Skip to content

Commit

Permalink
Support keyboard selection in SelectabledRegion (flutter#112584)
Browse files Browse the repository at this point in the history 
* Support keyboard selection in selectable region

* fix some comments

* addressing comments
  • Loading branch information
@chunhtai
chunhtai committed Nov 4, 2022
1 parent cfb2f15 commit 80bf355
Show file tree
Hide file tree
Showing 12 changed files with 1,893 additions and 117 deletions.
74 changes: 74 additions & 0 deletions examples/api/lib/material/selectable_region/selectable_region.0.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -194,6 +194,80 @@ class _RenderSelectableAdapter extends RenderProxyBox with Selectable, Selection
_start = Offset.zero;
_end = Offset.infinite;
break;
case SelectionEventType.granularlyExtendSelection:
result = SelectionResult.end;
final GranularlyExtendSelectionEvent extendSelectionEvent = event as GranularlyExtendSelectionEvent;
// Initialize the offset it there is no ongoing selection.
if (_start == null || _end == null) {
if (extendSelectionEvent.forward) {
_start = _end = Offset.zero;
} else {
_start = _end = Offset.infinite;
}
}
// Move the corresponding selection edge.
final Offset newOffset = extendSelectionEvent.forward ? Offset.infinite : Offset.zero;
if (extendSelectionEvent.isEnd) {
if (newOffset == _end) {
result = extendSelectionEvent.forward ? SelectionResult.next : SelectionResult.previous;
}
_end = newOffset;
} else {
if (newOffset == _start) {
result = extendSelectionEvent.forward ? SelectionResult.next : SelectionResult.previous;
}
_start = newOffset;
}
break;
case SelectionEventType.directionallyExtendSelection:
result = SelectionResult.end;
final DirectionallyExtendSelectionEvent extendSelectionEvent = event as DirectionallyExtendSelectionEvent;
// Convert to local coordinates.
final double horizontalBaseLine = globalToLocal(Offset(event.dx, 0)).dx;
final Offset newOffset;
final bool forward;
switch(extendSelectionEvent.direction) {
case SelectionExtendDirection.backward:
case SelectionExtendDirection.previousLine:
forward = false;
// Initialize the offset it there is no ongoing selection.
if (_start == null || _end == null) {
_start = _end = Offset.infinite;
}
// Move the corresponding selection edge.
if (extendSelectionEvent.direction == SelectionExtendDirection.previousLine || horizontalBaseLine < 0) {
newOffset = Offset.zero;
} else {
newOffset = Offset.infinite;
}
break;
case SelectionExtendDirection.nextLine:
case SelectionExtendDirection.forward:
forward = true;
// Initialize the offset it there is no ongoing selection.
if (_start == null || _end == null) {
_start = _end = Offset.zero;
}
// Move the corresponding selection edge.
if (extendSelectionEvent.direction == SelectionExtendDirection.nextLine || horizontalBaseLine > size.width) {
newOffset = Offset.infinite;
} else {
newOffset = Offset.zero;
}
break;
}
if (extendSelectionEvent.isEnd) {
if (newOffset == _end) {
result = forward ? SelectionResult.next : SelectionResult.previous;
}
_end = newOffset;
} else {
if (newOffset == _start) {
result = forward ? SelectionResult.next : SelectionResult.previous;
}
_start = newOffset;
}
break;
}
_updateGeometry();
return result;
Expand Down
230 changes: 223 additions & 7 deletions packages/flutter/lib/src/rendering/paragraph.dart
View file
Original file line number Diff line number Diff line change
Expand Up @@ -4,15 +4,17 @@

import 'dart:collection';
import 'dart:math' as math;
import 'dart:ui' as ui show BoxHeightStyle, BoxWidthStyle, Gradient, PlaceholderAlignment, Shader, TextBox, TextHeightBehavior;
import 'dart:ui' as ui show BoxHeightStyle, BoxWidthStyle, Gradient, LineMetrics, PlaceholderAlignment, Shader, TextBox, TextHeightBehavior;

import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/scheduler.dart';
import 'package:flutter/semantics.dart';
import 'package:flutter/services.dart';

import 'box.dart';
import 'debug.dart';
import 'editable.dart';
import 'layer.dart';
import 'object.dart';
import 'selection.dart';
Expand Down Expand Up @@ -151,11 +153,11 @@ class RenderParagraph extends RenderBox
_cachedCombinedSemanticsInfos = null;
_extractPlaceholderSpans(value);
markNeedsLayout();
_removeSelectionRegistrarSubscription();
_disposeSelectableFragments();
_updateSelectionRegistrarSubscription();
break;
}
_removeSelectionRegistrarSubscription();
_disposeSelectableFragments();
_updateSelectionRegistrarSubscription();
}

/// The ongoing selections in this paragraph.
Expand Down Expand Up @@ -226,7 +228,7 @@ class RenderParagraph extends RenderBox
if (end == -1) {
end = plainText.length;
}
result.add(_SelectableFragment(paragraph: this, range: TextRange(start: start, end: end)));
result.add(_SelectableFragment(paragraph: this, range: TextRange(start: start, end: end), fullText: plainText));
start = end;
}
start += 1;
Expand Down Expand Up @@ -439,6 +441,10 @@ class RenderParagraph extends RenderBox
return getOffsetForCaret(position, Rect.zero) + Offset(0, getFullHeightForCaret(position) ?? 0.0);
}

List<ui.LineMetrics> _computeLineMetrics() {
return _textPainter.computeLineMetrics();
}

@override
double computeMinIntrinsicWidth(double height) {
if (!_canComputeIntrinsics()) {
Expand Down Expand Up @@ -1027,6 +1033,28 @@ class RenderParagraph extends RenderBox
return _textPainter.getWordBoundary(position);
}

TextRange _getLineAtOffset(TextPosition position) => _textPainter.getLineBoundary(position);

TextPosition _getTextPositionAbove(TextPosition position) {
// -0.5 of preferredLineHeight points to the middle of the line above.
final double preferredLineHeight = _textPainter.preferredLineHeight;
final double verticalOffset = -0.5 * preferredLineHeight;
return _getTextPositionVertical(position, verticalOffset);
}

TextPosition _getTextPositionBelow(TextPosition position) {
// 1.5 of preferredLineHeight points to the middle of the line below.
final double preferredLineHeight = _textPainter.preferredLineHeight;
final double verticalOffset = 1.5 * preferredLineHeight;
return _getTextPositionVertical(position, verticalOffset);
}

TextPosition _getTextPositionVertical(TextPosition position, double verticalOffset) {
final Offset caretOffset = _textPainter.getOffsetForCaret(position, Rect.zero);
final Offset caretOffsetTranslated = caretOffset.translate(0.0, verticalOffset);
return _textPainter.getPositionForOffset(caretOffsetTranslated);
}

/// Returns the size of the text as laid out.
///
/// This can differ from [size] if the text overflowed or if the [constraints]
Expand Down Expand Up @@ -1271,16 +1299,18 @@ class RenderParagraph extends RenderBox
/// [PlaceHolderSpan]. The [RenderParagraph] splits itself on [PlaceHolderSpan]
/// to create multiple `_SelectableFragment`s so that they can be selected
/// separately.
class _SelectableFragment with Selectable, ChangeNotifier {
class _SelectableFragment with Selectable, ChangeNotifier implements TextLayoutMetrics {
_SelectableFragment({
required this.paragraph,
required this.fullText,
required this.range,
}) : assert(range.isValid && !range.isCollapsed && range.isNormalized) {
_selectionGeometry = _getSelectionGeometry();
}

final TextRange range;
final RenderParagraph paragraph;
final String fullText;

TextPosition? _textSelectionStart;
TextPosition? _textSelectionEnd;
Expand Down Expand Up @@ -1356,6 +1386,22 @@ class _SelectableFragment with Selectable, ChangeNotifier {
final SelectWordSelectionEvent selectWord = event as SelectWordSelectionEvent;
result = _handleSelectWord(selectWord.globalPosition);
break;
case SelectionEventType.granularlyExtendSelection:
final GranularlyExtendSelectionEvent granularlyExtendSelection = event as GranularlyExtendSelectionEvent;
result = _handleGranularlyExtendSelection(
granularlyExtendSelection.forward,
granularlyExtendSelection.isEnd,
granularlyExtendSelection.granularity,
);
break;
case SelectionEventType.directionallyExtendSelection:
final DirectionallyExtendSelectionEvent directionallyExtendSelection = event as DirectionallyExtendSelectionEvent;
result = _handleDirectionallyExtendSelection(
directionallyExtendSelection.dx,
directionallyExtendSelection.isEnd,
directionallyExtendSelection.direction,
);
break;
}

if (existingSelectionStart != _textSelectionStart ||
Expand All @@ -1373,7 +1419,7 @@ class _SelectableFragment with Selectable, ChangeNotifier {
final int start = math.min(_textSelectionStart!.offset, _textSelectionEnd!.offset);
final int end = math.max(_textSelectionStart!.offset, _textSelectionEnd!.offset);
return SelectedContent(
plainText: paragraph.text.toPlainText(includeSemanticsLabels: false).substring(start, end),
plainText: fullText.substring(start, end),
);
}

Expand Down Expand Up @@ -1466,6 +1512,155 @@ class _SelectableFragment with Selectable, ChangeNotifier {
return SelectionResult.end;
}

SelectionResult _handleDirectionallyExtendSelection(double horizontalBaseline, bool isExtent, SelectionExtendDirection movement) {
final Matrix4 transform = paragraph.getTransformTo(null);
if (transform.invert() == 0.0) {
switch(movement) {
case SelectionExtendDirection.previousLine:
case SelectionExtendDirection.backward:
return SelectionResult.previous;
case SelectionExtendDirection.nextLine:
case SelectionExtendDirection.forward:
return SelectionResult.next;
}
}
final double baselineInParagraphCoordinates = MatrixUtils.transformPoint(transform, Offset(horizontalBaseline, 0)).dx;
assert(!baselineInParagraphCoordinates.isNaN);
final TextPosition newPosition;
final SelectionResult result;
switch(movement) {
case SelectionExtendDirection.previousLine:
case SelectionExtendDirection.nextLine:
assert(_textSelectionEnd != null && _textSelectionStart != null);
final TextPosition targetedEdge = isExtent ? _textSelectionEnd! : _textSelectionStart!;
final MapEntry<TextPosition, SelectionResult> moveResult = _handleVerticalMovement(
targetedEdge,
horizontalBaselineInParagraphCoordinates: baselineInParagraphCoordinates,
below: movement == SelectionExtendDirection.nextLine,
);
newPosition = moveResult.key;
result = moveResult.value;
break;
case SelectionExtendDirection.forward:
case SelectionExtendDirection.backward:
_textSelectionEnd ??= movement == SelectionExtendDirection.forward
? TextPosition(offset: range.start)
: TextPosition(offset: range.end, affinity: TextAffinity.upstream);
_textSelectionStart ??= _textSelectionEnd;
final TextPosition targetedEdge = isExtent ? _textSelectionEnd! : _textSelectionStart!;
final Offset edgeOffsetInParagraphCoordinates = paragraph._getOffsetForPosition(targetedEdge);
final Offset baselineOffsetInParagraphCoordinates = Offset(
baselineInParagraphCoordinates,
// Use half of line height to point to the middle of the line.
edgeOffsetInParagraphCoordinates.dy - paragraph._textPainter.preferredLineHeight / 2,
);
newPosition = paragraph.getPositionForOffset(baselineOffsetInParagraphCoordinates);
result = SelectionResult.end;
break;
}
if (isExtent) {
_textSelectionEnd = newPosition;
} else {
_textSelectionStart = newPosition;
}
return result;
}

SelectionResult _handleGranularlyExtendSelection(bool forward, bool isExtent, TextGranularity granularity) {
_textSelectionEnd ??= forward
? TextPosition(offset: range.start)
: TextPosition(offset: range.end, affinity: TextAffinity.upstream);
_textSelectionStart ??= _textSelectionEnd;
final TextPosition targetedEdge = isExtent ? _textSelectionEnd! : _textSelectionStart!;
if (forward && (targetedEdge.offset == range.end)) {
return SelectionResult.next;
}
if (!forward && (targetedEdge.offset == range.start)) {
return SelectionResult.previous;
}
final SelectionResult result;
final TextPosition newPosition;
switch (granularity) {
case TextGranularity.character:
final String text = range.textInside(fullText);
newPosition = _getNextPosition(CharacterBoundary(text), targetedEdge, forward);
result = SelectionResult.end;
break;
case TextGranularity.word:
final String text = range.textInside(fullText);
newPosition = _getNextPosition(WhitespaceBoundary(text) + WordBoundary(this), targetedEdge, forward);
result = SelectionResult.end;
break;
case TextGranularity.line:
newPosition = _getNextPosition(LineBreak(this), targetedEdge, forward);
result = SelectionResult.end;
break;
case TextGranularity.document:
final String text = range.textInside(fullText);
newPosition = _getNextPosition(DocumentBoundary(text), targetedEdge, forward);
if (forward && newPosition.offset == range.end) {
result = SelectionResult.next;
} else if (!forward && newPosition.offset == range.start) {
result = SelectionResult.previous;
} else {
result = SelectionResult.end;
}
break;
}

if (isExtent) {
_textSelectionEnd = newPosition;
} else {
_textSelectionStart = newPosition;
}
return result;
}

TextPosition _getNextPosition(TextBoundary boundary, TextPosition position, bool forward) {
if (forward) {
return _clampTextPosition(
(PushTextPosition.forward + boundary).getTrailingTextBoundaryAt(position)
);
}
return _clampTextPosition(
(PushTextPosition.backward + boundary).getLeadingTextBoundaryAt(position),
);
}

MapEntry<TextPosition, SelectionResult> _handleVerticalMovement(TextPosition position, {required double horizontalBaselineInParagraphCoordinates, required bool below}) {
final List<ui.LineMetrics> lines = paragraph._computeLineMetrics();
final Offset offset = paragraph.getOffsetForCaret(position, Rect.zero);
int currentLine = lines.length - 1;
for (final ui.LineMetrics lineMetrics in lines) {
if (lineMetrics.baseline > offset.dy) {
currentLine = lineMetrics.lineNumber;
break;
}
}
final TextPosition newPosition;
if (below && currentLine == lines.length - 1) {
newPosition = TextPosition(offset: range.end, affinity: TextAffinity.upstream);
} else if (!below && currentLine == 0) {
newPosition = TextPosition(offset: range.start);
} else {
final int newLine = below ? currentLine + 1 : currentLine - 1;
newPosition = _clampTextPosition(
paragraph.getPositionForOffset(Offset(horizontalBaselineInParagraphCoordinates, lines[newLine].baseline))
);
}
final SelectionResult result;
if (newPosition.offset == range.start) {
result = SelectionResult.previous;
} else if (newPosition.offset == range.end) {
result = SelectionResult.next;
} else {
result = SelectionResult.end;
}
assert(result != SelectionResult.next || below);
assert(result != SelectionResult.previous || !below);
return MapEntry<TextPosition, SelectionResult>(newPosition, result);
}

/// Whether the given text position is contained in current selection
/// range.
///
Expand Down Expand Up @@ -1596,4 +1791,25 @@ class _SelectableFragment with Selectable, ChangeNotifier {
);
}
}

@override
TextSelection getLineAtOffset(TextPosition position) {
final TextRange line = paragraph._getLineAtOffset(position);
final int start = line.start.clamp(range.start, range.end); // ignore_clamp_double_lint
final int end = line.end.clamp(range.start, range.end); // ignore_clamp_double_lint
return TextSelection(baseOffset: start, extentOffset: end);
}

@override
TextPosition getTextPositionAbove(TextPosition position) {
return _clampTextPosition(paragraph._getTextPositionAbove(position));
}

@override
TextPosition getTextPositionBelow(TextPosition position) {
return _clampTextPosition(paragraph._getTextPositionBelow(position));
}

@override
TextRange getWordBoundary(TextPosition position) => paragraph.getWordBoundary(position);
}

0 comments on commit 80bf355

Please sign in to comment.