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PiliPlus/lib/common/widgets/image_viewer/viewer.dart
dom 2220372e4f tweaks
Signed-off-by: dom <githubaccount56556@proton.me>
2026-03-25 12:58:49 +08:00

549 lines
16 KiB
Dart

/*
* This file is part of PiliPlus
*
* PiliPlus is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* PiliPlus is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with PiliPlus. If not, see <https://www.gnu.org/licenses/>.
*/
import 'dart:math' as math;
import 'package:PiliPlus/common/widgets/gesture/horizontal_drag_gesture_recognizer.dart'
show touchSlopH;
import 'package:PiliPlus/common/widgets/gesture/image_horizontal_drag_gesture_recognizer.dart';
import 'package:PiliPlus/utils/extension/num_ext.dart';
import 'package:easy_debounce/easy_throttle.dart';
import 'package:flutter/foundation.dart';
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:flutter/physics.dart' show FrictionSimulation;
import 'package:flutter/scheduler.dart' show SchedulerBinding;
import 'package:flutter/services.dart' show HardwareKeyboard;
///
/// created by dom on 2026/02/14
///
class Viewer extends StatefulWidget {
const Viewer({
super.key,
required this.minScale,
required this.maxScale,
this.isLongPic = false,
required this.containerSize,
required this.childSize,
required this.onDragStart,
required this.onDragUpdate,
required this.onDragEnd,
required this.doubleTapGestureRecognizer,
required this.horizontalDragGestureRecognizer,
required this.onChangePage,
required this.child,
});
final double minScale;
final double maxScale;
final bool isLongPic;
final Size containerSize;
final Size childSize;
final Widget child;
final ValueChanged<ScaleStartDetails>? onDragStart;
final ValueChanged<ScaleUpdateDetails>? onDragUpdate;
final ValueChanged<ScaleEndDetails>? onDragEnd;
final ValueChanged<int>? onChangePage;
final DoubleTapGestureRecognizer doubleTapGestureRecognizer;
final ImageHorizontalDragGestureRecognizer horizontalDragGestureRecognizer;
@override
State<StatefulWidget> createState() => _ViewerState();
}
class _ViewerState extends State<Viewer> with SingleTickerProviderStateMixin {
static const double _scaleFactor = kDefaultMouseScrollToScaleFactor;
_GestureType? _gestureType;
final Matrix4 _matrix = Matrix4.identity();
late double __scale;
double get _scale => __scale;
set _scale(double value) {
__scale = value;
_matrix[0] = _matrix[5] = _matrix[10] = value;
}
late Offset __position;
Offset get _position => __position;
set _position(Offset value) {
__position = value;
_matrix
..[12] = value.dx
..[13] = value.dy;
}
Offset? _scalePos;
double? _scaleStart;
Offset? _referenceFocalPoint;
late Size _imageSize;
late final DoubleTapGestureRecognizer _doubleTapGestureRecognizer;
late final ImageHorizontalDragGestureRecognizer
_horizontalDragGestureRecognizer;
late final ScaleGestureRecognizer _scaleGestureRecognizer;
Offset? _downPos;
late final AnimationController _animationController;
late double _scaleFrom, _scaleTo;
late Offset _positionFrom, _positionTo;
void _listener() {
final t = Curves.easeOut.transform(_animationController.value);
_scale = t.lerp(_scaleFrom, _scaleTo);
_position = Offset.lerp(_positionFrom, _positionTo, t)!;
setState(() {});
}
void _reset() {
_scale = widget.minScale;
_position = .zero;
}
void _initSize() {
_reset();
_imageSize = applyBoxFit(
.scaleDown,
widget.childSize,
widget.containerSize,
).destination;
if (widget.isLongPic) {
final containerWidth = widget.containerSize.width;
final containerHeight = widget.containerSize.height;
final imageHeight = _imageSize.height * _scale;
_position = Offset(
(1 - _scale) * containerWidth / 2,
(imageHeight - _scale * containerHeight) / 2,
);
}
}
@override
void initState() {
super.initState();
_initSize();
_animationController = AnimationController(
vsync: this,
duration: const Duration(milliseconds: 300),
)..addListener(_listener);
_doubleTapGestureRecognizer = widget.doubleTapGestureRecognizer;
_horizontalDragGestureRecognizer = widget.horizontalDragGestureRecognizer;
_scaleGestureRecognizer = ScaleGestureRecognizer(debugOwner: this)
..dragStartBehavior = .start
..onStart = _onScaleStart
..onUpdate = _onScaleUpdate
..onEnd = _onScaleEnd
..gestureSettings = DeviceGestureSettings(touchSlop: touchSlopH);
}
@override
void didUpdateWidget(Viewer oldWidget) {
super.didUpdateWidget(oldWidget);
if (oldWidget.containerSize != widget.containerSize ||
oldWidget.childSize != widget.childSize) {
_initSize();
}
}
@override
void dispose() {
_stopFling();
_animationController
..removeListener(_listener)
..dispose();
_scaleGestureRecognizer.dispose();
super.dispose();
}
Offset _toScene(Offset localFocalPoint) {
return (localFocalPoint - _position) / _scale;
}
Offset _clampPosition(Offset offset, double scale) {
final containerSize = widget.containerSize;
final imageWidth = _imageSize.width * scale;
final imageHeight = _imageSize.height * scale;
final center = containerSize * (1 - scale) / 2;
final dxOffset = (imageWidth - containerSize.width) / 2;
final dyOffset = (imageHeight - containerSize.height) / 2;
return Offset(
imageWidth > containerSize.width
? clampDouble(
offset.dx,
center.width - dxOffset,
center.width + dxOffset,
)
: center.width,
imageHeight > containerSize.height
? clampDouble(
offset.dy,
center.height - dyOffset,
center.height + dyOffset,
)
: center.height,
);
}
Offset _matrixTranslate(Offset translation) {
if (translation == .zero) {
return _position;
}
return _clampPosition(_position + translation * _scale, _scale);
}
void _onDoubleTapDown(TapDownDetails details) {
_downPos = details.localPosition;
}
void _onDoubleTap() {
if (!mounted) return;
if (_animationController.isAnimating) return;
EasyThrottle.throttle(
'VIEWER_TAP',
const Duration(milliseconds: 555),
_handleDoubleTap,
);
}
void _handleDoubleTap() {
if (!mounted) return;
if (_animationController.isAnimating) return;
_stopFling();
_scaleFrom = _scale;
_positionFrom = _position;
double endScale;
if (_scale == widget.minScale) {
endScale = widget.maxScale * 0.6;
if (endScale <= widget.minScale) {
endScale = widget.maxScale;
}
} else {
endScale = widget.minScale;
}
final position = _clampPosition(
Offset.lerp(_downPos!, _position, endScale / _scale)!,
endScale,
);
_scaleTo = endScale;
_positionTo = position;
_animationController
..duration = const Duration(milliseconds: 300)
..forward(from: 0);
}
static bool _calc(Offset initialPosition, Offset lastPosition) {
final offset = lastPosition - initialPosition;
return offset.dy.abs() > offset.dx.abs();
}
void _onScaleStart(ScaleStartDetails details) {
_stopFling();
if (_animationController.isAnimating) {
_animationController.stop();
}
if (details.pointerCount == 1) {
if (widget.isLongPic) {
final imageHeight = _scale * _imageSize.height;
final containerHeight = widget.containerSize.height;
if (_scalePos != null && _calc(_scalePos!, details.focalPoint)) {
final bool drag;
if (details.focalPoint.dy > _scalePos!.dy) {
drag = _position.dy.equals(
(imageHeight - _scale * containerHeight) / 2,
1e-6,
);
} else {
drag = _position.dy.equals(containerHeight - imageHeight, 1e-6);
}
if (drag) {
_gestureType = .drag;
widget.onDragStart?.call(details);
return;
}
}
} else if (_scale == widget.minScale) {
_gestureType = .drag;
widget.onDragStart?.call(details);
return;
}
}
_scaleStart = _scale;
_referenceFocalPoint = _toScene(details.localFocalPoint);
}
void _onScaleUpdate(ScaleUpdateDetails details) {
if (_gestureType == .drag) {
widget.onDragUpdate?.call(details);
return;
}
if (details.scale != 1.0) {
_gestureType = .scale;
_scale = clampDouble(
_scaleStart! * details.scale,
widget.minScale,
widget.maxScale,
);
final Offset focalPointSceneScaled = _toScene(details.localFocalPoint);
_position = _matrixTranslate(
focalPointSceneScaled - _referenceFocalPoint!,
);
setState(() {});
} else {
_gestureType = .pan;
final Offset focalPointScene = _toScene(details.localFocalPoint);
final Offset translationChange = focalPointScene - _referenceFocalPoint!;
_position = _matrixTranslate(translationChange);
_referenceFocalPoint = _toScene(details.localFocalPoint);
setState(() {});
}
}
/// ref https://github.com/ahnaineh/custom_interactive_viewer
int? _flingFrameCallbackId;
Simulation? _flingSimulation;
Duration? _flingStartTime;
double _lastFlingElapsedSeconds = 0.0;
Offset _flingDirection = Offset.zero;
/// Calculate appropriate friction based on velocity magnitude
double _calculateDynamicFriction(double velocityMagnitude) {
// Use higher friction for faster flicks
// These values can be tuned for the feel you want
if (velocityMagnitude > 5000) {
return 0.03; // Higher friction for very fast flicks
} else if (velocityMagnitude > 3000) {
return 0.02; // Medium friction for moderate flicks
} else {
return 0.01; // Lower friction for gentle movements
}
}
void _startFling(Velocity velocity) {
_stopFling();
final double velocityMagnitude = velocity.pixelsPerSecond.distance;
final double frictionCoefficient = _calculateDynamicFriction(
velocityMagnitude,
);
_flingSimulation = FrictionSimulation(
frictionCoefficient,
0.0,
velocityMagnitude,
);
_flingDirection = velocityMagnitude > 0
? velocity.pixelsPerSecond / velocityMagnitude
: Offset.zero;
_flingStartTime = null;
_lastFlingElapsedSeconds = 0.0;
_scheduleFlingFrame();
}
void _scheduleFlingFrame() {
_flingFrameCallbackId = SchedulerBinding.instance.scheduleFrameCallback(
_handleFlingFrame,
);
}
void _handleFlingFrame(Duration timeStamp) {
if (_flingSimulation == null) return;
_flingStartTime ??= timeStamp;
final double elapsedSeconds =
(timeStamp - _flingStartTime!).inMicroseconds / 1e6;
final double distance = _flingSimulation!.x(elapsedSeconds);
final double prevDistance = _flingSimulation!.x(_lastFlingElapsedSeconds);
final double delta = distance - prevDistance;
_lastFlingElapsedSeconds = elapsedSeconds;
if ((prevDistance != 0.0 && delta.abs() < 0.1) ||
_flingSimulation!.isDone(elapsedSeconds)) {
_stopFling();
return;
}
final Offset movement = _flingDirection * delta;
_position = _clampPosition(_position + movement, _scale);
setState(() {});
if (_flingSimulation!.isDone(elapsedSeconds)) {
_stopFling();
} else {
_scheduleFlingFrame();
}
}
void _stopFling() {
if (_flingFrameCallbackId != null) {
SchedulerBinding.instance.cancelFrameCallbackWithId(
_flingFrameCallbackId!,
);
_flingFrameCallbackId = null;
}
_flingStartTime = null;
_lastFlingElapsedSeconds = 0.0;
_flingSimulation = null;
}
/// ref [InteractiveViewer]
void _onScaleEnd(ScaleEndDetails details) {
switch (_gestureType) {
case _GestureType.pan:
final double velocityMagnitude =
details.velocity.pixelsPerSecond.distance;
if (velocityMagnitude >= 200.0) {
_startFling(details.velocity);
}
case _GestureType.scale:
// if (details.scaleVelocity.abs() < 0.1) {
// return;
// }
// final double scale = _scale;
// final FrictionSimulation frictionSimulation = FrictionSimulation(
// _interactionEndFrictionCoefficient * _scaleFactor,
// scale,
// details.scaleVelocity / 10,
// );
// final double tFinal = _getFinalTime(
// details.scaleVelocity.abs(),
// _interactionEndFrictionCoefficient,
// effectivelyMotionless: 0.1,
// );
// _scaleAnimation = _scaleController.drive(
// Tween<double>(
// begin: scale,
// end: frictionSimulation.x(tFinal),
// ).chain(CurveTween(curve: Curves.decelerate)),
// )..addListener(_handleScaleAnimation);
// _animationController
// ..duration = Duration(milliseconds: (tFinal * 1000).round())
// ..forward(from: 0);
break;
case _GestureType.drag:
widget.onDragEnd?.call(details);
case null:
}
_scalePos = null;
_gestureType = null;
}
@override
Widget build(BuildContext context) {
return Listener(
behavior: .opaque,
onPointerDown: _onPointerDown,
onPointerPanZoomStart: _onPointerPanZoomStart,
onPointerSignal: _onPointerSignal,
child: ClipRect(
child: Transform(
transform: _matrix,
child: widget.child,
),
),
);
}
void _onPointerDown(PointerDownEvent event) {
_scalePos = event.position;
_doubleTapGestureRecognizer
..onDoubleTapDown = _onDoubleTapDown
..onDoubleTap = _onDoubleTap;
_horizontalDragGestureRecognizer.addPointer(
event,
isPointerAllowed: _isAtEdge(event.localPosition),
);
_scaleGestureRecognizer.addPointer(event);
}
void _onPointerPanZoomStart(PointerPanZoomStartEvent event) {
_scaleGestureRecognizer.addPointerPanZoom(event);
}
bool _isAtEdge(Offset position) {
if (_scale <= widget.minScale) {
_horizontalDragGestureRecognizer.setAtBothEdges();
return true;
}
final containerWidth = widget.containerSize.width;
final imageWidth = _imageSize.width * _scale;
if (imageWidth <= containerWidth) {
_horizontalDragGestureRecognizer.setAtBothEdges();
return true;
}
final dx = (1 - _scale) * containerWidth / 2;
final dxOffset = (imageWidth - containerWidth) / 2;
if (_position.dx.equals(dx + dxOffset, 1e-6)) {
_horizontalDragGestureRecognizer.isAtLeftEdge = true;
return true;
}
if (_position.dx.equals(dx - dxOffset, 1e-6)) {
_horizontalDragGestureRecognizer.isAtRightEdge = true;
return true;
}
return false;
}
void _onPointerSignal(PointerSignalEvent event) {
if (event is PointerScrollEvent) {
if (widget.onChangePage != null &&
!HardwareKeyboard.instance.isControlPressed) {
widget.onChangePage!.call(event.scrollDelta.dy < 0 ? -1 : 1);
return;
}
_stopFling();
final double scaleChange = math.exp(-event.scrollDelta.dy / _scaleFactor);
final Offset local = event.localPosition;
final Offset focalPointScene = _toScene(local);
_scale = clampDouble(
_scale * scaleChange,
widget.minScale,
widget.maxScale,
);
final Offset focalPointSceneScaled = _toScene(local);
_position = _matrixTranslate(focalPointSceneScaled - focalPointScene);
setState(() {});
}
}
}
enum _GestureType { pan, scale, drag }