Liquid glass

Liquid Glass Design

Implement Apple's Liquid Glass design language across all Apple UI frameworks. Covers SwiftUI (.glassEffect()), AppKit (NSGlassEffectView), UIKit (UIGlassEffect + UIVisualEffectView), and WidgetKit (rendering modes, accented content, glass elements in widgets).

When This Skill Activates

• User wants glass/blur effects on views
• User asks about Liquid Glass or modern Apple design
• User needs transparent, interactive UI elements
• User wants morphing transitions between views
• User is implementing glass effects in UIKit with UIVisualEffectView
• User needs UIGlassEffect or UIGlassContainerEffect
• User asks about scroll view edge effects in UIKit
• User wants Liquid Glass in widgets (WidgetKit)
• User needs to support accented rendering mode in widgets
• User asks about widget textures or mounting styles on visionOS

Design Rules (WWDC25)

Liquid Glass is the material of the navigation layer — bars, toolbars, floating controls — never the content layer (tables, lists, rows in a scroll view).

Rule	Detail
Never glass on glass	Don't stack glass. Elements sitting ON glass don't get the material again — style them with fills and vibrancy.
Two variants — never mix them	Regular (default): works at any size, over anything, with adaptive legibility. Clear: only when ALL three hold — media-rich content underneath, a dimming layer is acceptable, and bold bright content sits above. Clear has no adaptive behaviors. One variant per interface.
Tint only primary actions	"When every element is tinted, nothing stands out."
No steady-state intersections	In resting layouts, content shouldn't sit half-under a glass element — reposition or scale the content instead.
Strip decorated bars	Remove customized bar backgrounds and borders; build hierarchy through layout and grouping, not decoration. Never group a symbol with a text label in one toolbar group. Action sheets spring from their source element.

Scroll edge effects keep floating elements separated from scrolling content: soft (gradual fade — the iOS default) vs hard (denser, with a dividing line — mostly macOS). One per view edge, and they're not decorative — don't add one where no floating UI elements exist.

Shape system — let containers do the math:

Shape	Radius	Use
Fixed	Constant	Standalone elements
Capsule	Half the element height	Phone-scale controls — add extra margin from the screen edge
Concentric	Parent radius minus padding	Nested containers (inner radii auto-calculate); iPad/Mac elements concentric with the window edge

Accessibility comes free at the system level: Reduced Motion decreases lensing and elastic effects; Increased Contrast renders glass elements black/white with a contrasting border. (Lensing is how glass appears — it materializes by modulating how it bends light, and adaptive shadows flip small elements light/dark for legibility over any content.)

Quick Start (SwiftUI)

Basic Glass Effect

import SwiftUI

Text("Hello, World!")
    .font(.title)
    .padding()
    .glassEffect()  // Capsule shape by default

Custom Shape

Text("Hello")
    .padding()
    .glassEffect(in: .rect(cornerRadius: 16))

// Available shapes:
// .capsule (default)
// .rect(cornerRadius: CGFloat)
// .rect(corner: .containerConcentric) — radius derived from the container, keeps nested shapes concentric
// .circle

Interactive Glass

Button("Tap Me") {
    // action
}
.padding()
.glassEffect(.regular.interactive())

Tinted Glass

Text("Important")
    .padding()
    .glassEffect(.regular.tint(.blue))

Glass Configuration Options

Option	Description	Example
.regular	Standard glass effect	.glassEffect(.regular)
.tint(Color)	Add color tint	.glassEffect(.regular.tint(.orange))
.interactive()	Scale, bounce, and shimmer on touch/hover	.glassEffect(.regular.interactive())

Multiple Glass Effects

GlassEffectContainer

When using multiple glass elements, wrap them in GlassEffectContainer for:

• Better rendering performance
• Proper blending between effects
• Morphing transitions

This is correctness, not just performance: glass can not sample other glass, so nearby glass elements must share ONE container to render and blend correctly.

GlassEffectContainer(spacing: 40.0) {
    HStack(spacing: 40.0) {
        Image(systemName: "star.fill")
            .frame(width: 80, height: 80)
            .font(.system(size: 36))
            .glassEffect()

        Image(systemName: "heart.fill")
            .frame(width: 80, height: 80)
            .font(.system(size: 36))
            .glassEffect()
    }
}

Spacing Parameter:

• Controls when effects merge
• Smaller spacing = views must be closer to merge
• Larger spacing = effects merge at greater distances

Uniting Glass Effects

Combine views into a single glass effect using glassEffectUnion:

@Namespace private var namespace

GlassEffectContainer(spacing: 20.0) {
    HStack(spacing: 20.0) {
        ForEach(items.indices, id: \.self) { index in
            Image(systemName: items[index])
                .frame(width: 60, height: 60)
                .glassEffect()
                .glassEffectUnion(
                    id: index < 2 ? "group1" : "group2",
                    namespace: namespace
                )
        }
    }
}

Morphing Transitions

Create fluid morphing effects when views appear/disappear.

Setup

1. Create a namespace
2. Assign glass effect IDs
3. Use animations on state changes

struct MorphingToolbar: View {
    @State private var isExpanded = false
    @Namespace private var namespace

    var body: some View {
        GlassEffectContainer(spacing: 40.0) {
            HStack(spacing: 40.0) {
                // Always visible
                Image(systemName: "pencil")
                    .frame(width: 60, height: 60)
                    .glassEffect()
                    .glassEffectID("pencil", in: namespace)

                // Conditionally visible - will morph in/out
                if isExpanded {
                    Image(systemName: "eraser")
                        .frame(width: 60, height: 60)
                        .glassEffect()
                        .glassEffectID("eraser", in: namespace)

                    Image(systemName: "ruler")
                        .frame(width: 60, height: 60)
                        .glassEffect()
                        .glassEffectID("ruler", in: namespace)
                }
            }
        }

        Button("Toggle") {
            withAnimation(.spring(response: 0.4, dampingFraction: 0.8)) {
                isExpanded.toggle()
            }
        }
        .buttonStyle(.glass)
    }
}

Button Styles

Glass Button

Button("Standard") {
    // action
}
.buttonStyle(.glass)

Glass Prominent Button

Button("Primary Action") {
    // action
}
.buttonStyle(.glassProminent)

Advanced Techniques

Background Extension

Extend a hero image beyond the safe area — the system mirrors and blurs it under bars and sidebars:

Image("hero")
    .backgroundExtensionEffect()

Or stretch content under sidebar or inspector:

NavigationSplitView {
    SidebarView()
} detail: {
    DetailView()
        .background {
            Image("wallpaper")
                .resizable()
                .ignoresSafeArea()
        }
}

Horizontal Scroll Under Sidebar

ScrollView(.horizontal) {
    HStack {
        ForEach(items) { item in
            ItemView(item: item)
        }
    }
}
.scrollExtensionMode(.underSidebar)

Tab Bar Behaviors

TabView {
    // tabs
}
.tabBarMinimizeBehavior(.onScrollDown)  // Tab bar recedes while scrolling content
.tabViewBottomAccessory {               // Persistent control docked above the tab bar
    MiniPlayerView()
}

Toolbar Spacers

Split toolbar items into separate glass groups instead of customizing bar backgrounds:

.toolbar {
    ToolbarItem { editButton }
    ToolbarSpacer(.fixed)      // Visual break — starts a new glass group
    ToolbarItem { shareButton }
    ToolbarSpacer(.flexible)   // Pushes the following group apart
    ToolbarItem { doneButton }
}

Scroll Edge Effect Style

ScrollView { content }
    .scrollEdgeEffectStyle(.hard, for: .top)  // Hard style for dense UI, mostly macOS

Sheets

Remove custom presentationBackground modifiers — they interfere with the sheet's glass material and its morphing behavior.

AppKit Implementation

NSGlassEffectView

import AppKit

// Create glass effect view
let glassView = NSGlassEffectView(frame: NSRect(x: 20, y: 20, width: 200, height: 100))
glassView.cornerRadius = 16.0
glassView.tintColor = NSColor.systemBlue.withAlphaComponent(0.3)

// Create content
let label = NSTextField(labelWithString: "Glass Content")
label.translatesAutoresizingMaskIntoConstraints = false

// Set content view
glassView.contentView = label

// Add constraints
if let contentView = glassView.contentView {
    NSLayoutConstraint.activate([
        label.centerXAnchor.constraint(equalTo: contentView.centerXAnchor),
        label.centerYAnchor.constraint(equalTo: contentView.centerYAnchor)
    ])
}

NSGlassEffectContainerView

// Create container
let container = NSGlassEffectContainerView(frame: bounds)
container.spacing = 40.0

// Create content view
let contentView = NSView(frame: container.bounds)
container.contentView = contentView

// Add glass views to content
let glass1 = NSGlassEffectView(frame: NSRect(x: 20, y: 50, width: 150, height: 100))
let glass2 = NSGlassEffectView(frame: NSRect(x: 190, y: 50, width: 150, height: 100))

contentView.addSubview(glass1)
contentView.addSubview(glass2)

Interactive AppKit Glass

class InteractiveGlassView: NSGlassEffectView {
    override init(frame: NSRect) {
        super.init(frame: frame)
        setupTracking()
    }

    required init?(coder: NSCoder) {
        super.init(coder: coder)
        setupTracking()
    }

    private func setupTracking() {
        let options: NSTrackingArea.Options = [
            .mouseEnteredAndExited,
            .activeInActiveApp
        ]
        let trackingArea = NSTrackingArea(
            rect: bounds,
            options: options,
            owner: self,
            userInfo: nil
        )
        addTrackingArea(trackingArea)
    }

    override func mouseEntered(with event: NSEvent) {
        super.mouseEntered(with: event)
        NSAnimationContext.runAnimationGroup { context in
            context.duration = 0.2
            animator().tintColor = NSColor.systemBlue.withAlphaComponent(0.2)
        }
    }

    override func mouseExited(with event: NSEvent) {
        super.mouseExited(with: event)
        NSAnimationContext.runAnimationGroup { context in
            context.duration = 0.2
            animator().tintColor = nil
        }
    }
}

Common Patterns

Floating Action Bar

struct FloatingActionBar: View {
    @Namespace private var namespace

    var body: some View {
        GlassEffectContainer(spacing: 20) {
            HStack(spacing: 16) {
                ForEach(actions) { action in
                    Button {
                        action.perform()
                    } label: {
                        Image(systemName: action.icon)
                            .font(.title2)
                    }
                    .frame(width: 44, height: 44)
                    .glassEffect(.regular.interactive())
                    .glassEffectID(action.id, in: namespace)
                }
            }
            .padding(.horizontal, 8)
            .padding(.vertical, 4)
        }
    }
}

Card with Glass Effect

For a card floating above content (e.g. overlaid on a map). Cards inside a scrolling list are content-layer — don't use glass there. Note the icon uses a fill, not a second glassEffect: elements on glass never get glass again.

struct GlassCard: View {
    let title: String
    let subtitle: String
    let icon: String

    var body: some View {
        HStack(spacing: 16) {
            Image(systemName: icon)
                .font(.title)
                .frame(width: 50, height: 50)
                .background(.blue.opacity(0.15), in: .rect(cornerRadius: 12))

            VStack(alignment: .leading) {
                Text(title)
                    .font(.headline)
                Text(subtitle)
                    .font(.subheadline)
                    .foregroundStyle(.secondary)
            }

            Spacer()
        }
        .padding()
        .glassEffect(in: .rect(cornerRadius: 16))
    }
}

Tab Bar with Morphing

struct GlassTabBar: View {
    @Binding var selection: Int
    @Namespace private var namespace

    let tabs = [
        ("house", "Home"),
        ("magnifyingglass", "Search"),
        ("person", "Profile")
    ]

    var body: some View {
        GlassEffectContainer(spacing: 30) {
            HStack(spacing: 30) {
                ForEach(tabs.indices, id: \.self) { index in
                    Button {
                        withAnimation(.spring(response: 0.35, dampingFraction: 0.8)) {
                            selection = index
                        }
                    } label: {
                        VStack(spacing: 4) {
                            Image(systemName: tabs[index].0)
                                .font(.title2)
                            Text(tabs[index].1)
                                .font(.caption)
                        }
                        .frame(width: 70, height: 60)
                    }
                    .glassEffect(
                        selection == index
                            ? .regular.tint(.blue).interactive()
                            : .regular.interactive()
                    )
                    .glassEffectID("tab\(index)", in: namespace)
                }
            }
        }
    }
}

Migration from Old API

Before (Old Approach)

// Old: Using materials directly
VStack {
    Text("Content")
}
.padding()
.background(.ultraThinMaterial)
.cornerRadius(16)

After (New API)

// New: Using glassEffect modifier
VStack {
    Text("Content")
}
.padding()
.glassEffect(in: .rect(cornerRadius: 16))

Key Differences

Old Approach	New API
.background(.material)	.glassEffect()
Manual corner radius	Shape parameter
No interactivity	.interactive() modifier
Manual tinting	.tint(Color) modifier
No morphing	glassEffectID + @Namespace
No container grouping	GlassEffectContainer

UIKit Implementation

UIGlassEffect

Use UIVisualEffectView with a UIGlassEffect to create glass surfaces in UIKit:

import UIKit

let glassEffect = UIGlassEffect()
let visualEffectView = UIVisualEffectView(effect: glassEffect)
visualEffectView.frame = CGRect(x: 50, y: 100, width: 300, height: 200)
visualEffectView.layer.cornerRadius = 20
visualEffectView.clipsToBounds = true

let label = UILabel()
label.text = "Liquid Glass"
label.textAlignment = .center
label.frame = visualEffectView.bounds
visualEffectView.contentView.addSubview(label)
view.addSubview(visualEffectView)

Customizing the Glass Effect

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

Interactive Glass in UIKit

Set isInteractive = true on a UIGlassEffect to make it respond to touch:

let interactiveGlassEffect = UIGlassEffect()
interactiveGlassEffect.isInteractive = true

let glassButton = UIButton(frame: CGRect(x: 50, y: 300, width: 200, height: 50))
glassButton.setTitle("Glass Button", for: .normal)
glassButton.setTitleColor(.white, for: .normal)

let buttonEffectView = UIVisualEffectView(effect: interactiveGlassEffect)
buttonEffectView.frame = glassButton.bounds
buttonEffectView.layer.cornerRadius = 15
buttonEffectView.clipsToBounds = true

glassButton.insertSubview(buttonEffectView, at: 0)
view.addSubview(glassButton)

UIGlassContainerEffect

Use UIGlassContainerEffect when combining multiple glass elements. This is the UIKit equivalent of SwiftUI's GlassEffectContainer -- it enables proper blending and morphing between glass views:

let containerEffect = UIGlassContainerEffect()
containerEffect.spacing = 40.0

let containerView = UIVisualEffectView(effect: containerEffect)
containerView.frame = CGRect(x: 50, y: 400, width: 300, height: 200)

let firstGlassEffect = UIGlassEffect()
let firstGlassView = UIVisualEffectView(effect: firstGlassEffect)
firstGlassView.frame = CGRect(x: 20, y: 20, width: 100, height: 100)
firstGlassView.layer.cornerRadius = 20
firstGlassView.clipsToBounds = true

let secondGlassEffect = UIGlassEffect()
secondGlassEffect.tintColor = UIColor.systemPink.withAlphaComponent(0.3)
let secondGlassView = UIVisualEffectView(effect: secondGlassEffect)
secondGlassView.frame = CGRect(x: 80, y: 60, width: 100, height: 100)
secondGlassView.layer.cornerRadius = 20
secondGlassView.clipsToBounds = true

containerView.contentView.addSubview(firstGlassView)
containerView.contentView.addSubview(secondGlassView)
view.addSubview(containerView)

Scroll View Edge Effects

UIKit scroll views now support configurable edge effects for Liquid Glass integration:

let scrollView = UIScrollView(frame: view.bounds)
scrollView.topEdgeEffect.style = .automatic
scrollView.bottomEdgeEffect.style = .hard
scrollView.leftEdgeEffect.isHidden = true
scrollView.rightEdgeEffect.isHidden = true

Available Edge Effect Styles:

Style	Description
.automatic	System determines style based on context
.hard	Hard cutoff with a dividing line

UIScrollEdgeElementContainerInteraction

Coordinates glass elements (such as bottom toolbars) with scroll edge behavior:

let interaction = UIScrollEdgeElementContainerInteraction()
interaction.scrollView = scrollView
interaction.edge = .bottom
buttonContainer.addInteraction(interaction)

Toolbar Integration

UIKit navigation bar items integrate with Liquid Glass automatically; hidesSharedBackground opts an item out of the shared glass bar:

let shareButton = UIBarButtonItem(
    barButtonSystemItem: .action,
    target: self,
    action: #selector(shareAction)
)
let favoriteButton = UIBarButtonItem(
    image: UIImage(systemName: "heart"),
    style: .plain,
    target: self,
    action: #selector(favoriteAction)
)
favoriteButton.hidesSharedBackground = true
navigationItem.rightBarButtonItems = [shareButton, favoriteButton]

UIKit vs SwiftUI Comparison

SwiftUI	UIKit
.glassEffect()	UIVisualEffectView(effect: UIGlassEffect())
.glassEffect(.regular.interactive())	UIGlassEffect() with isInteractive = true
.glassEffect(.regular.tint(.blue))	UIGlassEffect() with tintColor = ...
GlassEffectContainer(spacing:)	UIGlassContainerEffect() with spacing
.buttonStyle(.glass)	Insert UIVisualEffectView as button subview

WidgetKit Implementation

Rendering Modes

Widgets support two rendering modes that affect how Liquid Glass is displayed:

Mode	Description
Full Color	Default mode. Displays all colors, images, and transparency as designed.
Accented	Used when tinted or clear appearance is chosen. Primary and accented content tinted white (iOS and macOS). Background replaced with themed glass or tinted color effect.

Accented Mode

Detect the rendering mode and adapt layout accordingly. Use .widgetAccentable() to mark views that should be tinted in accented mode:

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

    var body: some View {
        if renderingMode == .accented {
            // Layout optimized for accented mode
            AccentedWidgetLayout()
        } else {
            // Standard full-color layout
            FullColorWidgetLayout()
        }
    }
}

Grouping Accent Content

HStack(alignment: .center, spacing: 0) {
    VStack(alignment: .leading) {
        Text("Widget Title")
            .font(.headline)
            .widgetAccentable()
        Text("Widget Subtitle")
    }
    Image(systemName: "star.fill")
        .widgetAccentable()
}

Image Rendering in Accented Mode

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

Container Backgrounds

Define a container background for your widget content:

var body: some View {
    VStack {
        // Widget content
    }
    .containerBackground(for: .widget) {
        Color.blue.opacity(0.2)
    }
}

Background Removal

Prevent the system from removing the widget background. Note that marking a background as non-removable excludes the widget from contexts that require removable backgrounds (iPad Lock Screen, StandBy):

var body: some WidgetConfiguration {
    StaticConfiguration(kind: "MyWidget", provider: Provider()) { entry in
        MyWidgetView(entry: entry)
    }
    .containerBackgroundRemovable(false)
}

visionOS Textures and Mounting Styles

Widget Textures

// Default glass texture
.widgetTexture(.glass)

// Paper-like texture
.widgetTexture(.paper)

Mounting Styles

.supportedMountingStyles([.recessed, .elevated])

Style	Description
.recessed	Widget appears embedded into a vertical surface
.elevated	Widget appears on top of a surface

Custom Glass Elements in Widgets

Apply .glassEffect() and .buttonStyle(.glass) directly within widget views:

// Glass text element
Text("Custom Element")
    .padding()
    .glassEffect()

// Glass image element
Image(systemName: "star.fill")
    .frame(width: 60, height: 60)
    .glassEffect(.regular, in: .rect(cornerRadius: 12))

// Glass button in widget
Button("Action") { }
    .buttonStyle(.glass)

Best Practices

1. Use GlassEffectContainer for multiple glass views

   • Improves rendering performance
   • Enables morphing transitions

2. Apply glass effect last in modifier chain

   • After frame, padding, and content modifiers

3. Choose appropriate spacing in containers

   • Controls when effects blend together

4. Use animations for state changes

   • Enables smooth morphing transitions

5. Add interactivity for touchable elements

   • .interactive() for buttons and controls

6. Tint sparingly — reserve tint for the primary action

   • See Design Rules: tinting everything makes nothing stand out

7. Consistent shapes across your app

   • Establish a shape language (all capsules, or all rounded rects)

Checklist

SwiftUI

• Use .glassEffect() instead of .background(.material)
• Wrap multiple glass views in GlassEffectContainer
• Add @Namespace for morphing transitions
• Use .glassEffectID() on views that appear/disappear
• Add .interactive() for touchable elements
• Use .buttonStyle(.glass) for glass buttons
• Test animations for smooth morphing

UIKit

• Use UIVisualEffectView with UIGlassEffect for glass surfaces
• Set isInteractive = true on glass effects for touchable elements
• Wrap multiple glass views in UIGlassContainerEffect
• Configure scroll view edge effects (.automatic or .hard)
• Use UIScrollEdgeElementContainerInteraction for scroll-coordinated toolbars
• Use hidesSharedBackground for toolbar items that need independent glass

WidgetKit

• Detect widgetRenderingMode and adapt layout for accented mode
• Mark accent content with .widgetAccentable()
• Set .widgetAccentedRenderingMode() on images
• Define .containerBackground(for: .widget) for backgrounds
• Use .containerBackgroundRemovable(false) only when necessary
• Apply .glassEffect() and .buttonStyle(.glass) in widget views
• Configure .widgetTexture() and .supportedMountingStyles() for visionOS

General

• Glass only on the navigation layer — never on content (tables, lists)
• No glass stacked on glass; one variant (Regular or Clear) per interface
• Only the primary action is tinted
• Consider performance with many glass effects
• Support both light and dark appearances

References

SwiftUI

• Applying Liquid Glass to custom views
• Landmarks: Building an app with Liquid Glass
• SwiftUI GlassEffectContainer

AppKit

• AppKit NSGlassEffectView

UIKit

• UIKit UIGlassEffect
• UIKit UIGlassContainerEffect
• UIKit UIVisualEffectView
• UIScrollEdgeElementContainerInteraction

WidgetKit

• WidgetKit Rendering Modes
• widgetAccentable()
• containerBackground(for:)