Windows QPA: Fix window frame calculation in multi-monitor setups

When introducing EnableNonClientDpiScaling() for QTBUG-53255, the window
frame calculation was not adapted. That is, window frames were calculated
from the style for the primary screen only, causing

- minimum size constraints not being calculated correctly for applications
  on secondary screens when populating the MINMAXINFO structure.
- warnings about not being able to apply a geometry when moving fixed
  size windows across screens.

The calculation of the frames for propagating size hints is also no longer
required after 3035400f36731c400adb9204b94e9afe346a71b7, which retrieves
them from the WM_NCCALCSIZE message; QWindowsWindow::fullFrameMargins() can
be used instead.

For newly created windows, use the newly added AdjustWindowRectExForDpi()
function to calculate the initial frame size.

Change QWindowsGeometryHint from a class to a collection of static functions
and add overloads to calculate the frame.

In checkForScreenChanged(), update the margins until WM_NCCALCSIZE is
received.

Task-number: QTBUG-67777
Task-number: QTBUG-65580
Task-number: QTBUG-53255
Change-Id: Iff2d382b2b316adec6c1a0622ae8015dba6de371
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>
Reviewed-by: Andre de la Rocha <andre.rocha@qt.io>

1 files changed, 4 insertions, 0 deletions

diff --git a/src/plugins/platforms/windows/qwindowscontext.h b/src/plugins/platforms/windows/qwindowscontext.h
index fd6c72668c..4908f14629 100644
--- a/src/plugins/platforms/windows/qwindowscontext.h
+++ b/src/plugins/platforms/windows/qwindowscontext.h
@@ -102,6 +102,7 @@ struct QWindowsUser32DLL
     typedef BOOL (WINAPI *RemoveClipboardFormatListener)(HWND);
     typedef BOOL (WINAPI *GetDisplayAutoRotationPreferences)(DWORD *);
     typedef BOOL (WINAPI *SetDisplayAutoRotationPreferences)(DWORD);
+    typedef BOOL (WINAPI *AdjustWindowRectExForDpi)(LPRECT,DWORD,BOOL,DWORD,UINT);
     typedef BOOL (WINAPI *EnableNonClientDpiScaling)(HWND);
     typedef int  (WINAPI *GetWindowDpiAwarenessContext)(HWND);
     typedef int  (WINAPI *GetAwarenessFromDpiAwarenessContext)(int);
@@ -131,6 +132,7 @@ struct QWindowsUser32DLL
     GetDisplayAutoRotationPreferences getDisplayAutoRotationPreferences = nullptr;
     SetDisplayAutoRotationPreferences setDisplayAutoRotationPreferences = nullptr;
 
+    AdjustWindowRectExForDpi adjustWindowRectExForDpi = nullptr;
     EnableNonClientDpiScaling enableNonClientDpiScaling = nullptr;
     GetWindowDpiAwarenessContext getWindowDpiAwarenessContext = nullptr;
     GetAwarenessFromDpiAwarenessContext getAwarenessFromDpiAwarenessContext = nullptr;
@@ -201,6 +203,8 @@ public:
     QWindowsWindow *findPlatformWindowAt(HWND parent, const QPoint &screenPoint,
                                              unsigned cwex_flags) const;
 
+    static bool shouldHaveNonClientDpiScaling(const QWindow *window);
+
     QWindow *windowUnderMouse() const;
     void clearWindowUnderMouse();