Chromatic Glass

// Default — gentle RGB split, internal only
SWChromaticGlass {
    Image("photo").resizable().scaledToFill()
}
.frame(width: 250, height: 350)
.clipShape(RoundedRectangle(cornerRadius: 16))

// Tilt-driven, stronger separation
@State private var tilt: CGSize = .zero

SWChromaticGlass(tilt: tilt, separation: 0.6) { cardArtwork }
    .gesture(
        DragGesture()
            .onChanged { v in
                tilt = CGSize(width: v.translation.width / 100,
                              height: v.translation.height / 100)
            }
            .onEnded { _ in withAnimation(.spring) { tilt = .zero } }
    )

1. Copy SWChromaticGlass.swift and SWChromaticGlass.metal into your Xcode target, keeping the MIT attribution header on both files.
2. Confirm the deployment target is iOS 18+ / macOS 15+.
3. Wrap a card / photo in SWChromaticGlass { ... }; clip it to a RoundedRectangle.
4. Keep the maxSampleOffset of CGSize(width: 28, height: 28) in the renderer — it must comfortably exceed the maximum pixel offset the shader reaches (≈ 22 px in the corners). See Gotchas.
5. Drive tilt from a DragGesture so the fringing follows the card's rotation.

• maxSampleOffset is load-bearing. Unlike the foil family, this effect samples neighbouring pixels (R/B channels at position ± offset). The offset is separation × (edgeFactor × 0.85 + 0.15) × 14 px, where edgeFactor = (2 × distance from centre)^1.5 is 1 at the edge midpoints and ≈ 1.68 in the corners — so at separation = 1 the shader reaches ≈ 14 px at the edges and ≈ 22 px in the corners; the renderer requests 28 px of headroom. If you drop it to .zero (as the foil family uses), the layer pre-clips its content and the RGB fringing is truncated at the edges. Do not copy .zero from the other skills here.
• The 0.15 floor inside offsetAmount keeps a baseline split even at the centre, so the fringing reads across the whole photo rather than only at the corners.
• The effect is deliberately subtle — it reads as glass-over-card, not a glitch. Raise separation and intensity together for a stronger split.
• There is no TimelineView: the shader ignores its time argument, so the renderer passes 0 and the layer re-renders only when tilt, intensity or separation change — a still card costs nothing per frame.