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// 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 'localizations.dart';
import 'text_selection_toolbar.dart';
import 'text_selection_toolbar_button.dart';
import 'theme.dart';
// Read off from the output on iOS 12. This color does not vary with the
// application's theme color.
const double _kSelectionHandleOverlap = 1.5;
// Extracted from https://developer.apple.com/design/resources/.
const double _kSelectionHandleRadius = 6;
// Minimal padding from tip of the selection toolbar arrow to horizontal edges of the
// screen. Eyeballed value.
const double _kArrowScreenPadding = 26.0;
// Generates the child that's passed into CupertinoTextSelectionToolbar.
class _CupertinoTextSelectionControlsToolbar extends StatefulWidget {
const _CupertinoTextSelectionControlsToolbar({
Key? key,
required this.clipboardStatus,
required this.endpoints,
required this.globalEditableRegion,
required this.handleCopy,
required this.handleCut,
required this.handlePaste,
required this.handleSelectAll,
required this.selectionMidpoint,
required this.textLineHeight,
}) : super(key: key);
final ClipboardStatusNotifier? clipboardStatus;
final List<TextSelectionPoint> endpoints;
final Rect globalEditableRegion;
final VoidCallback? handleCopy;
final VoidCallback? handleCut;
final VoidCallback? handlePaste;
final VoidCallback? handleSelectAll;
final Offset selectionMidpoint;
final double textLineHeight;
@override
_CupertinoTextSelectionControlsToolbarState createState() => _CupertinoTextSelectionControlsToolbarState();
}
class _CupertinoTextSelectionControlsToolbarState extends State<_CupertinoTextSelectionControlsToolbar> {
ClipboardStatusNotifier? _clipboardStatus;
void _onChangedClipboardStatus() {
setState(() {
// Inform the widget that the value of clipboardStatus has changed.
});
}
@override
void initState() {
super.initState();
if (widget.handlePaste != null) {
_clipboardStatus = widget.clipboardStatus ?? ClipboardStatusNotifier();
_clipboardStatus!.addListener(_onChangedClipboardStatus);
_clipboardStatus!.update();
}
}
@override
void didUpdateWidget(_CupertinoTextSelectionControlsToolbar oldWidget) {
super.didUpdateWidget(oldWidget);
if (oldWidget.clipboardStatus != widget.clipboardStatus) {
if (_clipboardStatus != null) {
_clipboardStatus!.removeListener(_onChangedClipboardStatus);
_clipboardStatus!.dispose();
}
_clipboardStatus = widget.clipboardStatus ?? ClipboardStatusNotifier();
_clipboardStatus!.addListener(_onChangedClipboardStatus);
if (widget.handlePaste != null) {
_clipboardStatus!.update();
}
}
}
@override
void dispose() {
super.dispose();
// When used in an Overlay, this can be disposed after its creator has
// already disposed _clipboardStatus.
if (_clipboardStatus != null && !_clipboardStatus!.disposed) {
_clipboardStatus!.removeListener(_onChangedClipboardStatus);
if (widget.clipboardStatus == null) {
_clipboardStatus!.dispose();
}
}
}
@override
Widget build(BuildContext context) {
// Don't render the menu until the state of the clipboard is known.
if (widget.handlePaste != null
&& _clipboardStatus!.value == ClipboardStatus.unknown) {
return const SizedBox(width: 0.0, height: 0.0);
}
assert(debugCheckHasMediaQuery(context));
final MediaQueryData mediaQuery = MediaQuery.of(context);
// The toolbar should appear below the TextField when there is not enough
// space above the TextField to show it, assuming there's always enough
// space at the bottom in this case.
final double anchorX = (widget.selectionMidpoint.dx + widget.globalEditableRegion.left).clamp(
_kArrowScreenPadding + mediaQuery.padding.left,
mediaQuery.size.width - mediaQuery.padding.right - _kArrowScreenPadding,
);
// The y-coordinate has to be calculated instead of directly quoting
// selectionMidpoint.dy, since the caller
// (TextSelectionOverlay._buildToolbar) does not know whether the toolbar is
// going to be facing up or down.
final Offset anchorAbove = Offset(
anchorX,
widget.endpoints.first.point.dy - widget.textLineHeight + widget.globalEditableRegion.top,
);
final Offset anchorBelow = Offset(
anchorX,
widget.endpoints.last.point.dy + widget.globalEditableRegion.top,
);
final List<Widget> items = <Widget>[];
final CupertinoLocalizations localizations = CupertinoLocalizations.of(context);
final Widget onePhysicalPixelVerticalDivider =
SizedBox(width: 1.0 / MediaQuery.of(context).devicePixelRatio);
void addToolbarButton(
String text,
VoidCallback onPressed,
) {
if (items.isNotEmpty) {
items.add(onePhysicalPixelVerticalDivider);
}
items.add(CupertinoTextSelectionToolbarButton.text(
onPressed: onPressed,
text: text,
));
}
if (widget.handleCut != null) {
addToolbarButton(localizations.cutButtonLabel, widget.handleCut!);
}
if (widget.handleCopy != null) {
addToolbarButton(localizations.copyButtonLabel, widget.handleCopy!);
}
if (widget.handlePaste != null
&& _clipboardStatus!.value == ClipboardStatus.pasteable) {
addToolbarButton(localizations.pasteButtonLabel, widget.handlePaste!);
}
if (widget.handleSelectAll != null) {
addToolbarButton(localizations.selectAllButtonLabel, widget.handleSelectAll!);
}
// If there is no option available, build an empty widget.
if (items.isEmpty) {
return const SizedBox(width: 0.0, height: 0.0);
}
return CupertinoTextSelectionToolbar(
anchorAbove: anchorAbove,
anchorBelow: anchorBelow,
children: items,
);
}
}
/// Draws a single text selection handle with a bar and a ball.
class _TextSelectionHandlePainter extends CustomPainter {
const _TextSelectionHandlePainter(this.color);
final Color color;
@override
void paint(Canvas canvas, Size size) {
const double halfStrokeWidth = 1.0;
final Paint paint = Paint()..color = color;
final Rect circle = Rect.fromCircle(
center: const Offset(_kSelectionHandleRadius, _kSelectionHandleRadius),
radius: _kSelectionHandleRadius,
);
final Rect line = Rect.fromPoints(
const Offset(
_kSelectionHandleRadius - halfStrokeWidth,
2 * _kSelectionHandleRadius - _kSelectionHandleOverlap,
),
Offset(_kSelectionHandleRadius + halfStrokeWidth, size.height),
);
final Path path = Path()
..addOval(circle)
// Draw line so it slightly overlaps the circle.
..addRect(line);
canvas.drawPath(path, paint);
}
@override
bool shouldRepaint(_TextSelectionHandlePainter oldPainter) => color != oldPainter.color;
}
/// iOS Cupertino styled text selection controls.
class CupertinoTextSelectionControls extends TextSelectionControls {
/// Returns the size of the Cupertino handle.
@override
Size getHandleSize(double textLineHeight) {
return Size(
_kSelectionHandleRadius * 2,
textLineHeight + _kSelectionHandleRadius * 2 - _kSelectionHandleOverlap,
);
}
/// Builder for iOS-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 _CupertinoTextSelectionControlsToolbar(
clipboardStatus: clipboardStatus,
endpoints: endpoints,
globalEditableRegion: globalEditableRegion,
handleCut: canCut(delegate) ? () => handleCut(delegate) : null,
handleCopy: canCopy(delegate) ? () => handleCopy(delegate, clipboardStatus) : null,
handlePaste: canPaste(delegate) ? () => handlePaste(delegate) : null,
handleSelectAll: canSelectAll(delegate) ? () => handleSelectAll(delegate) : null,
selectionMidpoint: selectionMidpoint,
textLineHeight: textLineHeight,
);
}
/// Builder for iOS text selection edges.
@override
Widget buildHandle(BuildContext context, TextSelectionHandleType type, double textLineHeight, [VoidCallback? onTap]) {
// iOS selection handles do not respond to taps.
// 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 = getHandleSize(textLineHeight);
final Widget handle = SizedBox.fromSize(
size: desiredSize,
child: CustomPaint(
painter: _TextSelectionHandlePainter(CupertinoTheme.of(context).primaryColor),
),
);
// [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:
return handle;
case TextSelectionHandleType.right:
// Right handle is a vertical mirror of the left.
return Transform(
transform: Matrix4.identity()
..translate(desiredSize.width / 2, desiredSize.height / 2)
..rotateZ(math.pi)
..translate(-desiredSize.width / 2, -desiredSize.height / 2),
child: handle,
);
// iOS doesn't draw anything for collapsed selections.
case TextSelectionHandleType.collapsed:
return const SizedBox();
}
}
/// Gets anchor for cupertino-style text selection handles.
///
/// See [TextSelectionControls.getHandleAnchor].
@override
Offset getHandleAnchor(TextSelectionHandleType type, double textLineHeight) {
final Size handleSize = getHandleSize(textLineHeight);
switch (type) {
// The circle is at the top for the left handle, and the anchor point is
// all the way at the bottom of the line.
case TextSelectionHandleType.left:
return Offset(
handleSize.width / 2,
handleSize.height,
);
// The right handle is vertically flipped, and the anchor point is near
// the top of the circle to give slight overlap.
case TextSelectionHandleType.right:
return Offset(
handleSize.width / 2,
handleSize.height - 2 * _kSelectionHandleRadius + _kSelectionHandleOverlap,
);
// A collapsed handle anchors itself so that it's centered.
case TextSelectionHandleType.collapsed:
return Offset(
handleSize.width / 2,
textLineHeight + (handleSize.height - textLineHeight) / 2,
);
}
}
}
/// Text selection controls that follows iOS design conventions.
final TextSelectionControls cupertinoTextSelectionControls = CupertinoTextSelectionControls();