From 1d4b23f718cd418a57320e3bf3ebf2f730204024 Mon Sep 17 00:00:00 2001
From: ahopper <alan@samsararesearch.com>
Date: Sun, 6 Jan 2019 09:14:22 +0000
Subject: [PATCH] fix resize with high dpi on windows

---
 src/Windows/Avalonia.Win32/WindowImpl.cs | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/Windows/Avalonia.Win32/WindowImpl.cs b/src/Windows/Avalonia.Win32/WindowImpl.cs
index fe1c06326f..2b8627a041 100644
--- a/src/Windows/Avalonia.Win32/WindowImpl.cs
+++ b/src/Windows/Avalonia.Win32/WindowImpl.cs
@@ -119,7 +119,7 @@ namespace Avalonia.Win32
         }
 
         public Size ClientSize
-        {
+        { 
             get
             {
                 UnmanagedMethods.RECT rect;
@@ -153,10 +153,14 @@ namespace Avalonia.Win32
 
         public void Resize(Size value)
         {
-            var clientRect = ClientSize;
-            if (value != clientRect)
+            int requestedClientWidth = (int)(value.Width * Scaling);
+            int requestedClientHeight = (int)(value.Height * Scaling);
+            UnmanagedMethods.RECT clientRect;
+            UnmanagedMethods.GetClientRect(_hwnd, out clientRect);
+           
+            // do comparison after scaling to avoid rounding issues
+            if (requestedClientWidth != clientRect.Width || requestedClientHeight != clientRect.Height)
             {
-                value *= Scaling;
                 UnmanagedMethods.RECT windowRect;
                 UnmanagedMethods.GetWindowRect(_hwnd, out windowRect);
 
@@ -165,8 +169,8 @@ namespace Avalonia.Win32
                     IntPtr.Zero,
                     0,
                     0,
-                    (int)(value.Width + (windowRect.Width - clientRect.Width)),
-                    (int)(value.Height + (windowRect.Height - clientRect.Height)),
+                    requestedClientWidth + (windowRect.Width - clientRect.Width),
+                    requestedClientHeight + (windowRect.Height - clientRect.Height),
                     UnmanagedMethods.SetWindowPosFlags.SWP_RESIZE);
             }
         }