LineByLineTextAnimator 🎬✨

WWDC‐style per‐line text reveal & hide animation for UILabel 🚀

• 🔠 Line‐by‐line staggered animation (cascade)
• ↕️ Opacity 0 → 1 and Y‐offset 8pt → 0
• 📐 Scale 0.96 → 1.0 (anchor at bottom)
• 🌫️ Blur 8 → 0 (iOS 17+ GPU via CIFilter; fallback on iOS 16 to UIVisualEffectView)
• ▶️ Animate In (animateIn) and ⏹️ Animate Out (animateOut)
• 🪄 Triggers only when the label’s superview exists
• ⚡️ Caching of TextKit line layout for performance

• iOS 16.4+
• Swift 5.7+
• UIKit

i️ Important: The original UILabel being animated must have:

• lineBreakMode = .byWordWrapping
• Initially isHidden = true

1. Copy LineByLineTextAnimator.swift into your project.

2. Ensure you import:

   import UIKit
   import CoreText
   import CoreImage

// Ensure label.frame is final and label.layoutIfNeeded() has been called
label.isHidden = true // initial state
LineByLineTextAnimator.animateIn(
 label: label, // your multiline UILabel
 totalDuration: 0.56, // optional, default 0.56s
 cascadeFraction: 0.45 // optional, default 0.45
)

// Hide immediately and play reverse animation
label.isHidden = true
LineByLineTextAnimator.animateOut(
 label: label,
 totalDuration: 0.56,
 cascadeFraction: 0.45
)

In your view controller:

override func viewDidAppear(_ animated: Bool) {
 super.viewDidAppear(animated)
 // Reveal once
 label.isHidden = true
 LineByLineTextAnimator.animateIn(label: label)
}
@IBAction func didTapHide(_ sender: UIButton) {
 // Hide on demand
 label.isHidden = true
 LineByLineTextAnimator.animateOut(label: label)
}

• Timing: adjust totalDuration & cascadeFraction.
• Spring physics: tweak UISpringTimingParameters(mass:stiffness:damping:initialVelocity:) in the code.
• Blur radius: modify values in the CIFilter or fallback animation.

• Call label.layoutIfNeeded() before animation.
• Reuse UILabels to benefit from line‐layout caching.

MIT — free to use and modify.