Add image-sized window restoration feature

Src/FlyPhotos/Display/Controllers/CanvasController.cs

@@ -77,9 +77,15 @@ internal partial class CanvasController : ICanvasController
     // A Lock is used because Matrix3x2 (6 floats) and Rect (4 doubles) are not atomically writable,
     // making volatile inadequate. Contention is negligible: pointer events are rare vs. 144 Hz Update.
     private Matrix3x2 _hitTestMatInv = Matrix3x2.Identity;
+
+    /// <summary>The latest canvas transform published for UI-thread bounds calculations.</summary>
+    private Matrix3x2 _hitTestMat = Matrix3x2.Identity;
     private Rect _hitTestImageRect;
     private readonly Lock _hitTestLock = new();
 
+    /// <summary>The image origin to preserve during the next image-sized window resize.</summary>
+    private Point? _imageSizedResizeOrigin;
+
     private int _zoomPercentUiUpdatePending;
     private int _pendingZoomPercent;
     private int _lastDispatchedZoomPercent = -1;
@@ -429,6 +435,7 @@ private void D2dCanvas_Update(ICanvasAnimatedControl sender, CanvasAnimatedUpdat
         // ④ Publish the current transform for UI-thread hit-testing (IsPressedOnImage).
         lock (_hitTestLock)
         {
+            _hitTestMat = _canvasViewState.Mat;
             _hitTestMatInv = _canvasViewState.MatInv;
             _hitTestImageRect = _canvasViewState.ImageRect;
         }
@@ -460,7 +467,13 @@ private void D2dCanvas_SizeChanged(object sender, SizeChangedEventArgs args)
     {
         var newSize = args.NewSize.AdjustForDpi(_d2dCanvas);
         var previousSize = args.PreviousSize.AdjustForDpi(_d2dCanvas);
-        SafeEnqueue(v => v.HandleSizeChange(newSize, previousSize));
+        if (_imageSizedResizeOrigin is { } imageOrigin)
+        {
+            _imageSizedResizeOrigin = null;
+            SafeEnqueue(v => v.HandleImageSizedWindowResize(imageOrigin));
+        }
+        else
+            SafeEnqueue(v => v.HandleSizeChange(newSize, previousSize));
     }
 
     /// <summary>
@@ -507,6 +520,47 @@ public bool IsPressedOnImage(Point position)
                                    && tp.X <= imageRect.Right && tp.Y <= imageRect.Bottom;
     }
 
+    /// <summary>
+    /// Tries to get the axis-aligned bounds of the displayed image in physical canvas pixels.
+    /// </summary>
+    /// <param name="bounds">The displayed image bounds when available.</param>
+    /// <returns><see langword="true"/> when valid image bounds are available; otherwise, <see langword="false"/>.</returns>
+    public bool TryGetDisplayedImageBounds(out Rect bounds)
+    {
+        Matrix3x2 transform;
+        Rect imageRect;
+        lock (_hitTestLock)
+        {
+            transform = _hitTestMat;
+            imageRect = _hitTestImageRect;
+        }
+
+        if (imageRect.Width <= 0 || imageRect.Height <= 0)
+        {
+            bounds = default;
+            return false;
+        }
+
+        var topLeft = Vector2.Transform(new Vector2((float)imageRect.Left, (float)imageRect.Top), transform);
+        var topRight = Vector2.Transform(new Vector2((float)imageRect.Right, (float)imageRect.Top), transform);
+        var bottomLeft = Vector2.Transform(new Vector2((float)imageRect.Left, (float)imageRect.Bottom), transform);
+        var bottomRight = Vector2.Transform(new Vector2((float)imageRect.Right, (float)imageRect.Bottom), transform);
+
+        var left = MathF.Min(MathF.Min(topLeft.X, topRight.X), MathF.Min(bottomLeft.X, bottomRight.X));
+        var top = MathF.Min(MathF.Min(topLeft.Y, topRight.Y), MathF.Min(bottomLeft.Y, bottomRight.Y));
+        var right = MathF.Max(MathF.Max(topLeft.X, topRight.X), MathF.Max(bottomLeft.X, bottomRight.X));
+        var bottom = MathF.Max(MathF.Max(topLeft.Y, topRight.Y), MathF.Max(bottomLeft.Y, bottomRight.Y));
+        bounds = new Rect(left, top, right - left, bottom - top);
+        return true;
+    }
+
+    /// <summary>
+    /// Marks the next canvas resize as an image-sized window resize and preserves the image's screen position.
+    /// </summary>
+    /// <param name="imageBounds">The displayed image bounds before the window is resized.</param>
+    public void PrepareForImageSizedWindow(Rect imageBounds) =>
+        _imageSizedResizeOrigin = new Point(imageBounds.Left, imageBounds.Top);
+
     // --- Settings ---
 
     public void HandleCheckeredBackgroundChange() => _pump.Wake(); // wake the canvas; Draw() reads the setting live

Src/FlyPhotos/Display/Controllers/CanvasViewManager.cs

@@ -436,6 +436,18 @@ public void HandleSizeChange(Size newSize, Size previousSize)
         }
     }
 
+    /// <summary>
+    /// Keeps the current scale and moves the displayed image bounds to the new canvas origin.
+    /// </summary>
+    public void HandleImageSizedWindowResize(Point previousImageOrigin)
+    {
+        ClearActiveAnimation();
+        _canvasViewState.ImagePos.X -= previousImageOrigin.X;
+        _canvasViewState.ImagePos.Y -= previousImageOrigin.Y;
+        _canvasViewState.UpdateTransform();
+        ViewChanged?.Invoke();
+    }
+
     /// <summary>
     /// Saves the current view for <paramref name="photoPath"/> if "RememberPerPhoto" is enabled and the
     /// user has actually modified the view (panned, zoomed, or rotated). Pan is stored normalized to the

Src/FlyPhotos/Infra/Configuration/AppSettings.cs

@@ -50,6 +50,7 @@ public class AppSettings
     public bool AutoHideMouse { get; set; } = false;
     public bool AutoHideCaptionButtons { get; set; } = false;
     public bool ClickOutsideImageToRestoreWindow { get; set; } = true;
+    public bool SizeWindowToImageOnRestore { get; set; } = false;
     public bool CtrlDragToMoveWindow { get; set; } = true;
     public bool UseExternalExeForContextMenu { get; set; } = false;
     public bool ShowExternalAppShortcuts { get; set; } = false;

Src/FlyPhotos/Infra/Interop/Win32Methods.cs

@@ -204,6 +204,33 @@ public struct SHELLEXECUTEINFO
 
     #region Window placement (user32.dll)
 
+    /// <summary>Retrieves the dimensions of a window's client area.</summary>
+    [LibraryImport("user32.dll")]
+    [return: MarshalAs(UnmanagedType.Bool)]
+    internal static partial bool GetClientRect(nint hWnd, out RECT lpRect);
+
+    /// <summary>Converts client-area coordinates to screen coordinates.</summary>
+    [LibraryImport("user32.dll")]
+    [return: MarshalAs(UnmanagedType.Bool)]
+    internal static partial bool ClientToScreen(nint hWnd, ref POINT lpPoint);
+
+    /// <summary>Retrieves the DPI value for a window.</summary>
+    [LibraryImport("user32.dll")]
+    internal static partial uint GetDpiForWindow(nint hWnd);
+
+    /// <summary>Retrieves a system metric for the specified DPI.</summary>
+    [LibraryImport("user32.dll")]
+    internal static partial int GetSystemMetricsForDpi(int nIndex, uint dpi);
+
+    /// <summary>Width of a sizing window frame.</summary>
+    internal const int SM_CXSIZEFRAME = 32;
+
+    /// <summary>Height of a sizing window frame.</summary>
+    internal const int SM_CYSIZEFRAME = 33;
+
+    /// <summary>Thickness of the padded border around a resizable window.</summary>
+    internal const int SM_CXPADDEDBORDER = 92;
+
 #pragma warning disable SYSLIB1054
     /// <summary>
     /// Retrieves the show state and the restored, minimized, and maximized positions of the specified window.
@@ -293,6 +320,9 @@ internal struct WINDOWPLACEMENT
     /// </summary>
     internal const uint SW_SHOWMAXIMIZED = 3;
 
+    /// <summary>Activates and displays a window in its normal position and size.</summary>
+    internal const uint SW_SHOWNORMAL = 1;
+
     #endregion
 
     #region Native stream access — bypasses Windows Storage Broker (shcore.dll)

Src/FlyPhotos/Strings/en-US/Resources.resw

@@ -762,6 +762,12 @@ Esc : Close Settings or Exit App</value>
   <data name="SettingsCardClickOutsideImageToRestoreWindow.Header" xml:space="preserve">
     <value>Click outside image to restore window</value>
   </data>
+  <data name="SettingsCardSizeWindowToImageOnRestore.Description" xml:space="preserve">
+    <value>When restoring the window by clicking outside the image, resize it to match the displayed image.</value>
+  </data>
+  <data name="SettingsCardSizeWindowToImageOnRestore.Header" xml:space="preserve">
+    <value>Size restored window to image</value>
+  </data>
   <data name="SettingsCardAutoHideCaptionButtons.Description" xml:space="preserve">
     <value>The minimize, maximize, and close buttons are shown only when the mouse is near the top of the window.</value>
   </data>
@@ -819,4 +825,4 @@ High Quality Cubic – Highest-quality scaling for photos.</value>
   <data name="MenuItemDelete.Text" xml:space="preserve">
     <value>Delete</value>
   </data>
-</root>
+</root>

Src/FlyPhotos/Strings/ru-RU/Resources.resw

@@ -763,6 +763,12 @@ Esc : Закрыть параметры или выйти из приложен
   <data name="SettingsCardClickOutsideImageToRestoreWindow.Header" xml:space="preserve">
     <value>Клик вне изображения для восстановления окна</value>
   </data>
+  <data name="SettingsCardSizeWindowToImageOnRestore.Description" xml:space="preserve">
+    <value>При восстановлении окна кликом вне изображения изменять его размер под отображаемое изображение.</value>
+  </data>
+  <data name="SettingsCardSizeWindowToImageOnRestore.Header" xml:space="preserve">
+    <value>Размер окна по изображению</value>
+  </data>
   <data name="SettingsCardAutoHideCaptionButtons.Description" xml:space="preserve">
     <value>Кнопки свертывания, развертывания и закрытия отображаются только тогда, когда мышь находится у верхнего края окна.</value>
   </data>

Src/FlyPhotos/UI/Behaviors/WindowFullScreenManager.cs

@@ -3,6 +3,7 @@
 using FlyPhotos.Infra.Interop;
 using Microsoft.UI.Windowing;
 using Microsoft.UI.Xaml;
+using Windows.Graphics;
 using WinRT.Interop;
 
 namespace FlyPhotos.UI.Behaviors;
@@ -81,6 +82,45 @@ internal void Restore(UIElement? exitFullScreenButton = null)
         }
     }
 
+    /// <summary>
+    /// Restores the window and makes its client area match the requested screen-space rectangle.
+    /// </summary>
+    /// <param name="clientRect">The desired client-area rectangle in physical screen pixels.</param>
+    /// <param name="exitFullScreenButton">The optional button to hide when leaving full-screen mode.</param>
+    internal void RestoreToClientRect(RectInt32 clientRect, UIElement? exitFullScreenButton = null)
+    {
+        var hwnd = WindowNative.GetWindowHandle(_window);
+        var dpi = Win32Methods.GetDpiForWindow(hwnd);
+        var frameX = Win32Methods.GetSystemMetricsForDpi(Win32Methods.SM_CXSIZEFRAME, dpi) +
+                     Win32Methods.GetSystemMetricsForDpi(Win32Methods.SM_CXPADDEDBORDER, dpi);
+        var frameY = Win32Methods.GetSystemMetricsForDpi(Win32Methods.SM_CYSIZEFRAME, dpi) +
+                     Win32Methods.GetSystemMetricsForDpi(Win32Methods.SM_CXPADDEDBORDER, dpi);
+
+        Win32Methods.GetWindowPlacement(hwnd, out var placement);
+        placement.rcNormalPosition = new Win32Methods.RECT
+        {
+            Left = clientRect.X - frameX,
+            Top = clientRect.Y - frameY,
+            Right = clientRect.X + clientRect.Width + frameX,
+            Bottom = clientRect.Y + clientRect.Height + frameY
+        };
+        placement.showCmd = Win32Methods.SW_SHOWNORMAL;
+
+        var wasFullScreen = AppWindow.Presenter.Kind == AppWindowPresenterKind.FullScreen;
+
+        // While full-screen, update the hidden normal placement first. Switching presenters then
+        // reveals the window directly at its destination instead of briefly showing the old bounds.
+        Win32Methods.SetWindowPlacement(hwnd, in placement);
+
+        if (wasFullScreen)
+        {
+            exitFullScreenButton?.Visibility = Visibility.Collapsed;
+            AppWindow.SetPresenter(AppWindowPresenterKind.Overlapped);
+            _wasMaximizedBeforeFullScreen = false;
+            FullScreenToggled?.Invoke(false);
+        }
+    }
+
     /// <summary>
     ///     Toggles the window between full-screen mode and the normal overlapped state.
     ///     Tracks previous maximized state to avoid flickering when returning from full-screen.

Src/FlyPhotos/UI/Views/PhotoDisplayWindow.xaml.cs

@@ -26,7 +26,9 @@
 using Microsoft.UI.Xaml.Controls.Primitives;
 using Microsoft.UI.Xaml.Input;
 using NLog;
+using Windows.Graphics;
 using WinUIEx;
+using WinRT.Interop;
 
 namespace FlyPhotos.UI.Views;
 
@@ -563,7 +565,12 @@ private void D2dCanvas_PointerReleased(object sender, PointerRoutedEventArgs e)
                     !(currentPoint.Position.Y < AppTitlebar.ActualHeight) &&
                     !_canvasController.IsPressedOnImage(dpiAdjustedPosition) &&
                     _windFullScreenManager.IsMaximizedOrFullScreen)
-                    _windFullScreenManager.Restore(ButtonFullScreenClose);
+                {
+                    if (AppConfig.Settings.SizeWindowToImageOnRestore)
+                        RestoreWindowToImage();
+                    else
+                        _windFullScreenManager.Restore(ButtonFullScreenClose);
+                }
                 break;
 
             case PointerUpdateKind.MiddleButtonReleased:
@@ -1069,6 +1076,48 @@ private void ToggleMaximizeRestore()
             _windFullScreenManager.Maximize();
     }
 
+    /// <summary>
+    /// Restores the window with its client area sized around the currently displayed image.
+    /// </summary>
+    private void RestoreWindowToImage()
+    {
+        if (!_canvasController.TryGetDisplayedImageBounds(out var imageBounds))
+        {
+            _windFullScreenManager.Restore(ButtonFullScreenClose);
+            return;
+        }
+
+        var hwnd = WindowNative.GetWindowHandle(this);
+        var clientOrigin = new Win32Methods.POINT();
+        if (!Win32Methods.ClientToScreen(hwnd, ref clientOrigin) ||
+            !Win32Methods.GetClientRect(hwnd, out var clientRect))
+        {
+            _windFullScreenManager.Restore(ButtonFullScreenClose);
+            return;
+        }
+
+        var dpiScale = D2dCanvas.Dpi / 96.0;
+        var canvasOffset = D2dCanvas.TransformToVisual(MainLayout).TransformPoint(default);
+        var canvasOffsetX = (int)Math.Round(canvasOffset.X * dpiScale);
+        var canvasOffsetY = (int)Math.Round(canvasOffset.Y * dpiScale);
+        var nonCanvasWidth = clientRect.Right - clientRect.Left - (int)Math.Round(D2dCanvas.ActualWidth * dpiScale);
+        var nonCanvasHeight = clientRect.Bottom - clientRect.Top - (int)Math.Round(D2dCanvas.ActualHeight * dpiScale);
+
+        var imageLeft = clientOrigin.X + canvasOffsetX + (int)Math.Floor(imageBounds.Left);
+        var imageTop = clientOrigin.Y + canvasOffsetY + (int)Math.Floor(imageBounds.Top);
+        var imageWidth = (int)Math.Ceiling(imageBounds.Right) - (int)Math.Floor(imageBounds.Left);
+        var imageHeight = (int)Math.Ceiling(imageBounds.Bottom) - (int)Math.Floor(imageBounds.Top);
+
+        _canvasController.PrepareForImageSizedWindow(imageBounds);
+        _windFullScreenManager.RestoreToClientRect(
+            new RectInt32(
+                imageLeft - canvasOffsetX,
+                imageTop - canvasOffsetY,
+                Math.Max(1, imageWidth + nonCanvasWidth),
+                Math.Max(1, imageHeight + nonCanvasHeight)),
+            ButtonFullScreenClose);
+    }
+
     private async Task AnimatePhotoDisplayWindowClose()
     {
         _settingWindow?.Close();

Src/FlyPhotos/UI/Views/Settings.xaml

@@ -279,6 +279,15 @@
                             <ToggleSwitch x:Name="ButtonClickOutsideImageToRestoreWindow" />
                         </controls:SettingsCard>
 
+                        <controls:SettingsCard
+                            x:Name="SettingsCardSizeWindowToImageOnRestore"
+                            x:Uid="SettingsCardSizeWindowToImageOnRestore"
+                            Margin="0,5,0,0"
+                            HeaderIcon="{ui:FontIcon Glyph=&#xE8A7;, FontFamily={StaticResource FluentIcons}}"
+                            IsEnabled="{x:Bind ButtonClickOutsideImageToRestoreWindow.IsOn, Mode=OneWay}">
+                            <ToggleSwitch x:Name="ButtonSizeWindowToImageOnRestore" />
+                        </controls:SettingsCard>
+
                         <controls:SettingsCard
                             x:Name="SettingsCardCtrlDragToMoveWindow"
                             x:Uid="SettingsCardCtrlDragToMoveWindow"
@@ -685,4 +694,4 @@
             </PivotItem>
         </Pivot>
     </Grid>
-</Window>
+</Window>

Src/FlyPhotos/UI/Views/Settings.xaml.cs

@@ -107,6 +107,7 @@ internal Settings()
         ButtonEnableAutoHideCaptionButtons.IsOn = AppConfig.Settings.AutoHideCaptionButtons;
         ButtonCtrlDragToMoveWindow.IsOn = AppConfig.Settings.CtrlDragToMoveWindow;
         ButtonClickOutsideImageToRestoreWindow.IsOn = AppConfig.Settings.ClickOutsideImageToRestoreWindow;
+        ButtonSizeWindowToImageOnRestore.IsOn = AppConfig.Settings.SizeWindowToImageOnRestore;
         ButtonEnableExternalShortcut.IsOn = AppConfig.Settings.ShowExternalAppShortcuts;
         ButtonDecodeRawData.IsOn = AppConfig.Settings.DecodeRawData;
 
@@ -140,6 +141,7 @@ internal Settings()
         ButtonEnableAutoHideCaptionButtons.Toggled += ButtonEnableAutoHideCaptionButtons_OnToggled;
         ButtonCtrlDragToMoveWindow.Toggled += ButtonCtrlDragToMoveWindow_OnToggled;
         ButtonClickOutsideImageToRestoreWindow.Toggled += ButtonClickOutsideImageToRestoreWindow_OnToggled;
+        ButtonSizeWindowToImageOnRestore.Toggled += ButtonSizeWindowToImageOnRestore_OnToggled;
         ButtonEnableExternalShortcut.Toggled += ButtonEnableExternalShortcut_OnToggled;
         ButtonDecodeRawData.Toggled += ButtonDecodeRawData_OnToggled;
         AppConfig.Settings.RawDecoderPriority.CollectionChanged += RawDecoderPriority_CollectionChanged;
@@ -251,6 +253,13 @@ private async void ButtonClickOutsideImageToRestoreWindow_OnToggled(object sende
         await AppConfig.SaveAsync();
     }
 
+    /// <summary>Persists whether image-sized restoration is enabled.</summary>
+    private async void ButtonSizeWindowToImageOnRestore_OnToggled(object sender, RoutedEventArgs e)
+    {
+        AppConfig.Settings.SizeWindowToImageOnRestore = ButtonSizeWindowToImageOnRestore.IsOn;
+        await AppConfig.SaveAsync();
+    }
+
     private async void ComboPanZoomNavBehaviour_OnSelectionChanged(object sender, SelectionChangedEventArgs e)
     {
         var panZoomEnum = GetPanZoomForIndex(ComboPanZoomNavBehaviour.SelectedIndex);
@@ -783,4 +792,4 @@ public static Windows.UI.Color FromHex(string hex)
         }
         return Windows.UI.Color.FromArgb(a, r, g, b);
     }
-}
+}