fix(input): reduce Receiver Master pointer stalls

TargetBridge-Sender/TBDisplaySender/ReceiverBackedVirtualDisplaySession.swift

@@ -156,6 +156,7 @@ final class ReceiverBackedVirtualDisplaySession {
         activatePreferredMode(for: display.displayID,
                               mode: resolvedMode,
                               refreshRate: preferredRefreshRate,
+                              hiDPI: profile.hiDPI,
                               savedChoice: savedChoice)
 
         virtualDisplay = display
@@ -183,13 +184,14 @@ final class ReceiverBackedVirtualDisplaySession {
     private func activatePreferredMode(for displayID: CGDirectDisplayID,
                                        mode: TBVirtualDisplayModeSize,
                                        refreshRate: Double,
+                                       hiDPI: Bool,
                                        savedChoice: TBVirtualDisplayModeMemory.Choice?) -> Bool {
         let timeout = Date().addingTimeInterval(2.0)
         while Date() < timeout {
             var success = false
             autoreleasepool {
                 let chosenMode = savedChoice.flatMap { savedMode(for: displayID, choice: $0) }
-                    ?? preferredMode(for: displayID, mode: mode, refreshRate: refreshRate)
+                    ?? preferredMode(for: displayID, mode: mode, refreshRate: refreshRate, hiDPI: hiDPI)
                 if let chosenMode {
                     success = CGDisplaySetDisplayMode(displayID, chosenMode, nil) == .success
                 }
@@ -223,8 +225,16 @@ final class ReceiverBackedVirtualDisplaySession {
         return candidates.first
     }
 
-    private func preferredMode(for displayID: CGDirectDisplayID, mode: TBVirtualDisplayModeSize, refreshRate: Double) -> CGDisplayMode? {
-        guard let modesCF = CGDisplayCopyAllDisplayModes(displayID, nil) else {
+    /// Select the mode by its backing pixels as well as its logical size. A
+    /// virtual HiDPI display exposes both a Retina 2x and a low-resolution 1x
+    /// variant that can report the same logical 2560x1440 size. Choosing only
+    /// by points made Render Matching restore the blurry 1x variant.
+    private func preferredMode(for displayID: CGDirectDisplayID,
+                               mode: TBVirtualDisplayModeSize,
+                               refreshRate: Double,
+                               hiDPI: Bool) -> CGDisplayMode? {
+        let options = [kCGDisplayShowDuplicateLowResolutionModes: kCFBooleanTrue] as CFDictionary
+        guard let modesCF = CGDisplayCopyAllDisplayModes(displayID, options) else {
             return nil
         }
         let modes = modesCF as? [CGDisplayMode] ?? []
@@ -233,10 +243,16 @@ final class ReceiverBackedVirtualDisplaySession {
             candidate.width == mode.width && candidate.height == mode.height
         }.sorted { $0.refreshRate > $1.refreshRate }
 
-        if let exactMatch = matchingModes.first(where: { abs($0.refreshRate - refreshRate) < 0.5 }) {
+        let expectedPixelWidth = hiDPI ? mode.backingWidth : mode.width
+        let expectedPixelHeight = hiDPI ? mode.backingHeight : mode.height
+        let backingMatches = matchingModes.filter { candidate in
+            candidate.pixelWidth == expectedPixelWidth && candidate.pixelHeight == expectedPixelHeight
+        }
+
+        if let exactMatch = backingMatches.first(where: { abs($0.refreshRate - refreshRate) < 0.5 }) {
             return exactMatch
         }
 
-        return matchingModes.first
+        return backingMatches.first ?? matchingModes.first
     }
 }

TargetBridge-Sender/TBDisplaySender/TBDisplaySenderService.swift

@@ -1274,6 +1274,7 @@ final class TBDisplaySenderSession: NSObject, ObservableObject, Identifiable, @u
     private var cursorDisplayID: CGDirectDisplayID = kCGNullDirectDisplay
     private var lastCursorPacket: TBMonitorCursor?
     private var injectedRemoteMouseLocation: CGPoint?
+    private var cachedLocalInputEventSource: CGEventSource?
     private var injectedLeftClickTracker = TBInjectedClickStateTracker()
     private let localPointerModifierBridge = TBLocalPointerModifierBridge()
     private var injectedCommandDown = false
@@ -2117,14 +2118,21 @@ final class TBDisplaySenderSession: NSObject, ObservableObject, Identifiable, @u
     }
 
     private func localInputEventSource() -> CGEventSource? {
+        if let cachedLocalInputEventSource {
+            return cachedLocalInputEventSource
+        }
         let source = CGEventSource(stateID: .hidSystemState)
         source?.localEventsSuppressionInterval = 0
+        cachedLocalInputEventSource = source
         return source
     }
 
     private func logLocalInputInjectionStateIfNeeded(context: String) {
-        let trusted = AXIsProcessTrusted()
-        TBInputDebugLog.log("sender input injection state trusted=\(trusted) context=\(context)")
+        if context == "mouseMove" {
+            TBInputDebugLog.logInputEvent("sender input injection state trusted=\(AXIsProcessTrusted()) context=\(context)")
+        } else {
+            TBInputDebugLog.log("sender input injection state trusted=\(AXIsProcessTrusted()) context=\(context)")
+        }
     }
 
     private func postLocalMouseMove(dx: Int, dy: Int, type: CGEventType = .mouseMoved, button: CGMouseButton = .left) {
@@ -2277,7 +2285,11 @@ final class TBDisplaySenderSession: NSObject, ObservableObject, Identifiable, @u
     }
 
     private func applyIncomingInputEvent(_ event: TBMonitorInputEvent, payload: Data) {
-        TBInputDebugLog.log("sender applying incoming event kind=\(event.kind)")
+        if event.kind == "move" || event.kind.hasSuffix("Drag") || event.kind == "scroll" {
+            TBInputDebugLog.logInputEvent("sender applying incoming event kind=\(event.kind)")
+        } else {
+            TBInputDebugLog.log("sender applying incoming event kind=\(event.kind)")
+        }
         switch event.kind {
         case "move":
             postLocalMouseMove(dx: event.dx ?? 0, dy: event.dy ?? 0)

TargetBridge-Sender/TBDisplayShared/TBInputDebugLog.swift

@@ -1,37 +1,69 @@
 import Foundation
 
-@MainActor
-enum TBInputDebugLog {
-    private static let fileManager = FileManager.default
+private final class TBAsyncInputDebugLogWriter: @unchecked Sendable {
+    private let fileManager = FileManager.default
+    private let writeQueue = DispatchQueue(label: "fd.tbdisplaysender.input-debug-log", qos: .utility)
 
-    private static var logURL: URL {
+    func enqueue(_ message: String) {
+        writeQueue.async { [self] in
+            write(message)
+        }
+    }
+
+    private func write(_ message: String) {
         let base = fileManager.urls(for: .applicationSupportDirectory, in: .userDomainMask).first
             ?? URL(fileURLWithPath: NSHomeDirectory()).appendingPathComponent("Library/Application Support", isDirectory: true)
-        return base
+        let url = base
             .appendingPathComponent("TargetBridge", isDirectory: true)
             .appendingPathComponent("Logs", isDirectory: true)
             .appendingPathComponent("input-debug.log", isDirectory: false)
-    }
-
-    static func log(_ message: String) {
         let timestamp = ISO8601DateFormatter().string(from: Date())
         let line = "\(timestamp) \(message)\n"
-        let url = logURL
         let directory = url.deletingLastPathComponent()
         try? fileManager.createDirectory(at: directory, withIntermediateDirectories: true)
 
-        if let data = line.data(using: .utf8) {
-            if fileManager.fileExists(atPath: url.path) {
-                if let handle = try? FileHandle(forWritingTo: url) {
-                    try? handle.seekToEnd()
-                    try? handle.write(contentsOf: data)
-                    try? handle.close()
-                }
-            } else {
-                try? data.write(to: url, options: .atomic)
+        guard let data = line.data(using: .utf8) else { return }
+        if fileManager.fileExists(atPath: url.path) {
+            if let handle = try? FileHandle(forWritingTo: url) {
+                try? handle.seekToEnd()
+                try? handle.write(contentsOf: data)
+                try? handle.close()
             }
+        } else {
+            try? data.write(to: url, options: .atomic)
         }
     }
+}
+
+@MainActor
+enum TBInputDebugLog {
+    private static let writer = TBAsyncInputDebugLogWriter()
+    private static var inputEventCount: UInt64 = 0
+    private static let inputEventBurstLimit: UInt64 = 20
+    private static let inputEventSampleInterval: UInt64 = 100
+
+    private static var logURL: URL {
+        let base = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask).first
+            ?? URL(fileURLWithPath: NSHomeDirectory()).appendingPathComponent("Library/Application Support", isDirectory: true)
+        return base
+            .appendingPathComponent("TargetBridge", isDirectory: true)
+            .appendingPathComponent("Logs", isDirectory: true)
+            .appendingPathComponent("input-debug.log", isDirectory: false)
+    }
+
+    static func log(_ message: String) {
+        writer.enqueue(message)
+    }
+
+    /// Mouse motion can arrive hundreds of times per second. Keep the first few
+    /// records plus a periodic sample, without putting file I/O on the input path.
+    static func logInputEvent(_ message: @autoclosure () -> String) {
+        inputEventCount &+= 1
+        let count = inputEventCount
+
+        guard count <= inputEventBurstLimit || count.isMultiple(of: inputEventSampleInterval) else { return }
+        log(message())
+    }
 
     static var currentLogPath: String {
         logURL.path

TargetBridge-Sender/TargetBridgeSupport/Info.plist

@@ -12,6 +12,12 @@
     <string>TargetBridge requires screen recording permission to capture the virtual display or mirror the desktop to the iMac.</string>
     <key>NSAppleEventsUsageDescription</key>
     <string>TargetBridge uses System Events to run shortcuts selected for Receiver is Master.</string>
+    <key>NSBonjourServices</key>
+    <array>
+        <string>_targetbridge._tcp</string>
+    </array>
+    <key>NSLocalNetworkUsageDescription</key>
+    <string>TargetBridge connects to your receiver over Thunderbolt Bridge or your local network.</string>
     <key>CFBundleURLTypes</key>
     <array>
         <dict>