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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:ui' as ui show PointerChange, PointerData, PointerSignalKind;
import 'events.dart';
export 'dart:ui' show PointerData;
export 'events.dart' show PointerEvent;
// Add `kPrimaryButton` to [buttons] when a pointer of certain devices is down.
//
// TODO(tongmu): This patch is supposed to be done by embedders. Patching it
// in framework is a workaround before [PointerEventConverter] is moved to embedders.
// https://github.com/flutter/flutter/issues/30454
int _synthesiseDownButtons(int buttons, PointerDeviceKind kind) {
switch (kind) {
case PointerDeviceKind.mouse:
case PointerDeviceKind.trackpad:
return buttons;
case PointerDeviceKind.touch:
case PointerDeviceKind.stylus:
case PointerDeviceKind.invertedStylus:
return buttons == 0 ? kPrimaryButton : buttons;
case PointerDeviceKind.unknown:
// We have no information about the device but we know we never want
// buttons to be 0 when the pointer is down.
return buttons == 0 ? kPrimaryButton : buttons;
}
}
/// Converts from engine pointer data to framework pointer events.
///
/// This takes [PointerDataPacket] objects, as received from the engine via
/// [dart:ui.PlatformDispatcher.onPointerDataPacket], and converts them to
/// [PointerEvent] objects.
class PointerEventConverter {
// This class is not meant to be instantiated or extended; this constructor
// prevents instantiation and extension.
PointerEventConverter._();
/// Expand the given packet of pointer data into a sequence of framework
/// pointer events.
///
/// The `devicePixelRatio` argument (usually given the value from
/// [dart:ui.FlutterView.devicePixelRatio]) is used to convert the incoming data
/// from physical coordinates to logical pixels. See the discussion at
/// [PointerEvent] for more details on the [PointerEvent] coordinate space.
static Iterable<PointerEvent> expand(Iterable<ui.PointerData> data, double devicePixelRatio) {
return data
.where((ui.PointerData datum) => datum.signalKind != ui.PointerSignalKind.unknown)
.map((ui.PointerData datum) {
final Offset position = Offset(datum.physicalX, datum.physicalY) / devicePixelRatio;
final Offset delta = Offset(datum.physicalDeltaX, datum.physicalDeltaY) / devicePixelRatio;
final double radiusMinor = _toLogicalPixels(datum.radiusMinor, devicePixelRatio);
final double radiusMajor = _toLogicalPixels(datum.radiusMajor, devicePixelRatio);
final double radiusMin = _toLogicalPixels(datum.radiusMin, devicePixelRatio);
final double radiusMax = _toLogicalPixels(datum.radiusMax, devicePixelRatio);
final Duration timeStamp = datum.timeStamp;
final PointerDeviceKind kind = datum.kind;
switch (datum.signalKind ?? ui.PointerSignalKind.none) {
case ui.PointerSignalKind.none:
switch (datum.change) {
case ui.PointerChange.add:
return PointerAddedEvent(
timeStamp: timeStamp,
kind: kind,
device: datum.device,
position: position,
obscured: datum.obscured,
pressureMin: datum.pressureMin,
pressureMax: datum.pressureMax,
distance: datum.distance,
distanceMax: datum.distanceMax,
radiusMin: radiusMin,
radiusMax: radiusMax,
orientation: datum.orientation,
tilt: datum.tilt,
embedderId: datum.embedderId,
);
case ui.PointerChange.hover:
return PointerHoverEvent(
timeStamp: timeStamp,
kind: kind,
device: datum.device,
position: position,
delta: delta,
buttons: datum.buttons,
obscured: datum.obscured,
pressureMin: datum.pressureMin,
pressureMax: datum.pressureMax,
distance: datum.distance,
distanceMax: datum.distanceMax,
size: datum.size,
radiusMajor: radiusMajor,
radiusMinor: radiusMinor,
radiusMin: radiusMin,
radiusMax: radiusMax,
orientation: datum.orientation,
tilt: datum.tilt,
synthesized: datum.synthesized,
embedderId: datum.embedderId,
);
case ui.PointerChange.down:
return PointerDownEvent(
timeStamp: timeStamp,
pointer: datum.pointerIdentifier,
kind: kind,
device: datum.device,
position: position,
buttons: _synthesiseDownButtons(datum.buttons, kind),
obscured: datum.obscured,
pressure: datum.pressure,
pressureMin: datum.pressureMin,
pressureMax: datum.pressureMax,
distanceMax: datum.distanceMax,
size: datum.size,
radiusMajor: radiusMajor,
radiusMinor: radiusMinor,
radiusMin: radiusMin,
radiusMax: radiusMax,
orientation: datum.orientation,
tilt: datum.tilt,
embedderId: datum.embedderId,
);
case ui.PointerChange.move:
return PointerMoveEvent(
timeStamp: timeStamp,
pointer: datum.pointerIdentifier,
kind: kind,
device: datum.device,
position: position,
delta: delta,
buttons: _synthesiseDownButtons(datum.buttons, kind),
obscured: datum.obscured,
pressure: datum.pressure,
pressureMin: datum.pressureMin,
pressureMax: datum.pressureMax,
distanceMax: datum.distanceMax,
size: datum.size,
radiusMajor: radiusMajor,
radiusMinor: radiusMinor,
radiusMin: radiusMin,
radiusMax: radiusMax,
orientation: datum.orientation,
tilt: datum.tilt,
platformData: datum.platformData,
synthesized: datum.synthesized,
embedderId: datum.embedderId,
);
case ui.PointerChange.up:
return PointerUpEvent(
timeStamp: timeStamp,
pointer: datum.pointerIdentifier,
kind: kind,
device: datum.device,
position: position,
buttons: datum.buttons,
obscured: datum.obscured,
pressure: datum.pressure,
pressureMin: datum.pressureMin,
pressureMax: datum.pressureMax,
distance: datum.distance,
distanceMax: datum.distanceMax,
size: datum.size,
radiusMajor: radiusMajor,
radiusMinor: radiusMinor,
radiusMin: radiusMin,
radiusMax: radiusMax,
orientation: datum.orientation,
tilt: datum.tilt,
embedderId: datum.embedderId,
);
case ui.PointerChange.cancel:
return PointerCancelEvent(
timeStamp: timeStamp,
pointer: datum.pointerIdentifier,
kind: kind,
device: datum.device,
position: position,
buttons: datum.buttons,
obscured: datum.obscured,
pressureMin: datum.pressureMin,
pressureMax: datum.pressureMax,
distance: datum.distance,
distanceMax: datum.distanceMax,
size: datum.size,
radiusMajor: radiusMajor,
radiusMinor: radiusMinor,
radiusMin: radiusMin,
radiusMax: radiusMax,
orientation: datum.orientation,
tilt: datum.tilt,
embedderId: datum.embedderId,
);
case ui.PointerChange.remove:
return PointerRemovedEvent(
timeStamp: timeStamp,
kind: kind,
device: datum.device,
position: position,
obscured: datum.obscured,
pressureMin: datum.pressureMin,
pressureMax: datum.pressureMax,
distanceMax: datum.distanceMax,
radiusMin: radiusMin,
radiusMax: radiusMax,
embedderId: datum.embedderId,
);
case ui.PointerChange.panZoomStart:
return PointerPanZoomStartEvent(
timeStamp: timeStamp,
pointer: datum.pointerIdentifier,
device: datum.device,
position: position,
embedderId: datum.embedderId,
synthesized: datum.synthesized,
);
case ui.PointerChange.panZoomUpdate:
final Offset pan =
Offset(datum.panX, datum.panY) / devicePixelRatio;
final Offset panDelta =
Offset(datum.panDeltaX, datum.panDeltaY) / devicePixelRatio;
return PointerPanZoomUpdateEvent(
timeStamp: timeStamp,
pointer: datum.pointerIdentifier,
device: datum.device,
position: position,
pan: pan,
panDelta: panDelta,
scale: datum.scale,
rotation: datum.rotation,
embedderId: datum.embedderId,
synthesized: datum.synthesized,
);
case ui.PointerChange.panZoomEnd:
return PointerPanZoomEndEvent(
timeStamp: timeStamp,
pointer: datum.pointerIdentifier,
device: datum.device,
position: position,
embedderId: datum.embedderId,
synthesized: datum.synthesized,
);
}
case ui.PointerSignalKind.scroll:
final Offset scrollDelta =
Offset(datum.scrollDeltaX, datum.scrollDeltaY) / devicePixelRatio;
return PointerScrollEvent(
timeStamp: timeStamp,
kind: kind,
device: datum.device,
position: position,
scrollDelta: scrollDelta,
embedderId: datum.embedderId,
);
case ui.PointerSignalKind.scrollInertiaCancel:
return PointerScrollInertiaCancelEvent(
timeStamp: timeStamp,
kind: kind,
device: datum.device,
position: position,
embedderId: datum.embedderId,
);
case ui.PointerSignalKind.scale:
return PointerScaleEvent(
timeStamp: timeStamp,
kind: kind,
device: datum.device,
position: position,
embedderId: datum.embedderId,
scale: datum.scale,
);
case ui.PointerSignalKind.unknown:
// This branch should already have 'unknown' filtered out, but
// we don't want to return anything or miss if someone adds a new
// enumeration to PointerSignalKind.
throw StateError('Unreachable');
}
});
}
static double _toLogicalPixels(double physicalPixels, double devicePixelRatio) => physicalPixels / devicePixelRatio;
}