Windows QPA: Update screen on child window DPI change

Windows does not send WM_DPICHANGED to child windows, which means
that the normal DPI change handling code does not run for QWindows
which are embedded in a foreign, non-Qt, window.

Add code which handles WM_DPICHANGED_AFTERPARENT. This event is
sent to all child windows, but not the top-level window. Call
checkForScreenChanged() here, similar to what the WM_DPICHANGED code
does.

This commit does not add code to resize the child window, since
it is uncertain if this is the responsibility of the window which
receives WM_DPICHANGED, or of each child window.

Done-with: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
Task-number: QTBUG-103383
Change-Id: Icf85dd0afa806609dbbe0ffc36efbc5127962c39
Reviewed-by: <stefan.wastl@native-instruments.de>
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
(cherry picked from commit 077eddb3e1aaba1517d67e7c83574c16e971dc67)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Morten Sørvig 2022-06-13 17:33:16 +02:00 committed by Qt Cherry-pick Bot
parent 393eb4fa97
commit 02c9117836
4 changed files with 19 additions and 2 deletions

View File

@ -106,6 +106,7 @@ enum WindowsEventType // Simplify event types
ExitSizeMoveEvent = WindowEventFlag + 23,
PointerActivateWindowEvent = WindowEventFlag + 24,
DpiScaledSizeEvent = WindowEventFlag + 25,
DpiChangedAfterParentEvent = WindowEventFlag + 27,
MouseEvent = MouseEventFlag + 1,
MouseWheelEvent = MouseEventFlag + 2,
CursorEvent = MouseEventFlag + 3,
@ -292,6 +293,8 @@ inline QtWindows::WindowsEventType windowsEventType(UINT message, WPARAM wParamI
return HIWORD(wParamIn) ? QtWindows::AcceleratorCommandEvent : QtWindows::MenuCommandEvent;
case WM_DPICHANGED:
return QtWindows::DpiChangedEvent;
case WM_DPICHANGED_AFTERPARENT:
return QtWindows::DpiChangedAfterParentEvent;
case WM_GETDPISCALEDSIZE:
return QtWindows::DpiScaledSizeEvent;
case WM_ENTERSIZEMOVE:

View File

@ -1325,6 +1325,9 @@ bool QWindowsContext::windowsProc(HWND hwnd, UINT message,
case QtWindows::DpiChangedEvent:
platformWindow->handleDpiChanged(hwnd, wParam, lParam);
return true;
case QtWindows::DpiChangedAfterParentEvent:
platformWindow->handleDpiChangedAfterParent(hwnd);
return true;
#if QT_CONFIG(sessionmanager)
case QtWindows::QueryEndSessionApplicationEvent: {
QWindowsSessionManager *sessionManager = platformSessionManager();

View File

@ -2007,6 +2007,14 @@ void QWindowsWindow::handleDpiChanged(HWND hwnd, WPARAM wParam, LPARAM lParam)
}
}
void QWindowsWindow::handleDpiChangedAfterParent(HWND hwnd)
{
// FIXME: refactor, do we really need this?
setSavedDpi(GetDpiForWindow(hwnd));
checkForScreenChanged(QWindowsWindow::FromDpiChange);
}
static QRect normalFrameGeometry(HWND hwnd)
{
WINDOWPLACEMENT wp;
@ -2150,12 +2158,14 @@ static inline bool equalDpi(const QDpi &d1, const QDpi &d2)
void QWindowsWindow::checkForScreenChanged(ScreenChangeMode mode)
{
if (parent() || QWindowsScreenManager::isSingleScreen())
if ((parent() && !parent()->isForeignWindow()) || QWindowsScreenManager::isSingleScreen())
return;
QPlatformScreen *currentScreen = screen();
auto topLevel = isTopLevel_sys() ? m_data.hwnd : GetAncestor(m_data.hwnd, GA_ROOT);
const QWindowsScreen *newScreen =
QWindowsContext::instance()->screenManager().screenForHwnd(m_data.hwnd);
QWindowsContext::instance()->screenManager().screenForHwnd(topLevel);
if (newScreen == nullptr || newScreen == currentScreen)
return;
// For screens with different DPI: postpone until WM_DPICHANGE

View File

@ -286,6 +286,7 @@ public:
void handleCompositionSettingsChanged();
void handleDpiScaledSize(WPARAM wParam, LPARAM lParam, LRESULT *result);
void handleDpiChanged(HWND hwnd, WPARAM wParam, LPARAM lParam);
void handleDpiChangedAfterParent(HWND hwnd);
static void displayChanged();
static void settingsChanged();