packages/flutter/lib/src/material/text_selection.dart - external/github.com/flutter/flutter - Git at Google

 // Copyright 2014 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'dart:math' as math;

 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';

 import 'debug.dart';
 import 'material_localizations.dart';
 import 'text_selection_theme.dart';
 import 'text_selection_toolbar.dart';
 import 'text_selection_toolbar_text_button.dart';
 import 'theme.dart';

 const double _kHandleSize = 22.0;

 // Padding between the toolbar and the anchor.
 const double _kToolbarContentDistanceBelow = _kHandleSize - 2.0;
 const double _kToolbarContentDistance = 8.0;

 /// Android Material styled text selection controls.
 class MaterialTextSelectionControls extends TextSelectionControls {
   /// Returns the size of the Material handle.
   @override
   Size getHandleSize(double textLineHeight) => const Size(_kHandleSize, _kHandleSize);

   /// Builder for material-style copy/paste text selection toolbar.
   @override
   Widget buildToolbar(
     BuildContext context,
     Rect globalEditableRegion,
     double textLineHeight,
     Offset selectionMidpoint,
     List<TextSelectionPoint> endpoints,
     TextSelectionDelegate delegate,
     ClipboardStatusNotifier clipboardStatus,
     Offset? lastSecondaryTapDownPosition,
   ) {
     return _TextSelectionControlsToolbar(
       globalEditableRegion: globalEditableRegion,
       textLineHeight: textLineHeight,
       selectionMidpoint: selectionMidpoint,
       endpoints: endpoints,
       delegate: delegate,
       clipboardStatus: clipboardStatus,
       handleCut: canCut(delegate) ? () => handleCut(delegate, clipboardStatus) : null,
       handleCopy: canCopy(delegate) ? () => handleCopy(delegate, clipboardStatus) : null,
       handlePaste: canPaste(delegate) ? () => handlePaste(delegate) : null,
       handleSelectAll: canSelectAll(delegate) ? () => handleSelectAll(delegate) : null,
     );
   }

   /// Builder for material-style text selection handles.
   @override
   Widget buildHandle(BuildContext context, TextSelectionHandleType type, double textHeight, [VoidCallback? onTap, double? startGlyphHeight, double? endGlyphHeight]) {
     final ThemeData theme = Theme.of(context);
     final Color handleColor = TextSelectionTheme.of(context).selectionHandleColor ?? theme.colorScheme.primary;
     final Widget handle = SizedBox(
       width: _kHandleSize,
       height: _kHandleSize,
       child: CustomPaint(
         painter: _TextSelectionHandlePainter(
           color: handleColor,
         ),
         child: GestureDetector(
           onTap: onTap,
           behavior: HitTestBehavior.translucent,
         ),
       ),
     );

     // [handle] is a circle, with a rectangle in the top left quadrant of that
     // circle (an onion pointing to 10:30). We rotate [handle] to point
     // straight up or up-right depending on the handle type.
     switch (type) {
       case TextSelectionHandleType.left: // points up-right
         return Transform.rotate(
           angle: math.pi / 2.0,
           child: handle,
         );
       case TextSelectionHandleType.right: // points up-left
         return handle;
       case TextSelectionHandleType.collapsed: // points up
         return Transform.rotate(
           angle: math.pi / 4.0,
           child: handle,
         );
     }
   }

   /// Gets anchor for material-style text selection handles.
   ///
   /// See [TextSelectionControls.getHandleAnchor].
   @override
   Offset getHandleAnchor(TextSelectionHandleType type, double textLineHeight, [double? startGlyphHeight, double? endGlyphHeight]) {
     switch (type) {
       case TextSelectionHandleType.left:
         return const Offset(_kHandleSize, 0);
       case TextSelectionHandleType.right:
         return Offset.zero;
       case TextSelectionHandleType.collapsed:
         return const Offset(_kHandleSize / 2, -4);
     }
   }

   @override
   bool canSelectAll(TextSelectionDelegate delegate) {
     // Android allows SelectAll when selection is not collapsed, unless
     // everything has already been selected.
     final TextEditingValue value = delegate.textEditingValue;
     return delegate.selectAllEnabled &&
            value.text.isNotEmpty &&
            !(value.selection.start == 0 && value.selection.end == value.text.length);
   }
 }

 // The label and callback for the available default text selection menu buttons.
 class _TextSelectionToolbarItemData {
   const _TextSelectionToolbarItemData({
     required this.label,
     required this.onPressed,
   });

   final String label;
   final VoidCallback onPressed;
 }

 // The highest level toolbar widget, built directly by buildToolbar.
 class _TextSelectionControlsToolbar extends StatefulWidget {
   const _TextSelectionControlsToolbar({
     Key? key,
     required this.clipboardStatus,
     required this.delegate,
     required this.endpoints,
     required this.globalEditableRegion,
     required this.handleCut,
     required this.handleCopy,
     required this.handlePaste,
     required this.handleSelectAll,
     required this.selectionMidpoint,
     required this.textLineHeight,
   }) : super(key: key);

   final ClipboardStatusNotifier clipboardStatus;
   final TextSelectionDelegate delegate;
   final List<TextSelectionPoint> endpoints;
   final Rect globalEditableRegion;
   final VoidCallback? handleCut;
   final VoidCallback? handleCopy;
   final VoidCallback? handlePaste;
   final VoidCallback? handleSelectAll;
   final Offset selectionMidpoint;
   final double textLineHeight;

   @override
   _TextSelectionControlsToolbarState createState() => _TextSelectionControlsToolbarState();
 }

 class _TextSelectionControlsToolbarState extends State<_TextSelectionControlsToolbar> with TickerProviderStateMixin {
   void _onChangedClipboardStatus() {
     setState(() {
       // Inform the widget that the value of clipboardStatus has changed.
     });
   }

   @override
   void initState() {
     super.initState();
     widget.clipboardStatus.addListener(_onChangedClipboardStatus);
     widget.clipboardStatus.update();
   }

   @override
   void didUpdateWidget(_TextSelectionControlsToolbar oldWidget) {
     super.didUpdateWidget(oldWidget);
     if (widget.clipboardStatus != oldWidget.clipboardStatus) {
       widget.clipboardStatus.addListener(_onChangedClipboardStatus);
       oldWidget.clipboardStatus.removeListener(_onChangedClipboardStatus);
     }
     widget.clipboardStatus.update();
   }

   @override
   void dispose() {
     super.dispose();
     // When used in an Overlay, it can happen that this is disposed after its
     // creator has already disposed _clipboardStatus.
     if (!widget.clipboardStatus.disposed) {
       widget.clipboardStatus.removeListener(_onChangedClipboardStatus);
     }
   }

   @override
   Widget build(BuildContext context) {
     // If there are no buttons to be shown, don't render anything.
     if (widget.handleCut == null && widget.handleCopy == null
         && widget.handlePaste == null && widget.handleSelectAll == null) {
       return const SizedBox.shrink();
     }
     // If the paste button is desired, don't render anything until the state of
     // the clipboard is known, since it's used to determine if paste is shown.
     if (widget.handlePaste != null
         && widget.clipboardStatus.value == ClipboardStatus.unknown) {
       return const SizedBox.shrink();
     }

     // Calculate the positioning of the menu. It is placed above the selection
     // if there is enough room, or otherwise below.
     final TextSelectionPoint startTextSelectionPoint = widget.endpoints[0];
     final TextSelectionPoint endTextSelectionPoint = widget.endpoints.length > 1
       ? widget.endpoints[1]
       : widget.endpoints[0];
     final Offset anchorAbove = Offset(
       widget.globalEditableRegion.left + widget.selectionMidpoint.dx,
       widget.globalEditableRegion.top + startTextSelectionPoint.point.dy - widget.textLineHeight - _kToolbarContentDistance,
     );
     final Offset anchorBelow = Offset(
       widget.globalEditableRegion.left + widget.selectionMidpoint.dx,
       widget.globalEditableRegion.top + endTextSelectionPoint.point.dy + _kToolbarContentDistanceBelow,
     );

     // Determine which buttons will appear so that the order and total number is
     // known. A button's position in the menu can slightly affect its
     // appearance.
     assert(debugCheckHasMaterialLocalizations(context));
     final MaterialLocalizations localizations = MaterialLocalizations.of(context);
     final List<_TextSelectionToolbarItemData> itemDatas = <_TextSelectionToolbarItemData>[
       if (widget.handleCut != null)
         _TextSelectionToolbarItemData(
           label: localizations.cutButtonLabel,
           onPressed: widget.handleCut!,
         ),
       if (widget.handleCopy != null)
         _TextSelectionToolbarItemData(
           label: localizations.copyButtonLabel,
           onPressed: widget.handleCopy!,
         ),
       if (widget.handlePaste != null
           && widget.clipboardStatus.value == ClipboardStatus.pasteable)
         _TextSelectionToolbarItemData(
           label: localizations.pasteButtonLabel,
           onPressed: widget.handlePaste!,
         ),
       if (widget.handleSelectAll != null)
         _TextSelectionToolbarItemData(
           label: localizations.selectAllButtonLabel,
           onPressed: widget.handleSelectAll!,
         ),
     ];

     // If there is no option available, build an empty widget.
     if (itemDatas.isEmpty) {
       return const SizedBox(width: 0.0, height: 0.0);
     }

     return TextSelectionToolbar(
       anchorAbove: anchorAbove,
       anchorBelow: anchorBelow,
       children: itemDatas.asMap().entries.map((MapEntry<int, _TextSelectionToolbarItemData> entry) {
         return TextSelectionToolbarTextButton(
           padding: TextSelectionToolbarTextButton.getPadding(entry.key, itemDatas.length),
           onPressed: entry.value.onPressed,
           child: Text(entry.value.label),
         );
       }).toList(),
     );
   }
 }

 /// Draws a single text selection handle which points up and to the left.
 class _TextSelectionHandlePainter extends CustomPainter {
   _TextSelectionHandlePainter({ required this.color });

   final Color color;

   @override
   void paint(Canvas canvas, Size size) {
     final Paint paint = Paint()..color = color;
     final double radius = size.width/2.0;
     final Rect circle = Rect.fromCircle(center: Offset(radius, radius), radius: radius);
     final Rect point = Rect.fromLTWH(0.0, 0.0, radius, radius);
     final Path path = Path()..addOval(circle)..addRect(point);
     canvas.drawPath(path, paint);
   }

   @override
   bool shouldRepaint(_TextSelectionHandlePainter oldPainter) {
     return color != oldPainter.color;
   }
 }

 /// Text selection controls that follow the Material Design specification.
 final TextSelectionControls materialTextSelectionControls = MaterialTextSelectionControls();
	// Copyright 2014 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'dart:math' as math;

	import 'package:flutter/rendering.dart';
	import 'package:flutter/widgets.dart';

	import 'debug.dart';
	import 'material_localizations.dart';
	import 'text_selection_theme.dart';
	import 'text_selection_toolbar.dart';
	import 'text_selection_toolbar_text_button.dart';
	import 'theme.dart';

	const double _kHandleSize = 22.0;

	// Padding between the toolbar and the anchor.
	const double _kToolbarContentDistanceBelow = _kHandleSize - 2.0;
	const double _kToolbarContentDistance = 8.0;

	/// Android Material styled text selection controls.
	class MaterialTextSelectionControls extends TextSelectionControls {
	/// Returns the size of the Material handle.
	@override
	Size getHandleSize(double textLineHeight) => const Size(_kHandleSize, _kHandleSize);

	/// Builder for material-style copy/paste text selection toolbar.
	@override
	Widget buildToolbar(
	BuildContext context,
	Rect globalEditableRegion,
	double textLineHeight,
	Offset selectionMidpoint,
	List<TextSelectionPoint> endpoints,
	TextSelectionDelegate delegate,
	ClipboardStatusNotifier clipboardStatus,
	Offset? lastSecondaryTapDownPosition,
	) {
	return _TextSelectionControlsToolbar(
	globalEditableRegion: globalEditableRegion,
	textLineHeight: textLineHeight,
	selectionMidpoint: selectionMidpoint,
	endpoints: endpoints,
	delegate: delegate,
	clipboardStatus: clipboardStatus,
	handleCut: canCut(delegate) ? () => handleCut(delegate, clipboardStatus) : null,
	handleCopy: canCopy(delegate) ? () => handleCopy(delegate, clipboardStatus) : null,
	handlePaste: canPaste(delegate) ? () => handlePaste(delegate) : null,
	handleSelectAll: canSelectAll(delegate) ? () => handleSelectAll(delegate) : null,
	);
	}

	/// Builder for material-style text selection handles.
	@override
	Widget buildHandle(BuildContext context, TextSelectionHandleType type, double textHeight, [VoidCallback? onTap, double? startGlyphHeight, double? endGlyphHeight]) {
	final ThemeData theme = Theme.of(context);
	final Color handleColor = TextSelectionTheme.of(context).selectionHandleColor ?? theme.colorScheme.primary;
	final Widget handle = SizedBox(
	width: _kHandleSize,
	height: _kHandleSize,
	child: CustomPaint(
	painter: _TextSelectionHandlePainter(
	color: handleColor,
	),
	child: GestureDetector(
	onTap: onTap,
	behavior: HitTestBehavior.translucent,
	),
	),
	);

	// [handle] is a circle, with a rectangle in the top left quadrant of that
	// circle (an onion pointing to 10:30). We rotate [handle] to point
	// straight up or up-right depending on the handle type.
	switch (type) {
	case TextSelectionHandleType.left: // points up-right
	return Transform.rotate(
	angle: math.pi / 2.0,
	child: handle,
	);
	case TextSelectionHandleType.right: // points up-left
	return handle;
	case TextSelectionHandleType.collapsed: // points up
	return Transform.rotate(
	angle: math.pi / 4.0,
	child: handle,
	);
	}
	}

	/// Gets anchor for material-style text selection handles.
	///
	/// See [TextSelectionControls.getHandleAnchor].
	@override
	Offset getHandleAnchor(TextSelectionHandleType type, double textLineHeight, [double? startGlyphHeight, double? endGlyphHeight]) {
	switch (type) {
	case TextSelectionHandleType.left:
	return const Offset(_kHandleSize, 0);
	case TextSelectionHandleType.right:
	return Offset.zero;
	case TextSelectionHandleType.collapsed:
	return const Offset(_kHandleSize / 2, -4);
	}
	}

	@override
	bool canSelectAll(TextSelectionDelegate delegate) {
	// Android allows SelectAll when selection is not collapsed, unless
	// everything has already been selected.
	final TextEditingValue value = delegate.textEditingValue;
	return delegate.selectAllEnabled &&
	value.text.isNotEmpty &&
	!(value.selection.start == 0 && value.selection.end == value.text.length);
	}
	}

	// The label and callback for the available default text selection menu buttons.
	class _TextSelectionToolbarItemData {
	const _TextSelectionToolbarItemData({
	required this.label,
	required this.onPressed,
	});

	final String label;
	final VoidCallback onPressed;
	}

	// The highest level toolbar widget, built directly by buildToolbar.
	class _TextSelectionControlsToolbar extends StatefulWidget {
	const _TextSelectionControlsToolbar({
	Key? key,
	required this.clipboardStatus,
	required this.delegate,
	required this.endpoints,
	required this.globalEditableRegion,
	required this.handleCut,
	required this.handleCopy,
	required this.handlePaste,
	required this.handleSelectAll,
	required this.selectionMidpoint,
	required this.textLineHeight,
	}) : super(key: key);

	final ClipboardStatusNotifier clipboardStatus;
	final TextSelectionDelegate delegate;
	final List<TextSelectionPoint> endpoints;
	final Rect globalEditableRegion;
	final VoidCallback? handleCut;
	final VoidCallback? handleCopy;
	final VoidCallback? handlePaste;
	final VoidCallback? handleSelectAll;
	final Offset selectionMidpoint;
	final double textLineHeight;

	@override
	_TextSelectionControlsToolbarState createState() => _TextSelectionControlsToolbarState();
	}

	class _TextSelectionControlsToolbarState extends State<_TextSelectionControlsToolbar> with TickerProviderStateMixin {
	void _onChangedClipboardStatus() {
	setState(() {
	// Inform the widget that the value of clipboardStatus has changed.
	});
	}

	@override
	void initState() {
	super.initState();
	widget.clipboardStatus.addListener(_onChangedClipboardStatus);
	widget.clipboardStatus.update();
	}

	@override
	void didUpdateWidget(_TextSelectionControlsToolbar oldWidget) {
	super.didUpdateWidget(oldWidget);
	if (widget.clipboardStatus != oldWidget.clipboardStatus) {
	widget.clipboardStatus.addListener(_onChangedClipboardStatus);
	oldWidget.clipboardStatus.removeListener(_onChangedClipboardStatus);
	}
	widget.clipboardStatus.update();
	}

	@override
	void dispose() {
	super.dispose();
	// When used in an Overlay, it can happen that this is disposed after its
	// creator has already disposed _clipboardStatus.
	if (!widget.clipboardStatus.disposed) {
	widget.clipboardStatus.removeListener(_onChangedClipboardStatus);
	}
	}

	@override
	Widget build(BuildContext context) {
	// If there are no buttons to be shown, don't render anything.
	if (widget.handleCut == null && widget.handleCopy == null
	&& widget.handlePaste == null && widget.handleSelectAll == null) {
	return const SizedBox.shrink();
	}
	// If the paste button is desired, don't render anything until the state of
	// the clipboard is known, since it's used to determine if paste is shown.
	if (widget.handlePaste != null
	&& widget.clipboardStatus.value == ClipboardStatus.unknown) {
	return const SizedBox.shrink();
	}

	// Calculate the positioning of the menu. It is placed above the selection
	// if there is enough room, or otherwise below.
	final TextSelectionPoint startTextSelectionPoint = widget.endpoints[0];
	final TextSelectionPoint endTextSelectionPoint = widget.endpoints.length > 1
	? widget.endpoints[1]
	: widget.endpoints[0];
	final Offset anchorAbove = Offset(
	widget.globalEditableRegion.left + widget.selectionMidpoint.dx,
	widget.globalEditableRegion.top + startTextSelectionPoint.point.dy - widget.textLineHeight - _kToolbarContentDistance,
	);
	final Offset anchorBelow = Offset(
	widget.globalEditableRegion.left + widget.selectionMidpoint.dx,
	widget.globalEditableRegion.top + endTextSelectionPoint.point.dy + _kToolbarContentDistanceBelow,
	);

	// Determine which buttons will appear so that the order and total number is
	// known. A button's position in the menu can slightly affect its
	// appearance.
	assert(debugCheckHasMaterialLocalizations(context));
	final MaterialLocalizations localizations = MaterialLocalizations.of(context);
	final List<_TextSelectionToolbarItemData> itemDatas = <_TextSelectionToolbarItemData>[
	if (widget.handleCut != null)
	_TextSelectionToolbarItemData(
	label: localizations.cutButtonLabel,
	onPressed: widget.handleCut!,
	),
	if (widget.handleCopy != null)
	_TextSelectionToolbarItemData(
	label: localizations.copyButtonLabel,
	onPressed: widget.handleCopy!,
	),
	if (widget.handlePaste != null
	&& widget.clipboardStatus.value == ClipboardStatus.pasteable)
	_TextSelectionToolbarItemData(
	label: localizations.pasteButtonLabel,
	onPressed: widget.handlePaste!,
	),
	if (widget.handleSelectAll != null)
	_TextSelectionToolbarItemData(
	label: localizations.selectAllButtonLabel,
	onPressed: widget.handleSelectAll!,
	),
	];

	// If there is no option available, build an empty widget.
	if (itemDatas.isEmpty) {
	return const SizedBox(width: 0.0, height: 0.0);
	}

	return TextSelectionToolbar(
	anchorAbove: anchorAbove,
	anchorBelow: anchorBelow,
	children: itemDatas.asMap().entries.map((MapEntry<int, _TextSelectionToolbarItemData> entry) {
	return TextSelectionToolbarTextButton(
	padding: TextSelectionToolbarTextButton.getPadding(entry.key, itemDatas.length),
	onPressed: entry.value.onPressed,
	child: Text(entry.value.label),
	);
	}).toList(),
	);
	}
	}

	/// Draws a single text selection handle which points up and to the left.
	class _TextSelectionHandlePainter extends CustomPainter {
	_TextSelectionHandlePainter({ required this.color });

	final Color color;

	@override
	void paint(Canvas canvas, Size size) {
	final Paint paint = Paint()..color = color;
	final double radius = size.width/2.0;
	final Rect circle = Rect.fromCircle(center: Offset(radius, radius), radius: radius);
	final Rect point = Rect.fromLTWH(0.0, 0.0, radius, radius);
	final Path path = Path()..addOval(circle)..addRect(point);
	canvas.drawPath(path, paint);
	}

	@override
	bool shouldRepaint(_TextSelectionHandlePainter oldPainter) {
	return color != oldPainter.color;
	}
	}

	/// Text selection controls that follow the Material Design specification.
	final TextSelectionControls materialTextSelectionControls = MaterialTextSelectionControls();