Windows: Add support for PerMonitorV2 DPI awareness

Add support for opting in to PerMonitorV2 DPI awareness
on the command line:
	-platform windows:dpiawareness=3

This mode is supported on Windows 10 and up. Setting it
requires using the new SetProcessDpiAwarenessContext
API, which can be resolved from user32.dll.

Task-number: QTBUG-68712
Change-Id: I37821e27a67e08c2e9fef25e494cfd7abed13314
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/plugins/platforms/windows/qwindowscontext.h b/src/plugins/platforms/windows/qwindowscontext.h
index aacdafebb6..99b4bb6c77 100644
--- a/src/plugins/platforms/windows/qwindowscontext.h
+++ b/src/plugins/platforms/windows/qwindowscontext.h
@@ -98,6 +98,7 @@ struct QWindowsUser32DLL
     typedef BOOL (WINAPI *GetPointerPenInfoHistory)(UINT32, UINT32 *, PVOID);
     typedef BOOL (WINAPI *SkipPointerFrameMessages)(UINT32);
     typedef BOOL (WINAPI *SetProcessDPIAware)();
+    typedef BOOL (WINAPI *SetProcessDpiAwarenessContext)(HANDLE);
     typedef BOOL (WINAPI *AddClipboardFormatListener)(HWND);
     typedef BOOL (WINAPI *RemoveClipboardFormatListener)(HWND);
     typedef BOOL (WINAPI *GetDisplayAutoRotationPreferences)(DWORD *);
@@ -123,6 +124,9 @@ struct QWindowsUser32DLL
     // Windows Vista onwards
     SetProcessDPIAware setProcessDPIAware = nullptr;
 
+    // Windows 10 version 1703 onwards
+    SetProcessDpiAwarenessContext setProcessDpiAwarenessContext = nullptr;
+
     // Clipboard listeners are present on Windows Vista onwards
     // but missing in MinGW 4.9 stub libs. Can be removed in MinGW 5.
     AddClipboardFormatListener addClipboardFormatListener = nullptr;
@@ -227,6 +231,7 @@ public:
     static void setTabletAbsoluteRange(int a);
     void setProcessDpiAwareness(QtWindows::ProcessDpiAwareness dpiAwareness);
     static int processDpiAwareness();
+    void setProcessDpiV2Awareness();
 
     static bool isDarkMode();