various fixes and improvements

1. Make all demo applications be able to record and restore the previous window geometry.
2. Improve the robustness of the widgets and quick implementation.

Signed-off-by: Yuhang Zhao <2546789017@qq.com>

examples/mainwindow/main.cpp

@@ -23,13 +23,10 @@
  */
 
 #include <QtWidgets/qapplication.h>
-#include <framelessconfig_p.h>
 #include "mainwindow.h"
 
 FRAMELESSHELPER_USE_NAMESPACE
 
-using namespace Global;
-
 int main(int argc, char *argv[])
 {
     // Not necessary, but better call this function, before the construction
@@ -38,8 +35,6 @@ int main(int argc, char *argv[])
 
     QApplication application(argc, argv);
 
-    FramelessConfig::instance()->set(Option::CenterWindowBeforeShow);
-
     MainWindow mainWindow;
     mainWindow.show();
 

examples/mainwindow/mainwindow.cpp

@@ -24,6 +24,10 @@
 
 #include "mainwindow.h"
 #include "ui_mainwindow.h"
+#include <QtCore/qsettings.h>
+#include <QtCore/qcoreapplication.h>
+#include <QtCore/qfileinfo.h>
+#include <QtCore/qdir.h>
 #include <QtWidgets/qboxlayout.h>
 #include <Utils>
 #include <StandardTitleBar>
@@ -34,6 +38,18 @@ FRAMELESSHELPER_USE_NAMESPACE
 
 using namespace Global;
 
+FRAMELESSHELPER_STRING_CONSTANT2(GeoKeyPath, "Window/Geometry")
+FRAMELESSHELPER_STRING_CONSTANT2(StateKeyPath, "Window/State")
+
+[[nodiscard]] static inline QSettings *appConfigFile()
+{
+    const QFileInfo fileInfo(QCoreApplication::applicationFilePath());
+    const QString iniFileName = fileInfo.completeBaseName() + FRAMELESSHELPER_STRING_LITERAL(".ini");
+    const QString iniFilePath = fileInfo.canonicalPath() + QDir::separator() + iniFileName;
+    const auto settings = new QSettings(iniFilePath, QSettings::IniFormat);
+    return settings;
+}
+
 MainWindow::MainWindow(QWidget *parent, const Qt::WindowFlags flags) : FramelessMainWindow(parent, flags)
 {
     initialize();
@@ -41,6 +57,14 @@ MainWindow::MainWindow(QWidget *parent, const Qt::WindowFlags flags) : Frameless
 
 MainWindow::~MainWindow() = default;
 
+void MainWindow::closeEvent(QCloseEvent *event)
+{
+    const QScopedPointer<QSettings> settings(appConfigFile());
+    settings->setValue(kGeoKeyPath, saveGeometry());
+    settings->setValue(kStateKeyPath, saveState());
+    FramelessMainWindow::closeEvent(event);
+}
+
 void MainWindow::initialize()
 {
     m_titleBar.reset(new StandardTitleBar(this));
@@ -60,6 +84,19 @@ void MainWindow::initialize()
     helper->setSystemButton(m_titleBar->maximizeButton(), SystemButtonType::Maximize);
     helper->setSystemButton(m_titleBar->closeButton(), SystemButtonType::Close);
     helper->setHitTestVisible(mb); // IMPORTANT!
+    connect(helper, &FramelessWidgetsHelper::ready, this, [this, helper](){
+        const QScopedPointer<QSettings> settings(appConfigFile());
+        const QByteArray geoData = settings->value(kGeoKeyPath).toByteArray();
+        const QByteArray stateData = settings->value(kStateKeyPath).toByteArray();
+        if (geoData.isEmpty()) {
+            helper->moveWindowToDesktopCenter();
+        } else {
+            restoreGeometry(geoData);
+        }
+        if (!stateData.isEmpty()) {
+            restoreState(stateData);
+        }
+    });
 
     setWindowTitle(tr("FramelessHelper demo application - Qt MainWindow"));
 }

examples/mainwindow/mainwindow.h

@@ -44,6 +44,9 @@ public:
     explicit MainWindow(QWidget *parent = nullptr, const Qt::WindowFlags flags = {});
     ~MainWindow() override;
 
+protected:
+    void closeEvent(QCloseEvent *event) override;
+
 private:
     void initialize();
 

examples/openglwidget/main.cpp

@@ -52,8 +52,6 @@
 #include <QApplication>
 #include <QSurfaceFormat>
 #include <QOpenGLContext>
-#include <framelesshelpercore_global.h>
-#include <framelessconfig_p.h>
 #include "mainwindow.h"
 
 // This example demonstrates easy, cross-platform usage of OpenGL ES 3.0 functions via
@@ -66,8 +64,6 @@
 
 FRAMELESSHELPER_USE_NAMESPACE
 
-using namespace Global;
-
 int main(int argc, char *argv[])
 {
     // Not necessary, but better call this function, before the construction
@@ -76,8 +72,6 @@ int main(int argc, char *argv[])
 
     QApplication application(argc, argv);
 
-    FramelessConfig::instance()->set(Option::CenterWindowBeforeShow);
-
     QSurfaceFormat fmt = {};
     fmt.setDepthBufferSize(24);
 

examples/openglwidget/mainwindow.cpp

@@ -24,6 +24,10 @@
 
 #include "mainwindow.h"
 #include "glwidget.h"
+#include <QtCore/qsettings.h>
+#include <QtCore/qcoreapplication.h>
+#include <QtCore/qfileinfo.h>
+#include <QtCore/qdir.h>
 #include <QtWidgets/qboxlayout.h>
 #include <FramelessWidgetsHelper>
 #include <StandardTitleBar>
@@ -33,6 +37,17 @@ FRAMELESSHELPER_USE_NAMESPACE
 
 using namespace Global;
 
+FRAMELESSHELPER_STRING_CONSTANT2(IniKeyPath, "Window/Geometry")
+
+[[nodiscard]] static inline QSettings *appConfigFile()
+{
+    const QFileInfo fileInfo(QCoreApplication::applicationFilePath());
+    const QString iniFileName = fileInfo.completeBaseName() + FRAMELESSHELPER_STRING_LITERAL(".ini");
+    const QString iniFilePath = fileInfo.canonicalPath() + QDir::separator() + iniFileName;
+    const auto settings = new QSettings(iniFilePath, QSettings::IniFormat);
+    return settings;
+}
+
 MainWindow::MainWindow(QWidget *parent) : FramelessWidget(parent)
 {
     initialize();
@@ -40,6 +55,13 @@ MainWindow::MainWindow(QWidget *parent) : FramelessWidget(parent)
 
 MainWindow::~MainWindow() = default;
 
+void MainWindow::closeEvent(QCloseEvent *event)
+{
+    const QScopedPointer<QSettings> settings(appConfigFile());
+    settings->setValue(kIniKeyPath, saveGeometry());
+    FramelessWidget::closeEvent(event);
+}
+
 void MainWindow::initialize()
 {
     resize(800, 600);
@@ -58,4 +80,13 @@ void MainWindow::initialize()
     helper->setSystemButton(m_titleBar->minimizeButton(), SystemButtonType::Minimize);
     helper->setSystemButton(m_titleBar->maximizeButton(), SystemButtonType::Maximize);
     helper->setSystemButton(m_titleBar->closeButton(), SystemButtonType::Close);
+    connect(helper, &FramelessWidgetsHelper::ready, this, [this, helper](){
+        const QScopedPointer<QSettings> settings(appConfigFile());
+        const QByteArray data = settings->value(kIniKeyPath).toByteArray();
+        if (data.isEmpty()) {
+            helper->moveWindowToDesktopCenter();
+        } else {
+            restoreGeometry(data);
+        }
+    });
 }

examples/openglwidget/mainwindow.h

@@ -41,6 +41,9 @@ public:
     explicit MainWindow(QWidget *parent = nullptr);
     ~MainWindow() override;
 
+protected:
+    void closeEvent(QCloseEvent *event) override;
+
 private:
     void initialize();
 

examples/quick/CMakeLists.txt

@@ -28,6 +28,8 @@ find_package(Qt${QT_VERSION_MAJOR} REQUIRED COMPONENTS QuickControls2)
 set(SOURCES
     qml.qrc
     main.cpp
+    settings.h
+    settings.cpp
 )
 
 if(WIN32)

examples/quick/MainWindow.qml

@@ -26,14 +26,33 @@ import QtQuick 2.0
 import QtQuick.Window 2.0
 import QtQuick.Controls 2.0
 import org.wangwenx190.FramelessHelper 1.0
+import Demo 1.0
 
 FramelessWindow {
     id: window
+    visible: false // Hide the window before we sets up it's correct size and position.
     width: 800
     height: 600
     title: qsTr("FramelessHelper demo application - Qt Quick")
     color: (FramelessUtils.systemTheme === FramelessHelperConstants.Dark)
             ? FramelessUtils.defaultSystemDarkColor : FramelessUtils.defaultSystemLightColor
+    onClosing: Settings.saveGeometry(window)
+
+    FramelessHelper.onReady: {
+        // Let FramelessHelper know what's our homemade title bar, otherwise
+        // our window won't be draggable.
+        FramelessHelper.titleBarItem = titleBar;
+        // Make our own items visible to the hit test and on Windows, enable
+        // the snap layouts feature (available since Windows 11).
+        FramelessHelper.setSystemButton(titleBar.minimizeButton, FramelessHelperConstants.Minimize);
+        FramelessHelper.setSystemButton(titleBar.maximizeButton, FramelessHelperConstants.Maximize);
+        FramelessHelper.setSystemButton(titleBar.closeButton, FramelessHelperConstants.Close);
+        if (!Settings.restoreGeometry(window)) {
+            FramelessHelper.moveWindowToDesktopCenter();
+        }
+        // Finally, show the window after everything is setted.
+        window.visible = true;
+    }
 
     Timer {
         interval: 500
@@ -55,19 +74,9 @@ FramelessWindow {
     StandardTitleBar {
         id: titleBar
         anchors {
-            top: window.topBorderBottom
+            top: window.topBorderBottom // IMPORTANT!
             left: parent.left
             right: parent.right
         }
-        Component.onCompleted: {
-            // Make our homemade title bar draggable, and open the system menu
-            // when the user right clicks on the title bar area.
-            FramelessHelper.titleBarItem = titleBar;
-            // Make our own items visible to the hit test and on Windows, enable
-            // the snap layout feature (available since Windows 11).
-            FramelessHelper.setSystemButton(titleBar.minimizeButton, FramelessHelperConstants.Minimize);
-            FramelessHelper.setSystemButton(titleBar.maximizeButton, FramelessHelperConstants.Maximize);
-            FramelessHelper.setSystemButton(titleBar.closeButton, FramelessHelperConstants.Close);
-        }
     }
 }

examples/quick/main.cpp

@@ -27,12 +27,10 @@
 #include <QtQuick/qquickwindow.h>
 #include <QtQuickControls2/qquickstyle.h>
 #include <framelessquickmodule.h>
-#include <framelessconfig_p.h>
+#include "settings.h"
 
 FRAMELESSHELPER_USE_NAMESPACE
 
-using namespace Global;
-
 int main(int argc, char *argv[])
 {
     // Not necessary, but better call this function, before the construction
@@ -41,8 +39,6 @@ int main(int argc, char *argv[])
 
     QGuiApplication application(argc, argv);
 
-    FramelessConfig::instance()->set(Option::CenterWindowBeforeShow);
-
     // Allow testing other RHI backends through environment variable.
     if (!qEnvironmentVariableIsSet("QSG_RHI_BACKEND")) {
         // This line is not relevant to FramelessHelper, we change
@@ -63,6 +59,13 @@ int main(int argc, char *argv[])
     // Don't forget to register our own custom QML types!
     FramelessHelper::Quick::registerTypes(&engine);
 
+    qmlRegisterSingletonType<Settings>("Demo", 1, 0, "Settings",
+        [](QQmlEngine *engine, QJSEngine *scriptEngine) -> QObject * {
+            Q_UNUSED(engine);
+            Q_UNUSED(scriptEngine);
+            return new Settings;
+        });
+
     // This line is not relevant to FramelessHelper, we change the default
     // Qt Quick Controls theme to "Basic" (Qt6) or "Default" (Qt5) just
     // because other themes will make our homemade system buttons look
@@ -73,11 +76,11 @@ int main(int argc, char *argv[])
     QQuickStyle::setStyle(FRAMELESSHELPER_STRING_LITERAL("Default"));
 #endif
 
-    const QUrl homepageUrl(FRAMELESSHELPER_STRING_LITERAL("qrc:///Demo/qml/MainWindow.qml"));
+    const QUrl mainUrl(FRAMELESSHELPER_STRING_LITERAL("qrc:///Demo/qml/MainWindow.qml"));
     const QMetaObject::Connection connection = QObject::connect(
         &engine, &QQmlApplicationEngine::objectCreated, &application,
-        [&homepageUrl, &connection](QObject *object, const QUrl &url) {
+        [&mainUrl, &connection](QObject *object, const QUrl &url) {
-            if (url != homepageUrl) {
+            if (url != mainUrl) {
                 return;
             }
             if (object) {
@@ -87,7 +90,7 @@ int main(int argc, char *argv[])
             }
         }, Qt::QueuedConnection);
 
-    engine.load(homepageUrl);
+    engine.load(mainUrl);
 
     return QCoreApplication::exec();
 }

examples/quick/settings.cpp

@@ -0,0 +1,77 @@
+/*
+ * MIT License
+ *
+ * Copyright (C) 2022 by wangwenx190 (Yuhang Zhao)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "settings.h"
+#include <QtCore/qsettings.h>
+#include <QtCore/qcoreapplication.h>
+#include <QtCore/qfileinfo.h>
+#include <QtCore/qdir.h>
+#include <QtCore/qdatastream.h>
+#include <QtGui/qwindow.h>
+
+FRAMELESSHELPER_STRING_CONSTANT2(IniKeyPath, "Window/Geometry")
+
+Settings::Settings(QObject *parent) : QObject(parent)
+{
+    const QFileInfo fileInfo(QCoreApplication::applicationFilePath());
+    const QString iniFileName = fileInfo.completeBaseName() + FRAMELESSHELPER_STRING_LITERAL(".ini");
+    const QString iniFilePath = fileInfo.canonicalPath() + QDir::separator() + iniFileName;
+    m_settings.reset(new QSettings(iniFilePath, QSettings::IniFormat));
+}
+
+Settings::~Settings() = default;
+
+void Settings::saveGeometry(QWindow *window)
+{
+    Q_ASSERT(window);
+    if (!window) {
+        return;
+    }
+    QByteArray data = {};
+    QDataStream stream(&data, QDataStream::WriteOnly);
+    stream.setVersion(QDataStream::Qt_5_6);
+    stream << window->geometry();
+    m_settings->setValue(kIniKeyPath, data);
+}
+
+bool Settings::restoreGeometry(QWindow *window)
+{
+    Q_ASSERT(window);
+    if (!window) {
+        return false;
+    }
+    const QByteArray data = m_settings->value(kIniKeyPath).toByteArray();
+    if (data.isEmpty()) {
+        return false;
+    }
+    QRect geometry = {};
+    QDataStream stream(data);
+    stream.setVersion(QDataStream::Qt_5_6);
+    stream >> geometry;
+    if (!geometry.isValid()) {
+        return false;
+    }
+    window->setGeometry(geometry);
+    return true;
+}

examples/quick/settings.h

@@ -0,0 +1,50 @@
+/*
+ * MIT License
+ *
+ * Copyright (C) 2022 by wangwenx190 (Yuhang Zhao)
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#pragma once
+
+#include <QtCore/qobject.h>
+#include <framelesshelpercore_global.h>
+
+QT_BEGIN_NAMESPACE
+class QWindow;
+class QSettings;
+QT_END_NAMESPACE
+
+class Settings : public QObject
+{
+    Q_OBJECT
+    Q_DISABLE_COPY_MOVE(Settings)
+
+public:
+    explicit Settings(QObject *parent = nullptr);
+    ~Settings() override;
+
+public Q_SLOTS:
+    void saveGeometry(QWindow *window);
+    Q_NODISCARD bool restoreGeometry(QWindow *window);
+
+private:
+    QScopedPointer<QSettings> m_settings;
+};

examples/widget/main.cpp

@@ -23,13 +23,10 @@
  */
 
 #include <QtWidgets/qapplication.h>
-#include <framelessconfig_p.h>
 #include "widget.h"
 
 FRAMELESSHELPER_USE_NAMESPACE
 
-using namespace Global;
-
 int main(int argc, char *argv[])
 {
     // Not necessary, but better call this function, before the construction
@@ -38,8 +35,6 @@ int main(int argc, char *argv[])
 
     QApplication application(argc, argv);
 
-    FramelessConfig::instance()->set(Option::CenterWindowBeforeShow);
-
     Widget widget;
     widget.show();
 

examples/widget/widget.cpp

@@ -24,6 +24,10 @@
 
 #include "widget.h"
 #include <QtCore/qdatetime.h>
+#include <QtCore/qsettings.h>
+#include <QtCore/qcoreapplication.h>
+#include <QtCore/qfileinfo.h>
+#include <QtCore/qdir.h>
 #include <QtWidgets/qlabel.h>
 #include <QtWidgets/qboxlayout.h>
 #include <FramelessManager>
@@ -36,6 +40,17 @@ FRAMELESSHELPER_USE_NAMESPACE
 
 using namespace Global;
 
+FRAMELESSHELPER_STRING_CONSTANT2(IniKeyPath, "Window/Geometry")
+
+[[nodiscard]] static inline QSettings *appConfigFile()
+{
+    const QFileInfo fileInfo(QCoreApplication::applicationFilePath());
+    const QString iniFileName = fileInfo.completeBaseName() + FRAMELESSHELPER_STRING_LITERAL(".ini");
+    const QString iniFilePath = fileInfo.canonicalPath() + QDir::separator() + iniFileName;
+    const auto settings = new QSettings(iniFilePath, QSettings::IniFormat);
+    return settings;
+}
+
 Widget::Widget(QWidget *parent) : FramelessWidget(parent)
 {
     initialize();
@@ -53,6 +68,13 @@ void Widget::timerEvent(QTimerEvent *event)
     }
 }
 
+void Widget::closeEvent(QCloseEvent *event)
+{
+    const QScopedPointer<QSettings> settings(appConfigFile());
+    settings->setValue(kIniKeyPath, saveGeometry());
+    FramelessWidget::closeEvent(event);
+}
+
 void Widget::initialize()
 {
     setWindowTitle(tr("FramelessHelper demo application - Qt Widgets"));
@@ -83,6 +105,15 @@ void Widget::initialize()
     helper->setSystemButton(m_titleBar->minimizeButton(), SystemButtonType::Minimize);
     helper->setSystemButton(m_titleBar->maximizeButton(), SystemButtonType::Maximize);
     helper->setSystemButton(m_titleBar->closeButton(), SystemButtonType::Close);
+    connect(helper, &FramelessWidgetsHelper::ready, this, [this, helper](){
+        const QScopedPointer<QSettings> settings(appConfigFile());
+        const QByteArray data = settings->value(kIniKeyPath).toByteArray();
+        if (data.isEmpty()) {
+            helper->moveWindowToDesktopCenter();
+        } else {
+            restoreGeometry(data);
+        }
+    });
 }
 
 void Widget::updateStyleSheet()

examples/widget/widget.h

@@ -45,6 +45,7 @@ public:
 
 protected:
     void timerEvent(QTimerEvent *event) override;
+    void closeEvent(QCloseEvent *event) override;
 
 private:
     void initialize();

include/FramelessHelper/Quick/framelessquickhelper.h

@@ -71,6 +71,7 @@ protected:
 
 Q_SIGNALS:
     void titleBarItemChanged();
+    void ready();
 
 private:
     QScopedPointer<FramelessQuickHelperPrivate> d_ptr;

include/FramelessHelper/Quick/private/framelessquickhelper_p.h

@@ -65,6 +65,8 @@ public:
     Q_NODISCARD bool isWindowFixedSize() const;
     void setWindowFixedSize(const bool value);
 
+    void emitSignalForAllInstances(const char *signal);
+
 private:
     Q_NODISCARD QRect mapItemGeometryToScene(const QQuickItem * const item) const;
     Q_NODISCARD bool isInSystemButtons(const QPoint &pos, QuickGlobal::SystemButtonType *button) const;

include/FramelessHelper/Widgets/framelesswidgetshelper.h

@@ -64,6 +64,7 @@ public Q_SLOTS:
 
 Q_SIGNALS:
     void titleBarWidgetChanged();
+    void ready();
 
 private:
     QScopedPointer<FramelessWidgetsHelperPrivate> d_ptr;

include/FramelessHelper/Widgets/private/framelesswidgetshelper_p.h

@@ -61,6 +61,8 @@ public:
     Q_NODISCARD bool isWindowFixedSize() const;
     void setWindowFixedSize(const bool value);
 
+    void emitSignalForAllInstances(const char *signal);
+
 private:
     Q_NODISCARD QRect mapWidgetGeometryToScene(const QWidget * const widget) const;
     Q_NODISCARD bool isInSystemButtons(const QPoint &pos, Global::SystemButtonType *button) const;

src/core/framelesshelper_win.cpp

@@ -163,7 +163,7 @@ FRAMELESSHELPER_STRING_CONSTANT(FindWindowW)
     switch (uMsg) {
     case WM_NCHITTEST: {
         // Try to determine what part of the window is being hovered here. This
-        // is absolutely critical to making sure the snap layout works!
+        // is absolutely critical to making sure the snap layouts works!
         const POINT nativeGlobalPos = {GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)};
         POINT nativeLocalPos = nativeGlobalPos;
         if (ScreenToClient(hWnd, &nativeLocalPos) == FALSE) {
@@ -371,7 +371,7 @@ FRAMELESSHELPER_STRING_CONSTANT(FindWindowW)
     const auto dragBarWindowHandle = reinterpret_cast<HWND>(dragBarWindowId);
     const UINT flags = (SWP_NOACTIVATE | (hide ? SWP_HIDEWINDOW : SWP_SHOWWINDOW));
     // As you can see from the code, we only use the drag bar window to activate the
-    // snap layout feature introduced in Windows 11. So you may wonder, why not just
+    // snap layouts feature introduced in Windows 11. So you may wonder, why not just
     // limit it to the rectangle of the three system buttons, instead of covering the
     // whole title bar area? Well, I've tried that solution already and unfortunately
     // it doesn't work. Since our current solution works well, I have no plan to dig
@@ -536,7 +536,6 @@ bool FramelessHelperWin::nativeEventFilter(const QByteArray &eventType, void *me
     const LPARAM lParam = msg->lParam;
     switch (uMsg) {
     case WM_NCCALCSIZE: {
-        const bool isFixedSize = data.params.isWindowFixedSize();
         // Windows是根据这个消息的返回值来设置窗口的客户区（窗口中真正显示的内容）
         // 和非客户区（标题栏、窗口边框、菜单栏和状态栏等Windows系统自行提供的部分
         // ，不过对于Qt来说，除了标题栏和窗口边框，非客户区基本也都是自绘的）的范
@@ -870,8 +869,7 @@ bool FramelessHelperWin::nativeEventFilter(const QByteArray &eventType, void *me
                 (GetAsyncKeyState(VK_RBUTTON) < 0) : (GetAsyncKeyState(VK_LBUTTON) < 0));
         const bool isTitleBar = (data.params.isInsideTitleBarDraggableArea(qtScenePos) && leftButtonPressed);
         const bool isFixedSize = data.params.isWindowFixedSize();
-        if( frameBorderVisible )
+        if (frameBorderVisible) {
-        {
             // This will handle the left, right and bottom parts of the frame
             // because we didn't change them.
             const LRESULT originalRet = DefWindowProcW(hWnd, WM_NCHITTEST, 0, lParam);
@@ -1066,8 +1064,7 @@ bool FramelessHelperWin::nativeEventFilter(const QByteArray &eventType, void *me
         case WM_DISPLAYCHANGE: // Sent to a window when the display resolution has changed.
         {
             const bool isFixedSize = data.params.isWindowFixedSize();
-            if( !resizeDragBarWindow(windowId, data.dragBarWindowId, isFixedSize) )
+            if (!resizeDragBarWindow(windowId, data.dragBarWindowId, isFixedSize)) {
-            {
                 qWarning() << "Failed to re-position the drag bar window.";
             }
         } break;

src/quick/framelessquickhelper.cpp

@@ -148,8 +148,7 @@ void FramelessQuickHelperPrivate::setTitleBarItem(QQuickItem *value)
         return;
     }
     data->titleBarItem = value;
-    Q_Q(FramelessQuickHelper);
+    emitSignalForAllInstances("titleBarItemChanged");
-    Q_EMIT q->titleBarItemChanged();
 }
 
 void FramelessQuickHelperPrivate::attachToWindow()
@@ -218,11 +217,11 @@ void FramelessQuickHelperPrivate::attachToWindow()
     // we reach here, and all the modifications from the Qt side will be lost
     // due to QPA will reset the position and size of the window during it's
     // initialization process.
-    QTimer::singleShot(0, this, [this, window](){
+    QTimer::singleShot(0, this, [this](){
         if (FramelessConfig::instance()->isSet(Option::CenterWindowBeforeShow)) {
             moveWindowToDesktopCenter();
         }
-        window->setVisible(true);
+        emitSignalForAllInstances("ready");
     });
 }
 
@@ -391,6 +390,27 @@ void FramelessQuickHelperPrivate::setWindowFixedSize(const bool value)
 #endif
 }
 
+void FramelessQuickHelperPrivate::emitSignalForAllInstances(const char *signal)
+{
+    Q_ASSERT(signal);
+    if (!signal) {
+        return;
+    }
+    Q_Q(FramelessQuickHelper);
+    const QQuickWindow * const window = q->window();
+    if (!window) {
+        return;
+    }
+    const auto rootObject = (window->contentItem() ? qobject_cast<const QObject *>(window->contentItem()) : qobject_cast<const QObject *>(window));
+    const auto instances = rootObject->findChildren<FramelessQuickHelper *>();
+    if (instances.isEmpty()) {
+        return;
+    }
+    for (auto &&instance : qAsConst(instances)) {
+        QMetaObject::invokeMethod(instance, signal);
+    }
+}
+
 QRect FramelessQuickHelperPrivate::mapItemGeometryToScene(const QQuickItem * const item) const
 {
     Q_ASSERT(item);
@@ -616,7 +636,7 @@ FramelessQuickHelper *FramelessQuickHelper::get(QObject *object)
     QObject *parent = nullptr;
     if (isItem(object)) {
         const auto item = qobject_cast<QQuickItem *>(object);
-        parent = (item->window() ? item->window()->contentItem() : item);
+        parent = ((item->window() && item->window()->contentItem()) ? item->window()->contentItem() : item);
     } else {
         parent = object;
     }
@@ -625,9 +645,8 @@ FramelessQuickHelper *FramelessQuickHelper::get(QObject *object)
         instance = new FramelessQuickHelper;
         if (isItem(parent)) {
             instance->setParentItem(qobject_cast<QQuickItem *>(parent));
-        } else {
-            instance->setParent(parent);
         }
+        instance->setParent(parent);
         // No need to do this here, we'll do it once the item has been assigned to a specific window.
         //instance->d_func()->attachToWindow();
     }
@@ -734,8 +753,16 @@ void FramelessQuickHelper::itemChange(const ItemChange change, const ItemChangeD
 {
     QQuickItem::itemChange(change, value);
     if ((change == ItemSceneChange) && value.window) {
-        if (parentItem() != value.window->contentItem()) {
+        QQuickItem * const rootItem = value.window->contentItem();
-            setParentItem(value.window->contentItem());
+        if (rootItem) {
+            if ((parentItem() != rootItem) || (parent() != rootItem)) {
+                setParentItem(rootItem);
+                setParent(rootItem);
+            }
+        } else {
+            if (parent() != value.window) {
+                setParent(value.window);
+            }
         }
         Q_D(FramelessQuickHelper);
         d->attachToWindow();

src/widgets/framelesswidgetshelper.cpp

@@ -128,6 +128,25 @@ void FramelessWidgetsHelperPrivate::setWindowFixedSize(const bool value)
 #endif
 }
 
+void FramelessWidgetsHelperPrivate::emitSignalForAllInstances(const char *signal)
+{
+    Q_ASSERT(signal);
+    if (!signal) {
+        return;
+    }
+    const QWidget * const window = getWindow();
+    if (!window) {
+        return;
+    }
+    const auto instances = window->findChildren<FramelessWidgetsHelper *>();
+    if (instances.isEmpty()) {
+        return;
+    }
+    for (auto &&instance : qAsConst(instances)) {
+        QMetaObject::invokeMethod(instance, signal);
+    }
+}
+
 void FramelessWidgetsHelperPrivate::setTitleBarWidget(QWidget *widget)
 {
     Q_ASSERT(widget);
@@ -143,8 +162,7 @@ void FramelessWidgetsHelperPrivate::setTitleBarWidget(QWidget *widget)
         return;
     }
     data->titleBarWidget = widget;
-    Q_Q(FramelessWidgetsHelper);
+    emitSignalForAllInstances("titleBarWidgetChanged");
-    Q_EMIT q->titleBarWidgetChanged();
 }
 
 QWidget *FramelessWidgetsHelperPrivate::getTitleBarWidget() const
@@ -245,11 +263,11 @@ void FramelessWidgetsHelperPrivate::attachToWindow()
     // we reach here, and all the modifications from the Qt side will be lost
     // due to QPA will reset the position and size of the window during it's
     // initialization process.
-    QTimer::singleShot(0, this, [this, window](){
+    QTimer::singleShot(0, this, [this](){
         if (FramelessConfig::instance()->isSet(Option::CenterWindowBeforeShow)) {
             moveWindowToDesktopCenter();
         }
-        window->setVisible(true);
+        emitSignalForAllInstances("ready");
     });
 }