feat(resize/apple): Match-window mid-stream resize trigger + settings (C3)

design/midstream-resolution-resize.md Phase 2, Apple client. The stream mode follows the session window/scene: a windowed macOS window resize or an iPad Stage Manager / Split View scene change renegotiates the host's virtual display + encoder via the existing PunktfunkConnection.requestMode, so a windowed session streams native-resolution pixels instead of scaling. Decode/present need nothing — VideoToolbox recreates its session on the keyframe-derived format-description change (§1 table). - MatchWindowFollower (new): the shared D2 trigger discipline — physical pixels even-floored + clamped ≥320×200, debounce to resize-end, ≥1 s between requests, skip a size equal to the live mode, request each distinct size at most once (stops re-asking a rejected size / looping on a host rollback). Pure normalize/request core is unit-tested (MatchWindowTests). - macOS StreamLayerView: fed from layoutPresenter() (bounds → convertToBacking), guarded to once-in-a-window. - iOS StreamViewController: fed from viewDidLayoutSubviews (bounds × render scale); iOS-only (iPhone fullscreen no-ops, tvOS uses AVDisplayManager). - Settings: "Match window" toggle in the Stream mode section (iOS + macOS), DefaultsKey.matchWindow, read per session by the follower. Verified on a Linux Swift 6.1.2 toolchain (the app target needs AppKit/UIKit, unavailable here): the real MatchWindowFollower.swift type-checks in Swift 5 mode against a connection stub, and the pure discipline + the follower's decision path pass a standalone harness (drag-settle + grow → exactly two switches, refresh preserved, no re-request loop). A full build + on-device run (macOS window, iPad Stage Manager) remains for a Mac. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
2026-07-11 13:36:03 +02:00
parent d0d9bd5bfb
commit 89ff326ebf
7 changed files with 228 additions and 3 deletions
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+// Match-window resize follower (design/midstream-resolution-resize.md D1/D2, client C3).
+//
+// The presenting view feeds this its PHYSICAL-PIXEL size on every layout; it debounces to
+// resize-end, spaces requests ≥ 1 s apart, and asks the connection to switch the host's virtual
+// display + encoder to match (`PunktfunkConnection.requestMode`) — so a windowed macOS session or
+// an iPad Stage Manager / Split View scene streams native-resolution pixels instead of scaling.
+// The decode/present side needs nothing: VideoToolbox recreates its session on the keyframe-derived
+// format-description change (the first new-mode AU is an IDR with fresh parameter sets).
+//
+// The trigger discipline is the shared cross-client one (mirrors the session binary's
+// `resize_decision`): physical pixels rounded DOWN to even (the host rejects odd dimensions) and
+// clamped ≥ 320×200; debounce to resize-end; ≥ 1 s between requests; skip a size equal to the live
+// mode; and request each distinct size at most once — which both stops re-asking a rejected size
+// and keeps a host-side rollback (accepted, rebuild failed, corrective ack restored the old mode)
+// from looping request → rollback → request.
+
+import Foundation
+
+/// The pure, side-effect-free core of the Match-window trigger — so the normalize/skip discipline
+/// is unit-tested without a live connection or a UI (`MatchWindowTests`).
+public enum MatchWindow {
+    /// Even-floor + clamp a physical-pixel size to a host-valid mode dimension: the host's
+    /// `validate_dimensions` rejects odd sizes, and we never ask below 320×200.
+    public static func normalize(widthPx: Int, heightPx: Int) -> (width: UInt32, height: UInt32) {
+        let evenClamp: (Int, UInt32) -> UInt32 = { px, minimum in
+            let even = UInt32(max(px, 0)) / 2 * 2
+            return max(even, minimum)
+        }
+        return (evenClamp(widthPx, 320), evenClamp(heightPx, 200))
+    }
+
+    /// Whether to request `target` now (the debounce has already settled; spacing is the caller's
+    /// timer): `nil` to skip — equal to the live mode, or already requested once (a rejected size /
+    /// a host rollback must not loop). `target` is expected already-[normalize]d.
+    public static func request(
+        target: (width: UInt32, height: UInt32),
+        current: (width: UInt32, height: UInt32),
+        lastRequested: (width: UInt32, height: UInt32)?
+    ) -> (width: UInt32, height: UInt32)? {
+        if target.width == current.width, target.height == current.height { return nil }
+        if let lr = lastRequested, lr.width == target.width, lr.height == target.height { return nil }
+        return target
+    }
+}
+
+/// Owns the debounce timer + serialization state and drives `PunktfunkConnection.requestMode` from
+/// the stream view's layout callbacks. Main-actor: the views feed it on the main thread and it reads
+/// the connection's live mode there. Enabled per session from the `matchWindow` setting.
+@MainActor
+public final class MatchWindowFollower {
+    private weak var connection: PunktfunkConnection?
+    private let debounce: TimeInterval
+    private let minSpacing: TimeInterval
+    private var enabled: Bool
+
+    private var work: DispatchWorkItem?
+    private var pendingSize: (width: Int, height: Int)?
+    private var lastRequested: (width: UInt32, height: UInt32)?
+    private var lastRequestAt: Date?
+
+    /// `debounce` = quiet time after the last size event before requesting (Win32 gets
+    /// `WM_EXITSIZEMOVE` for free; we debounce). `minSpacing` = floor between accepted requests
+    /// (a full host pipeline rebuild each). Defaults match the other clients.
+    public init(
+        connection: PunktfunkConnection,
+        enabled: Bool,
+        debounce: TimeInterval = 0.4,
+        minSpacing: TimeInterval = 1.0
+    ) {
+        self.connection = connection
+        self.enabled = enabled
+        self.debounce = debounce
+        self.minSpacing = minSpacing
+    }
+
+    /// Turn following on/off live (a mid-session settings change; off cancels a pending request).
+    public func setEnabled(_ on: Bool) {
+        enabled = on
+        if !on {
+            work?.cancel()
+            work = nil
+            pendingSize = nil
+        }
+    }
+
+    /// Feed the presenting view's current PHYSICAL-PIXEL size (its `bounds` × the backing/display
+    /// scale). Called from every layout pass; coalesced by the debounce so a drag-resize sends one
+    /// request at its end, never one per frame.
+    public func noteSize(widthPx: Int, heightPx: Int) {
+        guard enabled else { return }
+        pendingSize = (widthPx, heightPx)
+        schedule()
+    }
+
+    private func schedule() {
+        work?.cancel()
+        let item = DispatchWorkItem { [weak self] in self?.fire() }
+        work = item
+        DispatchQueue.main.asyncAfter(deadline: .now() + debounce, execute: item)
+    }
+
+    private func fire() {
+        guard enabled, let connection, let size = pendingSize else { return }
+        // ≥ 1 s spacing: a request went out recently → re-arm the debounce and retry later rather
+        // than fire early (keeps at most ~one request outstanding — the accept ack round-trips in
+        // milliseconds, ahead of the host's rebuild).
+        if let last = lastRequestAt, Date().timeIntervalSince(last) < minSpacing {
+            schedule()
+            return
+        }
+        let target = MatchWindow.normalize(widthPx: size.width, heightPx: size.height)
+        let mode = connection.currentMode()
+        pendingSize = nil
+        guard let req = MatchWindow.request(
+            target: target,
+            current: (mode.width, mode.height),
+            lastRequested: lastRequested
+        ) else { return }
+        // Keep the current refresh — Match-window follows SIZE, not rate.
+        connection.requestMode(width: req.width, height: req.height, refreshHz: mode.refreshHz)
+        lastRequested = req
+        lastRequestAt = Date()
+    }
+}