Liquid Glass Design System (iOS 26)

Patterns for implementing Apple's Liquid Glass — a dynamic material that blurs content behind it, reflects color and light from surrounding content, and reacts to touch and pointer interactions. Covers SwiftUI, UIKit, and WidgetKit integration.

When to Activate

• Building or updating apps for iOS 26+ with the new design language
• Implementing glass-style buttons, cards, toolbars, or containers
• Creating morphing transitions between glass elements
• Applying Liquid Glass effects to widgets
• Migrating existing blur/material effects to the new Liquid Glass API

Core Pattern — SwiftUI

Basic Glass Effect

The simplest way to add Liquid Glass to any view:

Text("Hello, World!")
    .font(.title)
    .padding()
    .glassEffect()  // Default: regular variant, capsule shape

Customizing Shape and Tint

Text("Hello, World!")
    .font(.title)
    .padding()
    .glassEffect(.regular.tint(.orange).interactive(), in: .rect(cornerRadius: 16.0))

Key customization options:

• .regular — standard glass effect
• .tint(Color) — add color tint for prominence
• .interactive() — react to touch and pointer interactions
• Shape: .capsule (default), .rect(cornerRadius:), .circle

Glass Button Styles

Button("Click Me") { /* action */ }
    .buttonStyle(.glass)

Button("Important") { /* action */ }
    .buttonStyle(.glassProminent)

GlassEffectContainer for Multiple Elements

Always wrap multiple glass views in a container for performance and morphing:

GlassEffectContainer(spacing: 40.0) {
    HStack(spacing: 40.0) {
        Image(systemName: "scribble.variable")
            .frame(width: 80.0, height: 80.0)
            .font(.system(size: 36))
            .glassEffect()

        Image(systemName: "eraser.fill")
            .frame(width: 80.0, height: 80.0)
            .font(.system(size: 36))
            .glassEffect()
    }
}

The spacing parameter controls merge distance — closer elements blend their glass shapes together.

Uniting Glass Effects

Combine multiple views into a single glass shape with glassEffectUnion:

@Namespace private var namespace

GlassEffectContainer(spacing: 20.0) {
    HStack(spacing: 20.0) {
        ForEach(symbolSet.indices, id: \.self) { item in
            Image(systemName: symbolSet[item])
                .frame(width: 80.0, height: 80.0)
                .glassEffect()
                .glassEffectUnion(id: item < 2 ? "group1" : "group2", namespace: namespace)
        }
    }
}

Morphing Transitions

Create smooth morphing when glass elements appear/disappear:

@State private var isExpanded = false
@Namespace private var namespace

GlassEffectContainer(spacing: 40.0) {
    HStack(spacing: 40.0) {
        Image(systemName: "scribble.variable")
            .frame(width: 80.0, height: 80.0)
            .glassEffect()
            .glassEffectID("pencil", in: namespace)

        if isExpanded {
            Image(systemName: "eraser.fill")
                .frame(width: 80.0, height: 80.0)
                .glassEffect()
                .glassEffectID("eraser", in: namespace)
        }
    }
}

Button("Toggle") {
    withAnimation { isExpanded.toggle() }
}
.buttonStyle(.glass)

Extending Horizontal Scrolling Under Sidebar

To allow horizontal scroll content to extend under a sidebar or inspector, ensure the ScrollView content reaches the leading/trailing edges of the container. The system automatically handles the under-sidebar scrolling behavior when the layout extends to the edges — no additional modifier is needed.

Core Pattern — UIKit

Basic UIGlassEffect

let glassEffect = UIGlassEffect()
glassEffect.tintColor = UIColor.systemBlue.withAlphaComponent(0.3)
glassEffect.isInteractive = true

let visualEffectView = UIVisualEffectView(effect: glassEffect)
visualEffectView.translatesAutoresizingMaskIntoConstraints = false
visualEffectView.layer.cornerRadius = 20
visualEffectView.clipsToBounds = true

view.addSubview(visualEffectView)
NSLayoutConstraint.activate([
    visualEffectView.centerXAnchor.constraint(equalTo: view.centerXAnchor),
    visualEffectView.centerYAnchor.constraint(equalTo: view.centerYAnchor),
    visualEffectView.widthAnchor.constraint(equalToConstant: 200),
    visualEffectView.heightAnchor.constraint(equalToConstant: 120)
])

// Add content to contentView
let label = UILabel()
label.text = "Liquid Glass"
label.translatesAutoresizingMaskIntoConstraints = false
visualEffectView.contentView.addSubview(label)
NSLayoutConstraint.activate([
    label.centerXAnchor.constraint(equalTo: visualEffectView.contentView.centerXAnchor),
    label.centerYAnchor.constraint(equalTo: visualEffectView.contentView.centerYAnchor)
])

UIGlassContainerEffect for Multiple Elements

let containerEffect = UIGlassContainerEffect()
containerEffect.spacing = 40.0

let containerView = UIVisualEffectView(effect: containerEffect)

let firstGlass = UIVisualEffectView(effect: UIGlassEffect())
let secondGlass = UIVisualEffectView(effect: UIGlassEffect())

containerView.contentView.addSubview(firstGlass)
containerView.contentView.addSubview(secondGlass)

Scroll Edge Effects

scrollView.topEdgeEffect.style = .automatic
scrollView.bottomEdgeEffect.style = .hard
scrollView.leftEdgeEffect.isHidden = true

Toolbar Glass Integration

let favoriteButton = UIBarButtonItem(image: UIImage(systemName: "heart"), style: .plain, target: self, action: #selector(favoriteAction))
favoriteButton.hidesSharedBackground = true  // Opt out of shared glass background

Core Pattern — WidgetKit

Rendering Mode Detection

struct MyWidgetView: View {
    @Environment(\.widgetRenderingMode) var renderingMode

    var body: some View {
        if renderingMode == .accented {
            // Tinted mode: white-tinted, themed glass background
        } else {
            // Full color mode: standard appearance
        }
    }
}

Accent Groups for Visual Hierarchy

HStack {
    VStack(alignment: .leading) {
        Text("Title")
            .widgetAccentable()  // Accent group
        Text("Subtitle")
            // Primary group (default)
    }
    Image(systemName: "star.fill")
        .widgetAccentable()  // Accent group
}

Image Rendering in Accented Mode

Image("myImage")
    .widgetAccentedRenderingMode(.monochrome)

Container Background

VStack { /* content */ }
    .containerBackground(for: .widget) {
        Color.blue.opacity(0.2)
    }

Key Design Decisions

Best Practices

• Always use GlassEffectContainer when applying glass to multiple sibling views — it enables morphing and improves rendering performance
• Apply .glassEffect() after other appearance modifiers (frame, font, padding)
• Use .interactive() only on elements that respond to user interaction (buttons, toggleable items)
• Choose spacing carefully in containers to control when glass effects merge
• Use withAnimation when changing view hierarchies to enable smooth morphing transitions
• Test across appearances — light mode, dark mode, and accented/tinted modes
• Ensure accessibility contrast — text on glass must remain readable

Anti-Patterns to Avoid

• Using multiple standalone .glassEffect() views without a GlassEffectContainer
• Nesting too many glass effects — degrades performance and visual clarity
• Applying glass to every view — reserve for interactive elements, toolbars, and cards
• Forgetting clipsToBounds = true in UIKit when using corner radii
• Ignoring accented rendering mode in widgets — breaks tinted Home Screen appearance
• Using opaque backgrounds behind glass — defeats the translucency effect

When to Use

• Navigation bars, toolbars, and tab bars with the new iOS 26 design
• Floating action buttons and card-style containers
• Interactive controls that need visual depth and touch feedback
• Widgets that should integrate with the system's Liquid Glass appearance
• Morphing transitions between related UI states