private async void OnUriChanged()
{
if (_uri == null)
{
ReleaseContent();
return;
}
_surface = await SurfaceLoader.LoadFromUri(_uri);
if (_loadEffectDelegate != null)
{
_effectSurface = await SurfaceLoader.LoadFromUri(_uri, Size.Empty, _loadEffectDelegate);
}
// Async operations may take a while. If we've unloaded, return now.
if (_unloaded)
{
ReleaseContent();
return;
}
// Apply stretching policy
ApplyStretchingPolicy(new Size(ActualWidth, ActualHeight));
if (_effectBrush == null)
{
CompositionSurfaceBrush brush = (CompositionSurfaceBrush)_sprite.Brush;
if (brush != null)
{
brush.Surface = _surface;
}
else
{
_sprite.Brush = _compositor.CreateSurfaceBrush(_surface);
}
}
else
{
_effectBrush.SetSourceParameter("ImageSource", _compositor.CreateSurfaceBrush(_surface));
if (_effectSurface != null)
{
_effectBrush.SetSourceParameter("EffectSource", _compositor.CreateSurfaceBrush(_effectSurface));
}
_sprite.Brush = _effectBrush;
}
}
public async void SetEffectBrush(CompositionEffectBrush brush)
{
// Release previous brush if set
if (_effectBrush != null)
{
_effectBrush.Dispose();
_effectBrush = null;
}
if (_effectSurface != null)
{
_effectSurface.Dispose();
_effectSurface = null;
}
_effectBrush = brush;
// Set the new brush
if (_sprite != null)
{
// Release current brush
if (_sprite.Brush != null)
{
_sprite.Brush.Dispose();
}
if (_surface != null)
{
// If the effect brush is cleared, create a surface brush
if (_effectBrush == null)
{
_sprite.Brush = _compositor.CreateSurfaceBrush(_surface);
}
else
{
_effectBrush.SetSourceParameter("ImageSource", _compositor.CreateSurfaceBrush(_surface));
if (_loadEffectDelegate != null)
{
_effectSurface = await SurfaceLoader.LoadFromUri(_uri, Size.Empty, _loadEffectDelegate);
_effectBrush.SetSourceParameter("EffectSource", _compositor.CreateSurfaceBrush(_effectSurface));
}
_sprite.Brush = _effectBrush;
}
}
}
}
/// <summary>
/// MainPage_Loaded is used for all of our initialization to keep the UI thread mostly free.
/// </summary>
/// <param name="sender">not used</param>
/// <param name="e">not used</param>
private void MainPage_Loaded(object sender, RoutedEventArgs e)
{
_compositor = ElementCompositionPreview.GetElementVisual(sender as UIElement).Compositor;
_imageFactory = CompositionImageFactory.CreateCompositionImageFactory(_compositor);
var scrollProperties = ElementCompositionPreview.GetScrollViewerManipulationPropertySet(Scroller);
SurfaceLoader.Initialize(_compositor);
ParallaxingImage.LoadTimeEffectHandler = ApplyBlurEffect;
ParallaxingImage.Uri = new Uri("ms-appx:///assets/RollingWaves.jpg");
ParallaxingImage.SetEffectBrush(InitializeCrossFadeEffect());
var maskedBrush = InitializeCompositeEffect();
ParallaxingImage.SizeChanged += (s, ev) => { UpdateSizes(); };
InitializeBackgroundImageVisual(scrollProperties);
InitializeFrontVisual(scrollProperties, maskedBrush);
InitializeBehindVisual(scrollProperties, maskedBrush);
UpdateSizes();
}