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#553 viewer: prevent magnifier recognizer base to accept gestures it cannot handle

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This commit is contained in:
Thibault Deckers 2023-04-29 17:50:33 +02:00
parent 3306bc6340
commit d4e7ca4b3d
2 changed files with 57 additions and 44 deletions
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1
CHANGELOG.md
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@ -20,6 +20,7 @@ All notable changes to this project will be documented in this file.
### Fixed ### Fixed
- Video: switching to PiP when going home with gesture navigation - Video: switching to PiP when going home with gesture navigation
- Viewer: swiping gestures not being handled in some cases
- Viewer: multi-page context update when removing burst entries - Viewer: multi-page context update when removing burst entries
- Info: editing tags with placeholders - Info: editing tags with placeholders
- prevent editing item when Exif editing changes mime type - prevent editing item when Exif editing changes mime type

100
plugins/aves_magnifier/lib/src/core/scale_gesture_recognizer.dart
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@ -47,15 +47,16 @@ class MagnifierGestureRecognizer extends ScaleGestureRecognizer {
void handleEvent(PointerEvent event) { void handleEvent(PointerEvent event) {
if (scope.axis.isNotEmpty) { if (scope.axis.isNotEmpty) {
var didChangeConfiguration = false; var didChangeConfiguration = false;
final pointer = event.pointer;
if (event is PointerMoveEvent) { if (event is PointerMoveEvent) {
if (!event.synthesized) { if (!event.synthesized) {
_pointerLocations[event.pointer] = event.position; _pointerLocations[pointer] = event.position;
} }
} else if (event is PointerDownEvent) { } else if (event is PointerDownEvent) {
_pointerLocations[event.pointer] = event.position; _pointerLocations[pointer] = event.position;
didChangeConfiguration = true; didChangeConfiguration = true;
} else if (event is PointerUpEvent || event is PointerCancelEvent) { } else if (event is PointerUpEvent || event is PointerCancelEvent) {
_pointerLocations.remove(event.pointer); _pointerLocations.remove(pointer);
didChangeConfiguration = true; didChangeConfiguration = true;
} }
@ -67,7 +68,9 @@ class MagnifierGestureRecognizer extends ScaleGestureRecognizer {
_initialSpan = _currentSpan; _initialSpan = _currentSpan;
} }
_decideIfWeAcceptEvent(event); if (event is PointerMoveEvent && (_areMultiPointers() || (_shouldMove() && _isOverSlop(event.kind)))) {
acceptGesture(pointer);
}
} }
super.handleEvent(event); super.handleEvent(event);
} }
@ -93,54 +96,63 @@ class MagnifierGestureRecognizer extends ScaleGestureRecognizer {
_currentSpan = count > 0 ? totalDeviation / count : 0.0; _currentSpan = count > 0 ? totalDeviation / count : 0.0;
} }
void _decideIfWeAcceptEvent(PointerEvent event) { // when there are multiple pointers, we always accept the gesture to scale
if (event is! PointerMoveEvent) return; // as this is not competing with single taps or other drag gestures
bool _areMultiPointers() => _pointerLocations.keys.length >= 2;
if (_pointerLocations.keys.length >= 2) { bool _shouldMove() {
// when there are multiple pointers, we always accept the gesture to scale final move = _initialFocalPoint! - _currentFocalPoint!;
// as this is not competing with single taps or other drag gestures
acceptGesture(event.pointer); // e.g. vertical drag to adjust brightness instead of panning
return; if (scope.acceptPointerEvent?.call(move) ?? false) return true;
}
// e.g. double tap & drag for one finger zoom
if (doubleTapDetails.value != null) return true;
final validateAxis = scope.axis; final validateAxis = scope.axis;
final canFling = scope.escapeByFling; final canFling = scope.escapeByFling;
final move = _initialFocalPoint! - _currentFocalPoint!; if (validateAxis.length == 2) {
bool shouldMove = scope.acceptPointerEvent?.call(move) ?? false; // the image is the descendant of gesture detector(s) handling drag in both directions
final shouldMoveX = validateAxis.contains(Axis.horizontal) && hitDetector.shouldMoveX(move, canFling);
if (!shouldMove) { final shouldMoveY = validateAxis.contains(Axis.vertical) && hitDetector.shouldMoveY(move, canFling);
if (validateAxis.length == 2) { if (shouldMoveX == shouldMoveY) {
// the image is the descendant of gesture detector(s) handling drag in both directions // consistently can/cannot pan the image in both direction the same way
final shouldMoveX = validateAxis.contains(Axis.horizontal) && hitDetector.shouldMoveX(move, canFling); return shouldMoveX;
final shouldMoveY = validateAxis.contains(Axis.vertical) && hitDetector.shouldMoveY(move, canFling);
if (shouldMoveX == shouldMoveY) {
// consistently can/cannot pan the image in both direction the same way
shouldMove = shouldMoveX;
} else {
// can pan the image in one direction, but should yield to an ascendant gesture detector in the other one
// the gesture direction angle is in ]-pi, pi], cf `Offset` doc for details
shouldMove = (isXPan(move) && shouldMoveX) || (isYPan(move) && shouldMoveY);
}
} else { } else {
// the image is the descendant of a gesture detector handling drag in one direction // can pan the image in one direction, but should yield to an ascendant gesture detector in the other one
shouldMove = validateAxis.contains(Axis.vertical) ? hitDetector.shouldMoveY(move, canFling) : hitDetector.shouldMoveX(move, canFling); // the gesture direction angle is in ]-pi, pi], cf `Offset` doc for details
return (isXPan(move) && shouldMoveX) || (isYPan(move) && shouldMoveY);
} }
} else {
// the image is the descendant of a gesture detector handling drag in one direction
return validateAxis.contains(Axis.vertical) ? hitDetector.shouldMoveY(move, canFling) : hitDetector.shouldMoveX(move, canFling);
} }
}
final doubleTap = doubleTapDetails.value != null; bool _isOverSlop(PointerDeviceKind kind) {
if (shouldMove || doubleTap) { final spanDelta = (_currentSpan! - _initialSpan!).abs();
final pointerDeviceKind = event.kind; final focalPointDelta = (_currentFocalPoint! - _initialFocalPoint!).distance;
final spanDelta = (_currentSpan! - _initialSpan!).abs(); // warning: do not compare `focalPointDelta` to `kPanSlop`
final focalPointDelta = (_currentFocalPoint! - _initialFocalPoint!).distance; // `ScaleGestureRecognizer` uses `kPanSlop` (or platform settings, cf gestures/events.dart `computePanSlop`),
// warning: do not compare `focalPointDelta` to `kPanSlop` // but `HorizontalDragGestureRecognizer` uses `kTouchSlop` (or platform settings, cf gestures/events.dart `computeHitSlop`)
// `ScaleGestureRecognizer` uses `kPanSlop` (or platform settings, cf gestures/events.dart `computePanSlop`), // and the magnifier recognizer may compete with the `HorizontalDragGestureRecognizer` from a containing `PageView`
// but `HorizontalDragGestureRecognizer` uses `kTouchSlop` (or platform settings, cf gestures/events.dart `computeHitSlop`) // setting `touchSlopFactor` to 2 restores default `ScaleGestureRecognizer` behaviour as `kPanSlop = kTouchSlop * 2.0`
// and the magnifier recognizer may compete with the `HorizontalDragGestureRecognizer` from a containing `PageView` // setting `touchSlopFactor` in [0, 1] will allow this recognizer to accept the gesture before the one from `PageView`
// setting `touchSlopFactor` to 2 restores default `ScaleGestureRecognizer` behaviour as `kPanSlop = kTouchSlop * 2.0` return spanDelta > computeScaleSlop(kind) || focalPointDelta > computeHitSlop(kind, gestureSettings) * scope.touchSlopFactor;
// setting `touchSlopFactor` in [0, 1] will allow this recognizer to accept the gesture before the one from `PageView` }
if (spanDelta > computeScaleSlop(pointerDeviceKind) || focalPointDelta > computeHitSlop(pointerDeviceKind, gestureSettings) * scope.touchSlopFactor) {
acceptGesture(event.pointer); @override
} void resolve(GestureDisposition disposition) {
switch (disposition) {
case GestureDisposition.accepted:
// do not let super `ScaleGestureRecognizer` accept gestures
// when it should yield to other recognizers
final canAccept = _areMultiPointers() || _shouldMove();
super.resolve(canAccept ? GestureDisposition.accepted : GestureDisposition.rejected);
break;
case GestureDisposition.rejected:
super.resolve(disposition);
break;
} }
} }