windows_screen_guard #

Prevent screen capture and recording on Flutter Windows apps using the Windows display affinity API — the same method used by Netflix, banking apps, and enterprise software.

User sees content, capture tool sees black

How it works #

Windows exposes a kernel-level API called SetWindowDisplayAffinity. When called with the WDA_MONITOR flag, it instructs the GPU compositor to exclude your window from any capture pipeline. The result: every capture tool sees your window as solid black, while the user's own display is completely unaffected.

Because this happens at the driver level, no user-space screen capture software can bypass it — the same guarantee that lets Netflix play DRM content on Windows desktops.

windows_screen_guard wraps this API via Dart FFI using the win32 package. No platform channels, no C++ to write, no native plugin setup.

Shield activation animation

Features #

Feature	Details
	Makes your window appear black in all screenshots and recordings
	Swallows `VK_SNAPSHOT` at the OS level via `SetWindowsHookEx`
	Two lines of code to protect your entire app
	`SetWindowDisplayAffinity` works without elevated privileges
	Silent no-op on macOS, Linux, Android, and iOS
	Returns `ScreenGuardResult` with Win32 error code on failure

Installation #

dependencies:
  windows_screen_guard: ^0.1.0

flutter pub get

Quick start #

import 'package:windows_screen_guard/windows_screen_guard.dart';

void main() {
  WidgetsFlutterBinding.ensureInitialized();

  // Block all screen capture before the app renders.
  WindowsScreenGuard.protect();

  // Optionally also block the PrintScreen key.
  WindowsScreenGuard.blockPrintScreen();

  runApp(const MyApp());
}

Usage #

Enable protection #

final result = WindowsScreenGuard.protect();

if (result.success) {
  debugPrint('Screen capture is now blocked.');
} else {
  debugPrint('Failed — Win32 error code: ${result.errorCode}');
}

Disable protection #

WindowsScreenGuard.unprotect();

Block the PrintScreen key #

// Install a low-level keyboard hook that swallows VK_SNAPSHOT.
final hooked = WindowsScreenGuard.blockPrintScreen();

// Check state at any time.
print(WindowsScreenGuard.isPrintScreenBlocked); // true

// Remove the hook when no longer needed.
WindowsScreenGuard.unblockPrintScreen();

Toggle protection per screen #

Protect only sensitive screens rather than the entire app:

class SecureScreen extends StatefulWidget { ... }

class _SecureScreenState extends State<SecureScreen> {
  @override
  void initState() {
    super.initState();
    WindowsScreenGuard.protect();
  }

  @override
  void dispose() {
    WindowsScreenGuard.unprotect();
    super.dispose();
  }

  @override
  Widget build(BuildContext context) => const SensitiveContentWidget();
}

What gets blocked #

Capture method	`protect()`	`blockPrintScreen()`
PrintScreen key
`Win + PrintScreen`
`Win + Shift + S` (Snipping Tool)
`Win + G` (Xbox Game Bar)
OBS / third-party recorders
Remote desktop capture

protect() is the primary defence. blockPrintScreen() is an additional layer for the physical key only.

API reference #