From 4426df671e73bf722c3092e5fb25f0dd1f0ea970 Mon Sep 17 00:00:00 2001
From: Davide Giacometti <davide.giacometti@outlook.it>
Date: Mon, 5 Feb 2024 18:05:02 +0100
Subject: [PATCH] [Peek]Fix title bar glitch after maximizing window (#31172)

---
 .../Peek.UI/Extensions/WindowExtensions.cs    | 25 ++++++++++++++++---
 src/modules/peek/Peek.UI/NativeMethods.txt    |  4 ++-
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/src/modules/peek/Peek.UI/Extensions/WindowExtensions.cs b/src/modules/peek/Peek.UI/Extensions/WindowExtensions.cs
index c7fd32a875..b4f9b58b57 100644
--- a/src/modules/peek/Peek.UI/Extensions/WindowExtensions.cs
+++ b/src/modules/peek/Peek.UI/Extensions/WindowExtensions.cs
@@ -2,7 +2,6 @@
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using System;
 using System.Runtime.InteropServices;
 using ManagedCommon;
 using Microsoft.UI.Xaml;
@@ -25,12 +24,31 @@ namespace Peek.UI.Extensions
         internal static void CenterOnMonitor(this Window window, HWND hwndDesktop, double? width = null, double? height = null)
         {
             var hwndToCenter = new HWND(window.GetWindowHandle());
+
+            // If the window is maximized, restore to normal state before change its size
+            var placement = default(WINDOWPLACEMENT);
+            if (PInvoke.GetWindowPlacement(hwndToCenter, ref placement))
+            {
+                if (placement.showCmd == SHOW_WINDOW_CMD.SW_MAXIMIZE)
+                {
+                    placement.showCmd = SHOW_WINDOW_CMD.SW_SHOWNORMAL;
+                    if (!PInvoke.SetWindowPlacement(hwndToCenter, in placement))
+                    {
+                        Logger.LogError($"SetWindowPlacement failed with error {Marshal.GetLastWin32Error()}");
+                    }
+                }
+            }
+            else
+            {
+                Logger.LogError($"GetWindowPlacement failed with error {Marshal.GetLastWin32Error()}");
+            }
+
             var monitor = PInvoke.MonitorFromWindow(hwndDesktop, MONITOR_FROM_FLAGS.MONITOR_DEFAULTTONEAREST);
             MONITORINFO info = default(MONITORINFO);
             info.cbSize = 40;
             PInvoke.GetMonitorInfo(monitor, ref info);
             var dpi = PInvoke.GetDpiForWindow(new HWND(hwndDesktop));
-            PInvoke.GetWindowRect(new HWND(hwndToCenter), out RECT windowRect);
+            PInvoke.GetWindowRect(hwndToCenter, out RECT windowRect);
             var scalingFactor = dpi / 96d;
             var w = width.HasValue ? (int)(width * scalingFactor) : windowRect.right - windowRect.left;
             var h = height.HasValue ? (int)(height * scalingFactor) : windowRect.bottom - windowRect.top;
@@ -38,7 +56,8 @@ namespace Peek.UI.Extensions
             var cy = (info.rcMonitor.bottom + info.rcMonitor.top) / 2;
             var left = cx - (w / 2);
             var top = cy - (h / 2);
-            SetWindowPosOrThrow(new HWND(hwndToCenter), default(HWND), left, top, w, h, SET_WINDOW_POS_FLAGS.SWP_SHOWWINDOW);
+
+            SetWindowPosOrThrow(hwndToCenter, default(HWND), left, top, w, h, SET_WINDOW_POS_FLAGS.SWP_NOACTIVATE);
         }
 
         private static void SetWindowPosOrThrow(HWND hWnd, HWND hWndInsertAfter, int x, int y, int cx, int cy, SET_WINDOW_POS_FLAGS uFlags)
diff --git a/src/modules/peek/Peek.UI/NativeMethods.txt b/src/modules/peek/Peek.UI/NativeMethods.txt
index 3e15b22f94..e65e72c12f 100644
--- a/src/modules/peek/Peek.UI/NativeMethods.txt
+++ b/src/modules/peek/Peek.UI/NativeMethods.txt
@@ -17,4 +17,6 @@ _SVGIO
 MONITORINFO
 GetWindowRect
 SET_WINDOW_POS_FLAGS
-SetWindowPos
\ No newline at end of file
+SetWindowPos
+GetWindowPlacement
+SetWindowPlacement
\ No newline at end of file