From 0257bdf6eddfa63b770c644aab41dc7ed18670c1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Pedro?= <jpedrolmail@gmail.com>
Date: Sun, 21 Mar 2021 01:37:35 +0000
Subject: [PATCH] Implemented render scaling on Android.

---
 .../SkiaPlatform/AndroidFramebuffer.cs        |  6 ++--
 .../SkiaPlatform/FramebufferManager.cs        |  2 +-
 .../Platform/SkiaPlatform/TopLevelImpl.cs     | 28 ++++++-------------
 3 files changed, 14 insertions(+), 22 deletions(-)

diff --git a/src/Android/Avalonia.Android/Platform/SkiaPlatform/AndroidFramebuffer.cs b/src/Android/Avalonia.Android/Platform/SkiaPlatform/AndroidFramebuffer.cs
index 2afa4e83f1..b115917622 100644
--- a/src/Android/Avalonia.Android/Platform/SkiaPlatform/AndroidFramebuffer.cs
+++ b/src/Android/Avalonia.Android/Platform/SkiaPlatform/AndroidFramebuffer.cs
@@ -10,7 +10,7 @@ namespace Avalonia.Android.Platform.SkiaPlatform
     {
         private IntPtr _window;
 
-        public AndroidFramebuffer(Surface surface)
+        public AndroidFramebuffer(Surface surface, double scaling)
         {
             if(surface == null)
                 throw new ArgumentNullException(nameof(surface));
@@ -31,6 +31,8 @@ namespace Avalonia.Android.Platform.SkiaPlatform
 
             RowBytes = buffer.stride * (Format == PixelFormat.Rgb565 ? 2 : 4);
             Address = buffer.bits;
+
+            Dpi = scaling * new Vector(96, 96);
         }
 
         public void Dispose()
@@ -44,7 +46,7 @@ namespace Avalonia.Android.Platform.SkiaPlatform
         public IntPtr Address { get; set; }
         public PixelSize Size { get; }
         public int RowBytes { get; }
-        public Vector Dpi { get; } = new Vector(96, 96);
+        public Vector Dpi { get; }
         public PixelFormat Format { get; }
 
         [DllImport("android")]
diff --git a/src/Android/Avalonia.Android/Platform/SkiaPlatform/FramebufferManager.cs b/src/Android/Avalonia.Android/Platform/SkiaPlatform/FramebufferManager.cs
index 18c4796fae..56a4eb22d4 100644
--- a/src/Android/Avalonia.Android/Platform/SkiaPlatform/FramebufferManager.cs
+++ b/src/Android/Avalonia.Android/Platform/SkiaPlatform/FramebufferManager.cs
@@ -12,6 +12,6 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             _topLevel = topLevel;
         }
 
-        public ILockedFramebuffer Lock() => new AndroidFramebuffer(_topLevel.InternalView.Holder.Surface);
+        public ILockedFramebuffer Lock() => new AndroidFramebuffer(_topLevel.InternalView.Holder.Surface, _topLevel.RenderScaling);
     }
 }
diff --git a/src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs b/src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs
index 4fd9bc040b..fe237a1719 100644
--- a/src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs
+++ b/src/Android/Avalonia.Android/Platform/SkiaPlatform/TopLevelImpl.cs
@@ -39,8 +39,10 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             _gl = GlPlatformSurface.TryCreate(this);
             _framebuffer = new FramebufferManager(this);
 
-            MaxClientSize = new Size(_view.Resources.DisplayMetrics.WidthPixels,
-                _view.Resources.DisplayMetrics.HeightPixels);
+            RenderScaling = (int)_view.Resources.DisplayMetrics.Density;
+
+            MaxClientSize = new PixelSize(_view.Resources.DisplayMetrics.WidthPixels,
+                _view.Resources.DisplayMetrics.HeightPixels).ToSize(RenderScaling);
         }
 
         private bool _handleEvents;
@@ -60,19 +62,7 @@ namespace Avalonia.Android.Platform.SkiaPlatform
 
         public IInputRoot InputRoot { get; private set; }
 
-        public virtual Size ClientSize
-        {
-            get
-            {
-                if (_view == null)
-                    return new Size(0, 0);
-                return new Size(_view.Width, _view.Height);
-            }
-            set
-            {
-
-            }
-        }
+        public virtual Size ClientSize => Size.ToSize(RenderScaling);
 
         public IMouseDevice MouseDevice { get; } = new MouseDevice();
 
@@ -113,12 +103,12 @@ namespace Avalonia.Android.Platform.SkiaPlatform
 
         public Point PointToClient(PixelPoint point)
         {
-            return point.ToPoint(1);
+            return point.ToPoint(RenderScaling);
         }
 
         public PixelPoint PointToScreen(Point point)
         {
-            return PixelPoint.FromPoint(point, 1);
+            return PixelPoint.FromPoint(point, RenderScaling);
         }
 
         public void SetCursor(ICursorImpl cursor)
@@ -136,7 +126,7 @@ namespace Avalonia.Android.Platform.SkiaPlatform
             _view.Visibility = ViewStates.Visible;
         }
 
-        public double RenderScaling => 1;
+        public double RenderScaling { get; }
 
         void Draw()
         {
@@ -191,7 +181,7 @@ namespace Avalonia.Android.Platform.SkiaPlatform
 
             void ISurfaceHolderCallback.SurfaceChanged(ISurfaceHolder holder, Format format, int width, int height)
             {
-                var newSize = new Size(width, height);
+                var newSize = new PixelSize(width, height).ToSize(_tl.RenderScaling);
 
                 if (newSize != _oldSize)
                 {