public static Visual ApplyDropShadow(
LayerContext context,
Visual source,
DropShadowEffect dropShadowEffect)
{
if (!context.ObjectFactory.IsUapApiAvailable(nameof(CompositionVisualSurface), versionDependentFeatureDescription: "Drop Shadow"))
{
// The effect can't be displayed on the targeted version.
return(source);
}
Debug.Assert(dropShadowEffect.IsEnabled, "Precondition");
Debug.Assert(context is PreCompLayerContext || context is ShapeLayerContext, "Precondition");
// Shadow:
// +------------------+
// | Container Visual | -- Has the final composited result.
// +------------------+ <
// ^ Child #1 \ Child #2 (original layer)
// | (shadow layer) \
// | \
// +---------------------+ \
// | ApplyGaussianBlur() | \
// +---------------------+ +-----------------+
// ^ | ContainerVisual | - Original Visual node.
// | +-----------------+
// +----------------+ .
// | SpriteVisual | .
// +----------------+ .
// ^ Source .
// | .
// +--------------+ .
// | MaskBrush | .
// +--------------+ .
// ^ Source ^ Mask . Source
// | \ V
// +----------+ +---------------+
// |ColorBrush| | VisualSurface |
// +----------+ +---------------+
GaussianBlurEffect gaussianBlurEffect = new GaussianBlurEffect(
name: dropShadowEffect.Name + "_blur",
isEnabled: true,
blurriness: dropShadowEffect.Softness,
blurDimensions: new Animatable <Enum <BlurDimension> >(BlurDimension.HorizontalAndVertical),
repeatEdgePixels: new Animatable <bool>(true),
forceGpuRendering: true);
var factory = context.ObjectFactory;
var size = context.CompositionContext.Size;
if (context is PreCompLayerContext)
{
size = ConvertTo.Vector2(((PreCompLayerContext)context).Layer.Width, ((PreCompLayerContext)context).Layer.Height);
}
var visualSurface = factory.CreateVisualSurface();
visualSurface.SourceSize = size;
visualSurface.SourceVisual = source;
var maskBrush = factory.CreateMaskBrush();
var colorBrush = factory.CreateColorBrush(dropShadowEffect.Color.InitialValue);
var color = Optimizer.TrimAnimatable(context, dropShadowEffect.Color);
if (color.IsAnimated)
{
Animate.Color(context, color, colorBrush, nameof(colorBrush.Color));
}
else
{
colorBrush.Color = ConvertTo.Color(color.InitialValue);
}
maskBrush.Source = colorBrush;
maskBrush.Mask = factory.CreateSurfaceBrush(visualSurface);
var shadowSpriteVisual = factory.CreateSpriteVisual();
shadowSpriteVisual.Size = size;
shadowSpriteVisual.Brush = maskBrush;
var blurResult = ApplyGaussianBlur(context, shadowSpriteVisual, gaussianBlurEffect);
var opacity = Optimizer.TrimAnimatable(context, dropShadowEffect.Opacity);
if (opacity.IsAnimated)
{
Animate.Opacity(context, opacity, blurResult, nameof(blurResult.Opacity));
}
else
{
blurResult.Opacity = (float)opacity.InitialValue.Value;
}
// Convert direction and distance to a Vector3.
var direction = Optimizer.TrimAnimatable(context, dropShadowEffect.Direction);
var distance = Optimizer.TrimAnimatable(context, dropShadowEffect.Distance);
if (direction.IsAnimated)
{
if (distance.IsAnimated)
{
// Direction and distance are animated.
// NOTE: we could support this in some cases. The worst cases are
// where the keyframes don't line up, and/or the easings are different
// between distance and direction.
context.Issues.AnimatedLayerEffectParameters("drop shadow");
}
else
{
// Only direction is animated.
var distanceValue = distance.InitialValue;
var keyFrames = direction.KeyFrames.Select(
kf => new KeyFrame <Vector3>(kf.Frame, VectorFromRotationAndDistance(kf.Value, distanceValue), kf.Easing)).ToArray();
var directionAnimation = new TrimmedAnimatable <Vector3>(context, keyFrames[0].Value, keyFrames);
Animate.Vector3(context, directionAnimation, blurResult, nameof(blurResult.Offset));
}
}
else if (distance.IsAnimated)
{
// Only distance is animated.
var directionRadians = direction.InitialValue.Radians;
var keyFrames = distance.KeyFrames.Select(
kf => new KeyFrame <Vector3>(kf.Frame, VectorFromRotationAndDistance(directionRadians, kf.Value), kf.Easing)).ToArray();
var distanceAnimation = new TrimmedAnimatable <Vector3>(context, keyFrames[0].Value, keyFrames);
Animate.Vector3(context, distanceAnimation, blurResult, nameof(blurResult.Offset));
}
else
{
// Direction and distance are both not animated.
var directionRadians = direction.InitialValue.Radians;
var distanceValue = distance.InitialValue;
blurResult.Offset = ConvertTo.Vector3(VectorFromRotationAndDistance(direction.InitialValue, distance.InitialValue));
}
var result = factory.CreateContainerVisual();
result.Size = size;
result.Children.Add(blurResult);
// Check if ShadowOnly can be false
if (!dropShadowEffect.IsShadowOnly.IsAlways(true))
{
// Check if ShadowOnly can be true
if (!dropShadowEffect.IsShadowOnly.IsAlways(false))
{
var isVisible = FlipBoolAnimatable(dropShadowEffect.IsShadowOnly); // isVisible = !isShadowOnly
source.IsVisible = isVisible.InitialValue;
if (isVisible.IsAnimated)
{
Animate.Boolean(
context,
Optimizer.TrimAnimatable(context, isVisible),
source,
nameof(blurResult.IsVisible));
}
}
result.Children.Add(source);
}
return(result);
}
static LayerVisual ApplyDropShadow(PreCompLayerContext context, Visual visual, DropShadowEffect dropShadowEffect)
{
Debug.Assert(dropShadowEffect.IsEnabled, "Precondition");
// Create a LayerVisual so we can add a drop shadow.
var result = context.ObjectFactory.CreateLayerVisual();
result.Children.Add(visual);
// TODO: Due to a Composition bug, LayerVisual currently must be given a size for the drop
// shadow to show up correctly. And even then it is not reliable.
result.Size = context.CompositionContext.Size;
var shadow = context.ObjectFactory.CreateDropShadow();
result.Shadow = shadow;
shadow.SourcePolicy = CompositionDropShadowSourcePolicy.InheritFromVisualContent;
var isShadowOnly = Optimizer.TrimAnimatable(context, dropShadowEffect.IsShadowOnly);
if (!isShadowOnly.IsAlways(true))
{
context.Issues.ShadowOnlyShadowEffect();
}
// TODO - it's not clear whether BlurRadius and Softness are equivalent. We may
// need to scale Softness to convert it to BlurRadius.
var blurRadius = Optimizer.TrimAnimatable(context, dropShadowEffect.Softness);
if (blurRadius.IsAnimated)
{
Animate.Scalar(context, blurRadius, shadow, nameof(shadow.BlurRadius));
}
else
{
shadow.BlurRadius = (float)blurRadius.InitialValue;
}
var color = Optimizer.TrimAnimatable(context, dropShadowEffect.Color);
if (color.IsAnimated)
{
Animate.Color(context, color, shadow, nameof(shadow.Color));
}
else
{
shadow.Color = ConvertTo.Color(color.InitialValue);
}
var opacity = Optimizer.TrimAnimatable(context, dropShadowEffect.Opacity);
if (opacity.IsAnimated)
{
Animate.Opacity(context, opacity, shadow, nameof(shadow.Opacity));
}
else
{
shadow.Opacity = (float)opacity.InitialValue.Value;
}
// Convert direction and distance to a Vector3.
var direction = Optimizer.TrimAnimatable(context, dropShadowEffect.Direction);
var distance = Optimizer.TrimAnimatable(context, dropShadowEffect.Distance);
if (direction.IsAnimated)
{
if (distance.IsAnimated)
{
// Direction and distance are animated.
// NOTE: we could support this in some cases. The worst cases are
// where the keyframes don't line up, and/or the easings are different
// between distance and direction.
context.Issues.AnimatedLayerEffectParameters("drop shadow");
}
else
{
// Only direction is animated.
var distanceValue = distance.InitialValue;
var keyFrames = direction.KeyFrames.Select(
kf => new KeyFrame <Vector3>(kf.Frame, VectorFromRotationAndDistance(kf.Value, distanceValue), kf.Easing)).ToArray();
var directionAnimation = new TrimmedAnimatable <Vector3>(context, keyFrames[0].Value, keyFrames);
Animate.Vector3(context, directionAnimation, shadow, nameof(shadow.Offset));
}
}
else if (distance.IsAnimated)
{
// Only distance is animated.
var directionRadians = direction.InitialValue.Radians;
var keyFrames = distance.KeyFrames.Select(
kf => new KeyFrame <Vector3>(kf.Frame, VectorFromRotationAndDistance(directionRadians, kf.Value), kf.Easing)).ToArray();
var distanceAnimation = new TrimmedAnimatable <Vector3>(context, keyFrames[0].Value, keyFrames);
Animate.Vector3(context, distanceAnimation, shadow, nameof(shadow.Offset));
}
else
{
// Direction and distance are both not animated.
var directionRadians = direction.InitialValue.Radians;
var distanceValue = distance.InitialValue;
shadow.Offset = ConvertTo.Vector3(VectorFromRotationAndDistance(direction.InitialValue, distance.InitialValue));
}
return(result);
}