Add Copy Diagnostics menu item for multi-display debugging

Prints each NSScreen's frame/backing scale/CG display ID and each
SCDisplay's frame/point size, and copies it to the clipboard, so
secondary-display capture failures can be debugged from the menu bar.

💘 Generated with Crush

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

Sources/Kapture/App.swift

@@ -48,6 +48,13 @@ struct MenuView: View {
 
         Divider()
 
+        Button("Copy Diagnostics") {
+            let diag = CaptureController.shared.diagnostics()
+            let pasteboard = NSPasteboard.general
+            pasteboard.clearContents()
+            pasteboard.setString(diag, forType: .string)
+        }
+
         Button(LoginItem.isEnabled ? "Disable Launch at Login" : "Launch at Login") {
             if !LoginItem.toggle() {
                 let alert = NSAlert()

Sources/Kapture/CaptureController.swift

@@ -10,6 +10,38 @@ final class CaptureController: NSObject {
     private var previousApp: NSRunningApplication?
     private var overlayIDs: [Int] = []
 
+    /// Diagnostic snapshot for "Copy Diagnostics" menu item.
+    func diagnostics() -> String {
+        var lines: [String] = []
+        lines.append("Kapture diagnostics")
+        for (i, s) in NSScreen.screens.enumerated() {
+            let scale = s.backingScaleFactor
+            let cgID = (s.deviceDescription[NSDeviceDescriptionKey("NSScreenNumber")] as? NSNumber)?.uint32Value ?? 0
+            lines.append("screen[\(i)]: frame=\(s.frame) scale=\(scale) backingSize=\(s.frame.width*scale)x\(s.frame.height*scale) cgID=\(cgID)")
+        }
+        if #available(macOS 14.0, *) {
+            Task {
+                if let content = try? await SCShareableContent.current {
+                    for (i, d) in content.displays.enumerated() {
+                        lines.append("SCDisplay[\(i)]: frame=\(d.frame) width=\(d.width)x\(d.height) id=\(d.displayID)")
+                    }
+                } else {
+                    lines.append("SCShareableContent: unavailable (no Screen Recording permission?)")
+                }
+                let text = lines.joined(separator: "\n")
+                let pb = NSPasteboard.general
+                pb.clearContents()
+                pb.setString(text, forType: .string)
+            }
+        } else {
+            let text = lines.joined(separator: "\n")
+            let pb = NSPasteboard.general
+            pb.clearContents()
+            pb.setString(text, forType: .string)
+        }
+        return lines.joined(separator: "\n")
+    }
+
     func begin() {
         guard !isSelecting else { return }
         guard PermissionManager.isGranted else {
@@ -86,10 +118,12 @@ final class ScreenCapture {
 
     @available(macOS 14.0, *)
     private func crop(_ image: CGImage, to rect: NSRect, display: SCDisplay) -> CGImage? {
-        // Scale from the actual captured image dimensions, which reflect the
-        // stream's pixel output (retina => 2x, non-retina => 1x).
+        // The captured image may be at any scale (retina 2x, secondary display
+        // 1x, or trimmed by ScreenCaptureKit). Derive the pixel scale from the
+        // image we actually got, relative to the display's point frame.
         let scaleX = CGFloat(image.width) / display.frame.width
         let scaleY = CGFloat(image.height) / display.frame.height
+        guard scaleX > 0, scaleY > 0 else { return nil }
         let cgRect = CGRect(
             x: rect.minX,
             y: rect.minY,
@@ -102,14 +136,18 @@ final class ScreenCapture {
             width: cgRect.width * scaleX,
             height: cgRect.height * scaleY
         )
+        // Guard against negative offsets when the selection reaches beyond the
+        // display's frame (e.g. secondary monitor coordinate quirks).
+        let safeRect = pxRect.intersection(CGRect(x: 0, y: 0, width: CGFloat(image.width), height: CGFloat(image.height)))
+        guard safeRect.width >= 1, safeRect.height >= 1 else { return nil }
         guard let cropCtx = CGContext(
-            data: nil, width: Int(pxRect.width), height: Int(pxRect.height),
+            data: nil, width: Int(safeRect.width), height: Int(safeRect.height),
             bitsPerComponent: 8, bytesPerRow: 0,
             space: CGColorSpaceCreateDeviceRGB(),
             bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue
         ) else { return nil }
         cropCtx.interpolationQuality = .high
-        cropCtx.draw(image, in: CGRect(x: -pxRect.minX, y: -pxRect.minY, width: CGFloat(image.width), height: CGFloat(image.height)))
+        cropCtx.draw(image, in: CGRect(x: -safeRect.minX, y: -safeRect.minY, width: CGFloat(image.width), height: CGFloat(image.height)))
         return cropCtx.makeImage()
     }
 
@@ -135,13 +173,15 @@ final class ScreenCapture {
                 let excluded = content.windows.filter { excludedSet.contains($0.windowID) }
                 let filter = SCContentFilter(display: display, excludingWindows: excluded)
                 let config = SCStreamConfiguration()
-                // width/height are in points. Use the display's backing scale so
-                // retina captures come out at full pixel resolution.
-                let backingScale = NSScreen.screens.first(where: { $0.frame.contains(
-                    NSPoint(x: rect.midX, y: rect.midY)
-                ) })?.backingScaleFactor ?? 2
-                config.width = Int(display.frame.width * backingScale)
-                config.height = Int(display.frame.height * backingScale)
+                // SCDisplay.width/height are in POINTS; SCStreamConfiguration
+                // width/height are output PIXELS. Multiply by the backing scale
+                // of the screen containing the selection so retina displays are
+                // captured at full resolution and 1x displays stay 1x.
+                let backingScale = NSScreen.screens
+                    .first(where: { $0.frame.contains(NSPoint(x: rect.midX, y: rect.midY)) })?
+                    .backingScaleFactor ?? 1
+                config.width = Int(CGFloat(display.width) * backingScale)
+                config.height = Int(CGFloat(display.height) * backingScale)
                 config.showsCursor = true
 
                 guard let image = try? await SCScreenshotManager.captureImage(contentFilter: filter, configuration: config) else {

build-app.sh

@@ -108,9 +108,9 @@ cat > "$APP/Contents/Info.plist" <<'PLIST'
     <key>CFBundleIconFile</key>
     <string>Icon</string>
     <key>CFBundleShortVersionString</key>
-    <string>1.1.3</string>
+    <string>1.1.6</string>
     <key>CFBundleVersion</key>
-    <string>13</string>
+    <string>16</string>
     <key>LSUIElement</key>
     <true/>
     <key>NSHighResolutionCapable</key>