion of the viewport the rect's bottom exceeded
+    // the viewport edge and triggered a downward scroll.
+    testWidgets(
+      'left handle drag (AxisDirection.up) — proxy rect extends upward from offset',
+      (tester) async {
+        await buildScrollable(tester);
 
-      // expect(scroller.scrolling, false);
+        final scroller = _CapturingAutoScroller(scrollableState);
-      // expect(scroller.lastOffset, null);
+        const offset = Offset(100, 500);
+        const edgeOffset = 200.0;
 
-      // scroller.startAutoScroll(const Offset(10, 0));
+        scroller.startAutoScroll(
-      // expect(scroller.lastOffset, const Offset(10, 0));
+          offset,
+          edgeOffset: edgeOffset,
+          direction: AxisDirection.up,
+        );
 
-      // scroller.stopAutoScroll();
+        expect(scroller.capturedRect, isNotNull);
-      // expect(scroller.lastOffset, null);
 
-      // scroller.startAutoScroll(
+        // Rect must extend UPWARD: top = offset.dy - edgeOffset, bottom = offset.dy
-      //   const Offset(10, 0),
+        expect(
-      //   direction: AxisDirection.up,
+          scroller.capturedRect!.top,
-      // );
+          offset.dy - edgeOffset,
-    });
+          reason: 'proxy rect should start edgeOffset pixels ABOVE the handle',
+        );
+        expect(
+          scroller.capturedRect!.bottom,
+          offset.dy,
+          reason:
+              'proxy rect bottom should be at the handle position, not below it',
+        );
+
+        // Guard: bottom must NOT be offset.dy + edgeOffset (the old buggy value
+        // that caused downward scrolling when the handle was near the bottom of
+        // the viewport).
+        expect(
+          scroller.capturedRect!.bottom,
+          isNot(offset.dy + edgeOffset),
+          reason:
+              'old buggy value extended the rect downward, triggering wrong-direction scroll',
+        );
+      },
+    );
+
+    testWidgets(
+      'right handle drag (AxisDirection.down) — proxy rect is centered on offset',
+      (tester) async {
+        await buildScrollable(tester);
+
+        final scroller = _CapturingAutoScroller(scrollableState);
+        const offset = Offset(100, 300);
+        const edgeOffset = 200.0;
+
+        scroller.startAutoScroll(
+          offset,
+          edgeOffset: edgeOffset,
+          direction: AxisDirection.down,
+        );
+
+        expect(scroller.capturedRect, isNotNull);
+
+        // For AxisDirection.down the generic Rect.fromCenter path is used.
+        expect(
+          scroller.capturedRect!.center,
+          offset,
+          reason:
+              'right handle proxy rect should be centered on the handle offset',
+        );
+        expect(scroller.capturedRect!.width, edgeOffset);
+        expect(scroller.capturedRect!.height, edgeOffset);
+      },
+    );
+
+    testWidgets(
+      'no direction — proxy rect is centered on offset',
+      (tester) async {
+        await buildScrollable(tester);
+
+        final scroller = _CapturingAutoScroller(scrollableState);
+        const offset = Offset(50, 200);
+        const edgeOffset = 100.0;
+
+        scroller.startAutoScroll(offset, edgeOffset: edgeOffset);
+
+        expect(scroller.capturedRect, isNotNull);
+        expect(scroller.capturedRect!.center, offset);
+        expect(scroller.capturedRect!.width, edgeOffset);
+        expect(scroller.capturedRect!.height, edgeOffset);
+      },
+    );
   });
 }