fux translation

src/OnscreenTranslator/DirectXOverlay.cs

@@ -1,13 +1,13 @@
-using System.Diagnostics;
+using System.Diagnostics;
 using System.Drawing;
 using System.IO;
-using LibreTranslate.Net.Enhanced.Constants;
+using System.Net;
+using System.Text.RegularExpressions;
 using LibreTranslate.Net.Enhanced.Models;
 using Overlay.NET.Common;
 using Overlay.NET.Directx;
 using Process.NET.Windows;
 using TesseractOCR;
-using TesseractOCR.Enums;
 using Image = TesseractOCR.Pix.Image;
 using ImageFormat = System.Drawing.Imaging.ImageFormat;
 using Point = System.Drawing.Point;
@@ -17,9 +17,22 @@ namespace OnscreenTranslator;
 
 public class DirectXOverlay : DirectXOverlayPlugin
 {
+    private const string TessdataPath = "C:/Users/luis-/Downloads/tessdata-4.1.0/tessdata-4.1.0";
+
+    private static readonly Regex LineRegex =
+        new(@"class=['""]ocr_(?:line|textline|caption|header)['""][^>]*?title=['""]bbox (\d+) (\d+) (\d+) (\d+)");
+
+    private static readonly Regex WordRegex = new(@"class=['""]ocrx_word['""][^>]*>(.*?)</span>", RegexOptions.Singleline);
+    private static readonly Regex TagRegex = new("<[^>]+>");
+
     private readonly TickEngine _tickEngine = new();
     public readonly ISettings<OverlaySettings> Settings = new SerializableSettings<OverlaySettings>();
+    private readonly LibreTranslate.Net.Enhanced.LibreTranslate _libreTranslate = new("http://127.0.0.1:5000", "");
+    private int _backgroundBrush;
     private int _displayFps;
+    private Engine? _engine;
+    private TranslationLanguage? _engineLanguage;
+    private bool _excludedFromCapture;
     private int _font;
     private int _hugeFont;
     private int _i;
@@ -27,9 +40,21 @@ public class DirectXOverlay : DirectXOverlayPlugin
     private int _redBrush;
     private int _redOpacityBrush;
     private float _rotation;
+    private int _textBrush;
+    private bool _translating;
     private Stopwatch _watch;
-    private readonly List<Element> TranslatedElements = new();
+
-    private List<Element> UntranslatedElements = new();
+    // Replaced as a whole when a translation finishes and never mutated, so rendering can't see a half-built list
+    private IReadOnlyList<Element> _translatedElements = [];
+
+    public TranslationLanguage SourceLanguage { get; set; } = TranslationLanguage.Japanese;
+    public TranslationLanguage TargetLanguage { get; set; } = TranslationLanguage.German;
+
+    /// <summary>
+    ///     Skip LibreTranslate and show Tesseract's text as-is, for checking OCR results.
+    ///     Applies to the next TriggerTranslation.
+    /// </summary>
+    public bool ShowOcrText { get; set; }
 
     public override void Initialize(IWindow targetWindow)
     {
@@ -55,11 +80,15 @@ public class DirectXOverlay : DirectXOverlayPlugin
         //Console.Title = @"OverlayExample";
 
         OverlayWindow = new DirectXOverlayWindow(targetWindow.Handle, false);
+        // Keep the overlay out of the screenshots fed to Tesseract
+        _excludedFromCapture = OverlayWindow.ExcludeFromCapture();
         _watch = Stopwatch.StartNew();
 
         _redBrush = OverlayWindow.Graphics.CreateBrush(0x7FFF0000);
         _redOpacityBrush = OverlayWindow.Graphics.CreateBrush(Color.FromArgb(80, 255, 0, 0));
         _interiorBrush = OverlayWindow.Graphics.CreateBrush(0x7FFFFF00);
+        _backgroundBrush = OverlayWindow.Graphics.CreateBrush(Color.FromArgb(200, 0, 0, 0));
+        _textBrush = OverlayWindow.Graphics.CreateBrush(Color.FromArgb(255, 255, 255, 255));
 
         _font = OverlayWindow.Graphics.CreateFont("Arial", 20);
         _hugeFont = OverlayWindow.Graphics.CreateFont("Arial", 50, true);
@@ -121,7 +150,7 @@ public class DirectXOverlay : DirectXOverlayPlugin
         OverlayWindow.Graphics.BeginScene();
         OverlayWindow.Graphics.ClearScene();
 
-        RenderElements(TranslatedElements);
+        RenderElements(_translatedElements);
 
         if (_watch.ElapsedMilliseconds > 1000)
         {
@@ -138,110 +167,151 @@ public class DirectXOverlay : DirectXOverlayPlugin
         OverlayWindow.Graphics.EndScene();
     }
 
-    public void TriggerTranslation()
+    /// <summary>
+    ///     Captures the target window, reads its text and replaces the overlay with the translation.
+    ///     Must be called from the UI thread; calls made while a translation is running are ignored.
+    /// </summary>
+    public async Task TriggerTranslation()
     {
-        var HTML = GetScreenHTML();
+        if (_translating || OverlayWindow == null) return;
+        _translating = true;
 
-        UntranslatedElements = GetScreenElements(HTML);
+        try
-        TranslateElements();
+        {
+            using var screenshot = await CaptureTargetWindow();
+            var source = SourceLanguage;
+            var target = TargetLanguage;
+
+            // OCR takes a while, keep it off the UI thread so rendering continues
+            var html = await Task.Run(() => GetScreenHTML(screenshot, source));
+            var untranslatedElements = GetScreenElements(html, source);
+            var translatedElements = ShowOcrText
+                ? ShowUntranslated(untranslatedElements)
+                : await TranslateElements(untranslatedElements, source, target);
+
+            if (OverlayWindow == null) return; // disposed while translating
+
+            foreach (var element in translatedElements)
+            {
+                // Cover the original line, growing the box if the translation is longer
+                var size = OverlayWindow.Graphics.MeasureText(element.Output, _font);
+                element.BoxWidth = Math.Max(element.Width, (int)Math.Ceiling(size.Width));
+                element.BoxHeight = Math.Max(element.Height, (int)Math.Ceiling(size.Height));
+            }
+
+            _translatedElements = translatedElements;
+            // DrawText caches a layout per distinct string; drop the ones from the previous translation
+            OverlayWindow.Graphics.DeleteLayoutContainer();
+        }
+        finally
+        {
+            _translating = false;
+        }
     }
 
-    private string GetScreenHTML()
+    private string GetScreenHTML(MemoryStream screenshot, TranslationLanguage language)
     {
-        var mem = GetScreenDataFromTargetWindow();
+        // Loading the models is slow, so the engine is kept until the source language changes
-        var languages = new List<Language>();
+        if (_engine == null || _engineLanguage != language)
-        languages.Add(Language.Japanese);
+        {
-        languages.Add(Language.JapaneseVertical);
+            _engine?.Dispose();
-        languages.Add(Language.English);
+            _engine = new Engine(TessdataPath, language.OcrLanguages.ToList());
-        var engine = new Engine("C:/Users/luis-/Downloads/tessdata-4.1.0/tessdata-4.1.0", languages);
+            _engineLanguage = language;
-        var img = Image.LoadFromMemory(mem);
+        }
-        var page = engine.Process(img);
+
+        using var img = Image.LoadFromMemory(screenshot);
+        using var page = _engine.Process(img);
         return page.HOcrText();
     }
 
-    private List<Element> GetScreenElements(string HTML)
+    /// <summary>
+    ///     Turns hOCR into one element per text line, positioned at the line's bounding box.
+    /// </summary>
+    private static List<Element> GetScreenElements(string html, TranslationLanguage language)
     {
         var elements = new List<Element>();
+        var lines = LineRegex.Matches(html);
 
-        var Index = 0;
+        for (var i = 0; i < lines.Count; i++)
-        while (Index != -1)
         {
-            Index = HTML.IndexOf("class='ocrx_word'", Index);
+            var line = lines[i];
-            if (Index == -1) break;
+            var end = i + 1 < lines.Count ? lines[i + 1].Index : html.Length;
-            var BbboxIndex = HTML.IndexOf("bbox", Index);
+            var lineHtml = html.Substring(line.Index, end - line.Index);
-            if (BbboxIndex == -1) break;
-            var XIndex = BbboxIndex + 4;
-            var YIndex = HTML.IndexOf(" ", XIndex + 1);
-            if (YIndex == -1) break;
-            ++YIndex;
-            var YEnd = HTML.IndexOf(" ", YIndex + 1);
-            if (YEnd == -1) break;
 
-            var WordStart = HTML.IndexOf(">", YIndex);
+            // Word text may be wrapped in <strong>/<em> and contain entities like &amp;
-            if (WordStart == -1) break;
+            var words = WordRegex.Matches(lineHtml)
-            ++WordStart;
+                .Select(word => WebUtility.HtmlDecode(TagRegex.Replace(word.Groups[1].Value, "")).Trim())
-            var WordEnd = HTML.IndexOf("<", WordStart);
+                .Where(word => word.Length > 0);
-            if (WordEnd == -1) break;
+            var text = string.Join(language.JoinWordsWithSpace ? " " : "", words);
+            if (text.Length == 0) continue;
 
-            var NewElement = new Element();
+            var x0 = int.Parse(line.Groups[1].Value);
-            var XString = HTML.Substring(XIndex, YIndex - XIndex);
+            var y0 = int.Parse(line.Groups[2].Value);
-            var YString = HTML.Substring(YIndex, YEnd - YIndex);
+            elements.Add(new Element
-            NewElement.X = int.Parse(XString);
+            {
-            NewElement.Y = int.Parse(YString);
+                X = x0,
-            NewElement.Input = HTML.Substring(WordStart, WordEnd - WordStart);
+                Y = y0,
-            elements.Add(NewElement);
+                Width = int.Parse(line.Groups[3].Value) - x0,
-
+                Height = int.Parse(line.Groups[4].Value) - y0,
-            Index = WordEnd;
+                Input = text
+            });
         }
 
         return elements;
     }
 
-    private async void TranslateElements()
+    private async Task<List<Element>> TranslateElements(List<Element> elements, TranslationLanguage source,
+        TranslationLanguage target)
     {
-        var libreTranslate = new LibreTranslate.Net.Enhanced.LibreTranslate("http://127.0.0.1:5000", "");
+        var translated = new List<Element>();
 
-        TranslatedElements.Clear();
+        foreach (var element in elements)
-
-        foreach (var element in UntranslatedElements)
         {
-            if (element.Input == "")
+            var targetText = await _libreTranslate.TranslateAsync(new Translate
-                continue;
-
-            var Detection = await libreTranslate.DetectAsync(new Detect
             {
+                Source = source.Code,
+                Target = target.Code,
                 Text = element.Input
             });
+            if (string.IsNullOrWhiteSpace(targetText)) continue;
 
-            if (Detection != null)
+            element.Output = targetText;
-            {
+            translated.Add(element);
-                var First = Detection.FirstOrDefault();
-                if (First != null)
-                    if (First.Confidence == 0)
-                        continue;
-            }
-
-            var TargetText = await libreTranslate.TranslateAsync(new Translate
-            {
-                Source = LanguageCode.English,
-                Target = LanguageCode.German,
-                Text = element.Input
-            });
-            var New = element;
-            New.Output = TargetText;
-            TranslatedElements.Add(New);
         }
+
+        return translated;
     }
 
-    private void RenderElements(List<Element> elements)
+    private static List<Element> ShowUntranslated(List<Element> elements)
     {
+        foreach (var element in elements) element.Output = element.Input;
+        return elements;
+    }
+
+    private void RenderElements(IReadOnlyList<Element> elements)
+    {
+        const int padding = 4;
+
         foreach (var element in elements)
-            OverlayWindow.Graphics.DrawText(element.Input, _font, _redBrush, element.X, element.Y);
+        {
+            OverlayWindow.Graphics.FillRectangle(element.X - padding, element.Y - padding,
+                element.BoxWidth + padding * 2, element.BoxHeight + padding * 2, _backgroundBrush);
+            OverlayWindow.Graphics.DrawText(element.Output, _font, _textBrush, element.X, element.Y);
+        }
     }
 
     public override void Dispose()
     {
-        if (OverlayWindow != null) OverlayWindow.Dispose();
+        _tickEngine.IsTicking = false;
+        _tickEngine.PreTick -= OnPreTick;
+        _tickEngine.Tick -= OnTick;
+
+        OverlayWindow?.Dispose();
+        OverlayWindow = null;
+
+        _engine?.Dispose();
+        _engine = null;
+
         base.Dispose();
     }
 
@@ -252,31 +322,53 @@ public class DirectXOverlay : DirectXOverlayPlugin
         OverlayWindow.Graphics.EndScene();
     }
 
-    private MemoryStream GetScreenDataFromTargetWindow()
+    private async Task<MemoryStream> CaptureTargetWindow()
     {
-        var bounds = new Rectangle(TargetWindow.X,
+        // Without capture exclusion (Windows before 10 2004) the overlay would end up in its own screenshot
-            TargetWindow.Y,
+        var hideOverlay = !_excludedFromCapture && OverlayWindow.IsVisible;
-            TargetWindow.Width,
+        if (hideOverlay)
-            TargetWindow.Height);
-
-        using var bitmap = new Bitmap(bounds.Width, bounds.Height);
-        using (var g = Graphics.FromImage(bitmap))
         {
-            g.CopyFromScreen(new Point(bounds.Left, bounds.Top), Point.Empty, bounds.Size);
+            OverlayWindow.Hide();
+            await Task.Delay(50); // let DWM compose a frame without the overlay
         }
 
-        // bitmap.Save("C://test.jpg", ImageFormat.Jpeg);
+        try
-        System.Drawing.Image im = System.Drawing.Image.FromHbitmap(bitmap.GetHbitmap());
+        {
-        var mem = new MemoryStream();
+            // Use the overlay's bounds (GetWindowRect of the target), not TargetWindow.X/Y/Width/Height:
-        im.Save(mem, ImageFormat.Bmp);
+            // Process.NET reports the restored placement rect, which is wrong for snapped or maximized windows
-        return mem;
+            OverlayWindow.Update();
+            var bounds = new Rectangle(OverlayWindow.X,
+                OverlayWindow.Y,
+                OverlayWindow.Width,
+                OverlayWindow.Height);
+
+            using var bitmap = new Bitmap(bounds.Width, bounds.Height);
+            using (var g = Graphics.FromImage(bitmap))
+            {
+                g.CopyFromScreen(new Point(bounds.Left, bounds.Top), Point.Empty, bounds.Size);
+            }
+
+            // bitmap.Save("C://test.jpg", ImageFormat.Jpeg);
+            var mem = new MemoryStream();
+            bitmap.Save(mem, ImageFormat.Bmp);
+            mem.Position = 0;
+            return mem;
+        }
+        finally
+        {
+            if (hideOverlay) OverlayWindow.Show();
+        }
     }
 
-    private struct Element
+    private class Element
     {
         public int X;
         public int Y;
-        public string Input;
+        public int Width;
-        public string Output;
+        public int Height;
+        public int BoxWidth;
+        public int BoxHeight;
+        public string Input = "";
+        public string Output = "";
     }
-}
+}

src/OnscreenTranslator/MainWindow.xaml

@@ -9,6 +9,9 @@
     <Grid>
         <ComboBox x:Name="ComboBox" HorizontalAlignment="Left" Margin="319,208,0,0" VerticalAlignment="Top" Width="120" Loaded="ComboBox_Loaded" SelectionChanged="ComboBox_SelectionChanged"/>
         <Button x:Name="Translate" Content="Button" HorizontalAlignment="Left" Margin="444,209,0,0" VerticalAlignment="Top" Click="Translate_Click"/>
+        <ComboBox x:Name="SourceLanguageBox" HorizontalAlignment="Left" Margin="319,240,0,0" VerticalAlignment="Top" Width="120" SelectionChanged="SourceLanguageBox_SelectionChanged"/>
+        <ComboBox x:Name="TargetLanguageBox" HorizontalAlignment="Left" Margin="444,240,0,0" VerticalAlignment="Top" Width="120" SelectionChanged="TargetLanguageBox_SelectionChanged"/>
+        <CheckBox x:Name="ShowOcrTextBox" Content="Show OCR text only (no translation)" HorizontalAlignment="Left" Margin="319,270,0,0" VerticalAlignment="Top" Checked="ShowOcrTextBox_Changed" Unchecked="ShowOcrTextBox_Changed"/>
         <TextBlock x:Name="TextBlock" HorizontalAlignment="Center" Margin="0,297,0,0" TextWrapping="Wrap" Text="TextBlock" VerticalAlignment="Top"/>
 
     </Grid>

src/OnscreenTranslator/MainWindow.xaml.cs

@@ -4,6 +4,7 @@ using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Input;
 using System.Windows.Interop;
+using System.Windows.Threading;
 using Process.NET;
 using Process.NET.Memory;
 using Process.NET.Windows;
@@ -15,8 +16,8 @@ namespace OnscreenTranslator;
 /// </summary>
 public partial class MainWindow : Window
 {
-    private bool IsRendering;
+    private DirectXOverlay? Overlay;
-    private DirectXOverlay Overlay = new();
+    private readonly DispatcherTimer RenderTimer = new(DispatcherPriority.Render);
     private IWindow? TargetWindow;
     private System.Diagnostics.Process? TrackedProcess;
     
@@ -43,6 +44,55 @@ public partial class MainWindow : Window
     public MainWindow()
     {
         InitializeComponent();
+
+        SourceLanguageBox.ItemsSource = TranslationLanguage.All;
+        SourceLanguageBox.SelectedItem = TranslationLanguage.Japanese;
+        TargetLanguageBox.ItemsSource = TranslationLanguage.All;
+        TargetLanguageBox.SelectedItem = TranslationLanguage.German;
+
+        // Drives the overlay's tick engine on the UI thread, which owns the overlay window
+        RenderTimer.Interval = TimeSpan.FromMilliseconds(1000.0 / 60);
+        RenderTimer.Tick += (_, _) => Overlay?.Update();
+        RenderTimer.Start();
+
+        Closed += (_, _) =>
+        {
+            RenderTimer.Stop();
+            Overlay?.Dispose();
+        };
+    }
+
+    private void AttachOverlay(IWindow targetWindow)
+    {
+        TargetWindow = targetWindow;
+
+        // A fresh instance per target: Initialize subscribes tick handlers, so reusing one would stack them
+        Overlay?.Dispose();
+        Overlay = new DirectXOverlay
+        {
+            SourceLanguage = (TranslationLanguage)SourceLanguageBox.SelectedItem,
+            TargetLanguage = (TranslationLanguage)TargetLanguageBox.SelectedItem,
+            ShowOcrText = ShowOcrTextBox.IsChecked == true
+        };
+
+        var fps = 60;
+        Overlay.Settings.Current.UpdateRate = 1000 / fps;
+        Overlay.Initialize(targetWindow);
+        Overlay.Enable();
+    }
+
+    private async Task RunTranslation()
+    {
+        if (Overlay == null) return;
+
+        try
+        {
+            await Overlay.TriggerTranslation();
+        }
+        catch (Exception ex)
+        {
+            TextBlock.Text = $"Translation failed: {ex.Message}";
+        }
     }
     
     [DllImport("user32.dll", SetLastError = true)]
@@ -75,7 +125,7 @@ public partial class MainWindow : Window
                         int vkey = (((int)lParam >> 16) & 0xFFFF);
                         if (vkey == VK_F9)
                         {
-                            GetWindow();
+                            _ = GetWindow();
                         }
                         handled = true;
                         break;
@@ -85,7 +135,7 @@ public partial class MainWindow : Window
         return IntPtr.Zero;
     }
 
-    public void GetWindow()
+    public async Task GetWindow()
     {
         // Get own hWnd
         WindowInteropHelper windowHwnd = new(this);
@@ -115,19 +165,9 @@ public partial class MainWindow : Window
          if (process.MainWindowTitle == GetWindowTitle(targetHWnd))
          {
              var processSharp = new ProcessSharp(process, MemoryType.Remote);
-             TargetWindow = processSharp.WindowFactory.MainWindow;
+             AttachOverlay(processSharp.WindowFactory.MainWindow);
 
-             Overlay.Dispose();
+             await RunTranslation();
-
-             var fps = 60;
-             Overlay.Settings.Current.UpdateRate = 1000 / fps;
-             Overlay.Initialize(TargetWindow);
-
-             Overlay.ClearScreen();
-             
-             Overlay.TriggerTranslation();
-             
-             Overlay.Update();
 
              return;
          }
@@ -168,9 +208,24 @@ public partial class MainWindow : Window
         RegisterHotKey(handle, HOTKEY_ID, MOD_CONTROL, VK_F9); //CTRL + CAPS_LOCK
     }
 
-    private void Translate_Click(object sender, RoutedEventArgs e)
+    private async void Translate_Click(object sender, RoutedEventArgs e)
     {
-        if (Overlay != null) Overlay.TriggerTranslation();
+        await RunTranslation();
+    }
+
+    private void SourceLanguageBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
+    {
+        if (Overlay != null) Overlay.SourceLanguage = (TranslationLanguage)SourceLanguageBox.SelectedItem;
+    }
+
+    private void TargetLanguageBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
+    {
+        if (Overlay != null) Overlay.TargetLanguage = (TranslationLanguage)TargetLanguageBox.SelectedItem;
+    }
+
+    private void ShowOcrTextBox_Changed(object sender, RoutedEventArgs e)
+    {
+        if (Overlay != null) Overlay.ShowOcrText = ShowOcrTextBox.IsChecked == true;
     }
 
     private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
@@ -181,43 +236,11 @@ public partial class MainWindow : Window
         {
             TextBlock.Text = "FOund something";
             var processSharp = new ProcessSharp(TrackedProcess, MemoryType.Remote);
-            TargetWindow = processSharp.WindowFactory.MainWindow;
+            AttachOverlay(processSharp.WindowFactory.MainWindow);
-
-            Overlay.Dispose();
-
-            var fps = 60;
-            Overlay.Settings.Current.UpdateRate = 1000 / fps;
-            Overlay.Initialize(TargetWindow);
-
-            Overlay.ClearScreen();
         }
         else
         {
             TextBlock.Text = "FOund NOTHING";
         }
     }
-
-    private void StartRendering()
-    {
-        if (IsRendering)
-            return;
-
-        IsRendering = true;
-
-        if (TargetWindow == null) return;
-
-        Overlay = new DirectXOverlay();
-
-        var fps = 60;
-        Overlay.Settings.Current.UpdateRate = 1000 / fps;
-        Overlay.Initialize(TargetWindow);
-        Overlay.Enable();
-
-        var info = Overlay.Settings.Current;
-
-
-        while (true) Overlay.Update();
-
-        // Overlay.Update();
-    }
 }

src/OnscreenTranslator/TranslationLanguage.cs

@@ -0,0 +1,33 @@
+using LibreTranslate.Net.Enhanced.Constants;
+using TesseractOCR.Enums;
+
+namespace OnscreenTranslator;
+
+/// <summary>
+///     A language as both LibreTranslate and Tesseract know it.
+/// </summary>
+/// <param name="Name">Display name</param>
+/// <param name="Code">LibreTranslate language code</param>
+/// <param name="OcrLanguages">Tesseract models needed to read this language (tessdata must contain them)</param>
+/// <param name="JoinWordsWithSpace">False for scripts that don't separate words with spaces</param>
+public record TranslationLanguage(string Name, LanguageCode Code, Language[] OcrLanguages, bool JoinWordsWithSpace = true)
+{
+    public static readonly TranslationLanguage Japanese =
+        new("Japanese", LanguageCode.Japanese, [Language.Japanese, Language.JapaneseVertical], false);
+
+    public static readonly TranslationLanguage English = new("English", LanguageCode.English, [Language.English]);
+    public static readonly TranslationLanguage German = new("German", LanguageCode.German, [Language.German]);
+    public static readonly TranslationLanguage French = new("French", LanguageCode.French, [Language.French]);
+
+    public static readonly TranslationLanguage Spanish =
+        new("Spanish", LanguageCode.Spanish, [Language.SpanishCastilian]);
+
+    public static readonly TranslationLanguage Korean = new("Korean", LanguageCode.Korean, [Language.Korean]);
+
+    public static readonly TranslationLanguage Chinese =
+        new("Chinese", LanguageCode.Chinese, [Language.ChineseSimplified], false);
+
+    public static readonly TranslationLanguage[] All = [Japanese, English, German, French, Spanish, Korean, Chinese];
+
+    public override string ToString() => Name;
+}

src/Overlay.NET/Common/Native.cs

@@ -47,6 +47,20 @@ namespace Overlay.NET.Common {
         [DllImport("dwmapi.dll")]
         public static extern void DwmExtendFrameIntoClientArea(IntPtr hWnd, ref RawMargin pMargins);
 
+        [DllImport("user32.dll", SetLastError = true)]
+        public static extern bool SetWindowDisplayAffinity(IntPtr hWnd, uint dwAffinity);
+
+        public delegate IntPtr WndProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);
+
+        [DllImport("user32.dll", CharSet = CharSet.Unicode, SetLastError = true)]
+        public static extern ushort RegisterClassEx(ref WndClassEx lpwcx);
+
+        [DllImport("user32.dll", CharSet = CharSet.Unicode)]
+        public static extern IntPtr DefWindowProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam);
+
+        [DllImport("kernel32.dll", CharSet = CharSet.Unicode)]
+        public static extern IntPtr GetModuleHandle(string lpModuleName);
+
         public static IntPtr SetWindowLongPtr(IntPtr hWnd, int nIndex, IntPtr dwNewLong)
             => IntPtr.Size == 8 ? SetWindowLongPtr64(hWnd, nIndex, dwNewLong) : new IntPtr(SetWindowLong32(hWnd, nIndex, dwNewLong.ToInt32()));
 
@@ -80,6 +94,22 @@ namespace Overlay.NET.Common {
             public int Y;
         }
 
+        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
+        public struct WndClassEx {
+            public uint cbSize;
+            public uint style;
+            public IntPtr lpfnWndProc;
+            public int cbClsExtra;
+            public int cbWndExtra;
+            public IntPtr hInstance;
+            public IntPtr hIcon;
+            public IntPtr hCursor;
+            public IntPtr hbrBackground;
+            public string lpszMenuName;
+            public string lpszClassName;
+            public IntPtr hIconSm;
+        }
+
         [StructLayout(LayoutKind.Sequential)]
         public struct RawMargin {
             public int cxLeftWidth;

src/Overlay.NET/Common/WindowConstants.cs

@@ -13,15 +13,15 @@ namespace Overlay.NET.Common {
         public const int SmCyScreen = 1;
 
         /// <summary>
-        ///     The desktop class
+        ///     The overlay window class. Registered without a background brush so GDI never paints
+        ///     an opaque background over the target window (the "Static" system class does).
         /// </summary>
-        public const string DesktopClass = "Static"; // System Class for a static control
+        public const string OverlayClass = "OverlayNET_DirectXOverlay";
 
         /// <summary>
-        ///     The window style dx
+        ///     The window style dx. Created hidden; shown after the first transparent frame is presented.
         /// </summary>
         public const uint WindowStyleDx = 0x8000000 //WS_DISABLED
-                                          | 0x10000000 //WS_VISIBLE
                                           | 0x80000000; //WS_POPUP
 
         /// <summary>
@@ -38,6 +38,11 @@ namespace Overlay.NET.Common {
         /// </summary>
         public const int LwaAlpha = 0x00000002;
 
+        /// <summary>
+        ///     Excludes the window from screen captures (WDA_EXCLUDEFROMCAPTURE, Windows 10 2004+)
+        /// </summary>
+        public const uint WdaExcludeFromCapture = 0x11;
+
         /// <summary>
         ///     The HWND notopmost
         /// </summary>
@@ -73,6 +78,11 @@ namespace Overlay.NET.Common {
         /// </summary>
         public const uint SwShow = 5;
 
+        /// <summary>
+        ///     The sw show without activating (keeps focus on the target window)
+        /// </summary>
+        public const uint SwShowNa = 8;
+
         /// <summary>
         ///     The sw hide
         /// </summary>

src/Overlay.NET/Directx/Direct2DRenderer.cs

@@ -609,6 +609,15 @@ namespace Overlay.NET.Directx {
         /// <param name="x">The x.</param>
         /// <param name="y">The y.</param>
         /// <param name="bufferText">if set to <c>true</c> [buffer text].</param>
+        /// <summary>
+        ///     Measures the size the text takes when drawn with the given font.
+        /// </summary>
+        public System.Drawing.SizeF MeasureText(string text, int font) {
+            using (var layout = new TextLayout(_fontFactory, text, _fontContainer[font], float.MaxValue, float.MaxValue)) {
+                return new System.Drawing.SizeF(layout.Metrics.WidthIncludingTrailingWhitespace, layout.Metrics.Height);
+            }
+        }
+
         public void DrawText(string text, int font, int brush, int x, int y, bool bufferText = true) {
             if (bufferText) {
                 var bufferPos = -1;

src/Overlay.NET/Directx/DirectXOverlayWindow.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Runtime.InteropServices;
 using System.Threading;
 using System.Threading.Tasks;
 using Overlay.NET.Common;
@@ -102,7 +103,7 @@ namespace Overlay.NET.Directx {
         /// <exception cref="Exception">Could not create OverlayWindow</exception>
         public DirectXOverlayWindow(bool limitFps = true) {
             IsDisposing = false;
-            IsVisible = true;
+            IsVisible = false;
             IsTopMost = true;
 
             ParentWindowExists = false;
@@ -121,6 +122,8 @@ namespace Overlay.NET.Directx {
             Graphics = new Direct2DRenderer(Handle, limitFps);
 
             SetBounds(X, Y, Width, Height);
+
+            PresentEmptyFrameAndShow();
         }
 
         /// <summary>
@@ -142,7 +145,7 @@ namespace Overlay.NET.Directx {
             Native.GetWindowRect(parent, out bounds);
 
             IsDisposing = false;
-            IsVisible = true;
+            IsVisible = false;
             IsTopMost = true;
 
             ParentWindowExists = true;
@@ -162,6 +165,8 @@ namespace Overlay.NET.Directx {
             Graphics = new Direct2DRenderer(Handle, limitFps);
 
             SetBounds(X, Y, Width, Height);
+
+            PresentEmptyFrameAndShow();
         }
 
         /// <summary>
@@ -175,11 +180,69 @@ namespace Overlay.NET.Directx {
         ///     Clean up used ressources and destroy window
         /// </summary>
         public void Dispose() {
+            if (IsDisposing) {
+                return;
+            }
+
             IsDisposing = true;
+            // Already cleaned up; the finalizer would otherwise destroy the window a second time
+            GC.SuppressFinalize(this);
             Graphics.Dispose();
             Native.DestroyWindow(Handle);
         }
 
+        /// <summary>
+        ///     Keeps the window out of screen captures (BitBlt/CopyFromScreen, Graphics Capture), so the
+        ///     overlay never ends up in its own screenshots. Requires Windows 10 2004+.
+        /// </summary>
+        /// <returns>
+        ///     true on success
+        /// </returns>
+        public bool ExcludeFromCapture() => Native.SetWindowDisplayAffinity(Handle, WindowConstants.WdaExcludeFromCapture);
+
+        /// <summary>
+        ///     Presents a fully transparent frame before the window becomes visible, so it never shows
+        ///     undefined content on screen.
+        /// </summary>
+        private void PresentEmptyFrameAndShow() {
+            Graphics.BeginScene();
+            Graphics.ClearScene();
+            Graphics.EndScene();
+
+            Show();
+        }
+
+        /// <summary>
+        ///     Must stay referenced for the lifetime of the process, the window class points at it.
+        /// </summary>
+        private static readonly Native.WndProc WndProcDelegate = Native.DefWindowProc;
+
+        /// <summary>
+        ///     Whether the overlay window class was registered
+        /// </summary>
+        private static bool _classRegistered;
+
+        /// <summary>
+        ///     Registers the overlay window class without a background brush.
+        /// </summary>
+        private static void EnsureClassRegistered() {
+            if (_classRegistered) {
+                return;
+            }
+
+            var windowClass = new Native.WndClassEx {
+                cbSize = (uint) Marshal.SizeOf(typeof(Native.WndClassEx)),
+                lpfnWndProc = Marshal.GetFunctionPointerForDelegate(WndProcDelegate),
+                hInstance = Native.GetModuleHandle(null),
+                hbrBackground = IntPtr.Zero,
+                lpszClassName = WindowConstants.OverlayClass
+            };
+
+            // Returns 0 if the class already exists, which is fine; CreateWindowEx reports real failures
+            Native.RegisterClassEx(ref windowClass);
+            _classRegistered = true;
+        }
+
         /// <summary>
         ///     Creates a window with the information's stored in this class
         /// </summary>
@@ -187,9 +250,11 @@ namespace Overlay.NET.Directx {
         ///     true on success
         /// </returns>
         private bool CreateWindow() {
+            EnsureClassRegistered();
+
             Handle = Native.CreateWindowEx(
                 WindowConstants.WindowExStyleDx,
-                WindowConstants.DesktopClass,
+                WindowConstants.OverlayClass,
                 "",
                 WindowConstants.WindowStyleDx,
                 X,
@@ -198,7 +263,7 @@ namespace Overlay.NET.Directx {
                 Height,
                 IntPtr.Zero,
                 IntPtr.Zero,
-                IntPtr.Zero,
+                Native.GetModuleHandle(null),
                 IntPtr.Zero);
 
             if (Handle == IntPtr.Zero) {
@@ -297,7 +362,7 @@ namespace Overlay.NET.Directx {
                 return;
             }
 
-            Native.ShowWindow(Handle, WindowConstants.SwShow);
+            Native.ShowWindow(Handle, WindowConstants.SwShowNa);
             IsVisible = true;
 
             ExtendFrameIntoClient();