Add screen orientation support for Linux frame buffer and DRM applications.

src/Linux/Avalonia.LinuxFramebuffer/DrmOutputOptions.cs

@@ -1,4 +1,5 @@
 using Avalonia.Media;
+using Avalonia.Skia;
 
 namespace Avalonia.LinuxFramebuffer
 {
@@ -12,7 +13,13 @@ public class DrmOutputOptions
         /// Default: 1.0
         /// </summary>
         public double Scaling { get; set; } = 1.0;
-
+
+        /// <summary>
+        /// The orientation of the screen relative to the frame buffer memory orientation
+        /// Default: Normal
+        /// </summary>
+        public SurfaceOrientation Orientation { get; set; } = SurfaceOrientation.Normal;
+
         /// <summary>
         /// If true an two cycle buffer swapping is processed at init.
         /// Default: True

src/Linux/Avalonia.LinuxFramebuffer/FramebufferToplevelImpl.cs

@@ -7,9 +7,10 @@
 using Avalonia.LinuxFramebuffer.Output;
 using Avalonia.Platform;
 using Avalonia.Rendering.Composition;
- using Avalonia.Threading;
+using Avalonia.Skia;
+using Avalonia.Threading;
 
- namespace Avalonia.LinuxFramebuffer
+namespace Avalonia.LinuxFramebuffer
 {
     class FramebufferToplevelImpl : ITopLevelImpl, IScreenInfoProvider
     {
@@ -71,7 +72,14 @@ public void SetCursor(ICursorImpl? cursor)
         public Action? Closed { get; set; }
         public Action? LostFocus { get; set; }
 
-        public Size ScaledSize => _outputBackend.PixelSize.ToSize(RenderScaling);
+        public PixelSize RotatedSize => Orientation switch
+        {
+            SurfaceOrientation.Rotated90 => new PixelSize(_outputBackend.PixelSize.Height, _outputBackend.PixelSize.Width),
+            SurfaceOrientation.Rotated270 => new PixelSize(_outputBackend.PixelSize.Height, _outputBackend.PixelSize.Width),
+            _ => _outputBackend.PixelSize,
+        };
+
+        public Size ScaledSize => RotatedSize.ToSize(RenderScaling);
 
         public void SetTransparencyLevelHint(IReadOnlyList<WindowTransparencyLevel> transparencyLevel) { }
 
@@ -80,6 +88,18 @@ public void SetTransparencyLevelHint(IReadOnlyList<WindowTransparencyLevel> tran
         public void SetFrameThemeVariant(PlatformThemeVariant themeVariant) { }
 
         public AcrylicPlatformCompensationLevels AcrylicCompensationLevels { get; } = new AcrylicPlatformCompensationLevels(1, 1, 1);
+
+        // implements ISurfaceOrientation
+        public SurfaceOrientation Orientation
+        {
+            get => _outputBackend.Orientation;
+            set
+            {
+                _outputBackend.Orientation = value;
+                Resized?.Invoke(ScaledSize, WindowResizeReason.Unspecified);
+            }
+        }
+
         public object? TryGetFeature(Type featureType) => null;
     }
 }

src/Linux/Avalonia.LinuxFramebuffer/Input/IScreenInfoProvider.cs

@@ -1,6 +1,8 @@
+using Avalonia.Skia;
+
 namespace Avalonia.LinuxFramebuffer.Input
 {
-    public interface IScreenInfoProvider
+    public interface IScreenInfoProvider : ISurfaceOrientation
     {
         Size ScaledSize { get; }
     }

src/Linux/Avalonia.LinuxFramebuffer/Input/LibInput/LibInputBackend.cs

@@ -1,8 +1,10 @@
 using System;
 using System.IO;
+using System.Linq;
 using System.Threading;
 using Avalonia.Input;
 using Avalonia.Input.Raw;
+using Avalonia.Skia;
 using static Avalonia.LinuxFramebuffer.Input.LibInput.LibInputNativeUnsafeMethods;
 namespace Avalonia.LinuxFramebuffer.Input.LibInput
 {
@@ -30,12 +32,31 @@ private IInputRoot InputRoot
         private unsafe void InputThread(IntPtr ctx, LibInputBackendOptions options)
         {
             var fd = libinput_get_fd(ctx);
+            IntPtr[] devices = [.. options.Events!.Select(f => libinput_path_add_device(ctx, f))];
+            SurfaceOrientation screenOrientation = SurfaceOrientation.Unknown;
 
-            foreach (var f in options.Events!)
-                libinput_path_add_device(ctx, f);
             while (true)
             {
                 IntPtr ev;
+
+                if (_screen!.Orientation != screenOrientation)
+                {
+                    screenOrientation = _screen.Orientation;
+
+                    float[] matrix = screenOrientation switch
+                    {
+                        SurfaceOrientation.Rotated90 => [0, 1, 0, -1, 0, 1],
+                        SurfaceOrientation.Rotated180 => [-1, 0, 1, 0, -1, 1],
+                        SurfaceOrientation.Rotated270 => [0, -1, 1, 1, 0, 0],
+                        _ => [1, 0, 0, 0, 1, 0],    // Normal
+                    };
+
+                    foreach (var device in devices)
+                    {
+                        libinput_device_config_calibration_set_matrix(device, matrix);
+                    }
+                }
+
                 libinput_dispatch(ctx);
                 while ((ev = libinput_get_event(ctx)) != IntPtr.Zero)
                 {

src/Linux/Avalonia.LinuxFramebuffer/Input/LibInput/LibInputNativeUnsafeMethods.cs

@@ -55,6 +55,9 @@ public static IntPtr libinput_path_create_context() =>
         [DllImport(LibInput)]
         public extern static IntPtr libinput_path_remove_device(IntPtr device);
 
+        [DllImport(LibInput)]
+        public extern static int libinput_device_config_calibration_set_matrix(IntPtr device, float[] matrix);
+
         [DllImport(LibInput)]
         public extern static int libinput_get_fd(IntPtr ctx);
 

src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebufferPlatform.cs

@@ -142,7 +142,10 @@ public TopLevel? TopLevel
         {
             get
             {
-                EnsureTopLevel();
+                if (_topLevel == null)
+                {
+                    EnsureTopLevel();
+                }
                 return _topLevel;
             }
         }

src/Linux/Avalonia.LinuxFramebuffer/Output/DrmOutput.cs

@@ -8,6 +8,7 @@
 using Avalonia.OpenGL.Egl;
 using Avalonia.OpenGL.Surfaces;
 using Avalonia.Platform;
+using Avalonia.Skia;
 using static Avalonia.LinuxFramebuffer.NativeUnsafeMethods;
 using static Avalonia.LinuxFramebuffer.Output.LibDrm;
 
@@ -17,14 +18,22 @@ public unsafe class DrmOutput : IGlOutputBackend, IGlPlatformSurface
     {
         private DrmOutputOptions _outputOptions = new();
         private DrmCard _card;
-        public PixelSize PixelSize => _mode.Resolution;
+         public PixelSize PixelSize => _mode.Resolution;
 
         public double Scaling
         {
             get => _outputOptions.Scaling;
             set => _outputOptions.Scaling = value;
         }
 
+        // implements ISurfaceOrientation
+        public SurfaceOrientation Orientation
+        {
+            get => _outputOptions.Orientation;
+            set => _outputOptions.Orientation = value;
+        }
+
+
         class SharedContextGraphics : IPlatformGraphics
         {
             private readonly IPlatformGraphicsContext _context;
@@ -275,7 +284,7 @@ public void Dispose()
                 // We are wrapping GBM buffer chain associated with CRTC, and don't free it on a whim
             }
 
-            class RenderSession : IGlPlatformSurfaceRenderingSession
+            class RenderSession : IGlPlatformSurfaceRenderingSession, ISurfaceOrientation
             {
                 private readonly DrmOutput _parent;
                 private readonly IDisposable _clearContext;
@@ -338,6 +347,8 @@ public void Dispose()
                 public double Scaling => _parent.Scaling;
 
                 public bool IsYFlipped => false;
+
+                public SurfaceOrientation Orientation { get => _parent.Orientation; set => _parent.Orientation = value; }
             }
 
             public IGlPlatformSurfaceRenderingSession BeginDraw()

src/Linux/Avalonia.LinuxFramebuffer/Output/FbDevOutputOptions.cs

@@ -1,4 +1,5 @@
 using Avalonia.Platform;
+using Avalonia.Skia;
 
 namespace Avalonia.LinuxFramebuffer.Output;
 
@@ -28,6 +29,12 @@ public class FbDevOutputOptions
     /// </summary>
     public double Scaling { get; set; } = 1;
 
+    /// <summary>
+    /// The orientation of the screen relative to the frame buffer memory orientation
+    /// Default: Normal
+    /// </summary>
+    public SurfaceOrientation Orientation { get; set; } = SurfaceOrientation.Normal;
+
     /// <summary>
     /// If set to true, FBIO_WAITFORVSYNC ioctl and following memcpy call will run on a dedicated thread
     /// saving current one from doing nothing in a blocking call

src/Linux/Avalonia.LinuxFramebuffer/Output/FbdevOutput.cs

@@ -5,6 +5,7 @@
 using Avalonia.Controls.Platform.Surfaces;
 using Avalonia.LinuxFramebuffer.Output;
 using Avalonia.Platform;
+using Avalonia.Skia;
 
 namespace Avalonia.LinuxFramebuffer
 {
@@ -20,6 +21,9 @@ public sealed unsafe class FbdevOutput : IFramebufferPlatformSurface, IDisposabl
         private bool _lockedAtLeastOnce;
         public double Scaling { get; set; }
 
+        // implements ISurfaceOrientation
+        public SurfaceOrientation Orientation { get; set; }
+
         /// <summary>
         /// Create a Linux frame buffer device output
         /// </summary>
@@ -58,6 +62,8 @@ public FbdevOutput(FbDevOutputOptions options)
                 throw new Exception("Error: " + Marshal.GetLastWin32Error());
             _options = options;
             Scaling = options.Scaling;
+            Orientation = options.Orientation;
+
             try
             {
                 Init(options.PixelFormat);

src/Linux/Avalonia.LinuxFramebuffer/Output/IOutputBackend.cs

@@ -1,6 +1,8 @@
+using Avalonia.Skia;
+
 namespace Avalonia.LinuxFramebuffer.Output
 {
-    public interface IOutputBackend
+    public interface IOutputBackend : ISurfaceOrientation
     {
         PixelSize PixelSize { get; }
         double Scaling { get; set; }

src/Skia/Avalonia.Skia/DrawingContextImpl.cs

@@ -30,6 +30,7 @@ internal partial class DrawingContextImpl : IDrawingContextImpl,
         private readonly Matrix? _postTransform;
         private double _currentOpacity = 1.0f;
         private readonly bool _disableSubpixelTextRendering;
+        private Matrix _baseTransform;  // default canvas rotation
         private Matrix? _currentTransform;
         private bool _disposed;
         private GRContext? _grContext;
@@ -187,6 +188,7 @@ public DrawingContextImpl(CreateInfo createInfo, params IDisposable?[]? disposab
             Canvas = createInfo.Canvas ?? createInfo.Surface?.Canvas
                 ?? throw new ArgumentException("Invalid create info - no Canvas provided", nameof(createInfo));
 
+            _baseTransform = Canvas.TotalMatrix.ToAvaloniaMatrix();
             _intermediateSurfaceDpi = createInfo.Dpi;
             _disposables = disposables;
             _disableSubpixelTextRendering = createInfo.DisableSubpixelTextRendering;
@@ -374,7 +376,7 @@ public void DrawRectangle(IExperimentalAcrylicMaterial? material, RoundedRect re
             if (rect.Rect.Height <= 0 || rect.Rect.Width <= 0)
                 return;
             CheckLease();
-            
+
             var rc = rect.Rect.ToSKRect();
             SKRoundRect? skRoundRect = null;
 
@@ -542,7 +544,7 @@ public void DrawRegion(IBrush? brush, IPen? pen, IPlatformRenderInterfaceRegion
             if(r.IsEmpty)
                 return;
             CheckLease();
-            
+
             if (brush != null)
             {
                 using (var fill = CreatePaint(_fillPaint, brush, r.Bounds.ToRectUnscaled()))
@@ -567,7 +569,7 @@ public void DrawEllipse(IBrush? brush, IPen? pen, Rect rect)
             if (rect.Height <= 0 || rect.Width <= 0)
                 return;
             CheckLease();
-            
+
             var rc = rect.ToSKRect();
 
             if (brush != null)
@@ -677,7 +679,7 @@ private void RestoreCanvas()
             _currentTransform = null;
             Canvas.Restore();
         }
-        
+
         /// <inheritdoc />
         public void PopClip()
         {
@@ -844,7 +846,7 @@ public void PopOpacityMask()
         /// <inheritdoc />
         public Matrix Transform
         {
-            get { return _currentTransform ??= Canvas.TotalMatrix.ToAvaloniaMatrix(); }
+            get { return _currentTransform ??= _baseTransform.Invert() * Canvas.TotalMatrix.ToAvaloniaMatrix(); }
             set
             {
                 CheckLease();
@@ -860,7 +862,7 @@ public Matrix Transform
                     transform *= _postTransform.Value;
                 }
 
-                Canvas.SetMatrix(transform.ToSKMatrix());
+                Canvas.SetMatrix((_baseTransform * transform).ToSKMatrix());
             }
         }