Create Custom Visual Effects with SwiftUI - WWDC24

Introduction

At WWDC24, Apple introduced exciting updates for creating custom visual effects with SwiftUI. This article summarizes the “Create Custom Visual Effects with SwiftUI” session, highlighting new capabilities for enhancing your app’s visual experience.

Scroll

Scrolling Animations

SwiftUI’s ScrollView enables a variety of scrolling animations:

• Pagination Effect: Use the scrollTargetBehavior(_:) view modifier.

  ScrollView(.horizontal) {
      HStack {
          ForEach(0..<10) { index in
              Text("Page \(index)")
                  .frame(width: 300, height: 300)
                  .background(Color.blue)
                  .cornerRadius(20)
          }
      }
  }
  .scrollTargetBehavior(.paging)
  

• Circular Carousel Effect: Use the scrollTransition(_:axis:transition:) modifier.

• Parallax Effect: Combine scrollTransition(_:axis:transition:), containerRelativeFrame(_:alignment:), and clipShape(_:style:) view modifiers.

Visual Effects

Use the visualEffect(_:) view modifier to create gradient effects when scrolling.

Ensure animations and transitions remain natural and pleasant over time.

Text

Animating Text

The new TextRenderer API and Animation protocol allow animating individual lines of text. Lines are composed of runs, and runs of run slices (glyphs), enabling character-by-character animation.

Animating Text Sections

Use the TextAttribute API to animate specific text sections.

Gradients & Shading

MeshGradient

Create MeshGradient with a grid of points and colors.

MeshGradient(
    width: 2, 
    height: 2, 
    points: [
        CGPoint(x: 0, y: 0), CGPoint(x: 0.5, y: 0),
        CGPoint(x: 0, y: 0.5), CGPoint(x: 1, y: 1)
    ], 
    colors: [
        .red, .blue,
        .orange, .purple
    ]
)

Custom Shaders

Use Metal’s Shader Library for advanced animations using the device’s GPU. Create custom fills, colors, durations, or layer effects with Metal and port to Swift with the ViewModifier protocol.

Debugging Animations

Utilize a custom debug UI to quickly iterate and refine animations.

Conclusion

WWDC24 has brought powerful new tools for creating custom visual effects in SwiftUI. By leveraging these features, you can significantly enhance the visual appeal and user experience of your applications.