/// <summary>
/// Translates each of the layers in the given <see cref="CompositionContext"/>
/// to a <see cref="Visual"/>.
/// </summary>
/// <returns>The translated layers.</returns>
public static Visual[] TranslateLayersToVisuals(CompositionContext context)
{
var layerTranslators =
(from layer in context.Layers.GetLayersBottomToTop()
let layerTranslator = CreateTranslatorForLayer(context, layer)
where layerTranslator != null
select(layerTranslator: layerTranslator, layer: layer)).ToArray();
// Set descriptions on each translate layer so that it's clear where the layer starts.
if (context.Translation.AddDescriptions)
{
foreach (var(layerTranslator, layer) in layerTranslators)
{
// Add a description if not added already.
if (layerTranslator.ShortDescription is null)
{
layerTranslator.SetDescription(context, $"{layer.Type} layer: {layer.Name}");
}
}
}
// Go through the layers and compose matte layer and layer to be matted into
// the resulting visuals. Any layer that is not a matte or matted layer is
// simply returned unmodified.
var compositionGraphs = Masks.ComposeMattedLayers(context, layerTranslators).ToArray();
// Layers are translated into either a visual tree or a shape tree. Convert the list of Visual and
// Shape roots to a list of Visual roots by wrapping the shape trees in ShapeVisuals.
return(VisualsAndShapesToVisuals(context, compositionGraphs).ToArray());
}
public static LayerTranslator CreatePreCompLayerTranslator(PreCompLayerContext context)
{
// TODO - the animations produced inside a PreComp need to be time-mapped.
// Create the transform chain.
if (!Transforms.TryCreateContainerVisualTransformChain(context, out var rootNode, out var contentsNode))
{
// The layer is never visible.
return(null);
}
var result = context.ObjectFactory.CreateContainerVisual();
#if !NoClipping
// PreComps must clip to their size.
// Create another ContainerVisual to apply clipping to.
var clippingNode = context.ObjectFactory.CreateContainerVisual();
contentsNode.Children.Add(clippingNode);
contentsNode = clippingNode;
contentsNode.Clip = context.ObjectFactory.CreateInsetClip();
contentsNode.Size = context.ChildrenCompositionContext.Size;
#endif
// Add the translations of each layer to the clipping node. This will recursively
// add the tranlation of the layers in nested precomps.
var contentsChildren = contentsNode.Children;
foreach (var visual in Layers.TranslateLayersToVisuals(context.ChildrenCompositionContext))
{
contentsChildren.Add(visual);
}
// Add mask if the layer has masks.
// This must be done after all children are added to the content node.
bool layerHasMasks = false;
#if !NoClipping
layerHasMasks = context.Layer.Masks.Any();
#endif
if (layerHasMasks)
{
var compositedVisual = Masks.TranslateAndApplyMasksForLayer(context, rootNode);
result.Children.Add(compositedVisual);
}
else
{
result.Children.Add(rootNode);
}
return(new LayerTranslator.FromVisual(result));
}
internal override Visual?GetVisualRoot(CompositionContext context)
{
// Translate the SolidLayer to a Visual.
if (_context.Layer.IsHidden || _context.Layer.Transform.Opacity.IsAlways(LottieData.Opacity.Transparent))
{
// The layer does not render anything. Nothing to translate. This can happen when someone
// creates a solid layer to act like a Null layer.
return(null);
}
if (!Transforms.TryCreateContainerVisualTransformChain(_context, out var containerRootNode, out var containerContentNode))
{
// The layer is never visible.
return(null);
}
var rectangle = context.ObjectFactory.CreateSpriteVisual();
rectangle.Size = ConvertTo.Vector2(_context.Layer.Width, _context.Layer.Height);
containerContentNode.Children.Add(rectangle);
var layerHasMasks = false;
#if !NoClipping
layerHasMasks = _context.Layer.Masks.Any();
#endif
rectangle.Brush = Brushes.CreateNonAnimatedColorBrush(_context, _context.Layer.Color);
rectangle.SetDescription(context, () => "SolidLayerRectangle");
var result = layerHasMasks
? Masks.TranslateAndApplyMasksForLayer(_context, containerRootNode)
: containerRootNode;
Describe(context, result);
return(result);
}