// Copyright 2016 The Chromium Authors. All rights reserved. // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. import 'package:flutter/foundation.dart'; import 'package:flutter/rendering.dart'; import 'package:flutter/scheduler.dart'; import 'basic.dart'; import 'framework.dart'; /// Animated widget that automatically transitions its size over a given /// duration whenever the given child's size changes. class AnimatedSize extends SingleChildRenderObjectWidget { /// Creates a widget that animates its size to match that of its child. /// /// The [curve] and [duration] arguments must not be null. AnimatedSize({ Key key, Widget child, this.alignment: FractionalOffset.center, this.curve: Curves.linear, @required this.duration, @required this.vsync, }) : super(key: key, child: child); /// The alignment of the child within the parent when the parent is not yet /// the same size as the child. /// /// The x and y values of the alignment control the horizontal and vertical /// alignment, respectively. An x value of 0.0 means that the left edge of /// the child is aligned with the left edge of the parent whereas an x value /// of 1.0 means that the right edge of the child is aligned with the right /// edge of the parent. Other values interpolate (and extrapolate) linearly. /// For example, a value of 0.5 means that the center of the child is aligned /// with the center of the parent. final FractionalOffset alignment; /// The animation curve when transitioning this widget's size to match the /// child's size. final Curve curve; /// The duration when transitioning this widget's size to match the child's /// size. final Duration duration; /// The [TickerProvider] for this widget. final TickerProvider vsync; @override RenderAnimatedSize createRenderObject(BuildContext context) { return new RenderAnimatedSize( alignment: alignment, duration: duration, curve: curve, vsync: vsync, ); } @override void updateRenderObject(BuildContext context, RenderAnimatedSize renderObject) { renderObject ..alignment = alignment ..duration = duration ..curve = curve ..vsync = vsync; } }