/// <summary>
/// Creates the SurfaceImages based on the ItemsSource
/// </summary>
/// <returns>Task</returns>
private async Task CreateSurfaceImagesAsync()
{
if (_surfaceImagesCreated)
{
return;
}
var padding = Padding;
// Clear previous visuals
_surfaceVisuals.Clear();
_fluidItems.Clear();
_bgLayer.Children.RemoveAll();
_topLayer.Children.RemoveAll();
_selectedVisual = null;
// Dispose the surface images
for (var i = 0; i < _surfaceImages.Count; i++)
{
var surfaceImage = _surfaceImages.ElementAt(i);
surfaceImage.Dispose();
}
_surfaceImages.Clear();
if ((ItemsSource == null) || !ItemsSource.Any())
{
return;
}
var options = ImageSurfaceOptions.Default;
options.SurfaceBackgroundColor = Colors.Transparent;
var availableSize = new Size(_availableWidth, _availableHeight);
for (var i = 0; i < ItemsSource.Count(); i++)
{
// Create the surface image
var surfaceImage = await _generator.CreateImageSurfaceAsync(ItemsSource.ElementAt(i), availableSize, options);
_surfaceImages.Add(surfaceImage);
// Add a visual for the background
var containerVisual = _compositor.CreateSpriteVisual();
containerVisual.Size = availableSize.ToVector2();
containerVisual.Brush = _compositor.CreateColorBrush(ItemBackground);
containerVisual.Offset = new Vector3((float)padding.Left, (float)padding.Top, 0);
// Create the visual for the content
var contentVisual = _compositor.CreateSpriteVisual();
contentVisual.Size = availableSize.ToVector2();
var surfaceBrush = _compositor.CreateSurfaceBrush(surfaceImage.Surface);
surfaceBrush.UpdateSurfaceBrushOptions(Stretch, AlignX, AlignY);
contentVisual.Brush = surfaceBrush;
// Calculate the Inset Clip
var left = i * (_itemWidth + ItemGap.ToSingle());
var right = _availableWidth - (left + _itemWidth);
containerVisual.Properties.InsertScalar("LeftInset", left);
containerVisual.Properties.InsertScalar("RightInset", right);
containerVisual.Clip = _compositor.CreateInsetClip(left, 0, right, 0);
// Center Point
containerVisual.CenterPoint = new Vector3(left + (_itemWidth / 2f), (float)padding.Top + (_itemHeight / 2f), 0);
contentVisual.CenterPoint = containerVisual.CenterPoint;
containerVisual.ImplicitAnimations = _implicitAnimationCollection;
contentVisual.ImplicitAnimations = _implicitAnimationCollection;
// Set the container content
containerVisual.Children.InsertAtTop(contentVisual);
// Add to Background Layer
_bgLayer.Children.InsertAtTop(containerVisual);
// Add Visual to the fluid items
_fluidItems[containerVisual] = new Rect(padding.Left + left, padding.Top, _itemWidth, _itemHeight);
_surfaceVisuals[surfaceImage] = containerVisual;
}
}
/// <summary>
/// Handles the Arrange pass during Layout
/// </summary>
/// <param name="finalSize">Final Size of the control</param>
/// <returns>Total size occupied by all the Children</returns>
protected override Size ArrangeOverride(Size finalSize)
{
if ((ItemsSource == null) || !ItemsSource.Any())
{
return(finalSize);
}
// Resize the rootContainer
_rootContainer.Size = finalSize.ToVector2();
var padding = Padding;
var paddingSize = padding.CollapseThickness();
var width = finalSize.Width;
var height = finalSize.Height;
_itemCount = ItemsSource.Count();
_availableWidth = (width - paddingSize.Width).ToSingle();
_availableHeight = (height - paddingSize.Height).ToSingle();
var gapCount = _itemCount - 1;
var totalGap = (gapCount * ItemGap).ToSingle();
var availableNonGapWidth = _availableWidth - totalGap;
var availableNonGapHeight = _availableHeight;
_itemWidth = availableNonGapWidth / _itemCount;
_itemHeight = availableNonGapHeight;
_bannerBounds = new Rect(padding.Left, padding.Top, _availableWidth, _availableHeight);
// Update Visual sizes and surfaceImages
var availableSize = new Vector2(_availableWidth, _availableHeight);
_rootContainer.Size = availableSize;
_bgLayer.Size = availableSize;
_bgLayer.CenterPoint = new Vector3(_bgLayer.Size * 0.5f, 0);
_topLayer.Size = availableSize;
// Check if any visual is currently selected. If yes then obtain its index.
// The new visual at that index should be selected and added to the toplayer
var selectedVisualIndex = -1;
if (_selectedVisual != null)
{
foreach (var item in _fluidItems)
{
selectedVisualIndex++;
if (ReferenceEquals(item.Key, _selectedVisual))
{
break;
}
}
}
for (var index = 0; index < _surfaceImages.Count; index++)
{
// Get the surfaceImage
var surfaceImage = _surfaceImages.ElementAt(index);
// Get the visual corresponding to this surfaceImage
var itemVisual = _surfaceVisuals[surfaceImage];
if (itemVisual == null)
{
continue;
}
itemVisual.Size = availableSize;
itemVisual.CenterPoint = new Vector3(itemVisual.Size * 0.5f, 0);
var contentVisual = itemVisual.Children.ElementAt(0) as SpriteVisual;
if (contentVisual == null)
{
continue;
}
contentVisual.Size = availableSize;
contentVisual.CenterPoint = itemVisual.CenterPoint;
(contentVisual.Brush as CompositionSurfaceBrush)?.UpdateSurfaceBrushOptions(Stretch, AlignX, AlignY);
// Calculate the Inset Clip
var left = index * (_itemWidth + ItemGap.ToSingle());
var right = _availableWidth - (left + _itemWidth);
itemVisual.Properties.InsertScalar("LeftInset", left);
itemVisual.Properties.InsertScalar("RightInset", right);
itemVisual.Clip = (index == selectedVisualIndex)
? _compositor.CreateInsetClip(0, 0, 0, 0)
: _compositor.CreateInsetClip(left, 0, right, 0);
// Center Point
itemVisual.CenterPoint = new Vector3(left + (_itemWidth / 2f), (float)padding.Top + (_itemHeight / 2f), 0);
contentVisual.CenterPoint = itemVisual.CenterPoint;
// Update Fluid Items
_fluidItems[itemVisual] = new Rect(padding.Left + left, padding.Top, _itemWidth, _itemHeight);
}
// Update Animations' keyframes
_expandRightInset.InsertKeyFrame(1f, _availableWidth - _itemWidth);
_collapseInsetClip.InsertKeyFrame(1f, _availableWidth - _itemWidth);
return(finalSize);
}