Desktop keys: up/down + line modifier (#74425)

up/down arrows + cmd (optionally + shift) works on desktop to jump selection to beginning/end of field

packages/flutter/lib/src/rendering/editable.dart

@@ -712,33 +712,57 @@ class RenderEditable extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
     // case where the user moves the cursor to the end or beginning of the text
     // and then back up or down.
     if (downArrow || upArrow) {
-      // The caret offset gives a location in the upper left hand corner of
-      // the caret so the middle of the line above is a half line above that
-      // point and the line below is 1.5 lines below that point.
-      final double preferredLineHeight = _textPainter.preferredLineHeight;
-      final double verticalOffset = upArrow ? -0.5 * preferredLineHeight : 1.5 * preferredLineHeight;
-
-      final Offset caretOffset = _textPainter.getOffsetForCaret(TextPosition(offset: newSelection.extentOffset), _caretPrototype);
-      final Offset caretOffsetTranslated = caretOffset.translate(0.0, verticalOffset);
-      final TextPosition position = _textPainter.getPositionForOffset(caretOffsetTranslated);
-
-      // To account for the possibility where the user vertically highlights
-      // all the way to the top or bottom of the text, we hold the previous
-      // cursor location. This allows us to restore to this position in the
-      // case that the user wants to unhighlight some text.
-      if (position.offset == newSelection.extentOffset) {
-        if (downArrow) {
-          newSelection = newSelection.copyWith(extentOffset: _plainText.length);
-        } else if (upArrow) {
-          newSelection = newSelection.copyWith(extentOffset: 0);
+      if (lineModifier) {
+        if (upArrow) {
+          // Extend the selection to the beginning of the field.
+          final int upperOffset = math.max(0, math.max(
+            newSelection.baseOffset,
+            newSelection.extentOffset,
+          ));
+          newSelection = TextSelection(
+            baseOffset: shift ? upperOffset : 0,
+            extentOffset: 0,
+          );
+        } else {
+          // Extend the selection to the end of the field.
+          final int lowerOffset = math.max(0, math.min(
+            newSelection.baseOffset,
+            newSelection.extentOffset,
+          ));
+          newSelection = TextSelection(
+            baseOffset: shift ? lowerOffset : _plainText.length,
+            extentOffset: _plainText.length,
+          );
         }
-        _wasSelectingVerticallyWithKeyboard = shift;
-      } else if (_wasSelectingVerticallyWithKeyboard && shift) {
-        newSelection = newSelection.copyWith(extentOffset: _cursorResetLocation);
-        _wasSelectingVerticallyWithKeyboard = false;
       } else {
-        newSelection = newSelection.copyWith(extentOffset: position.offset);
-        _cursorResetLocation = newSelection.extentOffset;
+        // The caret offset gives a location in the upper left hand corner of
+        // the caret so the middle of the line above is a half line above that
+        // point and the line below is 1.5 lines below that point.
+        final double preferredLineHeight = _textPainter.preferredLineHeight;
+        final double verticalOffset = upArrow ? -0.5 * preferredLineHeight : 1.5 * preferredLineHeight;
+
+        final Offset caretOffset = _textPainter.getOffsetForCaret(TextPosition(offset: newSelection.extentOffset), _caretPrototype);
+        final Offset caretOffsetTranslated = caretOffset.translate(0.0, verticalOffset);
+        final TextPosition position = _textPainter.getPositionForOffset(caretOffsetTranslated);
+
+        // To account for the possibility where the user vertically highlights
+        // all the way to the top or bottom of the text, we hold the previous
+        // cursor location. This allows us to restore to this position in the
+        // case that the user wants to unhighlight some text.
+        if (position.offset == newSelection.extentOffset) {
+          if (downArrow) {
+            newSelection = newSelection.copyWith(extentOffset: _plainText.length);
+          } else if (upArrow) {
+            newSelection = newSelection.copyWith(extentOffset: 0);
+          }
+          _wasSelectingVerticallyWithKeyboard = shift;
+        } else if (_wasSelectingVerticallyWithKeyboard && shift) {
+          newSelection = newSelection.copyWith(extentOffset: _cursorResetLocation);
+          _wasSelectingVerticallyWithKeyboard = false;
+        } else {
+          newSelection = newSelection.copyWith(extentOffset: position.offset);
+          _cursorResetLocation = newSelection.extentOffset;
+        }
       }
     }
 

packages/flutter/test/widgets/editable_text_test.dart

@@ -4167,6 +4167,144 @@ void main() {
       reason: 'on $platform',
     );
 
+    // Jump to end.
+    await sendKeys(
+      tester,
+      <LogicalKeyboardKey>[
+        LogicalKeyboardKey.arrowDown,
+      ],
+      shift: false,
+      lineModifier: true,
+      platform: platform,
+    );
+
+    expect(
+      selection,
+      equals(
+        const TextSelection.collapsed(
+          offset: testText.length,
+          affinity: TextAffinity.downstream,
+        ),
+      ),
+      reason: 'on $platform',
+    );
+    expect(controller.text, equals(testText), reason: 'on $platform');
+
+    // Jump to start.
+    await sendKeys(
+      tester,
+      <LogicalKeyboardKey>[
+        LogicalKeyboardKey.arrowUp,
+      ],
+      shift: false,
+      lineModifier: true,
+      platform: platform,
+    );
+
+    expect(
+      selection,
+      equals(
+        const TextSelection.collapsed(
+          offset: 0,
+          affinity: TextAffinity.downstream,
+        ),
+      ),
+      reason: 'on $platform',
+    );
+    expect(controller.text, equals(testText), reason: 'on $platform');
+
+    // Move forward a few letters
+    await sendKeys(
+      tester,
+      <LogicalKeyboardKey>[
+        LogicalKeyboardKey.arrowRight,
+        LogicalKeyboardKey.arrowRight,
+        LogicalKeyboardKey.arrowRight,
+      ],
+      shift: false,
+      lineModifier: false,
+      platform: platform,
+    );
+
+    expect(
+      selection,
+      equals(
+        const TextSelection.collapsed(
+          offset: 3,
+          affinity: TextAffinity.downstream,
+        ),
+      ),
+      reason: 'on $platform',
+    );
+
+    // Select to end.
+    await sendKeys(
+      tester,
+      <LogicalKeyboardKey>[
+        LogicalKeyboardKey.arrowDown,
+      ],
+      shift: true,
+      lineModifier: true,
+      platform: platform,
+    );
+
+    expect(
+      selection,
+      equals(
+        const TextSelection(
+          baseOffset: 3,
+          extentOffset: testText.length,
+          affinity: TextAffinity.downstream,
+        ),
+      ),
+      reason: 'on $platform',
+    );
+
+    // Select to start, which extends the selection.
+    await sendKeys(
+      tester,
+      <LogicalKeyboardKey>[
+        LogicalKeyboardKey.arrowUp,
+      ],
+      shift: true,
+      lineModifier: true,
+      platform: platform,
+    );
+
+    expect(
+      selection,
+      equals(
+        const TextSelection(
+          baseOffset: testText.length,
+          extentOffset: 0,
+          affinity: TextAffinity.downstream,
+        ),
+      ),
+      reason: 'on $platform',
+    );
+
+    // Move to start again.
+    await sendKeys(
+      tester,
+      <LogicalKeyboardKey>[
+        LogicalKeyboardKey.arrowUp,
+      ],
+      shift: false,
+      lineModifier: false,
+      platform: platform,
+    );
+
+    expect(
+      selection,
+      equals(
+        const TextSelection.collapsed(
+          offset: 0,
+          affinity: TextAffinity.downstream,
+        ),
+      ),
+      reason: 'on $platform',
+    );
+
     // Jump forward three words.
     await sendKeys(
       tester,