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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 'package:flutter/foundation.dart';
import 'velocity_tracker.dart';
export 'dart:ui' show Offset, PointerDeviceKind;
export 'velocity_tracker.dart' show Velocity;
/// Details object for callbacks that use [GestureDragDownCallback].
///
/// See also:
///
/// * [DragGestureRecognizer.onDown], which uses [GestureDragDownCallback].
/// * [DragStartDetails], the details for [GestureDragStartCallback].
/// * [DragUpdateDetails], the details for [GestureDragUpdateCallback].
/// * [DragEndDetails], the details for [GestureDragEndCallback].
class DragDownDetails {
/// Creates details for a [GestureDragDownCallback].
///
/// The [globalPosition] argument must not be null.
DragDownDetails({
this.globalPosition = Offset.zero,
Offset? localPosition,
}) : localPosition = localPosition ?? globalPosition;
/// The global position at which the pointer contacted the screen.
///
/// Defaults to the origin if not specified in the constructor.
///
/// See also:
///
/// * [localPosition], which is the [globalPosition] transformed to the
/// coordinate space of the event receiver.
final Offset globalPosition;
/// The local position in the coordinate system of the event receiver at
/// which the pointer contacted the screen.
///
/// Defaults to [globalPosition] if not specified in the constructor.
final Offset localPosition;
@override
String toString() => '${objectRuntimeType(this, 'DragDownDetails')}($globalPosition)';
}
/// Signature for when a pointer has contacted the screen and might begin to
/// move.
///
/// The `details` object provides the position of the touch.
///
/// See [DragGestureRecognizer.onDown].
typedef GestureDragDownCallback = void Function(DragDownDetails details);
/// Details object for callbacks that use [GestureDragStartCallback].
///
/// See also:
///
/// * [DragGestureRecognizer.onStart], which uses [GestureDragStartCallback].
/// * [DragDownDetails], the details for [GestureDragDownCallback].
/// * [DragUpdateDetails], the details for [GestureDragUpdateCallback].
/// * [DragEndDetails], the details for [GestureDragEndCallback].
class DragStartDetails {
/// Creates details for a [GestureDragStartCallback].
///
/// The [globalPosition] argument must not be null.
DragStartDetails({
this.sourceTimeStamp,
this.globalPosition = Offset.zero,
Offset? localPosition,
this.kind,
}) : localPosition = localPosition ?? globalPosition;
/// Recorded timestamp of the source pointer event that triggered the drag
/// event.
///
/// Could be null if triggered from proxied events such as accessibility.
final Duration? sourceTimeStamp;
/// The global position at which the pointer contacted the screen.
///
/// Defaults to the origin if not specified in the constructor.
///
/// See also:
///
/// * [localPosition], which is the [globalPosition] transformed to the
/// coordinate space of the event receiver.
final Offset globalPosition;
/// The local position in the coordinate system of the event receiver at
/// which the pointer contacted the screen.
///
/// Defaults to [globalPosition] if not specified in the constructor.
final Offset localPosition;
/// The kind of the device that initiated the event.
final PointerDeviceKind? kind;
// TODO(ianh): Expose the current position, so that you can have a no-jump
// drag even when disambiguating (though of course it would lag the finger
// instead).
@override
String toString() => '${objectRuntimeType(this, 'DragStartDetails')}($globalPosition)';
}
/// {@template flutter.gestures.dragdetails.GestureDragStartCallback}
/// Signature for when a pointer has contacted the screen and has begun to move.
///
/// The `details` object provides the position of the touch when it first
/// touched the surface.
/// {@endtemplate}
///
/// See [DragGestureRecognizer.onStart].
typedef GestureDragStartCallback = void Function(DragStartDetails details);
/// Details object for callbacks that use [GestureDragUpdateCallback].
///
/// See also:
///
/// * [DragGestureRecognizer.onUpdate], which uses [GestureDragUpdateCallback].
/// * [DragDownDetails], the details for [GestureDragDownCallback].
/// * [DragStartDetails], the details for [GestureDragStartCallback].
/// * [DragEndDetails], the details for [GestureDragEndCallback].
class DragUpdateDetails {
/// Creates details for a [GestureDragUpdateCallback].
///
/// The [delta] argument must not be null.
///
/// If [primaryDelta] is non-null, then its value must match one of the
/// coordinates of [delta] and the other coordinate must be zero.
///
/// The [globalPosition] argument must be provided and must not be null.
DragUpdateDetails({
this.sourceTimeStamp,
this.delta = Offset.zero,
this.primaryDelta,
required this.globalPosition,
Offset? localPosition,
}) : assert(
primaryDelta == null
|| (primaryDelta == delta.dx && delta.dy == 0.0)
|| (primaryDelta == delta.dy && delta.dx == 0.0),
),
localPosition = localPosition ?? globalPosition;
/// Recorded timestamp of the source pointer event that triggered the drag
/// event.
///
/// Could be null if triggered from proxied events such as accessibility.
final Duration? sourceTimeStamp;
/// The amount the pointer has moved in the coordinate space of the event
/// receiver since the previous update.
///
/// If the [GestureDragUpdateCallback] is for a one-dimensional drag (e.g.,
/// a horizontal or vertical drag), then this offset contains only the delta
/// in that direction (i.e., the coordinate in the other direction is zero).
///
/// Defaults to zero if not specified in the constructor.
final Offset delta;
/// The amount the pointer has moved along the primary axis in the coordinate
/// space of the event receiver since the previous
/// update.
///
/// If the [GestureDragUpdateCallback] is for a one-dimensional drag (e.g.,
/// a horizontal or vertical drag), then this value contains the component of
/// [delta] along the primary axis (e.g., horizontal or vertical,
/// respectively). Otherwise, if the [GestureDragUpdateCallback] is for a
/// two-dimensional drag (e.g., a pan), then this value is null.
///
/// Defaults to null if not specified in the constructor.
final double? primaryDelta;
/// The pointer's global position when it triggered this update.
///
/// See also:
///
/// * [localPosition], which is the [globalPosition] transformed to the
/// coordinate space of the event receiver.
final Offset globalPosition;
/// The local position in the coordinate system of the event receiver at
/// which the pointer contacted the screen.
///
/// Defaults to [globalPosition] if not specified in the constructor.
final Offset localPosition;
@override
String toString() => '${objectRuntimeType(this, 'DragUpdateDetails')}($delta)';
}
/// {@template flutter.gestures.dragdetails.GestureDragUpdateCallback}
/// Signature for when a pointer that is in contact with the screen and moving
/// has moved again.
///
/// The `details` object provides the position of the touch and the distance it
/// has traveled since the last update.
/// {@endtemplate}
///
/// See [DragGestureRecognizer.onUpdate].
typedef GestureDragUpdateCallback = void Function(DragUpdateDetails details);
/// Details object for callbacks that use [GestureDragEndCallback].
///
/// See also:
///
/// * [DragGestureRecognizer.onEnd], which uses [GestureDragEndCallback].
/// * [DragDownDetails], the details for [GestureDragDownCallback].
/// * [DragStartDetails], the details for [GestureDragStartCallback].
/// * [DragUpdateDetails], the details for [GestureDragUpdateCallback].
class DragEndDetails {
/// Creates details for a [GestureDragEndCallback].
///
/// The [velocity] argument must not be null.
DragEndDetails({
this.velocity = Velocity.zero,
this.primaryVelocity,
}) : assert(
primaryVelocity == null
|| primaryVelocity == velocity.pixelsPerSecond.dx
|| primaryVelocity == velocity.pixelsPerSecond.dy,
);
/// The velocity the pointer was moving when it stopped contacting the screen.
///
/// Defaults to zero if not specified in the constructor.
final Velocity velocity;
/// The velocity the pointer was moving along the primary axis when it stopped
/// contacting the screen, in logical pixels per second.
///
/// If the [GestureDragEndCallback] is for a one-dimensional drag (e.g., a
/// horizontal or vertical drag), then this value contains the component of
/// [velocity] along the primary axis (e.g., horizontal or vertical,
/// respectively). Otherwise, if the [GestureDragEndCallback] is for a
/// two-dimensional drag (e.g., a pan), then this value is null.
///
/// Defaults to null if not specified in the constructor.
final double? primaryVelocity;
@override
String toString() => '${objectRuntimeType(this, 'DragEndDetails')}($velocity)';
}