| using System; |
| using System.Windows; |
| using System.Windows.Controls; |
| using System.Windows.Input; |
| using System.Windows.Media; |
| using System.Windows.Media.Animation; |
| |
| namespace Telerik.Windows.QuickStart |
| { |
| [TemplatePart(Name = "ScrollViewer", Type = typeof(ScrollViewer))] |
| public class AutoScrollPanel : ContentControl |
| { |
| #region - private fields - |
| private FrameworkElement content { get; set; } |
| private string PROPERTY_NAME = "(UIElement.RenderTransform).(TransformGroup.Children)[0].(TranslateTransform.Y)"; |
| private Point currentMousePosition = new Point(); |
| private ScrollViewer scrollViewer; |
| private double CurrentTransformY |
| { |
| get |
| { |
| return ((content.RenderTransform as TransformGroup).Children[0] as TranslateTransform).Y; |
| } |
| set |
| { |
| ((content.RenderTransform as TransformGroup).Children[0] as TranslateTransform).Y = value; |
| } |
| } |
| #endregion |
| |
| public AutoScrollPanel() |
| { |
| this.DefaultStyleKey = typeof(AutoScrollPanel); |
| Loaded += (sender, e) => { InitializeComponent(); }; |
| } |
| |
| public override void OnApplyTemplate() |
| { |
| base.OnApplyTemplate(); |
| |
| scrollViewer = this.GetTemplateChild("ScrollViewer") as ScrollViewer; |
| } |
| |
| private void InitializeComponent() |
| { |
| content = this.Content as FrameworkElement; |
| |
| content.RenderTransform = CreateTransformGroup(); |
| } |
| |
| private static TransformGroup CreateTransformGroup() |
| { |
| var transformGroup = new TransformGroup(); |
| transformGroup.Children.Add(new TranslateTransform()); |
| return transformGroup; |
| } |
| |
| |
| protected override void OnMouseMove(MouseEventArgs e) |
| { |
| base.OnMouseMove(e); |
| |
| currentMousePosition = e.GetPosition(scrollViewer); |
| |
| double newIndex = CreateNewTransformY(); |
| |
| var storyBoard = new CustomStoryboard(content); |
| SetStoryBoard(this, storyBoard); |
| |
| EasingValues easingValues = CreateEasingValues(newIndex); |
| |
| var doubleAnimation = new DoubleAnimationUsingKeyFrames(); |
| var k1 = new LinearDoubleKeyFrame |
| { |
| KeyTime = TimeSpan.FromMilliseconds(200), |
| Value = easingValues.EasingOne |
| }; |
| |
| var k2 = new LinearDoubleKeyFrame |
| { |
| KeyTime = TimeSpan.FromMilliseconds(500), |
| Value = easingValues.EasingTwo |
| }; |
| |
| var k3 = new LinearDoubleKeyFrame |
| { |
| KeyTime = TimeSpan.FromMilliseconds(1000), |
| Value = -newIndex |
| }; |
| |
| doubleAnimation.KeyFrames.Add(k1); |
| doubleAnimation.KeyFrames.Add(k2); |
| doubleAnimation.KeyFrames.Add(k3); |
| |
| storyBoard.AddAnimationTimeline(PROPERTY_NAME, doubleAnimation); |
| storyBoard.StartAnimation(this); |
| } |
| |
| |
| private int CreateNewTransformY() |
| { |
| // invisible size of the content in the scrollviewer |
| double scrollableHeight = scrollViewer.ScrollableHeight; |
| |
| // visible height of the content in scrollviewer |
| double viewPortHeight = scrollViewer.ViewportHeight; |
| |
| double index = currentMousePosition.Y / viewPortHeight; |
| |
| return (int)Math.Round(index * scrollableHeight); |
| } |
| |
| private EasingValues CreateEasingValues(double destinationPoint_Y) |
| { |
| EasingValues values = new EasingValues(); |
| |
| // Calculate the middle values from beggining and and of the animaiton |
| double v1 = (CurrentTransformY + destinationPoint_Y) / 3; |
| |
| values.EasingOne = CurrentTransformY - v1; |
| values.EasingTwo = CurrentTransformY - (v1 * 2); |
| |
| return values; |
| } |
| |
| protected override void OnMouseLeave(MouseEventArgs e) |
| { |
| base.OnMouseLeave(e); |
| |
| //StopAnimation(); |
| } |
| |
| internal void UpdatePosition() |
| { |
| StopAnimation(); |
| |
| double newIndex = CreateNewTransformY(); |
| |
| CurrentTransformY = -newIndex; |
| } |
| |
| public void StopAnimation() |
| { |
| var storyBoard = GetStoryBoard(this); |
| if (null != storyBoard && !storyBoard.IsFinished) |
| { |
| storyBoard.Pause(); |
| } |
| } |
| |
| #region - Attached properties - |
| |
| public static CustomStoryboard GetStoryBoard(DependencyObject obj) |
| { |
| return (CustomStoryboard)obj.GetValue(StoryBoardProperty); |
| } |
| |
| public static void SetStoryBoard(DependencyObject obj, CustomStoryboard value) |
| { |
| obj.SetValue(StoryBoardProperty, value); |
| } |
| |
| public static readonly DependencyProperty StoryBoardProperty = |
| DependencyProperty.RegisterAttached("StoryBoard", typeof(CustomStoryboard), typeof(AutoScrollPanel), null); |
| |
| #endregion |
| } |
| |
| internal class EasingValues |
| { |
| [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")] |
| public double EasingOne { get; set; } |
| [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")] |
| public double EasingTwo { get; set; } |
| } |
| } |
| |