From 63fae07d12791d45f6924cf063d7285254e25ddf Mon Sep 17 00:00:00 2001
From: Katayama Hirofumi MZ <katayama.hirofumi.mz@gmail.com>
Date: Mon, 7 Aug 2023 09:50:30 +0900
Subject: [PATCH] [SHELL32][SDK] Implement SHIsTempDisplayMode (#5523)

CORE-9277
---
 .../shell32/shelldesktop/CDesktopBrowser.cpp  | 30 +++++++++++++++++++
 dll/win32/shell32/stubs.cpp                   | 11 -------
 sdk/include/reactos/undocshell.h              |  2 ++
 3 files changed, 32 insertions(+), 11 deletions(-)

diff --git a/dll/win32/shell32/shelldesktop/CDesktopBrowser.cpp b/dll/win32/shell32/shelldesktop/CDesktopBrowser.cpp
index 3e45650e9c6..95327468757 100644
--- a/dll/win32/shell32/shelldesktop/CDesktopBrowser.cpp
+++ b/dll/win32/shell32/shelldesktop/CDesktopBrowser.cpp
@@ -520,3 +520,33 @@ BOOL WINAPI SHDesktopMessageLoop(HANDLE hDesktop)
 
     return TRUE;
 }
+
+/*************************************************************************
+ *  SHIsTempDisplayMode [SHELL32.724]
+ *
+ * Is the current display settings temporary?
+ */
+EXTERN_C BOOL WINAPI SHIsTempDisplayMode(VOID)
+{
+    TRACE("\n");
+
+    if (GetSystemMetrics(SM_REMOTESESSION) || GetSystemMetrics(SM_REMOTECONTROL))
+        return FALSE;
+
+    DEVMODEW DevMode;
+    ZeroMemory(&DevMode, sizeof(DevMode));
+    DevMode.dmSize = sizeof(DevMode);
+
+    if (!EnumDisplaySettingsW(NULL, ENUM_REGISTRY_SETTINGS, &DevMode))
+        return FALSE;
+
+    if (!DevMode.dmPelsWidth || !DevMode.dmPelsHeight)
+        return FALSE;
+
+    HDC hDC = GetDC(NULL);
+    DWORD cxWidth = GetDeviceCaps(hDC, HORZRES);
+    DWORD cyHeight = GetDeviceCaps(hDC, VERTRES);
+    ReleaseDC(NULL, hDC);
+
+    return (cxWidth != DevMode.dmPelsWidth || cyHeight != DevMode.dmPelsHeight);
+}
diff --git a/dll/win32/shell32/stubs.cpp b/dll/win32/shell32/stubs.cpp
index f3c79305971..bc8bf50f7b5 100644
--- a/dll/win32/shell32/stubs.cpp
+++ b/dll/win32/shell32/stubs.cpp
@@ -130,17 +130,6 @@ GetFileDescriptor(FILEGROUPDESCRIPTOR *pFileGroupDesc, BOOL bUnicode, INT iIndex
     return NULL;
 }
 
-/*
- * Unimplemented
- */
-EXTERN_C BOOL
-WINAPI
-SHIsTempDisplayMode(VOID)
-{
-    FIXME("SHIsTempDisplayMode() stub\n");
-    return FALSE;
-}
-
 /*
  * Unimplemented
  */
diff --git a/sdk/include/reactos/undocshell.h b/sdk/include/reactos/undocshell.h
index 1d87844e1a9..0b2b247f668 100644
--- a/sdk/include/reactos/undocshell.h
+++ b/sdk/include/reactos/undocshell.h
@@ -189,6 +189,8 @@ DWORD WINAPI SHNetConnectionDialog(
     LPCWSTR lpstrRemoteName,
     DWORD dwType);
 
+BOOL WINAPI SHIsTempDisplayMode(VOID);
+
 /****************************************************************************
  * Cabinet Window Messages
  */