packages/flutter/lib/src/cupertino/text_selection.dart - mirrors/flutter - Git at Google

 // Copyright 2017 The Chromium 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/widgets.dart';
 import 'package:flutter/rendering.dart';

 import 'button.dart';
 import 'colors.dart';
 import 'localizations.dart';

 // Padding around the line at the edge of the text selection that has 0 width and
 // the height of the text font.
 const double _kHandlesPadding = 18.0;
 // Minimal padding from all edges of the selection toolbar to all edges of the
 // viewport.
 const double _kToolbarScreenPadding = 8.0;
 const double _kToolbarHeight = 36.0;

 const Color _kToolbarBackgroundColor = Color(0xFF2E2E2E);
 const Color _kToolbarDividerColor = Color(0xFFB9B9B9);
 // Read off from the output on iOS 12. This color does not vary with the
 // application's theme color.
 const Color _kHandlesColor = Color(0xFF136FE0);

 // This offset is used to determine the center of the selection during a drag.
 // It's slightly below the center of the text so the finger isn't entirely
 // covering the text being selected.
 const Size _kSelectionOffset = Size(20.0, 30.0);
 const Size _kToolbarTriangleSize = Size(18.0, 9.0);
 const EdgeInsets _kToolbarButtonPadding = EdgeInsets.symmetric(vertical: 10.0, horizontal: 18.0);
 const BorderRadius _kToolbarBorderRadius = BorderRadius.all(Radius.circular(7.5));

 const TextStyle _kToolbarButtonFontStyle = TextStyle(
   inherit: false,
   fontSize: 14.0,
   letterSpacing: -0.11,
   fontWeight: FontWeight.w300,
   color: CupertinoColors.white,
 );

 /// Paints a triangle below the toolbar.
 class _TextSelectionToolbarNotchPainter extends CustomPainter {
   @override
   void paint(Canvas canvas, Size size) {
     final Paint paint = Paint()
         ..color = _kToolbarBackgroundColor
         ..style = PaintingStyle.fill;
     final Path triangle = Path()
         ..lineTo(_kToolbarTriangleSize.width / 2, 0.0)
         ..lineTo(0.0, _kToolbarTriangleSize.height)
         ..lineTo(-(_kToolbarTriangleSize.width / 2), 0.0)
         ..close();
     canvas.drawPath(triangle, paint);
   }

   @override
   bool shouldRepaint(_TextSelectionToolbarNotchPainter oldPainter) => false;
 }

 /// Manages a copy/paste text selection toolbar.
 class _TextSelectionToolbar extends StatelessWidget {
   const _TextSelectionToolbar({
     Key key,
     this.handleCut,
     this.handleCopy,
     this.handlePaste,
     this.handleSelectAll,
   }) : super(key: key);

   final VoidCallback handleCut;
   final VoidCallback handleCopy;
   final VoidCallback handlePaste;
   final VoidCallback handleSelectAll;

   @override
   Widget build(BuildContext context) {
     final List<Widget> items = <Widget>[];
     final Widget onePhysicalPixelVerticalDivider =
     SizedBox(width: 1.0 / MediaQuery.of(context).devicePixelRatio);
     final CupertinoLocalizations localizations = CupertinoLocalizations.of(context);

     if (handleCut != null)
       items.add(_buildToolbarButton(localizations.cutButtonLabel, handleCut));

     if (handleCopy != null) {
       if (items.isNotEmpty)
         items.add(onePhysicalPixelVerticalDivider);
       items.add(_buildToolbarButton(localizations.copyButtonLabel, handleCopy));
     }

     if (handlePaste != null) {
       if (items.isNotEmpty)
         items.add(onePhysicalPixelVerticalDivider);
       items.add(_buildToolbarButton(localizations.pasteButtonLabel, handlePaste));
     }

     if (handleSelectAll != null) {
       if (items.isNotEmpty)
         items.add(onePhysicalPixelVerticalDivider);
       items.add(_buildToolbarButton(localizations.selectAllButtonLabel, handleSelectAll));
     }

     final Widget triangle = SizedBox.fromSize(
       size: _kToolbarTriangleSize,
       child: CustomPaint(
         painter: _TextSelectionToolbarNotchPainter(),
       ),
     );

     return Column(
       mainAxisSize: MainAxisSize.min,
       children: <Widget>[
         ClipRRect(
           borderRadius: _kToolbarBorderRadius,
           child: DecoratedBox(
             decoration: BoxDecoration(
               color: _kToolbarDividerColor,
               borderRadius: _kToolbarBorderRadius,
               // Add a hairline border with the button color to avoid
               // antialiasing artifacts.
               border: Border.all(color: _kToolbarBackgroundColor, width: 0),
             ),
             child: Row(mainAxisSize: MainAxisSize.min, children: items),
           ),
         ),
         // TODO(xster): Position the triangle based on the layout delegate, and
         // avoid letting the triangle line up with any dividers.
         // https://github.com/flutter/flutter/issues/11274
         triangle,
         const Padding(padding: EdgeInsets.only(bottom: 10.0)),
       ],
     );
   }

   /// Builds a themed [CupertinoButton] for the toolbar.
   CupertinoButton _buildToolbarButton(String text, VoidCallback onPressed) {
     return CupertinoButton(
       child: Text(text, style: _kToolbarButtonFontStyle),
       color: _kToolbarBackgroundColor,
       minSize: _kToolbarHeight,
       padding: _kToolbarButtonPadding,
       borderRadius: null,
       pressedOpacity: 0.7,
       onPressed: onPressed,
     );
   }
 }

 /// Centers the toolbar around the given position, ensuring that it remains on
 /// screen.
 class _TextSelectionToolbarLayout extends SingleChildLayoutDelegate {
   _TextSelectionToolbarLayout(this.screenSize, this.globalEditableRegion, this.position);

   /// The size of the screen at the time that the toolbar was last laid out.
   final Size screenSize;

   /// Size and position of the editing region at the time the toolbar was last
   /// laid out, in global coordinates.
   final Rect globalEditableRegion;

   /// Anchor position of the toolbar, relative to the top left of the
   /// [globalEditableRegion].
   final Offset position;

   @override
   BoxConstraints getConstraintsForChild(BoxConstraints constraints) {
     return constraints.loosen();
   }

   @override
   Offset getPositionForChild(Size size, Size childSize) {
     final Offset globalPosition = globalEditableRegion.topLeft + position;

     double x = globalPosition.dx - childSize.width / 2.0;
     double y = globalPosition.dy - childSize.height;

     if (x < _kToolbarScreenPadding)
       x = _kToolbarScreenPadding;
     else if (x + childSize.width > screenSize.width - _kToolbarScreenPadding)
       x = screenSize.width - childSize.width - _kToolbarScreenPadding;

     if (y < _kToolbarScreenPadding)
       y = _kToolbarScreenPadding;
     else if (y + childSize.height > screenSize.height - _kToolbarScreenPadding)
       y = screenSize.height - childSize.height - _kToolbarScreenPadding;

     return Offset(x, y);
   }

   @override
   bool shouldRelayout(_TextSelectionToolbarLayout oldDelegate) {
     return screenSize != oldDelegate.screenSize
         || globalEditableRegion != oldDelegate.globalEditableRegion
         || position != oldDelegate.position;
   }
 }

 /// Draws a single text selection handle with a bar and a ball.
 ///
 /// Draws from a point of origin somewhere inside the size of the painter
 /// such that the ball is below the point of origin and the bar is above the
 /// point of origin.
 class _TextSelectionHandlePainter extends CustomPainter {
   _TextSelectionHandlePainter({this.origin});

   final Offset origin;

   @override
   void paint(Canvas canvas, Size size) {
     final Paint paint = Paint()
         ..color = _kHandlesColor
         ..strokeWidth = 2.0;
     // Draw circle below the origin that slightly overlaps the bar.
     canvas.drawCircle(origin.translate(0.0, 4.0), 5.5, paint);
     // Draw up from origin leaving 10 pixels of margin on top.
     canvas.drawLine(
       origin,
       origin.translate(
         0.0,
         -(size.height - 2.0 * _kHandlesPadding),
       ),
       paint,
     );
   }

   @override
   bool shouldRepaint(_TextSelectionHandlePainter oldPainter) => origin != oldPainter.origin;
 }

 class _CupertinoTextSelectionControls extends TextSelectionControls {
   @override
   Size handleSize = _kSelectionOffset; // Used for drag selection offset.

   /// Builder for iOS-style copy/paste text selection toolbar.
   @override
   Widget buildToolbar(BuildContext context, Rect globalEditableRegion, Offset position, TextSelectionDelegate delegate) {
     assert(debugCheckHasMediaQuery(context));
     return ConstrainedBox(
       constraints: BoxConstraints.tight(globalEditableRegion.size),
       child: CustomSingleChildLayout(
         delegate: _TextSelectionToolbarLayout(
           MediaQuery.of(context).size,
           globalEditableRegion,
           position,
         ),
         child: _TextSelectionToolbar(
           handleCut: canCut(delegate) ? () => handleCut(delegate) : null,
           handleCopy: canCopy(delegate) ? () => handleCopy(delegate) : null,
           handlePaste: canPaste(delegate) ? () => handlePaste(delegate) : null,
           handleSelectAll: canSelectAll(delegate) ? () => handleSelectAll(delegate) : null,
         ),
       ),
     );
   }

   /// Builder for iOS text selection edges.
   @override
   Widget buildHandle(BuildContext context, TextSelectionHandleType type, double textLineHeight) {
     // We want a size that's a vertical line the height of the text plus a 18.0
     // padding in every direction that will constitute the selection drag area.
     final Size desiredSize = Size(
       2.0 * _kHandlesPadding,
       textLineHeight + 2.0 * _kHandlesPadding,
     );

     final Widget handle = SizedBox.fromSize(
       size: desiredSize,
       child: CustomPaint(
         painter: _TextSelectionHandlePainter(
           // We give the painter a point of origin that's at the bottom baseline
           // of the selection cursor position.
           //
           // We give it in the form of an offset from the top left of the
           // SizedBox.
           origin: Offset(_kHandlesPadding, textLineHeight + _kHandlesPadding),
         ),
       ),
     );

     // [buildHandle]'s widget is positioned at the selection cursor's bottom
     // baseline. We transform the handle such that the SizedBox is superimposed
     // on top of the text selection endpoints.
     switch (type) {
       case TextSelectionHandleType.left: // The left handle is upside down on iOS.
         return Transform(
           transform: Matrix4.rotationZ(math.pi)
               ..translate(-_kHandlesPadding, -_kHandlesPadding),
           child: handle,
         );
       case TextSelectionHandleType.right:
         return Transform(
           transform: Matrix4.translationValues(
             -_kHandlesPadding,
             -(textLineHeight + _kHandlesPadding),
             0.0,
           ),
           child: handle,
         );
       case TextSelectionHandleType.collapsed: // iOS doesn't draw anything for collapsed selections.
         return Container();
     }
     assert(type != null);
     return null;
   }
 }

 /// Text selection controls that follows iOS design conventions.
 final TextSelectionControls cupertinoTextSelectionControls = _CupertinoTextSelectionControls();
	// Copyright 2017 The Chromium 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/widgets.dart';
	import 'package:flutter/rendering.dart';

	import 'button.dart';
	import 'colors.dart';
	import 'localizations.dart';

	// Padding around the line at the edge of the text selection that has 0 width and
	// the height of the text font.
	const double _kHandlesPadding = 18.0;
	// Minimal padding from all edges of the selection toolbar to all edges of the
	// viewport.
	const double _kToolbarScreenPadding = 8.0;
	const double _kToolbarHeight = 36.0;

	const Color _kToolbarBackgroundColor = Color(0xFF2E2E2E);
	const Color _kToolbarDividerColor = Color(0xFFB9B9B9);
	// Read off from the output on iOS 12. This color does not vary with the
	// application's theme color.
	const Color _kHandlesColor = Color(0xFF136FE0);

	// This offset is used to determine the center of the selection during a drag.
	// It's slightly below the center of the text so the finger isn't entirely
	// covering the text being selected.
	const Size _kSelectionOffset = Size(20.0, 30.0);
	const Size _kToolbarTriangleSize = Size(18.0, 9.0);
	const EdgeInsets _kToolbarButtonPadding = EdgeInsets.symmetric(vertical: 10.0, horizontal: 18.0);
	const BorderRadius _kToolbarBorderRadius = BorderRadius.all(Radius.circular(7.5));

	const TextStyle _kToolbarButtonFontStyle = TextStyle(
	inherit: false,
	fontSize: 14.0,
	letterSpacing: -0.11,
	fontWeight: FontWeight.w300,
	color: CupertinoColors.white,
	);

	/// Paints a triangle below the toolbar.
	class _TextSelectionToolbarNotchPainter extends CustomPainter {
	@override
	void paint(Canvas canvas, Size size) {
	final Paint paint = Paint()
	..color = _kToolbarBackgroundColor
	..style = PaintingStyle.fill;
	final Path triangle = Path()
	..lineTo(_kToolbarTriangleSize.width / 2, 0.0)
	..lineTo(0.0, _kToolbarTriangleSize.height)
	..lineTo(-(_kToolbarTriangleSize.width / 2), 0.0)
	..close();
	canvas.drawPath(triangle, paint);
	}

	@override
	bool shouldRepaint(_TextSelectionToolbarNotchPainter oldPainter) => false;
	}

	/// Manages a copy/paste text selection toolbar.
	class _TextSelectionToolbar extends StatelessWidget {
	const _TextSelectionToolbar({
	Key key,
	this.handleCut,
	this.handleCopy,
	this.handlePaste,
	this.handleSelectAll,
	}) : super(key: key);

	final VoidCallback handleCut;
	final VoidCallback handleCopy;
	final VoidCallback handlePaste;
	final VoidCallback handleSelectAll;

	@override
	Widget build(BuildContext context) {
	final List<Widget> items = <Widget>[];
	final Widget onePhysicalPixelVerticalDivider =
	SizedBox(width: 1.0 / MediaQuery.of(context).devicePixelRatio);
	final CupertinoLocalizations localizations = CupertinoLocalizations.of(context);

	if (handleCut != null)
	items.add(_buildToolbarButton(localizations.cutButtonLabel, handleCut));

	if (handleCopy != null) {
	if (items.isNotEmpty)
	items.add(onePhysicalPixelVerticalDivider);
	items.add(_buildToolbarButton(localizations.copyButtonLabel, handleCopy));
	}

	if (handlePaste != null) {
	if (items.isNotEmpty)
	items.add(onePhysicalPixelVerticalDivider);
	items.add(_buildToolbarButton(localizations.pasteButtonLabel, handlePaste));
	}

	if (handleSelectAll != null) {
	if (items.isNotEmpty)
	items.add(onePhysicalPixelVerticalDivider);
	items.add(_buildToolbarButton(localizations.selectAllButtonLabel, handleSelectAll));
	}

	final Widget triangle = SizedBox.fromSize(
	size: _kToolbarTriangleSize,
	child: CustomPaint(
	painter: _TextSelectionToolbarNotchPainter(),
	),
	);

	return Column(
	mainAxisSize: MainAxisSize.min,
	children: <Widget>[
	ClipRRect(
	borderRadius: _kToolbarBorderRadius,
	child: DecoratedBox(
	decoration: BoxDecoration(
	color: _kToolbarDividerColor,
	borderRadius: _kToolbarBorderRadius,
	// Add a hairline border with the button color to avoid
	// antialiasing artifacts.
	border: Border.all(color: _kToolbarBackgroundColor, width: 0),
	),
	child: Row(mainAxisSize: MainAxisSize.min, children: items),
	),
	),
	// TODO(xster): Position the triangle based on the layout delegate, and
	// avoid letting the triangle line up with any dividers.
	// https://github.com/flutter/flutter/issues/11274
	triangle,
	const Padding(padding: EdgeInsets.only(bottom: 10.0)),
	],
	);
	}

	/// Builds a themed [CupertinoButton] for the toolbar.
	CupertinoButton _buildToolbarButton(String text, VoidCallback onPressed) {
	return CupertinoButton(
	child: Text(text, style: _kToolbarButtonFontStyle),
	color: _kToolbarBackgroundColor,
	minSize: _kToolbarHeight,
	padding: _kToolbarButtonPadding,
	borderRadius: null,
	pressedOpacity: 0.7,
	onPressed: onPressed,
	);
	}
	}

	/// Centers the toolbar around the given position, ensuring that it remains on
	/// screen.
	class _TextSelectionToolbarLayout extends SingleChildLayoutDelegate {
	_TextSelectionToolbarLayout(this.screenSize, this.globalEditableRegion, this.position);

	/// The size of the screen at the time that the toolbar was last laid out.
	final Size screenSize;

	/// Size and position of the editing region at the time the toolbar was last
	/// laid out, in global coordinates.
	final Rect globalEditableRegion;

	/// Anchor position of the toolbar, relative to the top left of the
	/// [globalEditableRegion].
	final Offset position;

	@override
	BoxConstraints getConstraintsForChild(BoxConstraints constraints) {
	return constraints.loosen();
	}

	@override
	Offset getPositionForChild(Size size, Size childSize) {
	final Offset globalPosition = globalEditableRegion.topLeft + position;

	double x = globalPosition.dx - childSize.width / 2.0;
	double y = globalPosition.dy - childSize.height;

	if (x < _kToolbarScreenPadding)
	x = _kToolbarScreenPadding;
	else if (x + childSize.width > screenSize.width - _kToolbarScreenPadding)
	x = screenSize.width - childSize.width - _kToolbarScreenPadding;

	if (y < _kToolbarScreenPadding)
	y = _kToolbarScreenPadding;
	else if (y + childSize.height > screenSize.height - _kToolbarScreenPadding)
	y = screenSize.height - childSize.height - _kToolbarScreenPadding;

	return Offset(x, y);
	}

	@override
	bool shouldRelayout(_TextSelectionToolbarLayout oldDelegate) {
	return screenSize != oldDelegate.screenSize
	\|\| globalEditableRegion != oldDelegate.globalEditableRegion
	\|\| position != oldDelegate.position;
	}
	}

	/// Draws a single text selection handle with a bar and a ball.
	///
	/// Draws from a point of origin somewhere inside the size of the painter
	/// such that the ball is below the point of origin and the bar is above the
	/// point of origin.
	class _TextSelectionHandlePainter extends CustomPainter {
	_TextSelectionHandlePainter({this.origin});

	final Offset origin;

	@override
	void paint(Canvas canvas, Size size) {
	final Paint paint = Paint()
	..color = _kHandlesColor
	..strokeWidth = 2.0;
	// Draw circle below the origin that slightly overlaps the bar.
	canvas.drawCircle(origin.translate(0.0, 4.0), 5.5, paint);
	// Draw up from origin leaving 10 pixels of margin on top.
	canvas.drawLine(
	origin,
	origin.translate(
	0.0,
	-(size.height - 2.0 * _kHandlesPadding),
	),
	paint,
	);
	}

	@override
	bool shouldRepaint(_TextSelectionHandlePainter oldPainter) => origin != oldPainter.origin;
	}

	class _CupertinoTextSelectionControls extends TextSelectionControls {
	@override
	Size handleSize = _kSelectionOffset; // Used for drag selection offset.

	/// Builder for iOS-style copy/paste text selection toolbar.
	@override
	Widget buildToolbar(BuildContext context, Rect globalEditableRegion, Offset position, TextSelectionDelegate delegate) {
	assert(debugCheckHasMediaQuery(context));
	return ConstrainedBox(
	constraints: BoxConstraints.tight(globalEditableRegion.size),
	child: CustomSingleChildLayout(
	delegate: _TextSelectionToolbarLayout(
	MediaQuery.of(context).size,
	globalEditableRegion,
	position,
	),
	child: _TextSelectionToolbar(
	handleCut: canCut(delegate) ? () => handleCut(delegate) : null,
	handleCopy: canCopy(delegate) ? () => handleCopy(delegate) : null,
	handlePaste: canPaste(delegate) ? () => handlePaste(delegate) : null,
	handleSelectAll: canSelectAll(delegate) ? () => handleSelectAll(delegate) : null,
	),
	),
	);
	}

	/// Builder for iOS text selection edges.
	@override
	Widget buildHandle(BuildContext context, TextSelectionHandleType type, double textLineHeight) {
	// We want a size that's a vertical line the height of the text plus a 18.0
	// padding in every direction that will constitute the selection drag area.
	final Size desiredSize = Size(
	2.0 * _kHandlesPadding,
	textLineHeight + 2.0 * _kHandlesPadding,
	);

	final Widget handle = SizedBox.fromSize(
	size: desiredSize,
	child: CustomPaint(
	painter: _TextSelectionHandlePainter(
	// We give the painter a point of origin that's at the bottom baseline
	// of the selection cursor position.
	//
	// We give it in the form of an offset from the top left of the
	// SizedBox.
	origin: Offset(_kHandlesPadding, textLineHeight + _kHandlesPadding),
	),
	),
	);

	// [buildHandle]'s widget is positioned at the selection cursor's bottom
	// baseline. We transform the handle such that the SizedBox is superimposed
	// on top of the text selection endpoints.
	switch (type) {
	case TextSelectionHandleType.left: // The left handle is upside down on iOS.
	return Transform(
	transform: Matrix4.rotationZ(math.pi)
	..translate(-_kHandlesPadding, -_kHandlesPadding),
	child: handle,
	);
	case TextSelectionHandleType.right:
	return Transform(
	transform: Matrix4.translationValues(
	-_kHandlesPadding,
	-(textLineHeight + _kHandlesPadding),
	0.0,
	),
	child: handle,
	);
	case TextSelectionHandleType.collapsed: // iOS doesn't draw anything for collapsed selections.
	return Container();
	}
	assert(type != null);
	return null;
	}
	}

	/// Text selection controls that follows iOS design conventions.
	final TextSelectionControls cupertinoTextSelectionControls = _CupertinoTextSelectionControls();