dependencies: [
    .package(name: "Paralayout", url: "https://github.com/square/Paralayout.git", from: "1.0.0"),
]

/// Put a line at the bottom of the view, inset 20 points on each side.
let separator = Hairline.new(in: view, at: .maxYEdge, inset: 20)

// Determine how far we are into the transition of collapsing the header.
let headerCollapseAmount = Interpolation(of: header.frame.height, from: maxHeaderHeight, to: minHeaderHeight)

// The icon shrinks to half its usual size...
let avatarSize = headerCollapseAmount.interpolate(from: 80, to: 40)
avatar.frame.size = CGSize(width: avatarSize, height: avatarSize)

// ...as it completely fades out.
avatar.alpha = headerCollapseAmount.interpolate(from: 1, to: 0)

videoPlayer.frame = AspectRatio.widescreen.rect(toFit: bounds, at: .topCenter, in: view)

titleLabel.align(.leftCenter, with: icon, .rightCenter, horizontalOffset: 8)
icon.align(withSuperview: .topCenter, inset: 20)

let labelSize = label.frameSize(thatFits: bounds.insetBy(dx: 20, dy: 20).size, constraints: [ .fixedWidth, .maxHeight ])
titleLabel.wrap(toFitWidth: boundsWidth, margins: 20)

/// Vertically stack an icon, header, and button, with twice as much space at the bottom as the top.
selectionScreen.applySubviewDistribution([ 1.flexible, headerIcon, 8.fixed, headerLabel, 1.flexible, button, 2.flexible])

/// Left-align a pair of labels, one above the other, with equal space above the title and below the subtext (despite the subtext being a smaller font).
cell.applySubviewDistribution([ 1.flexible, titleLabel, 8.fixed, subtextLabel, 1.flexible ], alignment: .leading(inset: 10))

/// Equally size a pair of buttons with a hairline divider between them, and size/position them at the bottom of the alert.
alert.spreadOutSubviews([ cancelButton, acceptButton ], axis: .horizontal, margin: alert.hairlineWidth, inRect: alert.bounds.slice(from: .maxYEdge, amount: buttonHeight))