// // Tweener.cs // // Author: // Jason Smith // // Copyright (c) 2012 Xamarin Inc. // // Permission is hereby granted, free of charge, to any person obtaining a copy // of this software and associated documentation files (the "Software"), to deal // in the Software without restriction, including without limitation the rights // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell // copies of the Software, and to permit persons to whom the Software is // furnished to do so, subject to the following conditions: // // The above copyright notice and this permission notice shall be included in // all copies or substantial portions of the Software. // // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN // THE SOFTWARE. using System; using Xamarin.Forms.Internals; namespace Xamarin.Forms { internal class Tweener { long _lastMilliseconds; int _timer; public Tweener(uint length) { Value = 0.0f; Length = length; Loop = false; } public AnimatableKey Handle { get; set; } public uint Length { get; } public bool Loop { get; set; } public double Value { get; private set; } public event EventHandler Finished; public void Pause() { if (_timer != 0) { Ticker.Default.Remove(_timer); _timer = 0; } } public void Start() { Pause(); _lastMilliseconds = 0; _timer = Ticker.Default.Insert(step => { long ms = step + _lastMilliseconds; Value = Math.Min(1.0f, ms / (double)Length); _lastMilliseconds = ms; if (ValueUpdated != null) ValueUpdated(this, EventArgs.Empty); if (Value >= 1.0f) { if (Loop) { _lastMilliseconds = 0; Value = 0.0f; return true; } if (Finished != null) Finished(this, EventArgs.Empty); Value = 0.0f; _timer = 0; return false; } return true; }); } public void Stop() { Pause(); Value = 1.0f; if (Finished != null) Finished(this, EventArgs.Empty); Value = 0.0f; } public event EventHandler ValueUpdated; ~Tweener() { if (_timer != 0) { try { Ticker.Default.Remove(_timer); } catch (InvalidOperationException) { } } _timer = 0; } } }