chore: baseline usable version

libs/qwindowkit/examples/mainwindow/CMakeLists.txt

@@ -0,0 +1,10 @@
+project(QWKExample_MainWindow)
+
+file(GLOB _src *.h *.cpp)
+
+qwk_add_example(${PROJECT_NAME}
+    FEATURES cxx_std_17
+    SOURCES ${_src} mainwindow.qrc ../shared/resources/shared.qrc
+    QT_LINKS Core Gui Widgets # MultimediaWidgets
+    LINKS QWKWidgets WidgetFrame
+)

libs/qwindowkit/examples/mainwindow/dark-style.qss

@@ -0,0 +1,170 @@
+/* Window bar */
+
+QWK--WindowBar[bar-active=true] {
+    /*background-color: #3C3C3C;*/
+    background-color: transparent;
+}
+
+QWK--WindowBar[bar-active=false] {
+    /*background-color: #505050;*/
+    background-color: transparent;
+}
+
+
+/* Title label */
+
+QWK--WindowBar>QLabel#win-title-label {
+    padding: 0;
+    border: none;
+    color: #ECECEC;
+    background-color: transparent;
+    min-height: 28px;
+}
+
+
+/* System buttons */
+
+QWK--WindowBar>QAbstractButton[system-button=true] {
+    qproperty-iconSize: 12px 12px;
+    min-width: 50px;
+    border: none;
+    padding: 0;
+    background-color: transparent;
+}
+
+QWK--WindowBar>QAbstractButton#pin-button {
+    qproperty-iconNormal: url(":/window-bar/pin.svg");
+    qproperty-iconChecked: url(":/window-bar/pin-fill.svg");
+    qproperty-iconSize: 15px 15px;
+}
+
+QWK--WindowBar>QAbstractButton#pin-button:hover,
+QWK--WindowBar>QAbstractButton#pin-button:pressed {
+    background-color: rgba(255, 255, 255, 15%);
+}
+
+QWK--WindowBar>QAbstractButton#min-button {
+    qproperty-iconNormal: url(":/window-bar/minimize.svg");
+}
+
+QWK--WindowBar>QAbstractButton#min-button:hover,
+QWK--WindowBar>QAbstractButton#min-button:pressed {
+    background-color: rgba(255, 255, 255, 15%);
+}
+
+QWK--WindowBar>QAbstractButton#max-button {
+    qproperty-iconNormal: url(":/window-bar/maximize.svg");
+    qproperty-iconChecked: url(":/window-bar/restore.svg");
+}
+
+QWK--WindowBar>QAbstractButton#max-button:hover,
+QWK--WindowBar>QAbstractButton#max-button:pressed {
+    background-color: rgba(255, 255, 255, 15%);
+}
+
+QWK--WindowBar>QAbstractButton#close-button {
+    qproperty-iconNormal: url(":/window-bar/close.svg");
+}
+
+QWK--WindowBar>QAbstractButton#close-button:hover,
+QWK--WindowBar>QAbstractButton#close-button:pressed {
+    background-color: #e81123;
+}
+
+
+/* Icon button */
+
+QWK--WindowBar>QAbstractButton#icon-button {
+    qproperty-iconNormal: url(":/app/example.png");
+    qproperty-iconSize: 18px 18px;
+    min-width: 40px;
+    border: none;
+    padding: 0;
+    background-color: transparent;
+}
+
+
+/* Menu Bar */
+
+QMenuBar {
+    background-color: transparent;
+    border: none;
+}
+
+QMenuBar>QToolButton#qt_menubar_ext_button {
+    qproperty-icon: url(":/window-bar/more-line.svg");
+}
+
+QMenuBar>QToolButton#qt_menubar_ext_button:hover,
+QMenuBar>QToolButton#qt_menubar_ext_button:pressed {
+    background-color: rgba(255, 255, 255, 10%);
+}
+
+QMenuBar::item {
+    color: #CCCCCC;
+    border: none;
+    padding: 8px 12px;
+}
+
+QMenuBar::item:selected {
+    background-color: rgba(255, 255, 255, 10%);
+}
+
+
+/* Menu */
+
+QMenu {
+    padding: 4px;
+    background: #303030;
+    border: 1px solid transparent;
+}
+
+QMenu::indicator {
+    left: 6px;
+    width: 20px;
+    height: 20px;
+}
+
+QMenu::icon {
+    left: 6px;
+}
+
+QMenu::item {
+    background: transparent;
+    color: #CCCCCC;
+    padding: 6px 24px;
+}
+
+QMenu::item:selected {
+    color: white;
+    background-color: #0060C0;
+}
+
+QMenu::item:disabled {
+    color: #666666;
+    background-color: transparent;
+}
+
+QMenu::separator {
+    height: 2px;
+    background-color: #5B5B5B;
+    margin: 6px 0;
+}
+
+
+/* Window */
+
+MainWindow {
+    background-color: #1E1E1E;
+}
+
+MainWindow[custom-style=true] {
+    background-color: transparent;
+}
+
+QWidget#clock-widget {
+    font-size: 75px;
+    color: #FEFEFE;
+    font-weight: bold;
+    background-color: transparent;
+}

libs/qwindowkit/examples/mainwindow/light-style.qss

@@ -0,0 +1,168 @@
+/* Window bar */
+
+QWK--WindowBar[bar-active=true] {
+    background-color: #195ABE;
+    /* background-color: transparent; */
+}
+
+QWK--WindowBar[bar-active=false] {
+    background-color: #195ABE;
+    /* background-color: transparent; */
+}
+
+
+/* Title label */
+
+QWK--WindowBar>QLabel#win-title-label {
+    padding: 0;
+    border: none;
+    color: #ECECEC;
+    background-color: transparent;
+    min-height: 28px;
+}
+
+
+/* System buttons */
+
+QWK--WindowBar>QAbstractButton[system-button=true] {
+    qproperty-iconSize: 12px 12px;
+    min-width: 50px;
+    border: none;
+    padding: 0;
+    background-color: transparent;
+}
+
+QWK--WindowBar>QAbstractButton#pin-button {
+    qproperty-iconNormal: url(":/window-bar/pin.svg");
+    qproperty-iconChecked: url(":/window-bar/pin-fill.svg");
+    qproperty-iconSize: 15px 15px;
+}
+
+QWK--WindowBar>QAbstractButton#pin-button:hover,
+QWK--WindowBar>QAbstractButton#pin-button:pressed {
+    background-color: rgba(0, 0, 0, 15%);
+}
+
+QWK--WindowBar>QAbstractButton#min-button {
+    qproperty-iconNormal: url(":/window-bar/minimize.svg");
+}
+
+QWK--WindowBar>QAbstractButton#min-button:hover,
+QWK--WindowBar>QAbstractButton#min-button:pressed {
+    background-color: rgba(0, 0, 0, 15%);
+}
+
+QWK--WindowBar>QAbstractButton#max-button {
+    qproperty-iconNormal: url(":/window-bar/maximize.svg");
+    qproperty-iconChecked: url(":/window-bar/restore.svg");
+}
+
+QWK--WindowBar>QAbstractButton#max-button:hover,
+QWK--WindowBar>QAbstractButton#max-button:pressed {
+    background-color: rgba(0, 0, 0, 15%);
+}
+
+QWK--WindowBar>QAbstractButton#close-button {
+    qproperty-iconNormal: url(":/window-bar/close.svg");
+}
+
+QWK--WindowBar>QAbstractButton#close-button:hover,
+QWK--WindowBar>QAbstractButton#close-button:pressed {
+    background-color: #e81123;
+}
+
+
+/* Icon button */
+
+QWK--WindowBar>QAbstractButton#icon-button {
+    qproperty-iconNormal: url(":/app/example.png");
+    qproperty-iconSize: 18px 18px;
+    min-width: 40px;
+    border: none;
+    padding: 0;
+    background-color: transparent;
+}
+
+
+/* Menu Bar */
+
+QMenuBar {
+    background-color: transparent;
+    border: none;
+}
+
+QMenuBar>QToolButton#qt_menubar_ext_button {
+    qproperty-icon: url(":/window-bar/more-line.svg");
+}
+
+QMenuBar>QToolButton#qt_menubar_ext_button:hover,
+QMenuBar>QToolButton#qt_menubar_ext_button:pressed {
+    background-color: rgba(255, 255, 255, 10%);
+}
+
+QMenuBar::item {
+    color: #EEEEEE;
+    border: none;
+    padding: 8px 12px;
+}
+
+QMenuBar::item:selected {
+    background-color: rgba(255, 255, 255, 10%);
+}
+
+
+/* Menu */
+
+QMenu {
+    padding: 4px;
+    background: white;
+    border: 1px solid #E0E0E0;
+}
+
+QMenu::indicator {
+    left: 6px;
+    width: 20px;
+    height: 20px;
+}
+
+QMenu::icon {
+    left: 6px;
+}
+
+QMenu::item {
+    background: transparent;
+    color: #333333;
+    padding: 6px 24px;
+}
+
+QMenu::item:selected {
+    background-color: rgba(0, 0, 0, 10%);
+}
+
+QMenu::item:disabled {
+    color: #CCCCCC;
+}
+
+QMenu::separator {
+    height: 2px;
+    background-color: #CCCCCC;
+    margin: 6px 0;
+}
+
+
+/* Window */
+
+MainWindow {
+    background-color: #F3F3F3;
+}
+
+MainWindow[custom-style=true] {
+    background-color: transparent;
+}
+
+QWidget#clock-widget {
+    font-size: 75px;
+    color: #333333;
+    font-weight: bold;
+    background-color: transparent;
+}

libs/qwindowkit/examples/mainwindow/main.cpp

@@ -0,0 +1,34 @@
+// Copyright (C) 2023-2024 Stdware Collections (https://www.github.com/stdware)
+// Copyright (C) 2021-2023 wangwenx190 (Yuhang Zhao)
+// SPDX-License-Identifier: Apache-2.0
+
+#include <QtWidgets/QApplication>
+
+#include "mainwindow.h"
+
+int main(int argc, char *argv[]) {
+    qputenv("QT_WIN_DEBUG_CONSOLE", "attach");
+    qputenv("QSG_INFO", "1");
+    //qputenv("QT_WIDGETS_HIGHDPI_DOWNSCALE", "1");
+    //qputenv("QT_WIDGETS_RHI", "1");
+    //qputenv("QSG_RHI_BACKEND", "d3d12");
+    //qputenv("QSG_RHI_HDR", "scrgb");
+    //qputenv("QT_QPA_DISABLE_REDIRECTION_SURFACE", "1");
+
+#if QT_VERSION >= QT_VERSION_CHECK(5, 14, 0)
+    QGuiApplication::setHighDpiScaleFactorRoundingPolicy(
+        Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
+#endif
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
+    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+#endif
+
+    QCoreApplication::setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
+    QApplication a(argc, argv);
+
+    MainWindow w;
+    w.show();
+
+    return a.exec();
+}

libs/qwindowkit/examples/mainwindow/mainwindow.cpp

@@ -0,0 +1,385 @@
+// Copyright (C) 2023-2024 Stdware Collections (https://www.github.com/stdware)
+// Copyright (C) 2021-2023 wangwenx190 (Yuhang Zhao)
+// SPDX-License-Identifier: Apache-2.0
+
+#include "mainwindow.h"
+
+#include <QtCore/QDebug>
+#include <QtCore/QFile>
+#include <QtCore/QTime>
+#include <QtCore/QTimer>
+#include <QtGui/QPainter>
+#include <QtGui/QWindow>
+#include <QtWidgets/QApplication>
+#include <QtWidgets/QStyle>
+#include <QtWidgets/QPushButton>
+#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
+#  include <QtGui/QActionGroup>
+#else
+#  include <QtWidgets/QActionGroup>
+#endif
+
+// #include <QtWebEngineWidgets/QWebEngineView>
+
+#include <QWKWidgets/widgetwindowagent.h>
+
+#include <widgetframe/windowbar.h>
+#include <widgetframe/windowbutton.h>
+
+class ClockWidget : public QLabel {
+public:
+    explicit ClockWidget(QWidget *parent = nullptr) : QLabel(parent) {
+        startTimer(100);
+        setAlignment(Qt::AlignCenter);
+    }
+
+    ~ClockWidget() override = default;
+
+protected:
+    void timerEvent(QTimerEvent *event) override {
+        QLabel::timerEvent(event);
+        setText(QTime::currentTime().toString(QStringLiteral("hh:mm:ss")));
+    }
+};
+
+MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent) {
+    setAttribute(Qt::WA_DontCreateNativeAncestors);
+
+    installWindowAgent();
+
+#if 1
+    auto clockWidget = new ClockWidget();
+    clockWidget->setObjectName(QStringLiteral("clock-widget"));
+    clockWidget->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
+    setCentralWidget(clockWidget);
+#else
+    auto webView = new QWebEngineView();
+    webView->load(QUrl("https://www.baidu.com"));
+    setCentralWidget(webView);
+#endif
+
+    loadStyleSheet(Dark);
+
+    setWindowTitle(tr("Example MainWindow"));
+    resize(800, 600);
+
+    // setFixedHeight(600);
+    // windowAgent->centralize();
+}
+
+static inline void emulateLeaveEvent(QWidget *widget) {
+    Q_ASSERT(widget);
+    if (!widget) {
+        return;
+    }
+    QTimer::singleShot(0, widget, [widget]() {
+#if (QT_VERSION >= QT_VERSION_CHECK(5, 14, 0))
+        const QScreen *screen = widget->screen();
+#else
+        const QScreen *screen = widget->windowHandle()->screen();
+#endif
+        const QPoint globalPos = QCursor::pos(screen);
+        if (!QRect(widget->mapToGlobal(QPoint{0, 0}), widget->size()).contains(globalPos)) {
+            QCoreApplication::postEvent(widget, new QEvent(QEvent::Leave));
+            if (widget->testAttribute(Qt::WA_Hover)) {
+                const QPoint localPos = widget->mapFromGlobal(globalPos);
+                const QPoint scenePos = widget->window()->mapFromGlobal(globalPos);
+                static constexpr const auto oldPos = QPoint{};
+                const Qt::KeyboardModifiers modifiers = QGuiApplication::keyboardModifiers();
+#if (QT_VERSION >= QT_VERSION_CHECK(6, 4, 0))
+                const auto event =
+                    new QHoverEvent(QEvent::HoverLeave, scenePos, globalPos, oldPos, modifiers);
+                Q_UNUSED(localPos);
+#elif (QT_VERSION >= QT_VERSION_CHECK(6, 3, 0))
+                const auto event =  new QHoverEvent(QEvent::HoverLeave, localPos, globalPos, oldPos, modifiers);
+                Q_UNUSED(scenePos);
+#else
+                const auto event =  new QHoverEvent(QEvent::HoverLeave, localPos, oldPos, modifiers);
+                Q_UNUSED(scenePos);
+#endif
+                QCoreApplication::postEvent(widget, event);
+            }
+        }
+    });
+}
+
+MainWindow::~MainWindow() = default;
+
+bool MainWindow::event(QEvent *event) {
+    switch (event->type()) {
+        case QEvent::WindowActivate: {
+            auto menu = menuWidget();
+            if (menu) {
+                menu->setProperty("bar-active", true);
+                style()->polish(menu);
+            }
+            break;
+        }
+
+        case QEvent::WindowDeactivate: {
+            auto menu = menuWidget();
+            if (menu) {
+                menu->setProperty("bar-active", false);
+                style()->polish(menu);
+            }
+            break;
+        }
+
+        default:
+            break;
+    }
+    return QMainWindow::event(event);
+}
+
+void MainWindow::installWindowAgent() {
+    // 1. Setup window agent
+    windowAgent = new QWK::WidgetWindowAgent(this);
+    windowAgent->setup(this);
+
+    // 2. Construct your title bar
+    auto menuBar = [this]() {
+        auto menuBar = new QMenuBar(this);
+
+        // Virtual menu
+        auto file = new QMenu(tr("File(&F)"), menuBar);
+        file->addAction(new QAction(tr("New(&N)"), menuBar));
+        file->addAction(new QAction(tr("Open(&O)"), menuBar));
+        file->addSeparator();
+
+        auto edit = new QMenu(tr("Edit(&E)"), menuBar);
+        edit->addAction(new QAction(tr("Undo(&U)"), menuBar));
+        edit->addAction(new QAction(tr("Redo(&R)"), menuBar));
+
+        // Theme action
+        auto darkAction = new QAction(tr("Enable dark theme"), menuBar);
+        darkAction->setCheckable(true);
+        connect(darkAction, &QAction::triggered, this, [this](bool checked) {
+            loadStyleSheet(checked ? Dark : Light); //
+        });
+        connect(this, &MainWindow::themeChanged, darkAction, [this, darkAction]() {
+            darkAction->setChecked(currentTheme == Dark); //
+        });
+
+#ifdef Q_OS_WIN
+        auto noneAction = new QAction(tr("None"), menuBar);
+        noneAction->setData(QStringLiteral("none"));
+        noneAction->setCheckable(true);
+        noneAction->setChecked(true);
+
+        auto dwmBlurAction = new QAction(tr("Enable DWM blur"), menuBar);
+        dwmBlurAction->setData(QStringLiteral("dwm-blur"));
+        dwmBlurAction->setCheckable(true);
+
+        auto acrylicAction = new QAction(tr("Enable acrylic material"), menuBar);
+        acrylicAction->setData(QStringLiteral("acrylic-material"));
+        acrylicAction->setCheckable(true);
+
+        auto micaAction = new QAction(tr("Enable mica"), menuBar);
+        micaAction->setData(QStringLiteral("mica"));
+        micaAction->setCheckable(true);
+
+        auto micaAltAction = new QAction(tr("Enable mica alt"), menuBar);
+        micaAltAction->setData(QStringLiteral("mica-alt"));
+        micaAltAction->setCheckable(true);
+
+        auto winStyleGroup = new QActionGroup(menuBar);
+        winStyleGroup->addAction(noneAction);
+        winStyleGroup->addAction(dwmBlurAction);
+        winStyleGroup->addAction(acrylicAction);
+        winStyleGroup->addAction(micaAction);
+        winStyleGroup->addAction(micaAltAction);
+        connect(winStyleGroup, &QActionGroup::triggered, this,
+                [this, winStyleGroup](QAction *action) {
+                    // Unset all custom style attributes first, otherwise the style will not display
+                    // correctly
+                    for (const QAction *_act : winStyleGroup->actions()) {
+                        const QString data = _act->data().toString();
+                        if (data.isEmpty() || data == QStringLiteral("none")) {
+                            continue;
+                        }
+                        windowAgent->setWindowAttribute(data, false);
+                    }
+                    const QString data = action->data().toString();
+                    if (data == QStringLiteral("none")) {
+                        setProperty("custom-style", false);
+                    } else if (!data.isEmpty()) {
+                        windowAgent->setWindowAttribute(data, true);
+                        setProperty("custom-style", true);
+                    }
+                    style()->polish(this);
+                });
+
+#elif defined(Q_OS_MAC)
+        // Set whether to use system buttons (close/minimize/zoom)
+        // - true:  Hide system buttons (use custom UI controls)
+        // - false: Show native system buttons (default behavior)
+        windowAgent->setWindowAttribute(QStringLiteral("no-system-buttons"), false);
+
+        auto darkBlurAction = new QAction(tr("Dark blur"), menuBar);
+        darkBlurAction->setCheckable(true);
+        connect(darkBlurAction, &QAction::toggled, this, [this](bool checked) {
+            if (!windowAgent->setWindowAttribute(QStringLiteral("blur-effect"), "dark")) {
+                return;
+            }
+            if (checked) {
+                setProperty("custom-style", true);
+                style()->polish(this);
+            }
+        });
+
+        auto lightBlurAction = new QAction(tr("Light blur"), menuBar);
+        lightBlurAction->setCheckable(true);
+        connect(lightBlurAction, &QAction::toggled, this, [this](bool checked) {
+            if (!windowAgent->setWindowAttribute(QStringLiteral("blur-effect"), "light")) {
+                return;
+            }
+            if (checked) {
+                setProperty("custom-style", true);
+                style()->polish(this);
+            }
+        });
+
+        auto noBlurAction = new QAction(tr("No blur"), menuBar);
+        noBlurAction->setCheckable(true);
+        connect(noBlurAction, &QAction::toggled, this, [this](bool checked) {
+            if (!windowAgent->setWindowAttribute(QStringLiteral("blur-effect"), "none")) {
+                return;
+            }
+            if (checked) {
+                setProperty("custom-style", false);
+                style()->polish(this);
+            }
+        });
+
+        auto macStyleGroup = new QActionGroup(menuBar);
+        macStyleGroup->addAction(darkBlurAction);
+        macStyleGroup->addAction(lightBlurAction);
+        macStyleGroup->addAction(noBlurAction);
+#endif
+
+        // Real menu
+        auto settings = new QMenu(tr("Settings(&S)"), menuBar);
+        settings->addAction(darkAction);
+
+#ifdef Q_OS_WIN
+        settings->addSeparator();
+        settings->addAction(noneAction);
+        settings->addAction(dwmBlurAction);
+        settings->addAction(acrylicAction);
+        settings->addAction(micaAction);
+        settings->addAction(micaAltAction);
+#elif defined(Q_OS_MAC)
+        settings->addAction(darkBlurAction);
+        settings->addAction(lightBlurAction);
+        settings->addAction(noBlurAction);
+#endif
+
+        menuBar->addMenu(file);
+        menuBar->addMenu(edit);
+        menuBar->addMenu(settings);
+        return menuBar;
+    }();
+    menuBar->setObjectName(QStringLiteral("win-menu-bar"));
+
+    auto titleLabel = new QLabel();
+    titleLabel->setAlignment(Qt::AlignCenter);
+    titleLabel->setObjectName(QStringLiteral("win-title-label"));
+
+#ifndef Q_OS_MAC
+    auto iconButton = new QWK::WindowButton();
+    iconButton->setObjectName(QStringLiteral("icon-button"));
+    iconButton->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
+
+    auto pinButton = new QWK::WindowButton();
+    pinButton->setCheckable(true);
+    pinButton->setObjectName(QStringLiteral("pin-button"));
+    pinButton->setProperty("system-button", true);
+    pinButton->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
+
+    auto minButton = new QWK::WindowButton();
+    minButton->setObjectName(QStringLiteral("min-button"));
+    minButton->setProperty("system-button", true);
+    minButton->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
+
+    auto maxButton = new QWK::WindowButton();
+    maxButton->setCheckable(true);
+    maxButton->setObjectName(QStringLiteral("max-button"));
+    maxButton->setProperty("system-button", true);
+    maxButton->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
+
+    auto closeButton = new QWK::WindowButton();
+    closeButton->setObjectName(QStringLiteral("close-button"));
+    closeButton->setProperty("system-button", true);
+    closeButton->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
+#endif
+
+    auto windowBar = new QWK::WindowBar();
+#ifndef Q_OS_MAC
+    windowBar->setIconButton(iconButton);
+    windowBar->setPinButton(pinButton);
+    windowBar->setMinButton(minButton);
+    windowBar->setMaxButton(maxButton);
+    windowBar->setCloseButton(closeButton);
+#endif
+    windowBar->setMenuBar(menuBar);
+    windowBar->setTitleLabel(titleLabel);
+    windowBar->setHostWidget(this);
+
+    windowAgent->setTitleBar(windowBar);
+#ifndef Q_OS_MAC
+    windowAgent->setHitTestVisible(pinButton, true);
+    windowAgent->setSystemButton(QWK::WindowAgentBase::WindowIcon, iconButton);
+    windowAgent->setSystemButton(QWK::WindowAgentBase::Minimize, minButton);
+    windowAgent->setSystemButton(QWK::WindowAgentBase::Maximize, maxButton);
+    windowAgent->setSystemButton(QWK::WindowAgentBase::Close, closeButton);
+#endif
+    windowAgent->setHitTestVisible(menuBar, true);
+
+#if defined(Q_OS_MAC) && 0
+    windowAgent->setSystemButtonAreaCallback([](const QSize &size) {
+        static constexpr const int width = 75;
+        return QRect(QPoint(size.width() - width, 0), QSize(width, size.height())); //
+    });
+#endif
+
+    setMenuWidget(windowBar);
+
+
+#ifndef Q_OS_MAC
+    connect(windowBar, &QWK::WindowBar::pinRequested, this, [this, pinButton](bool pin) {
+        if (isHidden() || isMinimized() || isMaximized() || isFullScreen()) {
+            return;
+        }
+        setWindowFlag(Qt::WindowStaysOnTopHint, pin);
+        show();
+        pinButton->setChecked(pin);
+    });
+    connect(windowBar, &QWK::WindowBar::minimizeRequested, this, &QWidget::showMinimized);
+    connect(windowBar, &QWK::WindowBar::maximizeRequested, this, [this, maxButton](bool max) {
+        if (max) {
+            showMaximized();
+        } else {
+            showNormal();
+        }
+
+        // It's a Qt issue that if a QAbstractButton::clicked triggers a window's maximization,
+        // the button remains to be hovered until the mouse move. As a result, we need to
+        // manually send leave events to the button.
+        emulateLeaveEvent(maxButton);
+    });
+    connect(windowBar, &QWK::WindowBar::closeRequested, this, &QWidget::close);
+#endif
+}
+
+void MainWindow::loadStyleSheet(Theme theme) {
+    if (!styleSheet().isEmpty() && theme == currentTheme)
+        return;
+    currentTheme = theme;
+
+    if (QFile qss(theme == Dark ? QStringLiteral(":/dark-style.qss")
+                                : QStringLiteral(":/light-style.qss"));
+        qss.open(QIODevice::ReadOnly | QIODevice::Text)) {
+        setStyleSheet(QString::fromUtf8(qss.readAll()));
+        Q_EMIT themeChanged();
+    }
+}

libs/qwindowkit/examples/mainwindow/mainwindow.h

@@ -0,0 +1,42 @@
+// Copyright (C) 2023-2024 Stdware Collections (https://www.github.com/stdware)
+// Copyright (C) 2021-2023 wangwenx190 (Yuhang Zhao)
+// SPDX-License-Identifier: Apache-2.0
+
+#ifndef MAINWINDOW_H
+#define MAINWINDOW_H
+
+#include <QtWidgets/QMainWindow>
+
+namespace QWK {
+    class WidgetWindowAgent;
+    class StyleAgent;
+}
+
+class MainWindow : public QMainWindow {
+    Q_OBJECT
+public:
+    explicit MainWindow(QWidget *parent = nullptr);
+    ~MainWindow() override;
+
+    enum Theme {
+        Dark,
+        Light,
+    };
+    Q_ENUM(Theme)
+
+Q_SIGNALS:
+    void themeChanged();
+
+protected:
+    bool event(QEvent *event) override;
+
+private:
+    void installWindowAgent();
+    void loadStyleSheet(Theme theme);
+
+    Theme currentTheme{};
+
+    QWK::WidgetWindowAgent *windowAgent;
+};
+
+#endif // MAINWINDOW_H

libs/qwindowkit/examples/mainwindow/mainwindow.qrc

@@ -0,0 +1,6 @@
+<RCC>
+    <qresource prefix="/">
+        <file>dark-style.qss</file>
+        <file>light-style.qss</file>
+    </qresource>
+</RCC>