Drive capture selection through a CGEventTap

Panel event delivery is unreliable on macOS 26 (clicks pass through even
with the app active and the panel key). The selection flow is now driven
by a CGEventTap that sees and consumes mouse events system-wide: hover
highlights windows, clicks capture them (rounded), drags marquee-select,
Esc cancels. Requires Accessibility permission, prompted on first use;
falls back to panel events when unavailable.

💘 Generated with Crush

Assisted-by: Crush:deepseek-v4-flash-0731

Sources/Kapture/CaptureController.swift

@@ -1,27 +1,47 @@
 import AppKit
 import CoreGraphics
 import ScreenCaptureKit
+import ApplicationServices
 
 final class CaptureController: NSObject {
     static let shared = CaptureController()
 
-    private var overlays: [NSWindow] = []
+    private var overlays: [OverlayWindow] = []
     private(set) var isSelecting = false
     private var previousApp: NSRunningApplication?
     private var overlayIDs: [Int] = []
 
+    // Selection state (driven by the event tap; AppKit global coordinates)
+    private var marqueeStart: NSPoint?
+    private(set) var marqueeRect: NSRect?
+    private(set) var hoverFrame: NSRect?
+    private var trackedWindows: [(id: CGWindowID, frame: NSRect)] = []
+    private var lastWindowScan = Date.distantPast
+    private var eventTap: CFMachPort?
+
     /// Session event log for debugging (dumped via Copy Diagnostics).
+    /// Also appended to /tmp/kapture-debug.log so it survives relaunches.
     static var sessionLog: [String] = []
     static func log(_ line: String) {
-        sessionLog.append(line)
-        if sessionLog.count > 100 { sessionLog.removeFirst() }
+        let stamped = String(format: "%@ %@", DateFormatter.localizedString(from: Date(), dateStyle: .none, timeStyle: .medium), line)
+        sessionLog.append(stamped)
+        if sessionLog.count > 200 { sessionLog.removeFirst() }
         NSLog("[Kapture] \(line)")
+        let path = "/tmp/kapture-debug.log"
+        if let handle = FileHandle(forWritingAtPath: path) {
+            handle.seekToEndOfFile()
+            handle.write((stamped + "\n").data(using: .utf8)!)
+            handle.closeFile()
+        } else {
+            FileManager.default.createFile(atPath: path, contents: (stamped + "\n").data(using: .utf8))
+        }
     }
 
     /// Diagnostic snapshot for "Copy Diagnostics" menu item.
     func diagnostics() -> String {
         var lines: [String] = []
         lines.append("Kapture diagnostics — version \(Bundle.main.infoDictionary?["CFBundleShortVersionString"] ?? "?")")
+        lines.append("accessibility=\(AXIsProcessTrusted()) eventTap=\(eventTap != nil)")
         lines.append("--- session log (newest last) ---")
         lines.append(contentsOf: Self.sessionLog)
         lines.append("--- screens ---")
@@ -53,6 +73,8 @@ final class CaptureController: NSObject {
         return lines.joined(separator: "\n")
     }
 
+    // MARK: - Session lifecycle
+
     func begin() {
         guard !isSelecting else { return }
         guard PermissionManager.isGranted else {
@@ -61,25 +83,22 @@ final class CaptureController: NSObject {
         }
         isSelecting = true
         previousApp = NSWorkspace.shared.frontmostApplication
-        // Activation is ASYNC: isActive only flips on a later runloop tick
-        // (verified on macOS 26). Show overlays only once active, otherwise
-        // the first click can pass through to the windows below.
+        // Activation is async on macOS 26; wait a tick so the app is active
+        // before the overlays appear (otherwise clicks pass through).
         NSApp.activate(ignoringOtherApps: true)
         CaptureController.log("begin: activate issued, active=\(NSApp.isActive)")
         DispatchQueue.main.asyncAfter(deadline: .now() + 0.05) { [weak self] in
             guard let self, self.isSelecting else { return }
             CaptureController.log("begin: active=\(NSApp.isActive) — showing overlays")
             self.overlays = NSScreen.screens.map { screen in
-                OverlayWindow(
-                    screen: screen,
-                    onComplete: { [weak self] rect in self?.finishSelection(rect) },
-                    onCancel: { [weak self] in self?.cancelSelection() },
-                    onWindowPick: { [weak self] rect in self?.finishWindowPick(rect) }
-                )
+                let panel = OverlayWindow(screen: screen, controller: self)
+                (panel.contentView as? OverlayView)?.controller = self
+                return panel
             }
             self.overlays.forEach { $0.makeKeyAndOrderFront(nil) }
             self.overlayIDs = self.overlays.map { $0.windowNumber }
             CaptureController.log("begin: \(self.overlays.count) overlays, ids=\(self.overlayIDs), active=\(NSApp.isActive)")
+            self.installEventTap()
         }
     }
 
@@ -113,8 +132,12 @@ final class CaptureController: NSObject {
     }
 
     private func hideOverlays() {
+        removeEventTap()
         overlays.forEach { $0.orderOut(nil) }
         overlays = []
+        marqueeRect = nil
+        hoverFrame = nil
+        marqueeStart = nil
     }
 
     private func restorePreviousApp() {
@@ -122,6 +145,193 @@ final class CaptureController: NSObject {
         previousApp = nil
     }
 
+    private func renderOverlays() {
+        for overlay in overlays {
+            (overlay.contentView as? OverlayView)?.needsDisplay = true
+        }
+    }
+
+    // MARK: - Event tap
+
+    private func installEventTap() {
+        guard eventTap == nil else { return }
+        guard AXIsProcessTrusted() else {
+            CaptureController.log("tap: accessibility not granted — falling back to panel events")
+            PermissionManager.requestAccessibility()
+            return
+        }
+        let mask: CGEventMask = (1 << CGEventType.mouseMoved.rawValue)
+            | (1 << CGEventType.leftMouseDown.rawValue)
+            | (1 << CGEventType.leftMouseDragged.rawValue)
+            | (1 << CGEventType.leftMouseUp.rawValue)
+            | (1 << CGEventType.keyDown.rawValue)
+        guard let tap = CGEvent.tapCreate(
+            tap: .cghidEventTap,
+            place: .headInsertEventTap,
+            options: .defaultTap,
+            eventsOfInterest: CGEventMask(mask),
+            callback: Self.tapCallback,
+            userInfo: Unmanaged.passUnretained(self).toOpaque()
+        ) else {
+            CaptureController.log("tap: creation FAILED — falling back to panel events")
+            return
+        }
+        eventTap = tap
+        if let source = CFMachPortCreateRunLoopSource(nil, tap, 0) {
+            CFRunLoopAddSource(CFRunLoopGetMain(), source, .commonModes)
+        }
+        CGEvent.tapEnable(tap: tap, enable: true)
+        CaptureController.log("tap: installed")
+    }
+
+    private func removeEventTap() {
+        guard let tap = eventTap else { return }
+        CGEvent.tapEnable(tap: tap, enable: false)
+        if let source = CFMachPortCreateRunLoopSource(nil, tap, 0) {
+            CFRunLoopRemoveSource(CFRunLoopGetMain(), source, .commonModes)
+        }
+        CFMachPortInvalidate(tap)
+        eventTap = nil
+        CaptureController.log("tap: removed")
+    }
+
+    private static let tapCallback: CGEventTapCallBack = { _, type, event, refcon in
+        guard let refcon else { return Unmanaged.passUnretained(event) }
+        let controller = Unmanaged<CaptureController>.fromOpaque(refcon).takeUnretainedValue()
+        if let result = controller.handleTap(type, event) {
+            return Unmanaged.passUnretained(result)
+        }
+        return nil
+    }
+
+    /// Convert a CG global point (top-left origin) to AppKit global.
+    private func cgPointToAppKit(_ p: NSPoint) -> NSPoint {
+        guard let mainScreen = NSScreen.screens.first else { return p }
+        return NSPoint(x: p.x, y: mainScreen.frame.height - p.y)
+    }
+
+    /// Scan on-screen windows (AppKit global frames), front to back.
+    private func refreshTrackedWindows() {
+        guard let list = CGWindowListCopyWindowInfo(
+            [ .optionOnScreenOnly, .excludeDesktopElements ], kCGNullWindowID
+        ) as? [[String: Any]] else { trackedWindows = []; return }
+
+        let ownIDs = Set(overlayIDs)
+        var found: [(id: CGWindowID, frame: NSRect)] = []
+        for info in list {
+            guard let cid = info[kCGWindowNumber as String] as? CGWindowID,
+                  let bounds = info[kCGWindowBounds as String] as? [String: CGFloat],
+                  let layer = info[kCGWindowLayer as String] as? Int,
+                  layer == 0
+            else { continue }
+            if ownIDs.contains(Int(cid)) { continue }
+            let cgRect = NSRect(
+                x: bounds["X"] ?? 0,
+                y: bounds["Y"] ?? 0,
+                width: bounds["Width"] ?? 0,
+                height: bounds["Height"] ?? 0
+            )
+            guard cgRect.width >= 80, cgRect.height >= 60 else { continue }
+            let rect = Self.cgToAppKit(rect: cgRect)
+            // Skip windows filling an entire screen (fullscreen apps)
+            let coversWholeScreen = NSScreen.screens.contains { screen in
+                abs(screen.frame.width - rect.width) < 2 && abs(screen.frame.height - rect.height) < 2
+            }
+            guard !coversWholeScreen else { continue }
+            found.append((cid, rect))
+        }
+        trackedWindows = found
+    }
+
+    /// Convert a CGWindowList (top-left origin) frame into AppKit screen
+    /// coordinates (bottom-left origin).
+    private static func cgToAppKit(rect: NSRect) -> NSRect {
+        guard let mainScreen = NSScreen.screens.first else { return rect }
+        let y = mainScreen.frame.height - rect.origin.y - rect.height
+        return NSRect(x: rect.origin.x, y: y, width: rect.width, height: rect.height)
+    }
+
+    private func topmostWindowContaining(_ appKitPoint: NSPoint) -> NSRect? {
+        for (_, frame) in trackedWindows {
+            if frame.contains(appKitPoint) {
+                return frame
+            }
+        }
+        return nil
+    }
+
+    /// Returns the event to pass through, or nil to consume it.
+    func handleTap(_ type: CGEventType, _ event: CGEvent) -> CGEvent? {
+        guard isSelecting else { return event }
+
+        switch type {
+        case .tapDisabledByUserInput:
+            CGEvent.tapEnable(tap: eventTap!, enable: true)
+            return event
+        case .tapDisabledByTimeout:
+            CGEvent.tapEnable(tap: eventTap!, enable: true)
+            return event
+        case .keyDown:
+            if event.getIntegerValueField(.keyboardEventKeycode) == 53 {
+                CaptureController.log("tap: Esc — cancel")
+                cancelSelection()
+                return nil
+            }
+            return event
+        case .mouseMoved, .leftMouseDragged:
+            // Throttle window scans while moving
+            if Date().timeIntervalSince(lastWindowScan) > 0.15 {
+                lastWindowScan = Date()
+                refreshTrackedWindows()
+            }
+            let appKitPoint = cgPointToAppKit(NSPoint(x: event.location.x, y: event.location.y))
+            if type == .mouseMoved {
+                let frame = topmostWindowContaining(appKitPoint)
+                if frame != hoverFrame {
+                    hoverFrame = frame
+                    renderOverlays()
+                }
+                return event
+            }
+            // Drag: grow the marquee
+            guard let start = marqueeStart else { return nil }
+            let rect = NSRect(
+                x: min(start.x, appKitPoint.x),
+                y: min(start.y, appKitPoint.y),
+                width: abs(appKitPoint.x - start.x),
+                height: abs(appKitPoint.y - start.y)
+            )
+            marqueeRect = rect
+            hoverFrame = nil
+            renderOverlays()
+            return nil
+        case .leftMouseDown:
+            marqueeStart = cgPointToAppKit(NSPoint(x: event.location.x, y: event.location.y))
+            marqueeRect = nil
+            CaptureController.log("tap: mouseDown at \(marqueeStart.map { "\($0)" } ?? "?")")
+            return nil
+        case .leftMouseUp:
+            defer { marqueeStart = nil; marqueeRect = nil }
+            let appKitPoint = cgPointToAppKit(NSPoint(x: event.location.x, y: event.location.y))
+            let dragDistance = marqueeStart.map { hypot($0.x - appKitPoint.x, $0.y - appKitPoint.y) } ?? 0
+            if let rect = marqueeRect, dragDistance >= 4, rect.width >= 2, rect.height >= 2 {
+                CaptureController.log("tap: marquee complete \(rect)")
+                finishSelection(rect)
+            } else if let hover = hoverFrame {
+                CaptureController.log("tap: window pick \(hover)")
+                finishWindowPick(hover)
+            } else {
+                CaptureController.log("tap: click with no hover/marquee — cancel")
+                cancelSelection()
+            }
+            return nil
+        default:
+            return event
+        }
+    }
+
+    // MARK: - Capture
+
     private func capture(_ rect: NSRect, excludingWindowIDs ids: [Int], roundedCorners: Bool = false) {
         ScreenCapture.shared.capture(rect, excludingWindowIDs: ids, roundedCorners: roundedCorners) { [weak self] image in
             DispatchQueue.main.async {