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fix for double click not keeping track with event position #1271

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merged 4 commits into from
Jun 15, 2022
Merged

fix for double click not keeping track with event position #1271

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9e57afa
fix for double click not keeping track with event position
ibrierley Jun 10, 2022
0860c0b
dartformat
ibrierley Jun 10, 2022
cd9b0ad
dart format
ibrierley Jun 10, 2022
945f453
dart formtat
ibrierley Jun 10, 2022
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66 changes: 26 additions & 40 deletions lib/src/gestures/gestures.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -34,17 +34,12 @@ abstract class MapGestureMixin extends State<FlutterMap>
final newZoom = (mapState.zoom + pointerSignal.scrollDelta.dy * -0.005)
.clamp(minZoom, maxZoom);
// Calculate offset of mouse cursor from viewport center
final cursorPos = CustomPoint(
pointerSignal.localPosition.dx, pointerSignal.localPosition.dy);
final viewCenter = mapState.originalSize! / 2;
final offset = (cursorPos - viewCenter).rotate(mapState.rotationRad);
// Match new center coordinate to mouse cursor position
final scale = mapState.getZoomScale(newZoom, mapState.zoom);
final newOffset = offset * (1.0 - 1.0 / scale);
final mapCenter = mapState.project(mapState.center);
final newCenter = mapState.unproject(mapCenter + newOffset);
final List<dynamic> newCenterZoom = _getNewEventCenterZoomPosition(
_offsetToPoint(pointerSignal.localPosition), newZoom);

// Move to new center and zoom level
mapState.move(newCenter, newZoom, source: MapEventSource.scrollWheel);
mapState.move(newCenterZoom[0] as LatLng, newCenterZoom[1] as double,
source: MapEventSource.scrollWheel);
}
}

Expand Down Expand Up @@ -598,7 +593,6 @@ abstract class MapGestureMixin extends State<FlutterMap>

void handleDoubleTap(TapPosition tapPosition) {
_resetDoubleTapHold();

if (!options.allowPanning) {
return;
}
Expand All @@ -608,42 +602,38 @@ abstract class MapGestureMixin extends State<FlutterMap>

if (InteractiveFlag.hasFlag(
options.interactiveFlags, InteractiveFlag.doubleTapZoom)) {
final centerPos = _pointToOffset(mapState.originalSize!) / 2.0;
final newZoom = _getZoomForScale(mapState.zoom, 2);
final focalDelta = _getDoubleTapFocalDelta(
centerPos, tapPosition.relative!, newZoom - mapState.zoom);
final newCenter = _offsetToCrs(centerPos + focalDelta);
_startDoubleTapAnimation(newZoom, newCenter);
final centerZoom = _getNewEventCenterZoomPosition(
_offsetToPoint(tapPosition.relative!),
_getZoomForScale(mapState.zoom, 2));
_startDoubleTapAnimation(
centerZoom[1] as double, centerZoom[0] as LatLng);
}
}

Offset _getDoubleTapFocalDelta(
Offset centerPos, Offset tapPos, double zoomDiff) {
final tapDelta = tapPos - centerPos;
final zoomScale = 1 / math.pow(2, zoomDiff);
// The map center offset within which double-tap won't cause zooming to
// previously invisible area
final maxDelta = centerPos * (1 - zoomScale);
final tappedOutExtent =
tapDelta.dx.abs() > maxDelta.dx || tapDelta.dy.abs() > maxDelta.dy;
return tappedOutExtent
? _projectDeltaOnBounds(tapDelta, maxDelta)
: tapDelta;
}
// If we double click in the corner of a map, calculate the new
// center of the whole map after a zoom, to retain that offset position
// so that the same event LatLng is still under the cursor.

Offset _projectDeltaOnBounds(Offset delta, Offset maxDelta) {
final weightX = delta.dx.abs() / maxDelta.dx;
final weightY = delta.dy.abs() / maxDelta.dy;
return delta / math.max(weightX, weightY);
List<dynamic> _getNewEventCenterZoomPosition(
CustomPoint cursorPos, double newZoom) {
// Calculate offset of mouse cursor from viewport center
final viewCenter = mapState.originalSize! / 2;
final offset = (cursorPos - viewCenter).rotate(mapState.rotationRad);
// Match new center coordinate to mouse cursor position
final scale = mapState.getZoomScale(newZoom, mapState.zoom);
final newOffset = offset * (1.0 - 1.0 / scale);
final mapCenter = mapState.project(mapState.center);
final newCenter = mapState.unproject(mapCenter + newOffset);
return <dynamic>[newCenter, newZoom];
}

void _startDoubleTapAnimation(double newZoom, LatLng newCenter) {
_doubleTapZoomAnimation = Tween<double>(begin: mapState.zoom, end: newZoom)
.chain(CurveTween(curve: Curves.fastOutSlowIn))
.chain(CurveTween(curve: Curves.linear))
.animate(_doubleTapController);
_doubleTapCenterAnimation =
LatLngTween(begin: mapState.center, end: newCenter)
.chain(CurveTween(curve: Curves.fastOutSlowIn))
.chain(CurveTween(curve: Curves.linear))
.animate(_doubleTapController);
_doubleTapController.forward(from: 0);
}
Expand Down Expand Up @@ -775,10 +765,6 @@ abstract class MapGestureMixin extends State<FlutterMap>
return CustomPoint(offset.dx, offset.dy);
}

Offset _pointToOffset(CustomPoint point) {
return Offset(point.x.toDouble(), point.y.toDouble());
}

double _getZoomForScale(double startZoom, double scale) {
final resultZoom =
scale == 1.0 ? startZoom : startZoom + math.log(scale) / math.ln2;
Expand Down