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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:async';
import 'dart:math' as math;
import 'dart:ui' as ui;
import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/rendering.dart';
import 'package:flutter/scheduler.dart' show timeDilation;
import 'package:flutter/widgets.dart';
import 'constants.dart';
import 'debug.dart';
import 'material_state.dart';
import 'slider_theme.dart';
import 'theme.dart';
// Examples can assume:
// RangeValues _rangeValues = const RangeValues(0.3, 0.7);
// RangeValues _dollarsRange = const RangeValues(50, 100);
// void setState(VoidCallback fn) { }
/// [RangeSlider] uses this callback to paint the value indicator on the overlay.
/// Since the value indicator is painted on the Overlay; this method paints the
/// value indicator in a [RenderBox] that appears in the [Overlay].
typedef PaintRangeValueIndicator = void Function(PaintingContext context, Offset offset);
/// A Material Design range slider.
///
/// Used to select a range from a range of values.
///
/// {@youtube 560 315 https://www.youtube.com/watch?v=ufb4gIPDmEs}
///
/// {@tool dartpad}
/// ![A range slider widget, consisting of 5 divisions and showing the default
/// value indicator.](https://flutter.github.io/assets-for-api-docs/assets/material/range_slider.png)
///
/// This range values are in intervals of 20 because the Range Slider has 5
/// divisions, from 0 to 100. This means are values are split between 0, 20, 40,
/// 60, 80, and 100. The range values are initialized with 40 and 80 in this demo.
///
/// ** See code in examples/api/lib/material/range_slider/range_slider.0.dart **
/// {@end-tool}
///
/// A range slider can be used to select from either a continuous or a discrete
/// set of values. The default is to use a continuous range of values from [min]
/// to [max]. To use discrete values, use a non-null value for [divisions], which
/// indicates the number of discrete intervals. For example, if [min] is 0.0 and
/// [max] is 50.0 and [divisions] is 5, then the slider can take on the
/// discrete values 0.0, 10.0, 20.0, 30.0, 40.0, and 50.0.
///
/// The terms for the parts of a slider are:
///
/// * The "thumbs", which are the shapes that slide horizontally when the user
/// drags them to change the selected range.
/// * The "track", which is the horizontal line that the thumbs can be dragged
/// along.
/// * The "tick marks", which mark the discrete values of a discrete slider.
/// * The "overlay", which is a highlight that's drawn over a thumb in response
/// to a user tap-down gesture.
/// * The "value indicators", which are the shapes that pop up when the user
/// is dragging a thumb to show the value being selected.
/// * The "active" segment of the slider is the segment between the two thumbs.
/// * The "inactive" slider segments are the two track intervals outside of the
/// slider's thumbs.
///
/// The range slider will be disabled if [onChanged] is null or if the range
/// given by [min]..[max] is empty (i.e. if [min] is equal to [max]).
///
/// The range slider widget itself does not maintain any state. Instead, when
/// the state of the slider changes, the widget calls the [onChanged] callback.
/// Most widgets that use a range slider will listen for the [onChanged] callback
/// and rebuild the slider with new [values] to update the visual appearance of
/// the slider. To know when the value starts to change, or when it is done
/// changing, set the optional callbacks [onChangeStart] and/or [onChangeEnd].
///
/// By default, a slider will be as wide as possible, centered vertically. When
/// given unbounded constraints, it will attempt to make the track 144 pixels
/// wide (including margins on each side) and will shrink-wrap vertically.
///
/// Requires one of its ancestors to be a [Material] widget. This is typically
/// provided by a [Scaffold] widget.
///
/// Requires one of its ancestors to be a [MediaQuery] widget. Typically, a
/// [MediaQuery] widget is introduced by the [MaterialApp] or [WidgetsApp]
/// widget at the top of your application widget tree.
///
/// To determine how it should be displayed (e.g. colors, thumb shape, etc.),
/// a slider uses the [SliderThemeData] available from either a [SliderTheme]
/// widget, or the [ThemeData.sliderTheme] inside a [Theme] widget above it in
/// the widget tree. You can also override some of the colors with the
/// [activeColor] and [inactiveColor] properties, although more fine-grained
/// control of the colors, and other visual properties is achieved using a
/// [SliderThemeData].
///
/// See also:
///
/// * [SliderTheme] and [SliderThemeData] for information about controlling
/// the visual appearance of the slider.
/// * [Slider], for a single-valued slider.
/// * [Radio], for selecting among a set of explicit values.
/// * [Checkbox] and [Switch], for toggling a particular value on or off.
/// * <https://material.io/design/components/sliders.html>
/// * [MediaQuery], from which the text scale factor is obtained.
class RangeSlider extends StatefulWidget {
/// Creates a Material Design range slider.
///
/// The range slider widget itself does not maintain any state. Instead, when
/// the state of the slider changes, the widget calls the [onChanged] callback.
/// Most widgets that use a range slider will listen for the [onChanged] callback
/// and rebuild the slider with new [values] to update the visual appearance of
/// the slider. To know when the value starts to change, or when it is done
/// changing, set the optional callbacks [onChangeStart] and/or [onChangeEnd].
///
/// * [values], which determines currently selected values for this range
/// slider.
/// * [onChanged], which is called while the user is selecting a new value for
/// the range slider.
/// * [onChangeStart], which is called when the user starts to select a new
/// value for the range slider.
/// * [onChangeEnd], which is called when the user is done selecting a new
/// value for the range slider.
///
/// You can override some of the colors with the [activeColor] and
/// [inactiveColor] properties, although more fine-grained control of the
/// appearance is achieved using a [SliderThemeData].
///
/// The [values], [min], [max] must not be null. The [min] must be less than
/// or equal to the [max]. [values].start must be less than or equal to
/// [values].end. [values].start and [values].end must be greater than or
/// equal to the [min] and less than or equal to the [max]. The [divisions]
/// must be null or greater than 0.
RangeSlider({
super.key,
required this.values,
required this.onChanged,
this.onChangeStart,
this.onChangeEnd,
this.min = 0.0,
this.max = 1.0,
this.divisions,
this.labels,
this.activeColor,
this.inactiveColor,
this.overlayColor,
this.mouseCursor,
this.semanticFormatterCallback,
}) : assert(min <= max),
assert(values.start <= values.end),
assert(values.start >= min && values.start <= max),
assert(values.end >= min && values.end <= max),
assert(divisions == null || divisions > 0);
/// The currently selected values for this range slider.
///
/// The slider's thumbs are drawn at horizontal positions that corresponds to
/// these values.
final RangeValues values;
/// Called when the user is selecting a new value for the slider by dragging.
///
/// The slider passes the new values to the callback but does not actually
/// change state until the parent widget rebuilds the slider with the new
/// values.
///
/// If null, the slider will be displayed as disabled.
///
/// The callback provided to [onChanged] should update the state of the parent
/// [StatefulWidget] using the [State.setState] method, so that the parent
/// gets rebuilt; for example:
///
/// {@tool snippet}
///
/// ```dart
/// RangeSlider(
/// values: _rangeValues,
/// min: 1.0,
/// max: 10.0,
/// onChanged: (RangeValues newValues) {
/// setState(() {
/// _rangeValues = newValues;
/// });
/// },
/// )
/// ```
/// {@end-tool}
///
/// See also:
///
/// * [onChangeStart], which is called when the user starts changing the
/// values.
/// * [onChangeEnd], which is called when the user stops changing the values.
final ValueChanged<RangeValues>? onChanged;
/// Called when the user starts selecting new values for the slider.
///
/// This callback shouldn't be used to update the slider [values] (use
/// [onChanged] for that). Rather, it should be used to be notified when the
/// user has started selecting a new value by starting a drag or with a tap.
///
/// The values passed will be the last [values] that the slider had before the
/// change began.
///
/// {@tool snippet}
///
/// ```dart
/// RangeSlider(
/// values: _rangeValues,
/// min: 1.0,
/// max: 10.0,
/// onChanged: (RangeValues newValues) {
/// setState(() {
/// _rangeValues = newValues;
/// });
/// },
/// onChangeStart: (RangeValues startValues) {
/// print('Started change at $startValues');
/// },
/// )
/// ```
/// {@end-tool}
///
/// See also:
///
/// * [onChangeEnd] for a callback that is called when the value change is
/// complete.
final ValueChanged<RangeValues>? onChangeStart;
/// Called when the user is done selecting new values for the slider.
///
/// This differs from [onChanged] because it is only called once at the end
/// of the interaction, while [onChanged] is called as the value is getting
/// updated within the interaction.
///
/// This callback shouldn't be used to update the slider [values] (use
/// [onChanged] for that). Rather, it should be used to know when the user has
/// completed selecting a new [values] by ending a drag or a click.
///
/// {@tool snippet}
///
/// ```dart
/// RangeSlider(
/// values: _rangeValues,
/// min: 1.0,
/// max: 10.0,
/// onChanged: (RangeValues newValues) {
/// setState(() {
/// _rangeValues = newValues;
/// });
/// },
/// onChangeEnd: (RangeValues endValues) {
/// print('Ended change at $endValues');
/// },
/// )
/// ```
/// {@end-tool}
///
/// See also:
///
/// * [onChangeStart] for a callback that is called when a value change
/// begins.
final ValueChanged<RangeValues>? onChangeEnd;
/// The minimum value the user can select.
///
/// Defaults to 0.0. Must be less than or equal to [max].
///
/// If the [max] is equal to the [min], then the slider is disabled.
final double min;
/// The maximum value the user can select.
///
/// Defaults to 1.0. Must be greater than or equal to [min].
///
/// If the [max] is equal to the [min], then the slider is disabled.
final double max;
/// The number of discrete divisions.
///
/// Typically used with [labels] to show the current discrete values.
///
/// If null, the slider is continuous.
final int? divisions;
/// Labels to show as text in the [SliderThemeData.rangeValueIndicatorShape]
/// when the slider is active and [SliderThemeData.showValueIndicator]
/// is satisfied.
///
/// There are two labels: one for the start thumb and one for the end thumb.
///
/// Each label is rendered using the active [ThemeData]'s
/// [TextTheme.bodyLarge] text style, with the theme data's
/// [ColorScheme.onPrimary] color. The label's text style can be overridden
/// with [SliderThemeData.valueIndicatorTextStyle].
///
/// If null, then the value indicator will not be displayed.
///
/// See also:
///
/// * [RangeSliderValueIndicatorShape] for how to create a custom value
/// indicator shape.
final RangeLabels? labels;
/// The color of the track's active segment, i.e. the span of track between
/// the thumbs.
///
/// Defaults to [ColorScheme.primary].
///
/// Using a [SliderTheme] gives more fine-grained control over the
/// appearance of various components of the slider.
final Color? activeColor;
/// The color of the track's inactive segments, i.e. the span of tracks
/// between the min and the start thumb, and the end thumb and the max.
///
/// Defaults to [ColorScheme.primary] with 24% opacity.
///
/// Using a [SliderTheme] gives more fine-grained control over the
/// appearance of various components of the slider.
final Color? inactiveColor;
/// The highlight color that's typically used to indicate that
/// the range slider thumb is hovered or dragged.
///
/// If this property is null, [RangeSlider] will use [activeColor] with
/// an opacity of 0.12. If null, [SliderThemeData.overlayColor]
/// will be used, otherwise defaults to [ColorScheme.primary] with
/// an opacity of 0.12.
final MaterialStateProperty<Color?>? overlayColor;
/// The cursor for a mouse pointer when it enters or is hovering over the
/// widget.
///
/// If null, then the value of [SliderThemeData.mouseCursor] is used. If that
/// is also null, then [MaterialStateMouseCursor.clickable] is used.
///
/// See also:
///
/// * [MaterialStateMouseCursor], which can be used to create a [MouseCursor].
final MaterialStateProperty<MouseCursor?>? mouseCursor;
/// The callback used to create a semantic value from the slider's values.
///
/// Defaults to formatting values as a percentage.
///
/// This is used by accessibility frameworks like TalkBack on Android to
/// inform users what the currently selected value is with more context.
///
/// {@tool snippet}
///
/// In the example below, a slider for currency values is configured to
/// announce a value with a currency label.
///
/// ```dart
/// RangeSlider(
/// values: _dollarsRange,
/// min: 20.0,
/// max: 330.0,
/// onChanged: (RangeValues newValues) {
/// setState(() {
/// _dollarsRange = newValues;
/// });
/// },
/// semanticFormatterCallback: (double newValue) {
/// return '${newValue.round()} dollars';
/// }
/// )
/// ```
/// {@end-tool}
final SemanticFormatterCallback? semanticFormatterCallback;
// Touch width for the tap boundary of the slider thumbs.
static const double _minTouchTargetWidth = kMinInteractiveDimension;
@override
State<RangeSlider> createState() => _RangeSliderState();
@override
void debugFillProperties(DiagnosticPropertiesBuilder properties) {
super.debugFillProperties(properties);
properties.add(DoubleProperty('valueStart', values.start));
properties.add(DoubleProperty('valueEnd', values.end));
properties.add(ObjectFlagProperty<ValueChanged<RangeValues>>('onChanged', onChanged, ifNull: 'disabled'));
properties.add(ObjectFlagProperty<ValueChanged<RangeValues>>.has('onChangeStart', onChangeStart));
properties.add(ObjectFlagProperty<ValueChanged<RangeValues>>.has('onChangeEnd', onChangeEnd));
properties.add(DoubleProperty('min', min));
properties.add(DoubleProperty('max', max));
properties.add(IntProperty('divisions', divisions));
properties.add(StringProperty('labelStart', labels?.start));
properties.add(StringProperty('labelEnd', labels?.end));
properties.add(ColorProperty('activeColor', activeColor));
properties.add(ColorProperty('inactiveColor', inactiveColor));
properties.add(ObjectFlagProperty<ValueChanged<double>>.has('semanticFormatterCallback', semanticFormatterCallback));
}
}
class _RangeSliderState extends State<RangeSlider> with TickerProviderStateMixin {
static const Duration enableAnimationDuration = Duration(milliseconds: 75);
static const Duration valueIndicatorAnimationDuration = Duration(milliseconds: 100);
// Animation controller that is run when the overlay (a.k.a radial reaction)
// changes visibility in response to user interaction.
late AnimationController overlayController;
// Animation controller that is run when the value indicators change visibility.
late AnimationController valueIndicatorController;
// Animation controller that is run when enabling/disabling the slider.
late AnimationController enableController;
// Animation controllers that are run when transitioning between one value
// and the next on a discrete slider.
late AnimationController startPositionController;
late AnimationController endPositionController;
Timer? interactionTimer;
// Value Indicator paint Animation that appears on the Overlay.
PaintRangeValueIndicator? paintTopValueIndicator;
PaintRangeValueIndicator? paintBottomValueIndicator;
bool get _enabled => widget.onChanged != null;
bool _dragging = false;
bool _hovering = false;
void _handleHoverChanged(bool hovering) {
if (hovering != _hovering) {
setState(() { _hovering = hovering; });
}
}
@override
void initState() {
super.initState();
overlayController = AnimationController(
duration: kRadialReactionDuration,
vsync: this,
);
valueIndicatorController = AnimationController(
duration: valueIndicatorAnimationDuration,
vsync: this,
);
enableController = AnimationController(
duration: enableAnimationDuration,
vsync: this,
value: _enabled ? 1.0 : 0.0,
);
startPositionController = AnimationController(
duration: Duration.zero,
vsync: this,
value: _unlerp(widget.values.start),
);
endPositionController = AnimationController(
duration: Duration.zero,
vsync: this,
value: _unlerp(widget.values.end),
);
}
@override
void didUpdateWidget(RangeSlider oldWidget) {
super.didUpdateWidget(oldWidget);
if (oldWidget.onChanged == widget.onChanged) {
return;
}
final bool wasEnabled = oldWidget.onChanged != null;
final bool isEnabled = _enabled;
if (wasEnabled != isEnabled) {
if (isEnabled) {
enableController.forward();
} else {
enableController.reverse();
}
}
}
@override
void dispose() {
interactionTimer?.cancel();
overlayController.dispose();
valueIndicatorController.dispose();
enableController.dispose();
startPositionController.dispose();
endPositionController.dispose();
if (overlayEntry != null) {
overlayEntry!.remove();
overlayEntry = null;
}
super.dispose();
}
void _handleChanged(RangeValues values) {
assert(_enabled);
final RangeValues lerpValues = _lerpRangeValues(values);
if (lerpValues != widget.values) {
widget.onChanged!(lerpValues);
}
}
void _handleDragStart(RangeValues values) {
assert(widget.onChangeStart != null);
_dragging = true;
widget.onChangeStart!(_lerpRangeValues(values));
}
void _handleDragEnd(RangeValues values) {
assert(widget.onChangeEnd != null);
_dragging = false;
widget.onChangeEnd!(_lerpRangeValues(values));
}
// Returns a number between min and max, proportional to value, which must
// be between 0.0 and 1.0.
double _lerp(double value) => ui.lerpDouble(widget.min, widget.max, value)!;
// Returns a new range value with the start and end lerped.
RangeValues _lerpRangeValues(RangeValues values) {
return RangeValues(_lerp(values.start), _lerp(values.end));
}
// Returns a number between 0.0 and 1.0, given a value between min and max.
double _unlerp(double value) {
assert(value <= widget.max);
assert(value >= widget.min);
return widget.max > widget.min ? (value - widget.min) / (widget.max - widget.min) : 0.0;
}
// Returns a new range value with the start and end unlerped.
RangeValues _unlerpRangeValues(RangeValues values) {
return RangeValues(_unlerp(values.start), _unlerp(values.end));
}
// Finds closest thumb. If the thumbs are close to each other, no thumb is
// immediately selected while the drag displacement is zero. If the first
// non-zero displacement is negative, then the left thumb is selected, and if its
// positive, then the right thumb is selected.
Thumb? _defaultRangeThumbSelector(
TextDirection textDirection,
RangeValues values,
double tapValue,
Size thumbSize,
Size trackSize,
double dx, // The horizontal delta or displacement of the drag update.
) {
final double touchRadius = math.max(thumbSize.width, RangeSlider._minTouchTargetWidth) / 2;
final bool inStartTouchTarget = (tapValue - values.start).abs() * trackSize.width < touchRadius;
final bool inEndTouchTarget = (tapValue - values.end).abs() * trackSize.width < touchRadius;
// Use dx if the thumb touch targets overlap. If dx is 0 and the drag
// position is in both touch targets, no thumb is selected because it is
// ambiguous to which thumb should be selected. If the dx is non-zero, the
// thumb selection is determined by the direction of the dx. The left thumb
// is chosen for negative dx, and the right thumb is chosen for positive dx.
if (inStartTouchTarget && inEndTouchTarget) {
final bool towardsStart;
final bool towardsEnd;
switch (textDirection) {
case TextDirection.ltr:
towardsStart = dx < 0;
towardsEnd = dx > 0;
case TextDirection.rtl:
towardsStart = dx > 0;
towardsEnd = dx < 0;
}
if (towardsStart) {
return Thumb.start;
}
if (towardsEnd) {
return Thumb.end;
}
} else {
// Snap position on the track if its in the inactive range.
if (tapValue < values.start || inStartTouchTarget) {
return Thumb.start;
}
if (tapValue > values.end || inEndTouchTarget) {
return Thumb.end;
}
}
return null;
}
@override
Widget build(BuildContext context) {
assert(debugCheckHasMaterial(context));
assert(debugCheckHasMediaQuery(context));
final ThemeData theme = Theme.of(context);
SliderThemeData sliderTheme = SliderTheme.of(context);
// If the widget has active or inactive colors specified, then we plug them
// in to the slider theme as best we can. If the developer wants more
// control than that, then they need to use a SliderTheme. The default
// colors come from the ThemeData.colorScheme. These colors, along with
// the default shapes and text styles are aligned to the Material
// Guidelines.
const double defaultTrackHeight = 4;
const RangeSliderTrackShape defaultTrackShape = RoundedRectRangeSliderTrackShape();
const RangeSliderTickMarkShape defaultTickMarkShape = RoundRangeSliderTickMarkShape();
const SliderComponentShape defaultOverlayShape = RoundSliderOverlayShape();
const RangeSliderThumbShape defaultThumbShape = RoundRangeSliderThumbShape();
const RangeSliderValueIndicatorShape defaultValueIndicatorShape = RectangularRangeSliderValueIndicatorShape();
const ShowValueIndicator defaultShowValueIndicator = ShowValueIndicator.onlyForDiscrete;
const double defaultMinThumbSeparation = 8;
final Set<MaterialState> states = <MaterialState>{
if (!_enabled) MaterialState.disabled,
if (_hovering) MaterialState.hovered,
if (_dragging) MaterialState.dragged,
};
// The value indicator's color is not the same as the thumb and active track
// (which can be defined by activeColor) if the
// RectangularSliderValueIndicatorShape is used. In all other cases, the
// value indicator is assumed to be the same as the active color.
final RangeSliderValueIndicatorShape valueIndicatorShape = sliderTheme.rangeValueIndicatorShape ?? defaultValueIndicatorShape;
final Color valueIndicatorColor;
if (valueIndicatorShape is RectangularRangeSliderValueIndicatorShape) {
valueIndicatorColor = sliderTheme.valueIndicatorColor ?? Color.alphaBlend(theme.colorScheme.onSurface.withOpacity(0.60), theme.colorScheme.surface.withOpacity(0.90));
} else {
valueIndicatorColor = widget.activeColor ?? sliderTheme.valueIndicatorColor ?? theme.colorScheme.primary;
}
Color? effectiveOverlayColor() {
return widget.overlayColor?.resolve(states)
?? widget.activeColor?.withOpacity(0.12)
?? MaterialStateProperty.resolveAs<Color?>(sliderTheme.overlayColor, states)
?? theme.colorScheme.primary.withOpacity(0.12);
}
sliderTheme = sliderTheme.copyWith(
trackHeight: sliderTheme.trackHeight ?? defaultTrackHeight,
activeTrackColor: widget.activeColor ?? sliderTheme.activeTrackColor ?? theme.colorScheme.primary,
inactiveTrackColor: widget.inactiveColor ?? sliderTheme.inactiveTrackColor ?? theme.colorScheme.primary.withOpacity(0.24),
disabledActiveTrackColor: sliderTheme.disabledActiveTrackColor ?? theme.colorScheme.onSurface.withOpacity(0.32),
disabledInactiveTrackColor: sliderTheme.disabledInactiveTrackColor ?? theme.colorScheme.onSurface.withOpacity(0.12),
activeTickMarkColor: widget.inactiveColor ?? sliderTheme.activeTickMarkColor ?? theme.colorScheme.onPrimary.withOpacity(0.54),
inactiveTickMarkColor: widget.activeColor ?? sliderTheme.inactiveTickMarkColor ?? theme.colorScheme.primary.withOpacity(0.54),
disabledActiveTickMarkColor: sliderTheme.disabledActiveTickMarkColor ?? theme.colorScheme.onPrimary.withOpacity(0.12),
disabledInactiveTickMarkColor: sliderTheme.disabledInactiveTickMarkColor ?? theme.colorScheme.onSurface.withOpacity(0.12),
thumbColor: widget.activeColor ?? sliderTheme.thumbColor ?? theme.colorScheme.primary,
overlappingShapeStrokeColor: sliderTheme.overlappingShapeStrokeColor ?? theme.colorScheme.surface,
disabledThumbColor: sliderTheme.disabledThumbColor ?? Color.alphaBlend(theme.colorScheme.onSurface.withOpacity(.38), theme.colorScheme.surface),
overlayColor: effectiveOverlayColor(),
valueIndicatorColor: valueIndicatorColor,
rangeTrackShape: sliderTheme.rangeTrackShape ?? defaultTrackShape,
rangeTickMarkShape: sliderTheme.rangeTickMarkShape ?? defaultTickMarkShape,
rangeThumbShape: sliderTheme.rangeThumbShape ?? defaultThumbShape,
overlayShape: sliderTheme.overlayShape ?? defaultOverlayShape,
rangeValueIndicatorShape: valueIndicatorShape,
showValueIndicator: sliderTheme.showValueIndicator ?? defaultShowValueIndicator,
valueIndicatorTextStyle: sliderTheme.valueIndicatorTextStyle ?? theme.textTheme.bodyLarge!.copyWith(
color: theme.colorScheme.onPrimary,
),
minThumbSeparation: sliderTheme.minThumbSeparation ?? defaultMinThumbSeparation,
thumbSelector: sliderTheme.thumbSelector ?? _defaultRangeThumbSelector,
);
final MouseCursor effectiveMouseCursor = widget.mouseCursor?.resolve(states)
?? sliderTheme.mouseCursor?.resolve(states)
?? MaterialStateMouseCursor.clickable.resolve(states);
// This size is used as the max bounds for the painting of the value
// indicators. It must be kept in sync with the function with the same name
// in slider.dart.
Size screenSize() => MediaQuery.sizeOf(context);
return FocusableActionDetector(
enabled: _enabled,
onShowHoverHighlight: _handleHoverChanged,
includeFocusSemantics: false,
mouseCursor: effectiveMouseCursor,
child: CompositedTransformTarget(
link: _layerLink,
child: _RangeSliderRenderObjectWidget(
values: _unlerpRangeValues(widget.values),
divisions: widget.divisions,
labels: widget.labels,
sliderTheme: sliderTheme,
textScaleFactor: MediaQuery.of(context).textScaleFactor,
screenSize: screenSize(),
onChanged: _enabled && (widget.max > widget.min) ? _handleChanged : null,
onChangeStart: widget.onChangeStart != null ? _handleDragStart : null,
onChangeEnd: widget.onChangeEnd != null ? _handleDragEnd : null,
state: this,
semanticFormatterCallback: widget.semanticFormatterCallback,
hovering: _hovering,
),
),
);
}
final LayerLink _layerLink = LayerLink();
OverlayEntry? overlayEntry;
void showValueIndicator() {
if (overlayEntry == null) {
overlayEntry = OverlayEntry(
builder: (BuildContext context) {
return CompositedTransformFollower(
link: _layerLink,
child: _ValueIndicatorRenderObjectWidget(
state: this,
),
);
},
);
Overlay.of(context, debugRequiredFor: widget).insert(overlayEntry!);
}
}
}
class _RangeSliderRenderObjectWidget extends LeafRenderObjectWidget {
const _RangeSliderRenderObjectWidget({
required this.values,
required this.divisions,
required this.labels,
required this.sliderTheme,
required this.textScaleFactor,
required this.screenSize,
required this.onChanged,
required this.onChangeStart,
required this.onChangeEnd,
required this.state,
required this.semanticFormatterCallback,
required this.hovering,
});
final RangeValues values;
final int? divisions;
final RangeLabels? labels;
final SliderThemeData sliderTheme;
final double textScaleFactor;
final Size screenSize;
final ValueChanged<RangeValues>? onChanged;
final ValueChanged<RangeValues>? onChangeStart;
final ValueChanged<RangeValues>? onChangeEnd;
final SemanticFormatterCallback? semanticFormatterCallback;
final _RangeSliderState state;
final bool hovering;
@override
_RenderRangeSlider createRenderObject(BuildContext context) {
return _RenderRangeSlider(
values: values,
divisions: divisions,
labels: labels,
sliderTheme: sliderTheme,
theme: Theme.of(context),
textScaleFactor: textScaleFactor,
screenSize: screenSize,
onChanged: onChanged,
onChangeStart: onChangeStart,
onChangeEnd: onChangeEnd,
state: state,
textDirection: Directionality.of(context),
semanticFormatterCallback: semanticFormatterCallback,
platform: Theme.of(context).platform,
hovering: hovering,
gestureSettings: MediaQuery.gestureSettingsOf(context),
);
}
@override
void updateRenderObject(BuildContext context, _RenderRangeSlider renderObject) {
renderObject
// We should update the `divisions` ahead of `values`, because the `values`
// setter dependent on the `divisions`.
..divisions = divisions
..values = values
..labels = labels
..sliderTheme = sliderTheme
..theme = Theme.of(context)
..textScaleFactor = textScaleFactor
..screenSize = screenSize
..onChanged = onChanged
..onChangeStart = onChangeStart
..onChangeEnd = onChangeEnd
..textDirection = Directionality.of(context)
..semanticFormatterCallback = semanticFormatterCallback
..platform = Theme.of(context).platform
..hovering = hovering
..gestureSettings = MediaQuery.gestureSettingsOf(context);
}
}
class _RenderRangeSlider extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
_RenderRangeSlider({
required RangeValues values,
required int? divisions,
required RangeLabels? labels,
required SliderThemeData sliderTheme,
required ThemeData? theme,
required double textScaleFactor,
required Size screenSize,
required TargetPlatform platform,
required ValueChanged<RangeValues>? onChanged,
required SemanticFormatterCallback? semanticFormatterCallback,
required this.onChangeStart,
required this.onChangeEnd,
required _RangeSliderState state,
required TextDirection textDirection,
required bool hovering,
required DeviceGestureSettings gestureSettings,
}) : assert(values.start >= 0.0 && values.start <= 1.0),
assert(values.end >= 0.0 && values.end <= 1.0),
_platform = platform,
_semanticFormatterCallback = semanticFormatterCallback,
_labels = labels,
_values = values,
_divisions = divisions,
_sliderTheme = sliderTheme,
_theme = theme,
_textScaleFactor = textScaleFactor,
_screenSize = screenSize,
_onChanged = onChanged,
_state = state,
_textDirection = textDirection,
_hovering = hovering {
_updateLabelPainters();
final GestureArenaTeam team = GestureArenaTeam();
_drag = HorizontalDragGestureRecognizer()
..team = team
..onStart = _handleDragStart
..onUpdate = _handleDragUpdate
..onEnd = _handleDragEnd
..onCancel = _handleDragCancel
..gestureSettings = gestureSettings;
_tap = TapGestureRecognizer()
..team = team
..onTapDown = _handleTapDown
..onTapUp = _handleTapUp
..onTapCancel = _handleTapCancel
..gestureSettings = gestureSettings;
_overlayAnimation = CurvedAnimation(
parent: _state.overlayController,
curve: Curves.fastOutSlowIn,
);
_valueIndicatorAnimation = CurvedAnimation(
parent: _state.valueIndicatorController,
curve: Curves.fastOutSlowIn,
)..addStatusListener((AnimationStatus status) {
if (status == AnimationStatus.dismissed && _state.overlayEntry != null) {
_state.overlayEntry!.remove();
_state.overlayEntry = null;
}
});
_enableAnimation = CurvedAnimation(
parent: _state.enableController,
curve: Curves.easeInOut,
);
}
// Keep track of the last selected thumb so they can be drawn in the
// right order.
Thumb? _lastThumbSelection;
static const Duration _positionAnimationDuration = Duration(milliseconds: 75);
// This value is the touch target, 48, multiplied by 3.
static const double _minPreferredTrackWidth = 144.0;
// Compute the largest width and height needed to paint the slider shapes,
// other than the track shape. It is assumed that these shapes are vertically
// centered on the track.
double get _maxSliderPartWidth => _sliderPartSizes.map((Size size) => size.width).reduce(math.max);
double get _maxSliderPartHeight => _sliderPartSizes.map((Size size) => size.height).reduce(math.max);
List<Size> get _sliderPartSizes => <Size>[
_sliderTheme.overlayShape!.getPreferredSize(isEnabled, isDiscrete),
_sliderTheme.rangeThumbShape!.getPreferredSize(isEnabled, isDiscrete),
_sliderTheme.rangeTickMarkShape!.getPreferredSize(isEnabled: isEnabled, sliderTheme: sliderTheme),
];
double? get _minPreferredTrackHeight => _sliderTheme.trackHeight;
// This rect is used in gesture calculations, where the gesture coordinates
// are relative to the sliders origin. Therefore, the offset is passed as
// (0,0).
Rect get _trackRect => _sliderTheme.rangeTrackShape!.getPreferredRect(
parentBox: this,
sliderTheme: _sliderTheme,
isDiscrete: false,
);
static const Duration _minimumInteractionTime = Duration(milliseconds: 500);
final _RangeSliderState _state;
late Animation<double> _overlayAnimation;
late Animation<double> _valueIndicatorAnimation;
late Animation<double> _enableAnimation;
final TextPainter _startLabelPainter = TextPainter();
final TextPainter _endLabelPainter = TextPainter();
late HorizontalDragGestureRecognizer _drag;
late TapGestureRecognizer _tap;
bool _active = false;
late RangeValues _newValues;
late Offset _startThumbCenter;
late Offset _endThumbCenter;
Rect? overlayStartRect;
Rect? overlayEndRect;
bool get isEnabled => onChanged != null;
bool get isDiscrete => divisions != null && divisions! > 0;
double get _minThumbSeparationValue => isDiscrete ? 0 : sliderTheme.minThumbSeparation! / _trackRect.width;
RangeValues get values => _values;
RangeValues _values;
set values(RangeValues newValues) {
assert(newValues.start >= 0.0 && newValues.start <= 1.0);
assert(newValues.end >= 0.0 && newValues.end <= 1.0);
assert(newValues.start <= newValues.end);
final RangeValues convertedValues = isDiscrete ? _discretizeRangeValues(newValues) : newValues;
if (convertedValues == _values) {
return;
}
_values = convertedValues;
if (isDiscrete) {
// Reset the duration to match the distance that we're traveling, so that
// whatever the distance, we still do it in _positionAnimationDuration,
// and if we get re-targeted in the middle, it still takes that long to
// get to the new location.
final double startDistance = (_values.start - _state.startPositionController.value).abs();
_state.startPositionController.duration = startDistance != 0.0 ? _positionAnimationDuration * (1.0 / startDistance) : Duration.zero;
_state.startPositionController.animateTo(_values.start, curve: Curves.easeInOut);
final double endDistance = (_values.end - _state.endPositionController.value).abs();
_state.endPositionController.duration = endDistance != 0.0 ? _positionAnimationDuration * (1.0 / endDistance) : Duration.zero;
_state.endPositionController.animateTo(_values.end, curve: Curves.easeInOut);
} else {
_state.startPositionController.value = convertedValues.start;
_state.endPositionController.value = convertedValues.end;
}
markNeedsSemanticsUpdate();
}
TargetPlatform _platform;
TargetPlatform get platform => _platform;
set platform(TargetPlatform value) {
if (_platform == value) {
return;
}
_platform = value;
markNeedsSemanticsUpdate();
}
DeviceGestureSettings? get gestureSettings => _drag.gestureSettings;
set gestureSettings(DeviceGestureSettings? gestureSettings) {
_drag.gestureSettings = gestureSettings;
_tap.gestureSettings = gestureSettings;
}
SemanticFormatterCallback? _semanticFormatterCallback;
SemanticFormatterCallback? get semanticFormatterCallback => _semanticFormatterCallback;
set semanticFormatterCallback(SemanticFormatterCallback? value) {
if (_semanticFormatterCallback == value) {
return;
}
_semanticFormatterCallback = value;
markNeedsSemanticsUpdate();
}
int? get divisions => _divisions;
int? _divisions;
set divisions(int? value) {
if (value == _divisions) {
return;
}
_divisions = value;
markNeedsPaint();
}
RangeLabels? get labels => _labels;
RangeLabels? _labels;
set labels(RangeLabels? labels) {
if (labels == _labels) {
return;
}
_labels = labels;
_updateLabelPainters();
}
SliderThemeData get sliderTheme => _sliderTheme;
SliderThemeData _sliderTheme;
set sliderTheme(SliderThemeData value) {
if (value == _sliderTheme) {
return;
}
_sliderTheme = value;
markNeedsPaint();
}
ThemeData? get theme => _theme;
ThemeData? _theme;
set theme(ThemeData? value) {
if (value == _theme) {
return;
}
_theme = value;
markNeedsPaint();
}
double get textScaleFactor => _textScaleFactor;
double _textScaleFactor;
set textScaleFactor(double value) {
if (value == _textScaleFactor) {
return;
}
_textScaleFactor = value;
_updateLabelPainters();
}
Size get screenSize => _screenSize;
Size _screenSize;
set screenSize(Size value) {
if (value == screenSize) {
return;
}
_screenSize = value;
markNeedsPaint();
}
ValueChanged<RangeValues>? get onChanged => _onChanged;
ValueChanged<RangeValues>? _onChanged;
set onChanged(ValueChanged<RangeValues>? value) {
if (value == _onChanged) {
return;
}
final bool wasEnabled = isEnabled;
_onChanged = value;
if (wasEnabled != isEnabled) {
markNeedsPaint();
markNeedsSemanticsUpdate();
}
}
ValueChanged<RangeValues>? onChangeStart;
ValueChanged<RangeValues>? onChangeEnd;
TextDirection get textDirection => _textDirection;
TextDirection _textDirection;
set textDirection(TextDirection value) {
if (value == _textDirection) {
return;
}
_textDirection = value;
_updateLabelPainters();
}
/// True if this slider is being hovered over by a pointer.
bool get hovering => _hovering;
bool _hovering;
set hovering(bool value) {
if (value == _hovering) {
return;
}
_hovering = value;
_updateForHover(_hovering);
}
/// True if the slider is interactive and the start thumb is being
/// hovered over by a pointer.
bool _hoveringStartThumb = false;
bool get hoveringStartThumb => _hoveringStartThumb;
set hoveringStartThumb(bool value) {
if (value == _hoveringStartThumb) {
return;
}
_hoveringStartThumb = value;
_updateForHover(_hovering);
}
/// True if the slider is interactive and the end thumb is being
/// hovered over by a pointer.
bool _hoveringEndThumb = false;
bool get hoveringEndThumb => _hoveringEndThumb;
set hoveringEndThumb(bool value) {
if (value == _hoveringEndThumb) {
return;
}
_hoveringEndThumb = value;
_updateForHover(_hovering);
}
void _updateForHover(bool hovered) {
// Only show overlay when pointer is hovering the thumb.
if (hovered && (hoveringStartThumb || hoveringEndThumb)) {
_state.overlayController.forward();
} else {
_state.overlayController.reverse();
}
}
bool get showValueIndicator {
switch (_sliderTheme.showValueIndicator!) {
case ShowValueIndicator.onlyForDiscrete:
return isDiscrete;
case ShowValueIndicator.onlyForContinuous:
return !isDiscrete;
case ShowValueIndicator.always:
return true;
case ShowValueIndicator.never:
return false;
}
}
Size get _thumbSize => _sliderTheme.rangeThumbShape!.getPreferredSize(isEnabled, isDiscrete);
double get _adjustmentUnit {
switch (_platform) {
case TargetPlatform.iOS:
// Matches iOS implementation of material slider.
return 0.1;
case TargetPlatform.android:
case TargetPlatform.fuchsia:
case TargetPlatform.linux:
case TargetPlatform.macOS:
case TargetPlatform.windows:
// Matches Android implementation of material slider.
return 0.05;
}
}
void _updateLabelPainters() {
_updateLabelPainter(Thumb.start);
_updateLabelPainter(Thumb.end);
}
void _updateLabelPainter(Thumb thumb) {
if (labels == null) {
return;
}
final String text;
final TextPainter labelPainter;
switch (thumb) {
case Thumb.start:
text = labels!.start;
labelPainter = _startLabelPainter;
case Thumb.end:
text = labels!.end;
labelPainter = _endLabelPainter;
}
if (labels != null) {
labelPainter
..text = TextSpan(
style: _sliderTheme.valueIndicatorTextStyle,
text: text,
)
..textDirection = textDirection
..textScaleFactor = textScaleFactor
..layout();
} else {
labelPainter.text = null;
}
// Changing the textDirection can result in the layout changing, because the
// bidi algorithm might line up the glyphs differently which can result in
// different ligatures, different shapes, etc. So we always markNeedsLayout.
markNeedsLayout();
}
@override
void systemFontsDidChange() {
super.systemFontsDidChange();
_startLabelPainter.markNeedsLayout();
_endLabelPainter.markNeedsLayout();
_updateLabelPainters();
}
@override
void attach(PipelineOwner owner) {
super.attach(owner);
_overlayAnimation.addListener(markNeedsPaint);
_valueIndicatorAnimation.addListener(markNeedsPaint);
_enableAnimation.addListener(markNeedsPaint);
_state.startPositionController.addListener(markNeedsPaint);
_state.endPositionController.addListener(markNeedsPaint);
}
@override
void detach() {
_overlayAnimation.removeListener(markNeedsPaint);
_valueIndicatorAnimation.removeListener(markNeedsPaint);
_enableAnimation.removeListener(markNeedsPaint);
_state.startPositionController.removeListener(markNeedsPaint);
_state.endPositionController.removeListener(markNeedsPaint);
super.detach();
}
@override
void dispose() {
_startLabelPainter.dispose();
_endLabelPainter.dispose();
super.dispose();
}
double _getValueFromVisualPosition(double visualPosition) {
switch (textDirection) {
case TextDirection.rtl:
return 1.0 - visualPosition;
case TextDirection.ltr:
return visualPosition;
}
}
double _getValueFromGlobalPosition(Offset globalPosition) {
final double visualPosition = (globalToLocal(globalPosition).dx - _trackRect.left) / _trackRect.width;
return _getValueFromVisualPosition(visualPosition);
}
double _discretize(double value) {
double result = clampDouble(value, 0.0, 1.0);
if (isDiscrete) {
result = (result * divisions!).round() / divisions!;
}
return result;
}
RangeValues _discretizeRangeValues(RangeValues values) {
return RangeValues(_discretize(values.start), _discretize(values.end));
}
void _startInteraction(Offset globalPosition) {
_state.showValueIndicator();
final double tapValue = clampDouble(_getValueFromGlobalPosition(globalPosition), 0.0, 1.0);
_lastThumbSelection = sliderTheme.thumbSelector!(textDirection, values, tapValue, _thumbSize, size, 0);
if (_lastThumbSelection != null) {
_active = true;
// We supply the *current* values as the start locations, so that if we have
// a tap, it consists of a call to onChangeStart with the previous value and
// a call to onChangeEnd with the new value.
final RangeValues currentValues = _discretizeRangeValues(values);
if (_lastThumbSelection == Thumb.start) {
_newValues = RangeValues(tapValue, currentValues.end);
} else if (_lastThumbSelection == Thumb.end) {
_newValues = RangeValues(currentValues.start, tapValue);
}
_updateLabelPainter(_lastThumbSelection!);
onChangeStart?.call(currentValues);
onChanged!(_discretizeRangeValues(_newValues));
_state.overlayController.forward();
if (showValueIndicator) {
_state.valueIndicatorController.forward();
_state.interactionTimer?.cancel();
_state.interactionTimer =
Timer(_minimumInteractionTime * timeDilation, () {
_state.interactionTimer = null;
if (!_active && _state.valueIndicatorController.status == AnimationStatus.completed) {
_state.valueIndicatorController.reverse();
}
});
}
}
}
void _handleDragUpdate(DragUpdateDetails details) {
if (!_state.mounted) {
return;
}
final double dragValue = _getValueFromGlobalPosition(details.globalPosition);
// If no selection has been made yet, test for thumb selection again now
// that the value of dx can be non-zero. If this is the first selection of
// the interaction, then onChangeStart must be called.
bool shouldCallOnChangeStart = false;
if (_lastThumbSelection == null) {
_lastThumbSelection = sliderTheme.thumbSelector!(textDirection, values, dragValue, _thumbSize, size, details.delta.dx);
if (_lastThumbSelection != null) {
shouldCallOnChangeStart = true;
_active = true;
_state.overlayController.forward();
if (showValueIndicator) {
_state.valueIndicatorController.forward();
}
}
}
if (isEnabled && _lastThumbSelection != null) {
final RangeValues currentValues = _discretizeRangeValues(values);
if (onChangeStart != null && shouldCallOnChangeStart) {
onChangeStart!(currentValues);
}
final double currentDragValue = _discretize(dragValue);
if (_lastThumbSelection == Thumb.start) {
_newValues = RangeValues(math.min(currentDragValue, currentValues.end - _minThumbSeparationValue), currentValues.end);
} else if (_lastThumbSelection == Thumb.end) {
_newValues = RangeValues(currentValues.start, math.max(currentDragValue, currentValues.start + _minThumbSeparationValue));
}
onChanged!(_newValues);
}
}
void _endInteraction() {
if (!_state.mounted) {
return;
}
if (showValueIndicator && _state.interactionTimer == null) {
_state.valueIndicatorController.reverse();
}
if (_active && _state.mounted && _lastThumbSelection != null) {
final RangeValues discreteValues = _discretizeRangeValues(_newValues);
onChangeEnd?.call(discreteValues);
_active = false;
}
_state.overlayController.reverse();
}
void _handleDragStart(DragStartDetails details) {
_startInteraction(details.globalPosition);
}
void _handleDragEnd(DragEndDetails details) {
_endInteraction();
}
void _handleDragCancel() {
_endInteraction();
}
void _handleTapDown(TapDownDetails details) {
_startInteraction(details.globalPosition);
}
void _handleTapUp(TapUpDetails details) {
_endInteraction();
}
void _handleTapCancel() {
_endInteraction();
}
@override
bool hitTestSelf(Offset position) => true;
@override
void handleEvent(PointerEvent event, HitTestEntry entry) {
assert(debugHandleEvent(event, entry));
if (event is PointerDownEvent && isEnabled) {
// We need to add the drag first so that it has priority.
_drag.addPointer(event);
_tap.addPointer(event);
}
if (isEnabled) {
if (overlayStartRect != null) {
hoveringStartThumb = overlayStartRect!.contains(event.localPosition);
}
if (overlayEndRect != null) {
hoveringEndThumb = overlayEndRect!.contains(event.localPosition);
}
}
}
@override
double computeMinIntrinsicWidth(double height) => _minPreferredTrackWidth + _maxSliderPartWidth;
@override
double computeMaxIntrinsicWidth(double height) => _minPreferredTrackWidth + _maxSliderPartWidth;
@override
double computeMinIntrinsicHeight(double width) => math.max(_minPreferredTrackHeight!, _maxSliderPartHeight);
@override
double computeMaxIntrinsicHeight(double width) => math.max(_minPreferredTrackHeight!, _maxSliderPartHeight);
@override
bool get sizedByParent => true;
@override
Size computeDryLayout(BoxConstraints constraints) {
return Size(
constraints.hasBoundedWidth ? constraints.maxWidth : _minPreferredTrackWidth + _maxSliderPartWidth,
constraints.hasBoundedHeight ? constraints.maxHeight : math.max(_minPreferredTrackHeight!, _maxSliderPartHeight),
);
}
@override
void paint(PaintingContext context, Offset offset) {
final double startValue = _state.startPositionController.value;
final double endValue = _state.endPositionController.value;
// The visual position is the position of the thumb from 0 to 1 from left
// to right. In left to right, this is the same as the value, but it is
// reversed for right to left text.
final double startVisualPosition;
final double endVisualPosition;
switch (textDirection) {
case TextDirection.rtl:
startVisualPosition = 1.0 - startValue;
endVisualPosition = 1.0 - endValue;
case TextDirection.ltr:
startVisualPosition = startValue;
endVisualPosition = endValue;
}
final Rect trackRect = _sliderTheme.rangeTrackShape!.getPreferredRect(
parentBox: this,
offset: offset,
sliderTheme: _sliderTheme,
isDiscrete: isDiscrete,
);
_startThumbCenter = Offset(trackRect.left + startVisualPosition * trackRect.width, trackRect.center.dy);
_endThumbCenter = Offset(trackRect.left + endVisualPosition * trackRect.width, trackRect.center.dy);
if (isEnabled) {
final Size overlaySize = sliderTheme.overlayShape!.getPreferredSize(isEnabled, false);
overlayStartRect = Rect.fromCircle(center: _startThumbCenter, radius: overlaySize.width / 2.0);
overlayEndRect = Rect.fromCircle(center: _endThumbCenter, radius: overlaySize.width / 2.0);
}
_sliderTheme.rangeTrackShape!.paint(
context,
offset,
parentBox: this,
sliderTheme: _sliderTheme,
enableAnimation: _enableAnimation,
textDirection: _textDirection,
startThumbCenter: _startThumbCenter,
endThumbCenter: _endThumbCenter,
isDiscrete: isDiscrete,
isEnabled: isEnabled,
);
final bool startThumbSelected = _lastThumbSelection == Thumb.start;
final bool endThumbSelected = _lastThumbSelection == Thumb.end;
final Size resolvedscreenSize = screenSize.isEmpty ? size : screenSize;
if (!_overlayAnimation.isDismissed) {
if (startThumbSelected || hoveringStartThumb) {
_sliderTheme.overlayShape!.paint(
context,
_startThumbCenter,
activationAnimation: _overlayAnimation,
enableAnimation: _enableAnimation,
isDiscrete: isDiscrete,
labelPainter: _startLabelPainter,
parentBox: this,
sliderTheme: _sliderTheme,
textDirection: _textDirection,
value: startValue,
textScaleFactor: _textScaleFactor,
sizeWithOverflow: resolvedscreenSize,
);
}
if (endThumbSelected || hoveringEndThumb) {
_sliderTheme.overlayShape!.paint(
context,
_endThumbCenter,
activationAnimation: _overlayAnimation,
enableAnimation: _enableAnimation,
isDiscrete: isDiscrete,
labelPainter: _endLabelPainter,
parentBox: this,
sliderTheme: _sliderTheme,
textDirection: _textDirection,
value: endValue,
textScaleFactor: _textScaleFactor,
sizeWithOverflow: resolvedscreenSize,
);
}
}
if (isDiscrete) {
final double tickMarkWidth = _sliderTheme.rangeTickMarkShape!.getPreferredSize(
isEnabled: isEnabled,
sliderTheme: _sliderTheme,
).width;
final double padding = trackRect.height;
final double adjustedTrackWidth = trackRect.width - padding;
// If the tick marks would be too dense, don't bother painting them.
if (adjustedTrackWidth / divisions! >= 3.0 * tickMarkWidth) {
final double dy = trackRect.center.dy;
for (int i = 0; i <= divisions!; i++) {
final double value = i / divisions!;
// The ticks are mapped to be within the track, so the tick mark width
// must be subtracted from the track width.
final double dx = trackRect.left + value * adjustedTrackWidth + padding / 2;
final Offset tickMarkOffset = Offset(dx, dy);
_sliderTheme.rangeTickMarkShape!.paint(
context,
tickMarkOffset,
parentBox: this,
sliderTheme: _sliderTheme,
enableAnimation: _enableAnimation,
textDirection: _textDirection,
startThumbCenter: _startThumbCenter,
endThumbCenter: _endThumbCenter,
isEnabled: isEnabled,
);
}
}
}
final double thumbDelta = (_endThumbCenter.dx - _startThumbCenter.dx).abs();
final bool isLastThumbStart = _lastThumbSelection == Thumb.start;
final Thumb bottomThumb = isLastThumbStart ? Thumb.end : Thumb.start;
final Thumb topThumb = isLastThumbStart ? Thumb.start : Thumb.end;
final Offset bottomThumbCenter = isLastThumbStart ? _endThumbCenter : _startThumbCenter;
final Offset topThumbCenter = isLastThumbStart ? _startThumbCenter : _endThumbCenter;
final TextPainter bottomLabelPainter = isLastThumbStart ? _endLabelPainter : _startLabelPainter;
final TextPainter topLabelPainter = isLastThumbStart ? _startLabelPainter : _endLabelPainter;
final double bottomValue = isLastThumbStart ? endValue : startValue;
final double topValue = isLastThumbStart ? startValue : endValue;
final bool shouldPaintValueIndicators = isEnabled && labels != null && !_valueIndicatorAnimation.isDismissed && showValueIndicator;
if (shouldPaintValueIndicators) {
_state.paintBottomValueIndicator = (PaintingContext context, Offset offset) {
if (attached) {
_sliderTheme.rangeValueIndicatorShape!.paint(
context,
bottomThumbCenter,
activationAnimation: _valueIndicatorAnimation,
enableAnimation: _enableAnimation,
isDiscrete: isDiscrete,
isOnTop: false,
labelPainter: bottomLabelPainter,
parentBox: this,
sliderTheme: _sliderTheme,
textDirection: _textDirection,
thumb: bottomThumb,
value: bottomValue,
textScaleFactor: textScaleFactor,
sizeWithOverflow: resolvedscreenSize,
);
}
};
}
_sliderTheme.rangeThumbShape!.paint(
context,
bottomThumbCenter,
activationAnimation: _valueIndicatorAnimation,
enableAnimation: _enableAnimation,
isDiscrete: isDiscrete,
isOnTop: false,
textDirection: textDirection,
sliderTheme: _sliderTheme,
thumb: bottomThumb,
isPressed: bottomThumb == Thumb.start ? startThumbSelected : endThumbSelected,
);
if (shouldPaintValueIndicators) {
final double startOffset = sliderTheme.rangeValueIndicatorShape!.getHorizontalShift(
parentBox: this,
center: _startThumbCenter,
labelPainter: _startLabelPainter,
activationAnimation: _valueIndicatorAnimation,
textScaleFactor: textScaleFactor,
sizeWithOverflow: resolvedscreenSize,
);
final double endOffset = sliderTheme.rangeValueIndicatorShape!.getHorizontalShift(
parentBox: this,
center: _endThumbCenter,
labelPainter: _endLabelPainter,
activationAnimation: _valueIndicatorAnimation,
textScaleFactor: textScaleFactor,
sizeWithOverflow: resolvedscreenSize,
);
final double startHalfWidth = sliderTheme.rangeValueIndicatorShape!.getPreferredSize(
isEnabled,
isDiscrete,
labelPainter: _startLabelPainter,
textScaleFactor: textScaleFactor,
).width / 2;
final double endHalfWidth = sliderTheme.rangeValueIndicatorShape!.getPreferredSize(
isEnabled,
isDiscrete,
labelPainter: _endLabelPainter,
textScaleFactor: textScaleFactor,
).width / 2;
double innerOverflow = startHalfWidth + endHalfWidth;
switch (textDirection) {
case TextDirection.ltr:
innerOverflow += startOffset;
innerOverflow -= endOffset;
case TextDirection.rtl:
innerOverflow -= startOffset;
innerOverflow += endOffset;
}
_state.paintTopValueIndicator = (PaintingContext context, Offset offset) {
if (attached) {
_sliderTheme.rangeValueIndicatorShape!.paint(
context,
topThumbCenter,
activationAnimation: _valueIndicatorAnimation,
enableAnimation: _enableAnimation,
isDiscrete: isDiscrete,
isOnTop: thumbDelta < innerOverflow,
labelPainter: topLabelPainter,
parentBox: this,
sliderTheme: _sliderTheme,
textDirection: _textDirection,
thumb: topThumb,
value: topValue,
textScaleFactor: textScaleFactor,
sizeWithOverflow: resolvedscreenSize,
);
}
};
}
_sliderTheme.rangeThumbShape!.paint(
context,
topThumbCenter,
activationAnimation: _overlayAnimation,
enableAnimation: _enableAnimation,
isDiscrete: isDiscrete,
isOnTop: thumbDelta < sliderTheme.rangeThumbShape!.getPreferredSize(isEnabled, isDiscrete).width,
textDirection: textDirection,
sliderTheme: _sliderTheme,
thumb: topThumb,
isPressed: topThumb == Thumb.start ? startThumbSelected : endThumbSelected,
);
}
/// Describe the semantics of the start thumb.
SemanticsNode? _startSemanticsNode = SemanticsNode();
/// Describe the semantics of the end thumb.
SemanticsNode? _endSemanticsNode = SemanticsNode();
// Create the semantics configuration for a single value.
SemanticsConfiguration _createSemanticsConfiguration(
double value,
double increasedValue,
double decreasedValue,
VoidCallback increaseAction,
VoidCallback decreaseAction,
) {
final SemanticsConfiguration config = SemanticsConfiguration();
config.isEnabled = isEnabled;
config.textDirection = textDirection;
config.isSlider = true;
if (isEnabled) {
config.onIncrease = increaseAction;
config.onDecrease = decreaseAction;
}
if (semanticFormatterCallback != null) {
config.value = semanticFormatterCallback!(_state._lerp(value));
config.increasedValue = semanticFormatterCallback!(_state._lerp(increasedValue));
config.decreasedValue = semanticFormatterCallback!(_state._lerp(decreasedValue));
} else {
config.value = '${(value * 100).round()}%';
config.increasedValue = '${(increasedValue * 100).round()}%';
config.decreasedValue = '${(decreasedValue * 100).round()}%';
}
return config;
}
@override
void assembleSemanticsNode(
SemanticsNode node,
SemanticsConfiguration config,
Iterable<SemanticsNode> children,
) {
assert(children.isEmpty);
final SemanticsConfiguration startSemanticsConfiguration = _createSemanticsConfiguration(
values.start,
_increasedStartValue,
_decreasedStartValue,
_increaseStartAction,
_decreaseStartAction,
);
final SemanticsConfiguration endSemanticsConfiguration = _createSemanticsConfiguration(
values.end,
_increasedEndValue,
_decreasedEndValue,
_increaseEndAction,
_decreaseEndAction,
);
// Split the semantics node area between the start and end nodes.
final Rect leftRect = Rect.fromCenter(
center: _startThumbCenter,
width: kMinInteractiveDimension,
height: kMinInteractiveDimension,
);
final Rect rightRect = Rect.fromCenter(
center: _endThumbCenter,
width: kMinInteractiveDimension,
height: kMinInteractiveDimension,
);
switch (textDirection) {
case TextDirection.ltr:
_startSemanticsNode!.rect = leftRect;
_endSemanticsNode!.rect = rightRect;
case TextDirection.rtl:
_startSemanticsNode!.rect = rightRect;
_endSemanticsNode!.rect = leftRect;
}
_startSemanticsNode!.updateWith(config: startSemanticsConfiguration);
_endSemanticsNode!.updateWith(config: endSemanticsConfiguration);
final List<SemanticsNode> finalChildren = <SemanticsNode>[
_startSemanticsNode!,
_endSemanticsNode!,
];
node.updateWith(config: config, childrenInInversePaintOrder: finalChildren);
}
@override
void clearSemantics() {
super.clearSemantics();
_startSemanticsNode = null;
_endSemanticsNode = null;
}
@override
void describeSemanticsConfiguration(SemanticsConfiguration config) {
super.describeSemanticsConfiguration(config);
config.isSemanticBoundary = true;
}
double get _semanticActionUnit => divisions != null ? 1.0 / divisions! : _adjustmentUnit;
void _increaseStartAction() {
if (isEnabled) {
onChanged!(RangeValues(_increasedStartValue, values.end));
}
}
void _decreaseStartAction() {
if (isEnabled) {
onChanged!(RangeValues(_decreasedStartValue, values.end));
}
}
void _increaseEndAction() {
if (isEnabled) {
onChanged!(RangeValues(values.start, _increasedEndValue));
}
}
void _decreaseEndAction() {
if (isEnabled) {
onChanged!(RangeValues(values.start, _decreasedEndValue));
}
}
double get _increasedStartValue {
// Due to floating-point operations, this value can actually be greater than
// expected (e.g. 0.4 + 0.2 = 0.600000000001), so we limit to 2 decimal points.
final double increasedStartValue = double.parse((values.start + _semanticActionUnit).toStringAsFixed(2));
return increasedStartValue <= values.end - _minThumbSeparationValue ? increasedStartValue : values.start;
}
double get _decreasedStartValue {
return clampDouble(values.start - _semanticActionUnit, 0.0, 1.0);
}
double get _increasedEndValue {
return clampDouble(values.end + _semanticActionUnit, 0.0, 1.0);
}
double get _decreasedEndValue {
final double decreasedEndValue = values.end - _semanticActionUnit;
return decreasedEndValue >= values.start + _minThumbSeparationValue ? decreasedEndValue : values.end;
}
}
class _ValueIndicatorRenderObjectWidget extends LeafRenderObjectWidget {
const _ValueIndicatorRenderObjectWidget({
required this.state,
});
final _RangeSliderState state;
@override
_RenderValueIndicator createRenderObject(BuildContext context) {
return _RenderValueIndicator(
state: state,
);
}
@override
void updateRenderObject(BuildContext context, _RenderValueIndicator renderObject) {
renderObject._state = state;
}
}
class _RenderValueIndicator extends RenderBox with RelayoutWhenSystemFontsChangeMixin {
_RenderValueIndicator({
required _RangeSliderState state,
}) :_state = state {
_valueIndicatorAnimation = CurvedAnimation(
parent: _state.valueIndicatorController,
curve: Curves.fastOutSlowIn,
);
}
late Animation<double> _valueIndicatorAnimation;
late _RangeSliderState _state;
@override
bool get sizedByParent => true;
@override
void attach(PipelineOwner owner) {
super.attach(owner);
_valueIndicatorAnimation.addListener(markNeedsPaint);
_state.startPositionController.addListener(markNeedsPaint);
_state.endPositionController.addListener(markNeedsPaint);
}
@override
void detach() {
_valueIndicatorAnimation.removeListener(markNeedsPaint);
_state.startPositionController.removeListener(markNeedsPaint);
_state.endPositionController.removeListener(markNeedsPaint);
super.detach();
}
@override
void paint(PaintingContext context, Offset offset) {
_state.paintBottomValueIndicator?.call(context, offset);
_state.paintTopValueIndicator?.call(context, offset);
}
@override
Size computeDryLayout(BoxConstraints constraints) {
return constraints.smallest;
}
}