expand method Null safety
- Iterable<
PointerData> data, - double devicePixelRatio
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.
Implementation
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;
assert(position != null);
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;
assert(datum.change != null);
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.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');
}
});
}