Theseus

iOS 26 Liquid Glass effects – backported to iOS 13+

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What is Theseus?

Theseus gives you translucent UI components with blur, refraction, glare, and spring animations – the iOS 26 look, backported to iOS 13+. Same ship, rebuilt plank by plank for older waters.

Why?

Because some of us watched Apple unveil Liquid Glass at WWDC 2025 and quietly wondered if they could drop support for iOS 13. This is for everyone still supporting devices from 2015.

TabBar

Slider

Switch

Glass View

What you get

• The iOS 26 Liquid Glass look, running on devices from 2019
• Metal GPU rendering (with a sensible fallback for ancient hardware)
• Four drop-in components: TabBar, Slider, Switch, GlassView
• Accessibility support out of the box
• Automatic device adaptation – it won't melt an iPhone 8
• Spring-based morphing animations

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Table of Contents

• Installation
• Components
• Configuration
• Advanced

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Installation

Add to your Package.swift:

dependencies:[.package(url:"https://github.com/valzevul/Theseus.git", from:"1.0.0")]

Or in Xcode: File → Add Package Dependencies... → paste the repository URL.

Requirement	Version
iOS	13.0+
Swift	5.9+
Metal	Optional (fallback available)

Quick Start

import Theseus letglassView=TheseusView() glassView.shape.cornerRadius =20 glassView.sourceView = backgroundView view.addSubview(glassView)

SwiftUI

Theseus is a UIKit-based library. For SwiftUI, use UIViewRepresentable wrappers with the Coordinator pattern for proper two-way binding.

Complete, working wrappers are provided in:TheseusDemoSwiftUI/TheseusDemoSwiftUI/Helpers/TheseusViewRepresentable.swift

Includes:

• TheseusViewRepresentable – Core glass lens
• TheseusTabBarRepresentable – Tab bar with selection binding
• TheseusSwitchRepresentable – Toggle with @Binding isOn
• TheseusSliderRepresentable – Slider with @Binding value

Requirement	Version
Library	iOS 13+
SwiftUI demo	iOS 15+

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Components

Three controls, powered by TheseusView.

TheseusTabBar

The glass capsule floats over your selected tab.

lettabBar=TheseusTabBar() tabBar.items =[TheseusTabBarItem( icon:UIImage(systemName:"house"), title:"Home"),TheseusTabBarItem( icon:UIImage(systemName:"magnifyingglass"), title:"Search"), // ... ] tabBar.selectedIndex =0 tabBar.onItemSelected ={ index inprint("Selected tab: \(index)")}

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TheseusSlider

The knob stretches into a glass capsule while you drag, or snaps to positions if you need a stepper.

letslider=TheseusSlider() slider.minimumValue =0 slider.maximumValue =100 slider.setValue(50) // For discrete positions (like a stepper) slider.positionsCount =5 slider.markPositions =true

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TheseusSwitch

A toggle that morphs as you flick or drag it.

lettoggle=TheseusSwitch() toggle.isOn =true toggle.onTintColor =.systemGreen toggle.offTintColor =.systemGray4 toggle.onValueChanged ={ isOn inprint("Switch: \(isOn ?"ON":"OFF")")}

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TheseusView

The core building block. A fully customisable glass lens – use it to build your own components or as a standalone translucent overlay.

letglassView=TheseusView() // Shape glassView.shape.cornerRadius =24 glassView.shape.borderWidth =1.0 // Glass effect glassView.blur.radius =20 glassView.refraction.intensity =1.2 glassView.refraction.dispersion =3.0 // Appearance glassView.opacity =0.85 glassView.theme.tintColor =.systemBlue .withAlphaComponent(0.1) // Connect to background glassView.sourceView = backgroundImageView

TheseusView supports:

• Blur – Gaussian blur with configurable radius
• Refraction – Edge distortion with chromatic dispersion
• Edge effects – Fresnel rim glow and specular highlights
• Morphing – Spring-based shape animations

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Configuration

Basic

varconfig=TheseusConfiguration()
config.blur.radius =20
config.shape.cornerRadius =16
config.opacity =0.9
config.theme.tintColor =UIColor.systemBlue.withAlphaComponent(0.1)letglassView=TheseusView(configuration: config)

Advanced Configuration

// Refraction (glass distortion)
config.refraction.edgeWidth =22.0
config.refraction.intensity =1.45
config.refraction.dispersion =4.0
// Edge effects (fresnel / highlights)
config.edgeEffects.rimRange =45.0
config.edgeEffects.rimGlow =1.0
config.edgeEffects.rimHardness =12.0
// Glare (light reflection)
config.edgeEffects.glareRange =450.0
config.edgeEffects.glareIntensity =1.0
config.edgeEffects.lightAngle =.pi *0.3
config.edgeEffects.glareFocus =0.75
// Morphing animation
config.morph.tension =0.18
config.morph.friction =0.88
config.morph.smoothing =0.45

See TheseusConfiguration.swift for all available options.

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Advanced

Device Adaptation

Theseus automatically detects device capabilities and adjusts rendering:

Tier	RAM / Cores	Example Devices	Rendering
Tier 3	≥6GB, ≥6 cores	iPhone 12+	Full Metal + true refraction
Tier 2	≥4GB, ≥6 cores	iPhone 8–11	Metal, selective refraction
Tier 1	≥3GB	Older iPhones	Metal, cheap approximation
Tier 0	<3GB	Very old devices	UIVisualEffectView fallback

Override for Testing letsettings=TheseusSettings.shared settings.tierOverride =.tier0 settings.refractionPolicyOverride =.cheapApprox settings.resetToDefaults()

Accessibility

Theseus respects system settings automatically.

Setting	Behaviour
Reduce Transparency	Solid backgrounds instead of blur
Reduce Motion	Disables spring morphing animations
Low Power Mode	Downgrades effects, reduces frame rate

Performance

Pause rendering when views are hidden to save GPU cycles:

glassView.pauseRendering()
glassView.resumeRendering()

Demo Apps

Demo	Path	Description
UIKit	TheseusDemo/	All components with settings panel
SwiftUI	TheseusDemoSwiftUI/	Complete wrappers (iOS 15+)

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License

Apache License 2.0

If you ship Theseus, I'd love a mention in About → Credits.