Elevation

public struct Elevation : Equatable

Encapsulates design shadows and applies them to a layer.

This data structure is designed to closely match how shadows are exported from Figma and also how they are specified for web/CSS. cf. https://www.w3.org/TR/css-backgrounds-3/#box-shadow

  • Specifies the horizontal offset of the shadow.

    A positive value draws a shadow that is offset to the right of the box, a negative length to the left.

    Declaration

    Swift

    public let xOffset: CGFloat

  • Specifies the vertical offset of the shadow.

    A positive value offsets the shadow down, a negative one up.

    Declaration

    Swift

    public let yOffset: CGFloat

  • Specifies the blur radius.

    Negative values are invalid. If the blur value is zero, the shadow’s edge is sharp. Otherwise, the larger the value, the more the shadow’s edge is blurred

    Declaration

    Swift

    public let blur: CGFloat

  • Specifies the spread distance.

    Positive values cause the shadow to expand in all directions by the specified radius. Negative values cause the shadow to contract.

    Declaration

    Swift

    public let spread: CGFloat

  • Specifies the color of the shadow.

    This value should be opaque (i.e. alpha channel = 1.0 or 0xFF). opacity is a separate property.

    Declaration

    Swift

    public let color: UIColor

  • Specifies the opacity of the shadow.

    Possible values range from 0.0 to 1.0 (inclusive). 0 means no shadow, and 1 means fully opaque.

    Declaration

    Swift

    public let opacity: Float

  • Whether apply(layer:cornerRadius:) should set the shadowPath. Defaults to true.

    Should be false for layers that are not a simple rect or round-rect (e.g. ellipse, circle, donut, or other irregular shape such as a logo). Note that when false the spread property is ignored. Image rendering performance will be better when set to true (avoids an off-screen render pass).

    Declaration

    Swift

    public let useShadowPath: Bool

  • Initializes an elevation

    Declaration

    Swift

    public init(
    xOffset: CGFloat,
    yOffset: CGFloat,
    blur: CGFloat,
    spread: CGFloat,
    color: UIColor,
    opacity: Float,
    useShadowPath: Bool = true
)

    Parameters

    xOffset

    the horizontal offset of the shadow
    yOffset

    the vertical offset of the shadow
    blur

    the blur radius
    spread

    the spread distance
    color

    the color of the shadow
    opacity

    the opacity of the shadow
    useShadowPath

    whether to set the shadowPath. Default is true

  • Computes how far from the edges of the view the shadow will extend in each direction.

    This is determined by offset, blur, and spread, but not by opacity (unless zero). The rectangle enclosing the shadow should be the view’s frame outset by extent.

    Declaration

    Swift

    public var extent: UIEdgeInsets { get }

  • Applies elevation to a layer.

    In most cases cornerRadius should match layer.cornerRadius. Note: This method does not set layer.cornerRadius, only the layer’s shadow properties.

    Declaration

    Swift

    public func apply(layer: CALayer, cornerRadius: CGFloat? = nil)

    Parameters

    layer

    the layer to apply the elevation to.
    cornerRadius

    the corner radius to use for the shadow path. Pass nil to use layer.cornerRadius (the default). Ignored when useShadowPath == false