54 lines
1.4 KiB
Dart
54 lines
1.4 KiB
Dart
import 'package:equatable/equatable.dart';
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import 'package:flutter/widgets.dart';
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@immutable
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class ViewState extends Equatable {
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final Offset position;
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final double? scale;
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final Size? viewportSize, contentSize;
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static const ViewState zero = ViewState(
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position: Offset.zero,
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scale: 0,
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viewportSize: null,
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contentSize: null,
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);
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@override
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List<Object?> get props => [position, scale, viewportSize, contentSize];
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const ViewState({
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required this.position,
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required this.scale,
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required this.viewportSize,
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required this.contentSize,
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});
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ViewState copyWith({
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Offset? position,
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double? scale,
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Size? viewportSize,
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Size? contentSize,
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}) {
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return ViewState(
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position: position ?? this.position,
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scale: scale ?? this.scale,
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viewportSize: viewportSize ?? this.viewportSize,
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contentSize: contentSize ?? this.contentSize,
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);
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}
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Matrix4 get matrix {
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final _viewportSize = viewportSize ?? Size.zero;
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final _contentSize = contentSize ?? Size.zero;
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final _scale = scale ?? 1.0;
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final scaledContentSize = _contentSize * _scale;
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final viewOffset = _viewportSize.center(Offset.zero) - scaledContentSize.center(Offset.zero);
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return Matrix4.identity()
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..translateByDouble(position.dx, position.dy, 0, 1)
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..translateByDouble(viewOffset.dx, viewOffset.dy, 0, 1)
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..scaleByDouble(_scale, _scale, 1, 1);
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}
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}
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