AVMakeRectFill.swift

private func AVMakeRectFill(aspectRatio: CGSize, insideRect boundingRect: CGRect) -> CGRect {
	let targetSize = boundingRect.size
	
	if targetSize == .zero {
		return .zero
	}
	let widthRatio = targetSize.width  / aspectRatio.width
	let heightRatio = targetSize.height / aspectRatio.height
	let scalingFactor = max(widthRatio, heightRatio)
	
	let newSize = CGSize(
		width:  aspectRatio.width  * scalingFactor,
		height: aspectRatio.height * scalingFactor
	)
	
	let origin = CGPoint(
		x: (targetSize.width  - newSize.width)  / 2,
		y: (targetSize.height - newSize.height) / 2
	)
	return CGRect(origin: origin, size: newSize)
}