Win32: Add support for Per-Monitor V2 awareness

This adds basic support for the Per-Monitor V2 level of DPI awareness
in Windows 10, which allows for automatic DPI scaling of window
decorations.

This commit does not include resizing the window content area to match
the new window content scale.

Related to #1115.
Fixes #1294.

src/win32_init.c

@@ -62,17 +62,6 @@ BOOL WINAPI DllMain(HINSTANCE instance, DWORD reason, LPVOID reserved)
 
 #endif // _GLFW_BUILD_DLL
 
-// HACK: Define versionhelpers.h functions manually as MinGW lacks the header
-BOOL IsWindowsVersionOrGreater(WORD major, WORD minor, WORD sp)
-{
-    OSVERSIONINFOEXW osvi = { sizeof(osvi), major, minor, 0, 0, {0}, sp };
-    DWORD mask = VER_MAJORVERSION | VER_MINORVERSION | VER_SERVICEPACKMAJOR;
-    ULONGLONG cond = VerSetConditionMask(0, VER_MAJORVERSION, VER_GREATER_EQUAL);
-    cond = VerSetConditionMask(cond, VER_MINORVERSION, VER_GREATER_EQUAL);
-    cond = VerSetConditionMask(cond, VER_SERVICEPACKMAJOR, VER_GREATER_EQUAL);
-    return VerifyVersionInfoW(&osvi, mask, cond);
-}
-
 // Load necessary libraries (DLLs)
 //
 static GLFWbool loadLibraries(void)
@@ -100,6 +89,14 @@ static GLFWbool loadLibraries(void)
         GetProcAddress(_glfw.win32.user32.instance, "SetProcessDPIAware");
     _glfw.win32.user32.ChangeWindowMessageFilterEx_ = (PFN_ChangeWindowMessageFilterEx)
         GetProcAddress(_glfw.win32.user32.instance, "ChangeWindowMessageFilterEx");
+    _glfw.win32.user32.EnableNonClientDpiScaling_ = (PFN_EnableNonClientDpiScaling)
+        GetProcAddress(_glfw.win32.user32.instance, "EnableNonClientDpiScaling");
+    _glfw.win32.user32.SetProcessDpiAwarenessContext_ = (PFN_SetProcessDpiAwarenessContext)
+        GetProcAddress(_glfw.win32.user32.instance, "SetProcessDpiAwarenessContext");
+    _glfw.win32.user32.GetDpiForWindow_ = (PFN_GetDpiForWindow)
+        GetProcAddress(_glfw.win32.user32.instance, "GetDpiForWindow");
+    _glfw.win32.user32.AdjustWindowRectExForDpi_ = (PFN_AdjustWindowRectExForDpi)
+        GetProcAddress(_glfw.win32.user32.instance, "AdjustWindowRectExForDpi");
 
     _glfw.win32.dinput8.instance = LoadLibraryA("dinput8.dll");
     if (_glfw.win32.dinput8.instance)
@@ -155,6 +152,13 @@ static GLFWbool loadLibraries(void)
             GetProcAddress(_glfw.win32.shcore.instance, "GetDpiForMonitor");
     }
 
+    _glfw.win32.ntdll.instance = LoadLibraryA("ntdll.dll");
+    if (_glfw.win32.ntdll.instance)
+    {
+        _glfw.win32.ntdll.RtlVerifyVersionInfo_ = (PFN_RtlVerifyVersionInfo)
+            GetProcAddress(_glfw.win32.ntdll.instance, "RtlVerifyVersionInfo");
+    }
+
     return GLFW_TRUE;
 }
 
@@ -179,6 +183,9 @@ static void freeLibraries(void)
 
     if (_glfw.win32.shcore.instance)
         FreeLibrary(_glfw.win32.shcore.instance);
+
+    if (_glfw.win32.ntdll.instance)
+        FreeLibrary(_glfw.win32.ntdll.instance);
 }
 
 // Create key code translation tables
@@ -503,6 +510,36 @@ void _glfwUpdateKeyNamesWin32(void)
     }
 }
 
+// Replacement for IsWindowsVersionOrGreater as MinGW lacks versionhelpers.h
+//
+BOOL _glfwIsWindowsVersionOrGreaterWin32(WORD major, WORD minor, WORD sp)
+{
+    OSVERSIONINFOEXW osvi = { sizeof(osvi), major, minor, 0, 0, {0}, sp };
+    DWORD mask = VER_MAJORVERSION | VER_MINORVERSION | VER_SERVICEPACKMAJOR;
+    ULONGLONG cond = VerSetConditionMask(0, VER_MAJORVERSION, VER_GREATER_EQUAL);
+    cond = VerSetConditionMask(cond, VER_MINORVERSION, VER_GREATER_EQUAL);
+    cond = VerSetConditionMask(cond, VER_SERVICEPACKMAJOR, VER_GREATER_EQUAL);
+    // HACK: Use RtlVerifyVersionInfo instead of VerifyVersionInfoW as the
+    //       latter lies unless the user knew to embedd a non-default manifest
+    //       announcing support for Windows 10 via supportedOS GUID
+    return RtlVerifyVersionInfo(&osvi, mask, cond) == 0;
+}
+
+// Checks whether we are on at least the specified build of Windows 10
+//
+BOOL _glfwIsWindows10BuildOrGreaterWin32(WORD build)
+{
+    OSVERSIONINFOEXW osvi = { sizeof(osvi), 10, 0, build };
+    DWORD mask = VER_MAJORVERSION | VER_MINORVERSION | VER_BUILDNUMBER;
+    ULONGLONG cond = VerSetConditionMask(0, VER_MAJORVERSION, VER_GREATER_EQUAL);
+    cond = VerSetConditionMask(cond, VER_MINORVERSION, VER_GREATER_EQUAL);
+    cond = VerSetConditionMask(cond, VER_BUILDNUMBER, VER_GREATER_EQUAL);
+    // HACK: Use RtlVerifyVersionInfo instead of VerifyVersionInfoW as the
+    //       latter lies unless the user knew to embedd a non-default manifest
+    //       announcing support for Windows 10 via supportedOS GUID
+    return RtlVerifyVersionInfo(&osvi, mask, cond) == 0;
+}
+
 
 //////////////////////////////////////////////////////////////////////////
 //////                       GLFW platform API                      //////
@@ -524,7 +561,9 @@ int _glfwPlatformInit(void)
     createKeyTables();
     _glfwUpdateKeyNamesWin32();
 
-    if (IsWindows8Point1OrGreater())
+    if (_glfwIsWindows10CreatorsUpdateOrGreaterWin32())
+        SetProcessDpiAwarenessContext(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
+    else if (IsWindows8Point1OrGreater())
         SetProcessDpiAwareness(PROCESS_PER_MONITOR_DPI_AWARE);
     else if (IsWindowsVistaOrGreater())
         SetProcessDPIAware();

src/win32_monitor.c

@@ -324,9 +324,9 @@ void _glfwGetMonitorContentScaleWin32(HMONITOR handle, float* xscale, float* ysc
     }
 
     if (xscale)
-        *xscale = xdpi / 96.f;
+        *xscale = xdpi / (float) USER_DEFAULT_SCREEN_DPI;
     if (yscale)
-        *yscale = ydpi / 96.f;
+        *yscale = ydpi / (float) USER_DEFAULT_SCREEN_DPI;
 }
 
 

src/win32_platform.h

@@ -98,6 +98,12 @@
 #ifndef _WIN32_WINNT_WINBLUE
  #define _WIN32_WINNT_WINBLUE 0x0602
 #endif
+#ifndef WM_GETDPISCALEDSIZE
+ #define WM_GETDPISCALEDSIZE 0x02e4
+#endif
+#ifndef USER_DEFAULT_SCREEN_DPI
+ #define USER_DEFAULT_SCREEN_DPI 96
+#endif
 
 #if WINVER < 0x0601
 typedef struct
@@ -140,24 +146,33 @@ typedef enum
 } MONITOR_DPI_TYPE;
 #endif /*DPI_ENUMS_DECLARED*/
 
+#ifndef _DPI_AWARENESS_CONTEXTS_
+DECLARE_HANDLE(DPI_AWARENESS_CONTEXT);
+#define DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2 ((DPI_AWARENESS_CONTEXT) -4)
+#endif /*_DPI_AWARENESS_CONTEXTS_*/
+
 // HACK: Define versionhelpers.h functions manually as MinGW lacks the header
-BOOL IsWindowsVersionOrGreater(WORD major, WORD minor, WORD sp);
 #define IsWindowsXPOrGreater()                                 \
-    IsWindowsVersionOrGreater(HIBYTE(_WIN32_WINNT_WINXP),      \
+    _glfwIsWindowsVersionOrGreaterWin32(HIBYTE(_WIN32_WINNT_WINXP),   \
                                         LOBYTE(_WIN32_WINNT_WINXP), 0)
 #define IsWindowsVistaOrGreater()                                     \
-    IsWindowsVersionOrGreater(HIBYTE(_WIN32_WINNT_VISTA),      \
+    _glfwIsWindowsVersionOrGreaterWin32(HIBYTE(_WIN32_WINNT_VISTA),   \
                                         LOBYTE(_WIN32_WINNT_VISTA), 0)
 #define IsWindows7OrGreater()                                         \
-    IsWindowsVersionOrGreater(HIBYTE(_WIN32_WINNT_WIN7),       \
+    _glfwIsWindowsVersionOrGreaterWin32(HIBYTE(_WIN32_WINNT_WIN7),    \
                                         LOBYTE(_WIN32_WINNT_WIN7), 0)
 #define IsWindows8OrGreater()                                         \
-    IsWindowsVersionOrGreater(HIBYTE(_WIN32_WINNT_WIN8),       \
+    _glfwIsWindowsVersionOrGreaterWin32(HIBYTE(_WIN32_WINNT_WIN8),    \
                                         LOBYTE(_WIN32_WINNT_WIN8), 0)
 #define IsWindows8Point1OrGreater()                                   \
-    IsWindowsVersionOrGreater(HIBYTE(_WIN32_WINNT_WINBLUE),    \
+    _glfwIsWindowsVersionOrGreaterWin32(HIBYTE(_WIN32_WINNT_WINBLUE), \
                                         LOBYTE(_WIN32_WINNT_WINBLUE), 0)
 
+#define _glfwIsWindows10AnniversaryUpdateOrGreaterWin32() \
+    _glfwIsWindows10BuildOrGreaterWin32(14393)
+#define _glfwIsWindows10CreatorsUpdateOrGreaterWin32() \
+    _glfwIsWindows10BuildOrGreaterWin32(15063)
+
 // HACK: Define macros that some xinput.h variants don't
 #ifndef XINPUT_CAPS_WIRELESS
  #define XINPUT_CAPS_WIRELESS 0x0002
@@ -209,8 +224,16 @@ typedef HRESULT (WINAPI * PFN_DirectInput8Create)(HINSTANCE,DWORD,REFIID,LPVOID*
 // user32.dll function pointer typedefs
 typedef BOOL (WINAPI * PFN_SetProcessDPIAware)(void);
 typedef BOOL (WINAPI * PFN_ChangeWindowMessageFilterEx)(HWND,UINT,DWORD,CHANGEFILTERSTRUCT*);
+typedef BOOL (WINAPI * PFN_EnableNonClientDpiScaling)(HWND);
+typedef BOOL (WINAPI * PFN_SetProcessDpiAwarenessContext)(DPI_AWARENESS_CONTEXT);
+typedef UINT (WINAPI * PFN_GetDpiForWindow)(HWND);
+typedef BOOL (WINAPI * PFN_AdjustWindowRectExForDpi)(LPRECT,DWORD,BOOL,DWORD,UINT);
 #define SetProcessDPIAware _glfw.win32.user32.SetProcessDPIAware_
 #define ChangeWindowMessageFilterEx _glfw.win32.user32.ChangeWindowMessageFilterEx_
+#define EnableNonClientDpiScaling _glfw.win32.user32.EnableNonClientDpiScaling_
+#define SetProcessDpiAwarenessContext _glfw.win32.user32.SetProcessDpiAwarenessContext_
+#define GetDpiForWindow _glfw.win32.user32.GetDpiForWindow_
+#define AdjustWindowRectExForDpi _glfw.win32.user32.AdjustWindowRectExForDpi_
 
 // dwmapi.dll function pointer typedefs
 typedef HRESULT (WINAPI * PFN_DwmIsCompositionEnabled)(BOOL*);
@@ -226,6 +249,10 @@ typedef HRESULT (WINAPI * PFN_GetDpiForMonitor)(HMONITOR,MONITOR_DPI_TYPE,UINT*,
 #define SetProcessDpiAwareness _glfw.win32.shcore.SetProcessDpiAwareness_
 #define GetDpiForMonitor _glfw.win32.shcore.GetDpiForMonitor_
 
+// ntdll.dll function pointer typedefs
+typedef LONG (WINAPI * PFN_RtlVerifyVersionInfo)(OSVERSIONINFOEXW*,ULONG,ULONGLONG);
+#define RtlVerifyVersionInfo _glfw.win32.ntdll.RtlVerifyVersionInfo_
+
 typedef VkFlags VkWin32SurfaceCreateFlagsKHR;
 
 typedef struct VkWin32SurfaceCreateInfoKHR
@@ -326,6 +353,10 @@ typedef struct _GLFWlibraryWin32
         HINSTANCE                       instance;
         PFN_SetProcessDPIAware          SetProcessDPIAware_;
         PFN_ChangeWindowMessageFilterEx ChangeWindowMessageFilterEx_;
+        PFN_EnableNonClientDpiScaling   EnableNonClientDpiScaling_;
+        PFN_SetProcessDpiAwarenessContext SetProcessDpiAwarenessContext_;
+        PFN_GetDpiForWindow             GetDpiForWindow_;
+        PFN_AdjustWindowRectExForDpi    AdjustWindowRectExForDpi_;
     } user32;
 
     struct {
@@ -341,6 +372,11 @@ typedef struct _GLFWlibraryWin32
         PFN_GetDpiForMonitor            GetDpiForMonitor_;
     } shcore;
 
+    struct {
+        HINSTANCE                       instance;
+        PFN_RtlVerifyVersionInfo        RtlVerifyVersionInfo_;
+    } ntdll;
+
 } _GLFWlibraryWin32;
 
 // Win32-specific per-monitor data
@@ -399,6 +435,8 @@ void _glfwUnregisterWindowClassWin32(void);
 
 WCHAR* _glfwCreateWideStringFromUTF8Win32(const char* source);
 char* _glfwCreateUTF8FromWideStringWin32(const WCHAR* source);
+BOOL _glfwIsWindowsVersionOrGreaterWin32(WORD major, WORD minor, WORD sp);
+BOOL _glfwIsWindows10BuildOrGreaterWin32(WORD build);
 void _glfwInputErrorWin32(int error, const char* description);
 void _glfwUpdateKeyNamesWin32(void);
 

src/win32_window.c

@@ -186,14 +186,20 @@ static HICON createIcon(const GLFWimage* image,
     return handle;
 }
 
-// Translate client window size to full window size according to styles
+// Translate client window size to full window size according to styles and DPI
 //
 static void getFullWindowSize(DWORD style, DWORD exStyle,
                               int clientWidth, int clientHeight,
-                              int* fullWidth, int* fullHeight)
+                              int* fullWidth, int* fullHeight,
+                              UINT dpi)
 {
     RECT rect = { 0, 0, clientWidth, clientHeight };
+
+    if (_glfwIsWindows10AnniversaryUpdateOrGreaterWin32())
+        AdjustWindowRectExForDpi(&rect, style, FALSE, exStyle, dpi);
+    else
         AdjustWindowRectEx(&rect, style, FALSE, exStyle);
+
     *fullWidth = rect.right - rect.left;
     *fullHeight = rect.bottom - rect.top;
 }
@@ -206,7 +212,8 @@ static void applyAspectRatio(_GLFWwindow* window, int edge, RECT* area)
     const float ratio = (float) window->numer / (float) window->denom;
 
     getFullWindowSize(getWindowStyle(window), getWindowExStyle(window),
-                      0, 0, &xoff, &yoff);
+                      0, 0, &xoff, &yoff,
+                      GetDpiForWindow(window->win32.handle));
 
     if (edge == WMSZ_LEFT  || edge == WMSZ_BOTTOMLEFT ||
         edge == WMSZ_RIGHT || edge == WMSZ_BOTTOMRIGHT)
@@ -337,7 +344,16 @@ static void updateWindowStyles(const _GLFWwindow* window)
     style |= getWindowStyle(window);
 
     GetClientRect(window->win32.handle, &rect);
+
+    if (_glfwIsWindows10AnniversaryUpdateOrGreaterWin32())
+    {
+        AdjustWindowRectExForDpi(&rect, style, FALSE,
+                                 getWindowExStyle(window),
+                                 GetDpiForWindow(window->win32.handle));
+    }
+    else
         AdjustWindowRectEx(&rect, style, FALSE, getWindowExStyle(window));
+
     ClientToScreen(window->win32.handle, (POINT*) &rect.left);
     ClientToScreen(window->win32.handle, (POINT*) &rect.right);
     SetWindowLongW(window->win32.handle, GWL_STYLE, style);
@@ -557,9 +573,18 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
     if (!window)
     {
         // This is the message handling for the hidden helper window
+        // and for a regular window during its initial creation
 
         switch (uMsg)
         {
+            case WM_NCCREATE:
+            {
+                if (_glfwIsWindows10AnniversaryUpdateOrGreaterWin32())
+                    EnableNonClientDpiScaling(hWnd);
+
+                break;
+            }
+
             case WM_DISPLAYCHANGE:
                 _glfwPollMonitorsWin32();
                 break;
@@ -982,7 +1007,8 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
                 break;
 
             getFullWindowSize(getWindowStyle(window), getWindowExStyle(window),
-                              0, 0, &xoff, &yoff);
+                              0, 0, &xoff, &yoff,
+                              GetDpiForWindow(window->win32.handle));
 
             if (window->minwidth != GLFW_DONT_CARE &&
                 window->minheight != GLFW_DONT_CARE)
@@ -1035,10 +1061,49 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
             return 0;
         }
 
+        case WM_GETDPISCALEDSIZE:
+        {
+            // Adjust the window size to keep the client area size constant
+            if (_glfwIsWindows10CreatorsUpdateOrGreaterWin32())
+            {
+                RECT source = {0}, target = {0};
+                SIZE* size = (SIZE*) lParam;
+
+                AdjustWindowRectExForDpi(&source, getWindowStyle(window),
+                                         FALSE, getWindowExStyle(window),
+                                         GetDpiForWindow(window->win32.handle));
+                AdjustWindowRectExForDpi(&target, getWindowStyle(window),
+                                         FALSE, getWindowExStyle(window),
+                                         LOWORD(wParam));
+
+                size->cx += (target.right - target.left) -
+                            (source.right - source.left);
+                size->cy += (target.bottom - target.top) -
+                            (source.bottom - source.top);
+                return TRUE;
+            }
+
+            break;
+        }
+
         case WM_DPICHANGED:
         {
-            const float xscale = HIWORD(wParam) / 96.f;
+            const float xscale = HIWORD(wParam) / (float) USER_DEFAULT_SCREEN_DPI;
-            const float yscale = LOWORD(wParam) / 96.f;
+            const float yscale = LOWORD(wParam) / (float) USER_DEFAULT_SCREEN_DPI;
+
+            // Only apply the suggested size if the OS is new enough to have
+            // sent a WM_GETDPISCALEDSIZE before this
+            if (_glfwIsWindows10CreatorsUpdateOrGreaterWin32())
+            {
+                RECT* suggested = (RECT*) lParam;
+                SetWindowPos(window->win32.handle, HWND_TOP,
+                             suggested->left,
+                             suggested->top,
+                             suggested->right - suggested->left,
+                             suggested->bottom - suggested->top,
+                             SWP_NOACTIVATE | SWP_NOZORDER);
+            }
+
             _glfwInputWindowContentScale(window, xscale, yscale);
             break;
         }
@@ -1125,7 +1190,8 @@ static int createNativeWindow(_GLFWwindow* window,
 
         getFullWindowSize(style, exStyle,
                           wndconfig->width, wndconfig->height,
-                          &fullWidth, &fullHeight);
+                          &fullWidth, &fullHeight,
+                          USER_DEFAULT_SCREEN_DPI);
     }
 
     wideTitle = _glfwCreateWideStringFromUTF8Win32(wndconfig->title);
@@ -1164,6 +1230,21 @@ static int createNativeWindow(_GLFWwindow* window,
                                     WM_COPYGLOBALDATA, MSGFLT_ALLOW, NULL);
     }
 
+    // Adjust window size to account for the DPI scaled window frame
+    // This cannot be done until we know what monitor it was placed on
+    if (_glfwIsWindows10AnniversaryUpdateOrGreaterWin32() && !window->monitor)
+    {
+        RECT rect = { 0, 0, wndconfig->width, wndconfig->height };
+        ClientToScreen(window->win32.handle, (POINT*) &rect.left);
+        ClientToScreen(window->win32.handle, (POINT*) &rect.right);
+        AdjustWindowRectExForDpi(&rect, style, FALSE, exStyle,
+                                 GetDpiForWindow(window->win32.handle));
+        SetWindowPos(window->win32.handle, NULL,
+                     rect.left, rect.top,
+                     rect.right - rect.left, rect.bottom - rect.top,
+                     SWP_NOACTIVATE | SWP_NOZORDER);
+    }
+
     DragAcceptFiles(window->win32.handle, TRUE);
 
     if (fbconfig->transparent)
@@ -1360,8 +1441,19 @@ void _glfwPlatformGetWindowPos(_GLFWwindow* window, int* xpos, int* ypos)
 void _glfwPlatformSetWindowPos(_GLFWwindow* window, int xpos, int ypos)
 {
     RECT rect = { xpos, ypos, xpos, ypos };
+
+    if (_glfwIsWindows10AnniversaryUpdateOrGreaterWin32())
+    {
+        AdjustWindowRectExForDpi(&rect, getWindowStyle(window),
+                                 FALSE, getWindowExStyle(window),
+                                 GetDpiForWindow(window->win32.handle));
+    }
+    else
+    {
         AdjustWindowRectEx(&rect, getWindowStyle(window),
                            FALSE, getWindowExStyle(window));
+    }
+
     SetWindowPos(window->win32.handle, NULL, rect.left, rect.top, 0, 0,
                  SWP_NOACTIVATE | SWP_NOZORDER | SWP_NOSIZE);
 }
@@ -1390,8 +1482,19 @@ void _glfwPlatformSetWindowSize(_GLFWwindow* window, int width, int height)
     else
     {
         RECT rect = { 0, 0, width, height };
+
+        if (_glfwIsWindows10AnniversaryUpdateOrGreaterWin32())
+        {
+            AdjustWindowRectExForDpi(&rect, getWindowStyle(window),
+                                     FALSE, getWindowExStyle(window),
+                                     GetDpiForWindow(window->win32.handle));
+        }
+        else
+        {
             AdjustWindowRectEx(&rect, getWindowStyle(window),
                                FALSE, getWindowExStyle(window));
+        }
+
         SetWindowPos(window->win32.handle, HWND_TOP,
                      0, 0, rect.right - rect.left, rect.bottom - rect.top,
                      SWP_NOACTIVATE | SWP_NOOWNERZORDER | SWP_NOMOVE | SWP_NOZORDER);
@@ -1446,8 +1549,18 @@ void _glfwPlatformGetWindowFrameSize(_GLFWwindow* window,
 
     _glfwPlatformGetWindowSize(window, &width, &height);
     SetRect(&rect, 0, 0, width, height);
+
+    if (_glfwIsWindows10AnniversaryUpdateOrGreaterWin32())
+    {
+        AdjustWindowRectExForDpi(&rect, getWindowStyle(window),
+                                 FALSE, getWindowExStyle(window),
+                                 GetDpiForWindow(window->win32.handle));
+    }
+    else
+    {
         AdjustWindowRectEx(&rect, getWindowStyle(window),
                            FALSE, getWindowExStyle(window));
+    }
 
     if (left)
         *left = -rect.left;
@@ -1523,8 +1636,19 @@ void _glfwPlatformSetWindowMonitor(_GLFWwindow* window,
         else
         {
             RECT rect = { xpos, ypos, xpos + width, ypos + height };
+
+            if (_glfwIsWindows10AnniversaryUpdateOrGreaterWin32())
+            {
+                AdjustWindowRectExForDpi(&rect, getWindowStyle(window),
+                                         FALSE, getWindowExStyle(window),
+                                         GetDpiForWindow(window->win32.handle));
+            }
+            else
+            {
                 AdjustWindowRectEx(&rect, getWindowStyle(window),
                                    FALSE, getWindowExStyle(window));
+            }
+
             SetWindowPos(window->win32.handle, HWND_TOP,
                          rect.left, rect.top,
                          rect.right - rect.left, rect.bottom - rect.top,
@@ -1584,8 +1708,18 @@ void _glfwPlatformSetWindowMonitor(_GLFWwindow* window,
         else
             after = HWND_NOTOPMOST;
 
+        if (_glfwIsWindows10AnniversaryUpdateOrGreaterWin32())
+        {
+            AdjustWindowRectExForDpi(&rect, getWindowStyle(window),
+                                     FALSE, getWindowExStyle(window),
+                                     GetDpiForWindow(window->win32.handle));
+        }
+        else
+        {
             AdjustWindowRectEx(&rect, getWindowStyle(window),
                                FALSE, getWindowExStyle(window));
+        }
+
         SetWindowPos(window->win32.handle, after,
                      rect.left, rect.top,
                      rect.right - rect.left, rect.bottom - rect.top,