From 62078d2cc3a2e1ffa7bbc77a910b5a8a43488e11 Mon Sep 17 00:00:00 2001
From: daniel mayost <danielmayost@gmail.com>
Date: Thu, 26 May 2022 09:59:58 +0300
Subject: [PATCH] calculate mirrorTransform before renderTransform

---
 src/Avalonia.Base/Rendering/ImmediateRenderer.cs | 16 +++++++++-------
 .../Rendering/SceneGraph/SceneBuilder.cs         | 16 +++++++++-------
 src/Avalonia.Base/VisualExtensions.cs            | 13 +++++++------
 src/Avalonia.Controls/Viewbox.cs                 |  3 +--
 4 files changed, 26 insertions(+), 22 deletions(-)

diff --git a/src/Avalonia.Base/Rendering/ImmediateRenderer.cs b/src/Avalonia.Base/Rendering/ImmediateRenderer.cs
index 2c0298affa..54b2ce5a25 100644
--- a/src/Avalonia.Base/Rendering/ImmediateRenderer.cs
+++ b/src/Avalonia.Base/Rendering/ImmediateRenderer.cs
@@ -277,18 +277,20 @@ namespace Avalonia.Rendering
                 var m = Matrix.CreateTranslation(visual.Bounds.Position);
 
                 var renderTransform = Matrix.Identity;
+                
+                // this should be calculated BEFORE renderTransform
+                if (visual.HasMirrorTransform)
+                {
+                    var mirrorMatrix = new Matrix(-1.0, 0.0, 0.0, 1.0, visual.Bounds.Width, 0);
+                    renderTransform *= mirrorMatrix;
+                }
 
                 if (visual.RenderTransform != null)
                 {
                     var origin = visual.RenderTransformOrigin.ToPixels(new Size(visual.Bounds.Width, visual.Bounds.Height));
                     var offset = Matrix.CreateTranslation(origin);
-                    renderTransform = (-offset) * visual.RenderTransform.Value * (offset);
-                }
-
-                if (visual.HasMirrorTransform)
-                {
-                    var mirrorMatrix = new Matrix(-1.0, 0.0, 0.0, 1.0, visual.Bounds.Width, 0);
-                    renderTransform *= mirrorMatrix;
+                    var finalTransform = (-offset) * visual.RenderTransform.Value * (offset);
+                    renderTransform *= finalTransform;
                 }
 
                 m = renderTransform * m;
diff --git a/src/Avalonia.Base/Rendering/SceneGraph/SceneBuilder.cs b/src/Avalonia.Base/Rendering/SceneGraph/SceneBuilder.cs
index 019c3e0e9b..5dc426ab06 100644
--- a/src/Avalonia.Base/Rendering/SceneGraph/SceneBuilder.cs
+++ b/src/Avalonia.Base/Rendering/SceneGraph/SceneBuilder.cs
@@ -188,19 +188,21 @@ namespace Avalonia.Rendering.SceneGraph
 
                 var renderTransform = Matrix.Identity;
 
-                if (visual.RenderTransform != null)
-                {
-                    var origin = visual.RenderTransformOrigin.ToPixels(new Size(visual.Bounds.Width, visual.Bounds.Height));
-                    var offset = Matrix.CreateTranslation(origin);
-                    renderTransform = (-offset) * visual.RenderTransform.Value * (offset);
-                }
-
+                // this should be calculated BEFORE renderTransform
                 if (visual.HasMirrorTransform)
                 {
                     var mirrorMatrix = new Matrix(-1.0, 0.0, 0.0, 1.0, visual.Bounds.Width, 0);
                     renderTransform *= mirrorMatrix;
                 }
 
+                if (visual.RenderTransform != null)
+                {
+                    var origin = visual.RenderTransformOrigin.ToPixels(new Size(visual.Bounds.Width, visual.Bounds.Height));
+                    var offset = Matrix.CreateTranslation(origin);
+                    var finalTransform = (-offset) * visual.RenderTransform.Value * (offset);
+                    renderTransform *= finalTransform;
+                }
+
                 m = renderTransform * m;
 
                 using (contextImpl.BeginUpdate(node))
diff --git a/src/Avalonia.Base/VisualExtensions.cs b/src/Avalonia.Base/VisualExtensions.cs
index 3a3c2693d0..7a5bbb105c 100644
--- a/src/Avalonia.Base/VisualExtensions.cs
+++ b/src/Avalonia.Base/VisualExtensions.cs
@@ -101,6 +101,13 @@ namespace Avalonia
 
             while (v != ancestor)
             {
+                // this should be calculated BEFORE renderTransform
+                if (v.HasMirrorTransform)
+                {
+                    var mirrorMatrix = new Matrix(-1.0, 0.0, 0.0, 1.0, v.Bounds.Width, 0);
+                    result *= mirrorMatrix;
+                }
+
                 if (v.RenderTransform?.Value != null)
                 {
                     var origin = v.RenderTransformOrigin.ToPixels(v.Bounds.Size);
@@ -110,12 +117,6 @@ namespace Avalonia
                     result *= renderTransform;
                 }
 
-                if (v.HasMirrorTransform)
-                {
-                    var mirrorMatrix = new Matrix(-1.0, 0.0, 0.0, 1.0, v.Bounds.Width, 0);
-                    result *= mirrorMatrix;
-                }
-
                 var topLeft = v.Bounds.TopLeft;
 
                 if (topLeft != default)
diff --git a/src/Avalonia.Controls/Viewbox.cs b/src/Avalonia.Controls/Viewbox.cs
index 01667c5136..01a41a0157 100644
--- a/src/Avalonia.Controls/Viewbox.cs
+++ b/src/Avalonia.Controls/Viewbox.cs
@@ -1,7 +1,6 @@
 using Avalonia.Media;
 using Avalonia.Media.Immutable;
 using Avalonia.Metadata;
-using Avalonia.Layout;
 
 namespace Avalonia.Controls
 {
@@ -151,7 +150,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// A simple container control which hosts its child as a visual but not logical child.
         /// </summary>
-        private class ViewboxContainer : Layoutable
+        private class ViewboxContainer : Control
         {
             private IControl? _child;