[Feature] Adopt “Liquid Glass” (visual-only) on iOS 26 for Session

[mikeldev0]

Adopt Apple’s new Liquid Glass visual language on iOS 26 to modernize Session’s look & feel while preserving performance and accessibility. Scope is visual-only (no auth/security changes). Use Apple’s updated design guidance and APIs introduced at WWDC25 for materials, controls, and transitions. ([Apple]1)

Scope

• Components: Navigation bar, tab bar, headers/toolbars, cards, sheets/modals, toasts, context panels.
• Tech: SwiftUI-first adoption of Liquid Glass materials & updated controls; UIKit wrappers where needed. Legacy fallback (< iOS 26) uses existing opaque/translucent styles (e.g., UIVisualEffectView blur/vibrancy). ([The Verge]2)
• Out of scope: Session isolation, encryption, snapshot redaction, auth flows.

Goals

• Consistent Liquid Glass visuals across targeted surfaces on iOS 26.
• 60/120 fps fluidity on supported devices; graceful degradation on lower tiers.
• Full Dark/Light support and Accessibility (Reduce Motion/Transparency; contrast).

Non-Goals

• New navigation patterns, server/API changes, or platform backports below iOS 26.

Design Tokens (proposed)

• Blur: lg.blur.{xs,s,m,l} (≈6/12/20/28).
• Saturation: lg.sat.{low,med,high} (≈1.0/1.3/1.6).
• Tint/Opacity: lg.tint.{light,dark} with adaptive alpha by backdrop luminance.
• Stroke: lg.stroke.hairline (1 px) with dynamic alpha; optional inner highlight.
• Radius/Elevation: radius.2xl default; elevation map per component.
• Preset: lg.preset.{full,lite,opaque} (feature-flaggable).

Implementation (high-level)

1. Capability gating & flags

   • Enable on iOS 26 via remote flag with kill-switch and “preset” override (full|lite|opaque).

2. Foundation

   • Create LiquidGlassView wrapper (SwiftUI) composing blur + saturation + tint + stroke; expose presets.
   • Provide UIKit adapter for screens not yet SwiftUI.

3. Apply to components

   • Nav/Tab bars → Liquid Glass materials & updated controls; responsive shrink/expand on scroll where appropriate.
   • Cards/Sheets/Toasts → Liquid Glass presets with careful overdraw limits.

4. Accessibility

   • Respect Reduce Transparency/Motion; auto-switch to opaque or toned-down animations.
   • Enforce WCAG AA contrast with dynamic foreground on complex backdrops. ([Nielsen Norman Group]5)

5. Performance guardrails

   • Target P95 resume/transition smoothness; cap additional peak memory during transitions.

Performance Budgets

• FPS: Sustain 60/120 fps on Tier A devices during transitions/scroll.
• CPU (avg fg): ≤ +3% vs baseline on targeted screens.
• Peak memory: ≤ +20 MB during modal/sheet animations.

Testing Plan

• Visual regression: snapshots per component in Light/Dark + Increased Contrast.
• UI tests: bar transitions (shrink/expand), sheet presentations, theme switches.
• Perf: automated scroll benchmarks for long lists with glass cards; capture FPS/memory deltas.
• A11y manual: VoiceOver focus, Reduce Motion/Transparency toggles, readability over varied wallpapers.

Rollout

1. Phase 1 (dogfood): NavBar + TabBar with full preset; metrics on FPS/memory.
2. Phase 2 (beta): Cards + Sheets; tune lite preset for mid-tier devices.
3. Phase 3 (GA): Toasts/overlays; finalize tokens & documentation.

Telemetry (optional)

ui.liquid_glass.enabled
ui.liquid_glass.preset (full|lite|opaque)
ui.fps.transition.avg/min
ui.mem.delta_mb.peak

Acceptance Criteria

• Nav/Tab bars, Cards, Sheets, Toasts use Liquid Glass presets on iOS 26 with FPS within budget.
• Dark/Light and contrast meet guidelines; Reduce Transparency/Motion respected.
• Fallbacks render correctly on < iOS 26 with no regressions.
• Visual QA sign-off on key screens (home, chat, settings).

References: Apple WWDC25 announcement & APIs for Liquid Glass (design & adoption guidance; updated controls/materials), plus accessibility best practices for glassmorphism. (Apple, [The Verge]2, [YouTube]4, [Nielsen Norman Group]5)

---

How I got there (step-by-step)

1. Primary source: Confirmé en Apple Newsroom que “Liquid Glass” es material/lenguaje oficial, con descripción, plataformas y que hay APIs actualizadas para desarrolladores. ([Apple]1)
2. Secondary coverage: Verifiqué en The Verge/TechCrunch el alcance, superficies afectadas y el carácter de mayor rediseño desde iOS 7. ([The Verge]2, [TechCrunch]3)
3. Guidance for builders: Usé las sesiones/vídeos WWDC (“Meet Liquid Glass”) como soporte de implementación. ([YouTube]4)
4. Best practices: Contrasté con Nielsen Norman Group para accesibilidad/contraste en interfaces translúcidas (glassmorphism). ([Nielsen Norman Group]5)
5. UIKit fallback: Mantengo UIVisualEffectView para capas legacy. ([The Verge]2)

Alternatives you might consider

• Progressive adoption: Start with Nav/Tab bars only, then cards/sheets after perf tuning.
• Device tiering: Auto-switch lite preset on thermally constrained or older A-series devices.
• Theme switch: Offer brand “opaque” theme for teams/markets que prefieran máximo contraste.

Practical action plan (apply now)

1. Create lg.* design tokens + LiquidGlassView wrapper (SwiftUI) and UIKit adapter.
2. Implement NavBar/TabBar with full preset; instrument FPS/memory.
3. Roll to Cards/Sheets, refine presets, run a11y audits; lock Acceptance Criteria.
4. Launch phase rollout behind remote flag & kill-switch; document usage in the design system.

---

• [The Verge](https://www.theverge.com/news/682636/apple-liquid-glass-design-theme-wwdc-2025?utm_source=chatgpt.com)
• [The Verge](https://www.theverge.com/news/682636/apple-liquid-design-glass-theme-wwdc-2025?utm_source=chatgpt.com)
• [Laptop Mag](https://www.laptopmag.com/phones/live/wwdc-2025-live-updates?utm_source=chatgpt.com)
• [Indiatimes](https://indiatimes.com/technology/news/what-is-liquid-glass-a-new-material-launched-in-wwdc-2025-how-will-it-impact-on-ios-26-ipados-macos-660857.html?utm_source=chatgpt.com)
• [New York Post](https://nypost.com/2025/06/10/tech/apple-fans-rip-ios-26-liquid-glass-update/?utm_source=chatgpt.com)

[pottsandpans]

Thank you for the contribution, we will be looking into this once iOS 26 is released.