sideview.dart

import 'package:flutter/rendering.dart';
import 'package:flutter/widgets.dart';

class AnimatedEdgeSlide extends SingleChildRenderObjectWidget {
  const AnimatedEdgeSlide({
    required Widget super.child,
    required this.positionAnimation,
    super.key,
  });

  final Animation<double> positionAnimation;

  @override
  RenderObject createRenderObject(BuildContext context) {
    return RenderAnimatedEdgeSlide(
      positionAnimation: positionAnimation,
    );
  }

  @override
  void updateRenderObject(BuildContext context, covariant RenderObject renderObject) {
    (renderObject as RenderAnimatedEdgeSlide).positionAnimation = positionAnimation;
  }
}

class RenderAnimatedEdgeSlide extends RenderProxyBox {
  RenderAnimatedEdgeSlide({
    required Animation<double> positionAnimation,
  }) : _positionAnimation = positionAnimation;

  Animation<double> get positionAnimation => _positionAnimation;
  Animation<double> _positionAnimation;
  set positionAnimation(Animation<double> value) {
    if (value == _positionAnimation) {
      return;
    }
    if (attached) {
      _positionAnimation.removeListener(_animationListener);
    }
    _positionAnimation = value;
    if (attached) {
      _positionAnimation.addListener(_animationListener);
    }
  }

  @override
  void attach(covariant PipelineOwner owner) {
    super.attach(owner);
    _positionAnimation.addListener(_animationListener);
  }

  @override
  void detach() {
    _positionAnimation.removeListener(_animationListener);
    super.detach();
  }

  void _animationListener() => markNeedsLayout();

  @override
  void performLayout() {
    final child = this.child;

    if (child == null || _positionAnimation.value == 0) {
      size = Size.zero;
      return;
    }

    child.layout(constraints, parentUsesSize: true);

    size = Size(
      child.size.width * _positionAnimation.value,
      constraints.maxHeight,
    );
  }

  @override
  void paint(PaintingContext context, Offset offset) {
    if (child != null && _positionAnimation.value > 0) {
      context.paintChild(child!, offset);
    }
  }
}