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Windows QPA: also consider child windows for setting WS_EX_LAYERED

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Child windows on Windows cannot have a frame, so checking only for
Qt::FramelessWindowHint is not sufficient. Add an additional check
to see if the window is a native child (has the WS_CHILD flag).

Change-Id: Ib5cbec0f6157da687a5585e12a6c4c6935919538
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
(cherry picked from commit f56fc425f9a103ed71697314196649641ef3691c)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
This commit is contained in:
Timothée Keller 2023-08-04 10:15:18 +02:00 committed by Qt Cherry-pick Bot
parent a0981f1341
commit 5c0dea4760
2 changed files with 10 additions and 2 deletions
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11
src/plugins/platforms/windows/qwindowswindow.cpp
View File

@ -468,14 +468,21 @@ static bool shouldShowMaximizeButton(const QWindow *w, Qt::WindowFlags flags)
w->maximumSize() == QSize(QWINDOWSIZE_MAX, QWINDOWSIZE_MAX);
}
bool QWindowsWindow::hasNoNativeFrame(HWND hwnd, Qt::WindowFlags flags)
{
const LONG_PTR style = GetWindowLongPtr(hwnd, GWL_STYLE);
return (style & WS_CHILD) || (flags & Qt::FramelessWindowHint);
}
// Set the WS_EX_LAYERED flag on a HWND if required. This is required for
// translucent backgrounds, not fully opaque windows and for
// Qt::WindowTransparentForInput (in combination with WS_EX_TRANSPARENT).
bool QWindowsWindow::setWindowLayered(HWND hwnd, Qt::WindowFlags flags, bool hasAlpha, qreal opacity)
{
const LONG_PTR exStyle = GetWindowLongPtr(hwnd, GWL_EXSTYLE);
// Native children are frameless by nature, so check for that as well.
const bool needsLayered = (flags & Qt::WindowTransparentForInput)
|| (hasAlpha && (flags & Qt::FramelessWindowHint)) || opacity < 1.0;
|| (hasAlpha && hasNoNativeFrame(hwnd, flags)) || opacity < 1.0;
const bool isLayered = (exStyle & WS_EX_LAYERED);
if (needsLayered != isLayered) {
if (needsLayered) {
@ -491,7 +498,7 @@ static void setWindowOpacity(HWND hwnd, Qt::WindowFlags flags, bool hasAlpha, bo
{
if (QWindowsWindow::setWindowLayered(hwnd, flags, hasAlpha, level)) {
const BYTE alpha = BYTE(qRound(255.0 * level));
if (hasAlpha && !accelerated && (flags & Qt::FramelessWindowHint)) {
if (hasAlpha && !accelerated && QWindowsWindow::hasNoNativeFrame(hwnd, flags)) {
// Non-GL windows with alpha: Use blend function to update.
BLENDFUNCTION blend = {AC_SRC_OVER, 0, alpha, AC_SRC_ALPHA};
UpdateLayeredWindow(hwnd, nullptr, nullptr, nullptr, nullptr, nullptr, 0, &blend, ULW_ALPHA);

1
src/plugins/platforms/windows/qwindowswindow.h
View File

@ -305,6 +305,7 @@ public:
static inline void *userDataOf(HWND hwnd);
static inline void setUserDataOf(HWND hwnd, void *ud);
static bool hasNoNativeFrame(HWND hwnd, Qt::WindowFlags flags);
static bool setWindowLayered(HWND hwnd, Qt::WindowFlags flags, bool hasAlpha, qreal opacity);
bool isLayered() const;