/// <summary>
/// Zooms to the specified factor using an animation instead of
/// immediately jumping to that value as with ZoomToFactor().
/// </summary>
/// <remarks>
/// Note that calling ZoomToFactor() does not update ZoomFactor immediately,
/// so it is important to wait for it to change before calling this method.
/// </remarks>
/// <param name="scrollViewer"></param>
/// <param name="factor"></param>
/// <param name="duration"></param>
/// <param name="easingFunction"></param>
/// <returns></returns>
public static async Task ZoomToFactorWithAnimation(
this ScrollViewer scrollViewer,
double factor,
TimeSpan duration,
EasingFunctionBase easingFunction)
{
var handler = GetAnimatedScrollHandler(scrollViewer);
if (handler == null)
{
handler = new ScrollViewerAnimatedScrollHandler();
SetAnimatedScrollHandler(scrollViewer, handler);
}
await handler.ZoomToFactorWithAnimation(
factor, duration, easingFunction);
}
/// <summary>
/// Scrolls to the specified offset using an animation instead of
/// immediately jumping to that offset as with ScrollToVerticalOffset().
/// </summary>
/// <remarks>
/// Note that calling ScrollToVerticalOffset() does not update VerticalOffset immediately,
/// so it is important to wait for it to change before calling this method.
/// </remarks>
/// <param name="scrollViewer"></param>
/// <param name="offset"></param>
/// <param name="duration"></param>
/// <param name="easingFunction"></param>
/// <returns></returns>
public static async Task ScrollToVerticalOffsetWithAnimation(
this ScrollViewer scrollViewer,
double offset,
TimeSpan duration,
EasingFunctionBase easingFunction)
{
var handler = GetAnimatedScrollHandler(scrollViewer);
if (handler == null)
{
handler = new ScrollViewerAnimatedScrollHandler();
SetAnimatedScrollHandler(scrollViewer, handler);
}
await handler.ScrollToVerticalOffsetWithAnimation(
offset, duration, easingFunction);
}
/// <summary>
/// Handles changes to the AnimatedScrollHandler property.
/// </summary>
/// <param name="d">
/// The <see cref="DependencyObject"/> on which
/// the property has changed value.
/// </param>
/// <param name="e">
/// Event data that is issued by any event that
/// tracks changes to the effective value of this property.
/// </param>
private static void OnAnimatedScrollHandlerChanged(
DependencyObject d, DependencyPropertyChangedEventArgs e)
{
ScrollViewerAnimatedScrollHandler oldAnimatedScrollHandler = (ScrollViewerAnimatedScrollHandler)e.OldValue;
ScrollViewerAnimatedScrollHandler newAnimatedScrollHandler = (ScrollViewerAnimatedScrollHandler)d.GetValue(AnimatedScrollHandlerProperty);
var scrollViewer = d as ScrollViewer;
Debug.Assert(scrollViewer != null);
if (oldAnimatedScrollHandler != null)
{
oldAnimatedScrollHandler.Detach();
}
if (newAnimatedScrollHandler != null)
{
newAnimatedScrollHandler.Attach(scrollViewer);
}
}
public static void SetAnimatedScrollHandler(DependencyObject d, ScrollViewerAnimatedScrollHandler value)
{
d.SetValue(AnimatedScrollHandlerProperty, value);
}
