aves/lib/widgets/common/magnifier/magnifier.dart
2021-01-11 18:46:41 +09:00

130 lines
4.2 KiB
Dart

import 'package:aves/widgets/common/magnifier/controller/controller.dart';
import 'package:aves/widgets/common/magnifier/controller/state.dart';
import 'package:aves/widgets/common/magnifier/core/core.dart';
import 'package:aves/widgets/common/magnifier/scale/scale_boundaries.dart';
import 'package:aves/widgets/common/magnifier/scale/scale_level.dart';
import 'package:aves/widgets/common/magnifier/scale/state.dart';
import 'package:flutter/material.dart';
/// `Magnifier` is derived from `photo_view` package v0.9.2:
/// - removed image related aspects to focus on a general purpose pan/scale viewer (à la `InteractiveViewer`)
/// - removed rotation and many customization parameters
/// - removed ignorable/ignoring partial notifiers
/// - formatted, renamed and reorganized
/// - fixed gesture recognizers when used inside a scrollable widget like `PageView`
/// - fixed corner hit detection when in containers scrollable in both axes
/// - fixed corner hit detection issues due to imprecise double comparisons
/// - added single & double tap position feedback
/// - fixed focus when scaling by double-tap/pinch
class Magnifier extends StatefulWidget {
const Magnifier({
Key key,
@required this.child,
this.childSize,
this.controller,
this.maxScale,
this.minScale,
this.initialScale,
this.scaleStateCycle,
this.onTap,
this.gestureDetectorBehavior,
this.applyScale,
}) : super(key: key);
final Widget child;
/// The size of the custom [child]. This value is used to compute the relation between the child and the container's size to calculate the scale value.
final Size childSize;
/// Defines the maximum size in which the image will be allowed to assume, it is proportional to the original image size.
final ScaleLevel maxScale;
/// Defines the minimum size in which the image will be allowed to assume, it is proportional to the original image size.
final ScaleLevel minScale;
/// Defines the size the image will assume when the component is initialized, it is proportional to the original image size.
final ScaleLevel initialScale;
final MagnifierController controller;
final ScaleStateCycle scaleStateCycle;
final MagnifierTapCallback onTap;
final HitTestBehavior gestureDetectorBehavior;
final bool applyScale;
@override
State<StatefulWidget> createState() {
return _MagnifierState();
}
}
class _MagnifierState extends State<Magnifier> {
bool _controlledController;
MagnifierController _controller;
Size get childSize => widget.childSize;
@override
void initState() {
super.initState();
if (widget.controller == null) {
_controlledController = true;
_controller = MagnifierController();
} else {
_controlledController = false;
_controller = widget.controller;
}
}
@override
void didUpdateWidget(covariant Magnifier oldWidget) {
super.didUpdateWidget(oldWidget);
if (widget.controller == null) {
if (!_controlledController) {
_controlledController = true;
_controller = MagnifierController();
}
} else {
_controlledController = false;
_controller = widget.controller;
}
}
@override
void dispose() {
if (_controlledController) {
_controller.dispose();
}
super.dispose();
}
@override
Widget build(BuildContext context) {
return LayoutBuilder(
builder: (context, constraints) {
_controller.setScaleBoundaries(ScaleBoundaries(
widget.minScale ?? 0.0,
widget.maxScale ?? ScaleLevel(factor: double.infinity),
widget.initialScale ?? ScaleLevel(ref: ScaleReference.contained),
constraints.biggest,
widget.childSize?.isEmpty == true ? constraints.biggest : widget.childSize,
));
return MagnifierCore(
child: widget.child,
controller: _controller,
scaleStateCycle: widget.scaleStateCycle ?? defaultScaleStateCycle,
onTap: widget.onTap,
gestureDetectorBehavior: widget.gestureDetectorBehavior,
applyScale: widget.applyScale ?? true,
);
},
);
}
}
typedef MagnifierTapCallback = Function(
BuildContext context,
TapUpDetails details,
MagnifierState state,
Offset childTapPosition,
);