[DirectFB] Added configurable scaling support

samples/ControlCatalog.NetCore/Program.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Diagnostics;
+using System.Globalization;
 using System.Linq;
 using System.Threading;
 using Avalonia;
@@ -28,15 +29,24 @@ namespace ControlCatalog.NetCore
             }
 
             var builder = BuildAvaloniaApp();
+
+            double GetScaling()
+            {
+                var idx = Array.IndexOf(args, "--scaling");
+                if (idx != 0 && args.Length > idx + 1 &&
+                    double.TryParse(args[idx + 1], NumberStyles.Any, CultureInfo.InvariantCulture, out var scaling))
+                    return scaling;
+                return 1;
+            }
             if (args.Contains("--fbdev"))
             {
                 SilenceConsole();
-                return builder.StartLinuxFbDev(args);
+                return builder.StartLinuxFbDev(args, scaling: GetScaling());
             }
             else if (args.Contains("--drm"))
             {
                 SilenceConsole();
-                return builder.StartLinuxDrm(args);
+                return builder.StartLinuxDrm(args, scaling: GetScaling());
             }
             else
                 return builder.StartWithClassicDesktopLifetime(args);

src/Linux/Avalonia.LinuxFramebuffer/FramebufferToplevelImpl.cs

@@ -61,7 +61,7 @@ namespace Avalonia.LinuxFramebuffer
         public IMouseDevice MouseDevice => new MouseDevice();
         public IPopupImpl CreatePopup() => null;
 
-        public double Scaling => 1;
+        public double Scaling => _outputBackend.Scaling;
         public IEnumerable<object> Surfaces => new object[] {_outputBackend};
         public Action<RawInputEventArgs> Input { get; set; }
         public Action<Rect> Paint { get; set; }

src/Linux/Avalonia.LinuxFramebuffer/LinuxFramebufferPlatform.cs

@@ -107,11 +107,12 @@ namespace Avalonia.LinuxFramebuffer
 
 public static class LinuxFramebufferPlatformExtensions
 {
-    public static int StartLinuxFbDev<T>(this T builder, string[] args, string fbdev = null)
-        where T : AppBuilderBase<T>, new() => StartLinuxDirect(builder, args, new FbdevOutput(fbdev));
+    public static int StartLinuxFbDev<T>(this T builder, string[] args, string fbdev = null, double scaling = 1)
+        where T : AppBuilderBase<T>, new() =>
+        StartLinuxDirect(builder, args, new FbdevOutput(fbdev) {Scaling = scaling});
 
-    public static int StartLinuxDrm<T>(this T builder, string[] args, string card = null)
-        where T : AppBuilderBase<T>, new() => StartLinuxDirect(builder, args, new DrmOutput(card));
+    public static int StartLinuxDrm<T>(this T builder, string[] args, string card = null, double scaling = 1)
+        where T : AppBuilderBase<T>, new() => StartLinuxDirect(builder, args, new DrmOutput(card) {Scaling = scaling});
     
     public static int StartLinuxDirect<T>(this T builder, string[] args, IOutputBackend backend)
         where T : AppBuilderBase<T>, new()

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

@@ -14,7 +14,7 @@ namespace Avalonia.LinuxFramebuffer.Output
         private DrmCard _card;
         private readonly EglGlPlatformSurface _eglPlatformSurface;
         public PixelSize PixelSize => _mode.Resolution;
-
+        public double Scaling { get; set; }
         public DrmOutput(string path = null)
         {
             var card = new DrmCard(path);
@@ -233,7 +233,7 @@ namespace Avalonia.LinuxFramebuffer.Output
 
                 public PixelSize Size => _parent._mode.Resolution;
 
-                public double Scaling => 1;
+                public double Scaling => _parent.Scaling;
             }
 
             public IGlPlatformSurfaceRenderingSession BeginDraw()
@@ -241,6 +241,8 @@ namespace Avalonia.LinuxFramebuffer.Output
                 _parent._deferredContext.MakeCurrent(_parent._eglSurface);
                 return new RenderSession(_parent);
             }
+            
+            
         }
 
         IGlContext IWindowingPlatformGlFeature.ImmediateContext => _immediateContext;

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

@@ -9,16 +9,15 @@ namespace Avalonia.LinuxFramebuffer
 {
     public sealed unsafe class FbdevOutput : IFramebufferPlatformSurface, IDisposable, IOutputBackend
     {
-        private readonly Vector _dpi;
         private int _fd;
         private fb_fix_screeninfo _fixedInfo;
         private fb_var_screeninfo _varInfo;
         private IntPtr _mappedLength;
         private IntPtr _mappedAddress;
+        public double Scaling { get; set; }
 
-        public FbdevOutput(string fileName = null, Vector? dpi = null)
+        public FbdevOutput(string fileName = null)
         {
-            _dpi = dpi ?? new Vector(96, 96);
             fileName = fileName ?? Environment.GetEnvironmentVariable("FRAMEBUFFER") ?? "/dev/fb0";
             _fd = NativeUnsafeMethods.open(fileName, 2, 0);
             if (_fd <= 0)
@@ -101,7 +100,7 @@ namespace Avalonia.LinuxFramebuffer
         {
             if (_fd <= 0)
                 throw new ObjectDisposedException("LinuxFramebuffer");
-            return new LockedFramebuffer(_fd, _fixedInfo, _varInfo, _mappedAddress, _dpi);
+            return new LockedFramebuffer(_fd, _fixedInfo, _varInfo, _mappedAddress, new Vector(96, 96) * Scaling);
         }
 
 

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

@@ -3,5 +3,6 @@ namespace Avalonia.LinuxFramebuffer.Output
     public interface IOutputBackend
     {
         PixelSize PixelSize { get; }
+        double Scaling { get; set; }
     }
 }