converter.dart 9.22 KB
Newer Older
Ian Hickson's avatar
Ian Hickson committed
1
// Copyright 2014 The Flutter Authors. All rights reserved.
Ian Hickson's avatar
Ian Hickson committed
2 3 4
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

5

6
import 'dart:ui' as ui show PointerData, PointerChange, PointerSignalKind;
Ian Hickson's avatar
Ian Hickson committed
7 8 9

import 'events.dart';

10 11 12 13 14 15 16
// 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) {
17 18
    case PointerDeviceKind.mouse:
      return buttons;
19 20 21 22 23
    case PointerDeviceKind.touch:
    case PointerDeviceKind.stylus:
    case PointerDeviceKind.invertedStylus:
      return buttons | kPrimaryButton;
    default:
24 25 26
      // 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;
27 28 29
  }
}

30
/// Converts from engine pointer data to framework pointer events.
31 32 33 34
///
/// This takes [PointerDataPacket] objects, as received from the engine via
/// [dart:ui.Window.onPointerDataPacket], and converts them to [PointerEvent]
/// objects.
Ian Hickson's avatar
Ian Hickson committed
35
class PointerEventConverter {
36
  // This class is not meant to be instantiated or extended; this constructor
37 38
  // prevents instantiation and extension.
  // ignore: unused_element
39 40
  PointerEventConverter._();

41 42
  /// Expand the given packet of pointer data into a sequence of framework
  /// pointer events.
43 44 45 46 47
  ///
  /// The `devicePixelRatio` argument (usually given the value from
  /// [dart:ui.Window.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.
48
  static Iterable<PointerEvent> expand(Iterable<ui.PointerData> data, double devicePixelRatio) sync* {
49
    for (final ui.PointerData datum in data) {
50
      final Offset position = Offset(datum.physicalX, datum.physicalY) / devicePixelRatio;
51
      final Offset delta = Offset(datum.physicalDeltaX, datum.physicalDeltaY) / devicePixelRatio;
52 53 54 55
      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);
56 57
      final Duration timeStamp = datum.timeStamp;
      final PointerDeviceKind kind = datum.kind;
58
      assert(datum.change != null);
59 60 61
      if (datum.signalKind == null || datum.signalKind == ui.PointerSignalKind.none) {
        switch (datum.change) {
          case ui.PointerChange.add:
62
            yield PointerAddedEvent(
63 64 65 66 67 68 69 70 71
              timeStamp: timeStamp,
              kind: kind,
              device: datum.device,
              position: position,
              obscured: datum.obscured,
              pressureMin: datum.pressureMin,
              pressureMax: datum.pressureMax,
              distance: datum.distance,
              distanceMax: datum.distanceMax,
72 73
              radiusMin: radiusMin,
              radiusMax: radiusMax,
74
              orientation: datum.orientation,
75
              tilt: datum.tilt,
76
              embedderId: datum.embedderId,
77
            );
78 79
            break;
          case ui.PointerChange.hover:
80
            yield PointerHoverEvent(
81 82 83 84
              timeStamp: timeStamp,
              kind: kind,
              device: datum.device,
              position: position,
85
              delta: delta,
86 87 88 89 90 91
              buttons: datum.buttons,
              obscured: datum.obscured,
              pressureMin: datum.pressureMin,
              pressureMax: datum.pressureMax,
              distance: datum.distance,
              distanceMax: datum.distanceMax,
92
              size: datum.size,
93 94 95 96
              radiusMajor: radiusMajor,
              radiusMinor: radiusMinor,
              radiusMin: radiusMin,
              radiusMax: radiusMax,
97
              orientation: datum.orientation,
98
              tilt: datum.tilt,
99
              synthesized: datum.synthesized,
100
              embedderId: datum.embedderId,
101
            );
102 103 104
            break;
          case ui.PointerChange.down:
            yield PointerDownEvent(
105
              timeStamp: timeStamp,
106
              pointer: datum.pointerIdentifier,
107
              kind: kind,
108
              device: datum.device,
109
              position: position,
110
              buttons: _synthesiseDownButtons(datum.buttons, kind),
111 112 113 114 115
              obscured: datum.obscured,
              pressure: datum.pressure,
              pressureMin: datum.pressureMin,
              pressureMax: datum.pressureMax,
              distanceMax: datum.distanceMax,
116
              size: datum.size,
117 118 119 120
              radiusMajor: radiusMajor,
              radiusMinor: radiusMinor,
              radiusMin: radiusMin,
              radiusMax: radiusMax,
121
              orientation: datum.orientation,
122
              tilt: datum.tilt,
123
              embedderId: datum.embedderId,
124
            );
125 126 127
            break;
          case ui.PointerChange.move:
            yield PointerMoveEvent(
Ian Hickson's avatar
Ian Hickson committed
128
              timeStamp: timeStamp,
129
              pointer: datum.pointerIdentifier,
Ian Hickson's avatar
Ian Hickson committed
130
              kind: kind,
131
              device: datum.device,
Ian Hickson's avatar
Ian Hickson committed
132
              position: position,
133
              delta: delta,
134
              buttons: _synthesiseDownButtons(datum.buttons, kind),
Ian Hickson's avatar
Ian Hickson committed
135
              obscured: datum.obscured,
136 137
              pressure: datum.pressure,
              pressureMin: datum.pressureMin,
Ian Hickson's avatar
Ian Hickson committed
138 139
              pressureMax: datum.pressureMax,
              distanceMax: datum.distanceMax,
140
              size: datum.size,
141 142 143 144
              radiusMajor: radiusMajor,
              radiusMinor: radiusMinor,
              radiusMin: radiusMin,
              radiusMax: radiusMax,
Ian Hickson's avatar
Ian Hickson committed
145
              orientation: datum.orientation,
146
              tilt: datum.tilt,
147
              platformData: datum.platformData,
148
              synthesized: datum.synthesized,
149
              embedderId: datum.embedderId,
Ian Hickson's avatar
Ian Hickson committed
150
            );
151 152
            break;
          case ui.PointerChange.up:
153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172
            yield 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,
173
              embedderId: datum.embedderId,
174 175
            );
            break;
176
          case ui.PointerChange.cancel:
177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195
            yield 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,
196
              embedderId: datum.embedderId,
197
            );
198 199 200
            break;
          case ui.PointerChange.remove:
            yield PointerRemovedEvent(
Ian Hickson's avatar
Ian Hickson committed
201 202
              timeStamp: timeStamp,
              kind: kind,
203
              device: datum.device,
204
              position: position,
Ian Hickson's avatar
Ian Hickson committed
205 206 207 208
              obscured: datum.obscured,
              pressureMin: datum.pressureMin,
              pressureMax: datum.pressureMax,
              distanceMax: datum.distanceMax,
209 210
              radiusMin: radiusMin,
              radiusMax: radiusMax,
211
              embedderId: datum.embedderId,
Ian Hickson's avatar
Ian Hickson committed
212
            );
213 214 215
            break;
        }
      } else {
216
        switch (datum.signalKind!) {
217 218 219 220
          case ui.PointerSignalKind.scroll:
            final Offset scrollDelta =
                Offset(datum.scrollDeltaX, datum.scrollDeltaY) / devicePixelRatio;
            yield PointerScrollEvent(
221 222 223 224
              timeStamp: timeStamp,
              kind: kind,
              device: datum.device,
              position: position,
225
              scrollDelta: scrollDelta,
226
              embedderId: datum.embedderId,
227
            );
228 229 230 231 232 233 234 235
            break;
          case ui.PointerSignalKind.none:
            assert(false); // This branch should already have 'none' filtered out.
            break;
          case ui.PointerSignalKind.unknown:
            // Ignore unknown signals.
            break;
        }
Ian Hickson's avatar
Ian Hickson committed
236 237 238
      }
    }
  }
239

240
  static double _toLogicalPixels(double physicalPixels, double devicePixelRatio) => physicalPixels / devicePixelRatio;
Ian Hickson's avatar
Ian Hickson committed
241
}