Desktop edge scrolling (#93170)

packages/flutter/lib/src/cupertino/text_field.dart

@@ -967,15 +967,30 @@ class _CupertinoTextFieldState extends State<CupertinoTextField> with Restoratio
   }
 
   void _handleSelectionChanged(TextSelection selection, SelectionChangedCause? cause) {
-    if (cause == SelectionChangedCause.longPress) {
-      _editableText.bringIntoView(selection.base);
-    }
     final bool willShowSelectionHandles = _shouldShowSelectionHandles(cause);
     if (willShowSelectionHandles != _showSelectionHandles) {
       setState(() {
         _showSelectionHandles = willShowSelectionHandles;
       });
     }
+
+    switch (defaultTargetPlatform) {
+      case TargetPlatform.iOS:
+      case TargetPlatform.macOS:
+        if (cause == SelectionChangedCause.longPress
+            || cause == SelectionChangedCause.drag) {
+          _editableText.bringIntoView(selection.extent);
+        }
+        return;
+      case TargetPlatform.linux:
+      case TargetPlatform.windows:
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.android:
+        if (cause == SelectionChangedCause.drag) {
+          _editableText.bringIntoView(selection.extent);
+        }
+        return;
+    }
   }
 
   @override

packages/flutter/lib/src/gestures/monodrag.dart

@@ -614,7 +614,13 @@ class HorizontalDragGestureRecognizer extends DragGestureRecognizer {
 ///    some time has passed.
 class PanGestureRecognizer extends DragGestureRecognizer {
   /// Create a gesture recognizer for tracking movement on a plane.
-  PanGestureRecognizer({ Object? debugOwner }) : super(debugOwner: debugOwner);
+  PanGestureRecognizer({
+    Object? debugOwner,
+    Set<PointerDeviceKind>? supportedDevices,
+  }) : super(
+         debugOwner: debugOwner,
+         supportedDevices: supportedDevices,
+       );
 
   @override
   bool isFlingGesture(VelocityEstimate estimate, PointerDeviceKind kind) {

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

@@ -1075,15 +1075,19 @@ class _TextFieldState extends State<TextField> with RestorationMixin implements
     switch (Theme.of(context).platform) {
       case TargetPlatform.iOS:
       case TargetPlatform.macOS:
-        if (cause == SelectionChangedCause.longPress) {
+        if (cause == SelectionChangedCause.longPress
-          _editableText?.bringIntoView(selection.base);
+            || cause == SelectionChangedCause.drag) {
+          _editableText?.bringIntoView(selection.extent);
         }
         return;
-      case TargetPlatform.android:
-      case TargetPlatform.fuchsia:
       case TargetPlatform.linux:
       case TargetPlatform.windows:
-        // Do nothing.
+      case TargetPlatform.fuchsia:
+      case TargetPlatform.android:
+        if (cause == SelectionChangedCause.drag) {
+          _editableText?.bringIntoView(selection.extent);
+        }
+        return;
     }
   }
 

packages/flutter/lib/src/widgets/text_selection.dart

@@ -1527,11 +1527,9 @@ class _TextSelectionGestureDetectorState extends State<TextSelectionGestureDetec
     if (widget.onDragSelectionStart != null ||
         widget.onDragSelectionUpdate != null ||
         widget.onDragSelectionEnd != null) {
-      // TODO(mdebbar): Support dragging in any direction (for multiline text).
+      gestures[PanGestureRecognizer] = GestureRecognizerFactoryWithHandlers<PanGestureRecognizer>(
-      // https://github.com/flutter/flutter/issues/28676
+        () => PanGestureRecognizer(debugOwner: this, supportedDevices: <PointerDeviceKind>{ PointerDeviceKind.mouse }),
-      gestures[HorizontalDragGestureRecognizer] = GestureRecognizerFactoryWithHandlers<HorizontalDragGestureRecognizer>(
+        (PanGestureRecognizer instance) {
-        () => HorizontalDragGestureRecognizer(debugOwner: this, kind: PointerDeviceKind.mouse),
-        (HorizontalDragGestureRecognizer instance) {
           instance
             // Text selection should start from the position of the first pointer
             // down event.

packages/flutter/test/cupertino/text_field_test.dart

@@ -2414,7 +2414,7 @@ void main() {
     expect(firstCharEndpoint.length, 1);
     // The first character is now offscreen to the left.
     expect(firstCharEndpoint[0].point.dx, moreOrLessEquals(-308.20, epsilon: 0.25));
-  });
+  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));
 
   testWidgets(
     'long tap after a double tap select is not affected',

packages/flutter/test/material/text_field_test.dart

@@ -7794,9 +7794,379 @@ void main() {
     );
     expect(firstCharEndpoint.length, 1);
     // The first character is now offscreen to the left.
-    expect(firstCharEndpoint[0].point.dx, moreOrLessEquals(-257, epsilon: 1));
+    expect(firstCharEndpoint[0].point.dx, moreOrLessEquals(-257.0, epsilon: 1));
   }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));
 
+  testWidgets('mouse click and drag can edge scroll', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: 'Atwater Peel Sherbrooke Bonaventure Angrignon Peel Côte-des-Neiges',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: TextField(
+              controller: controller,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // Just testing the test and making sure that the last character is off
+    // the right side of the screen.
+    expect(textOffsetToPosition(tester, 66).dx, 1056);
+
+    final TestGesture gesture =
+        await tester.startGesture(
+          textOffsetToPosition(tester, 19),
+          pointer: 7,
+          kind: PointerDeviceKind.mouse,
+        );
+    addTearDown(gesture.removePointer);
+
+    await gesture.moveTo(textOffsetToPosition(tester, 56));
+    // To the edge of the screen basically.
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection(baseOffset: 19, extentOffset: 56),
+    );
+
+    // Keep moving out.
+    await gesture.moveTo(textOffsetToPosition(tester, 62));
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection(baseOffset: 19, extentOffset: 62),
+    );
+    await gesture.moveTo(textOffsetToPosition(tester, 66));
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection(baseOffset: 19, extentOffset: 66),
+    ); // We're at the edge now.
+    expect(find.byType(CupertinoButton), findsNothing);
+
+    await gesture.up();
+    await tester.pumpAndSettle();
+
+    // The selection isn't affected by the gesture lift.
+    expect(
+      controller.selection,
+      const TextSelection(baseOffset: 19, extentOffset: 66),
+    );
+
+    // The last character is now on screen near the right edge.
+    expect(
+      textOffsetToPosition(tester, 66).dx,
+      moreOrLessEquals(TestSemantics.fullScreen.width, epsilon: 2.0),
+    );
+
+    // The first character is now offscreen to the left.
+    expect(textOffsetToPosition(tester, 0).dx, moreOrLessEquals(-257.0, epsilon: 1));
+  }, variant: TargetPlatformVariant.all());
+
+  testWidgets('keyboard selection change scrolls the field', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: 'Atwater Peel Sherbrooke Bonaventure Angrignon Peel Côte-des-Neiges',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: TextField(
+              controller: controller,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // Just testing the test and making sure that the last character is off
+    // the right side of the screen.
+    expect(textOffsetToPosition(tester, 66).dx, 1056);
+
+    await tester.tapAt(textOffsetToPosition(tester, 13));
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 13),
+    );
+
+    // Move to position 56 with the right arrow (near the edge of the screen).
+    for (int i = 0; i < (56 - 13); i += 1) {
+      await tester.sendKeyEvent(LogicalKeyboardKey.arrowRight);
+    }
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 56),
+    );
+
+    // Keep moving out.
+    for (int i = 0; i < (62 - 56); i += 1) {
+      await tester.sendKeyEvent(LogicalKeyboardKey.arrowRight);
+    }
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 62),
+    );
+    for (int i = 0; i < (66 - 62); i += 1) {
+      await tester.sendKeyEvent(LogicalKeyboardKey.arrowRight);
+    }
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 66),
+    ); // We're at the edge now.
+
+    await tester.pumpAndSettle();
+
+    // The last character is now on screen near the right edge.
+    expect(
+      textOffsetToPosition(tester, 66).dx,
+      moreOrLessEquals(TestSemantics.fullScreen.width, epsilon: 2.0),
+    );
+
+    // The first character is now offscreen to the left.
+    expect(textOffsetToPosition(tester, 0).dx, moreOrLessEquals(-257.0, epsilon: 1));
+  }, variant: TargetPlatformVariant.all(),
+     skip: isBrowser, // [intended] Browser handles arrow keys differently.
+  );
+
+  testWidgets('long press drag can edge scroll vertically', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: 'Atwater Peel Sherbrooke Bonaventure Angrignon Peel Côte-des-Neigse Atwater Peel Sherbrooke Bonaventure Angrignon Peel Côte-des-Neiges',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: TextField(
+              maxLines: 2,
+              controller: controller,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // Just testing the test and making sure that the last character is outside
+    // the bottom of the field.
+    final int textLength = controller.text.length;
+    final double lineHeight = findRenderEditable(tester).preferredLineHeight;
+    final double firstCharY = textOffsetToPosition(tester, 0).dy;
+    expect(
+      textOffsetToPosition(tester, textLength).dy,
+      moreOrLessEquals(firstCharY + lineHeight * 2, epsilon: 1),
+    );
+
+    // Start long pressing on the first line.
+    final TestGesture gesture =
+        await tester.startGesture(textOffsetToPosition(tester, 19));
+    // TODO(justinmc): Make sure you've got all things torn down.
+    addTearDown(gesture.removePointer);
+    await tester.pump(const Duration(milliseconds: 500));
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 19),
+    );
+    await tester.pumpAndSettle();
+
+    // Move down to the second line.
+    await gesture.moveBy(Offset(0.0, lineHeight));
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 65),
+    );
+
+    // Still hasn't scrolled.
+    expect(
+      textOffsetToPosition(tester, 65).dy,
+      moreOrLessEquals(firstCharY + lineHeight, epsilon: 1),
+    );
+
+    // Keep selecting down to the third and final line.
+    await gesture.moveBy(Offset(0.0, lineHeight));
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 110),
+    );
+
+    // The last character is no longer three line heights down from the top of
+    // the field, it's now only two line heights down, because it has scrolled
+    // down by one line.
+    expect(
+      textOffsetToPosition(tester, 110).dy,
+      moreOrLessEquals(firstCharY + lineHeight, epsilon: 1),
+    );
+
+    // Likewise, the first character is now scrolled out of the top of the field
+    // by one line.
+    expect(
+      textOffsetToPosition(tester, 0).dy,
+      moreOrLessEquals(firstCharY - lineHeight, epsilon: 1),
+    );
+  }, variant: const TargetPlatformVariant(<TargetPlatform>{ TargetPlatform.iOS,  TargetPlatform.macOS }));
+
+  testWidgets('keyboard selection change scrolls the field vertically', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: 'Atwater Peel Sherbrooke Bonaventure Angrignon Peel Côte-des-Neiges Atwater Peel Sherbrooke Bonaventure Angrignon Peel Côte-des-Neiges',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: TextField(
+              maxLines: 2,
+              controller: controller,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // Just testing the test and making sure that the last character is outside
+    // the bottom of the field.
+    final int textLength = controller.text.length;
+    final double lineHeight = findRenderEditable(tester).preferredLineHeight;
+    final double firstCharY = textOffsetToPosition(tester, 0).dy;
+    expect(
+      textOffsetToPosition(tester, textLength).dy,
+      moreOrLessEquals(firstCharY + lineHeight * 2, epsilon: 1),
+    );
+
+    await tester.tapAt(textOffsetToPosition(tester, 13));
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 13),
+    );
+
+    // Move down to the second line.
+    await tester.sendKeyEvent(LogicalKeyboardKey.arrowDown);
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 59),
+    );
+
+    // Still hasn't scrolled.
+    expect(
+      textOffsetToPosition(tester, 66).dy,
+      moreOrLessEquals(firstCharY + lineHeight, epsilon: 1),
+    );
+
+    // Move down to the third and final line.
+    await tester.sendKeyEvent(LogicalKeyboardKey.arrowDown);
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection.collapsed(offset: 104),
+    );
+
+    // The last character is no longer three line heights down from the top of
+    // the field, it's now only two line heights down, because it has scrolled
+    // down by one line.
+    expect(
+      textOffsetToPosition(tester, textLength).dy,
+      moreOrLessEquals(firstCharY + lineHeight, epsilon: 1),
+    );
+
+    // Likewise, the first character is now scrolled out of the top of the field
+    // by one line.
+    expect(
+      textOffsetToPosition(tester, 0).dy,
+      moreOrLessEquals(firstCharY - lineHeight, epsilon: 1),
+    );
+  }, variant: TargetPlatformVariant.all(),
+     skip: isBrowser, // [intended] Browser handles arrow keys differently.
+  );
+
+  testWidgets('mouse click and drag can edge scroll vertically', (WidgetTester tester) async {
+    final TextEditingController controller = TextEditingController(
+      text: 'Atwater Peel Sherbrooke Bonaventure Angrignon Peel Côte-des-Neiges Atwater Peel Sherbrooke Bonaventure Angrignon Peel Côte-des-Neiges',
+    );
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Material(
+          child: Center(
+            child: TextField(
+              maxLines: 2,
+              controller: controller,
+            ),
+          ),
+        ),
+      ),
+    );
+
+    // Just testing the test and making sure that the last character is outside
+    // the bottom of the field.
+    final int textLength = controller.text.length;
+    final double lineHeight = findRenderEditable(tester).preferredLineHeight;
+    final double firstCharY = textOffsetToPosition(tester, 0).dy;
+    expect(
+      textOffsetToPosition(tester, textLength).dy,
+      moreOrLessEquals(firstCharY + lineHeight * 2, epsilon: 1),
+    );
+
+    // Start selecting on the first line.
+    final TestGesture gesture =
+        await tester.startGesture(
+          textOffsetToPosition(tester, 19),
+          pointer: 7,
+          kind: PointerDeviceKind.mouse,
+        );
+    addTearDown(gesture.removePointer);
+
+    // Still hasn't scrolled.
+    expect(
+      textOffsetToPosition(tester, 60).dy,
+      moreOrLessEquals(firstCharY + lineHeight, epsilon: 1),
+    );
+
+    // Select down to the second line.
+    await gesture.moveBy(Offset(0.0, lineHeight));
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection(baseOffset: 19, extentOffset: 65),
+    );
+
+    // Still hasn't scrolled.
+    expect(
+      textOffsetToPosition(tester, 60).dy,
+      moreOrLessEquals(firstCharY + lineHeight, epsilon: 1),
+    );
+
+    // Keep selecting down to the third and final line.
+    await gesture.moveBy(Offset(0.0, lineHeight));
+    await tester.pumpAndSettle();
+    expect(
+      controller.selection,
+      const TextSelection(baseOffset: 19, extentOffset: 110),
+    );
+
+    // The last character is no longer three line heights down from the top of
+    // the field, it's now only two line heights down, because it has scrolled
+    // down by one line.
+    expect(
+      textOffsetToPosition(tester, textLength).dy,
+      moreOrLessEquals(firstCharY + lineHeight, epsilon: 1),
+    );
+
+    // Likewise, the first character is now scrolled out of the top of the field
+    // by one line.
+    expect(
+      textOffsetToPosition(tester, 0).dy,
+      moreOrLessEquals(firstCharY - lineHeight, epsilon: 1),
+    );
+  }, variant: TargetPlatformVariant.all());
+
   testWidgets(
     'long tap after a double tap select is not affected',
     (WidgetTester tester) async {