68 lines
2.3 KiB
Dart
68 lines
2.3 KiB
Dart
import 'dart:math';
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import 'dart:ui';
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import 'package:aves/widgets/common/magnifier/controller/controller.dart';
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import 'package:aves/widgets/common/magnifier/scale/scale_level.dart';
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import 'package:equatable/equatable.dart';
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import 'package:flutter/foundation.dart';
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/// Internal class to wrap custom scale boundaries (min, max and initial)
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/// Also, stores values regarding the two sizes: the container and the child.
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@immutable
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class ScaleBoundaries extends Equatable {
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final ScaleLevel _minScale;
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final ScaleLevel _maxScale;
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final ScaleLevel _initialScale;
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final Size viewportSize;
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final Size childSize;
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@override
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List<Object?> get props => [_minScale, _maxScale, _initialScale, viewportSize, childSize];
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const ScaleBoundaries({
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required ScaleLevel minScale,
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required ScaleLevel maxScale,
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required ScaleLevel initialScale,
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required this.viewportSize,
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required this.childSize,
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}) : _minScale = minScale,
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_maxScale = maxScale,
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_initialScale = initialScale;
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double _scaleForLevel(ScaleLevel level) {
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final factor = level.factor;
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switch (level.ref) {
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case ScaleReference.contained:
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return factor * ScaleLevel.scaleForContained(viewportSize, childSize);
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case ScaleReference.covered:
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return factor * ScaleLevel.scaleForCovering(viewportSize, childSize);
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case ScaleReference.absolute:
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default:
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return factor;
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}
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}
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double get originalScale => 1.0 / window.devicePixelRatio;
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double get minScale => {_scaleForLevel(_minScale), originalScale, initialScale}.fold(double.infinity, min);
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double get maxScale => {_scaleForLevel(_maxScale), originalScale, initialScale}.fold(0, max);
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double get initialScale => _scaleForLevel(_initialScale);
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Offset get _viewportCenter => viewportSize.center(Offset.zero);
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Offset get _childCenter => childSize.center(Offset.zero);
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Offset viewportToStatePosition(MagnifierController controller, Offset viewportPosition) {
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return viewportPosition - _viewportCenter - controller.position;
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}
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Offset viewportToChildPosition(MagnifierController controller, Offset viewportPosition) {
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return viewportToStatePosition(controller, viewportPosition) / controller.scale! + _childCenter;
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}
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Offset childToStatePosition(double scale, Offset childPosition) {
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return (_childCenter - childPosition) * scale;
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}
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}
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