integrate Windows implementation into 2.0 Core API

examples/minimal/flwindow.cpp

@@ -10,10 +10,10 @@ FRAMELESSHELPER_USE_NAMESPACE
 
 FLWindow::FLWindow(QWidget *parent) : QWidget(parent)
 {
-	setWindowFlags(Qt::FramelessWindowHint);
+    setWindowFlags(Qt::FramelessWindowHint);
-	setupUi();
+    setupUi();
 
-	move(screen()->geometry().center() - frameGeometry().center());
+    move(screen()->geometry().center() - frameGeometry().center());
 }
 
 FLWindow::~FLWindow()
@@ -23,14 +23,14 @@ FLWindow::~FLWindow()
 
 void FLWindow::initFramelessWindow()
 {
-	FramelessHelper* helper = new FramelessHelper(windowHandle());
+    m_flsHelper = new FramelessHelper(windowHandle());
-	helper->setResizeBorderThickness(4);
+    m_flsHelper->setResizeBorderThickness(4);
-	helper->setTitleBarHeight(m_titleBarWidget->height());
+    m_flsHelper->setTitleBarHeight(m_titleBarWidget->height());
-	helper->setResizable(true);
+    m_flsHelper->setResizable(true);
-	helper->setHitTestVisible(m_minimizeButton);
+    m_flsHelper->setHitTestVisible(m_minimizeButton);
-	helper->setHitTestVisible(m_maximizeButton);
+    m_flsHelper->setHitTestVisible(m_maximizeButton);
-	helper->setHitTestVisible(m_closeButton);
+    m_flsHelper->setHitTestVisible(m_closeButton);
-	helper->install();
+    m_flsHelper->install();
 
 #ifdef Q_OS_MAC
     m_minimizeButton->hide();
@@ -47,26 +47,39 @@ void FLWindow::showEvent(QShowEvent *event)
     static bool inited = false;
     if (!inited) {
         inited = true;
-		initFramelessWindow();
+        initFramelessWindow();
     }
 }
 
+#ifdef Q_OS_WIN
+bool FLWindow::nativeEvent(const QByteArray &eventType, void *message, long *result)
+{
+    if (!m_flsHelper)
+        return QWidget::nativeEvent(eventType, message, result);
+
+    if (m_flsHelper->handleNativeEvent(this->windowHandle(), eventType, message, result))
+        return true;
+    else
+        return QWidget::nativeEvent(eventType, message, result);
+}
+#endif // Q_OS_WIN
+
 void FLWindow::setupUi()
 {
-	resize(800, 600);
+    resize(800, 600);
 
-	m_titleBarWidget = new QWidget(this);
+    m_titleBarWidget = new QWidget(this);
-	m_titleBarWidget->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
+    m_titleBarWidget->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);
-	m_titleBarWidget->setFixedHeight(40);
+    m_titleBarWidget->setFixedHeight(40);
-	m_titleBarWidget->setStyleSheet(QString::fromLatin1("background:grey"));
+    m_titleBarWidget->setStyleSheet(QString::fromLatin1("background:grey"));
 
     m_minimizeButton = new QPushButton(m_titleBarWidget);
-	m_minimizeButton->setText(QStringLiteral("Min"));
+    m_minimizeButton->setText(QStringLiteral("Min"));
     m_minimizeButton->setObjectName(QStringLiteral("MinimizeButton"));
     connect(m_minimizeButton, &QPushButton::clicked, this, &QWidget::showMinimized);
 
     m_maximizeButton = new QPushButton(m_titleBarWidget);
-	m_maximizeButton->setText(QStringLiteral("Max"));
+    m_maximizeButton->setText(QStringLiteral("Max"));
     m_maximizeButton->setObjectName(QStringLiteral("MaximizeButton"));
     connect(m_maximizeButton, &QPushButton::clicked, this, [this](){
         if (isMaximized() || isFullScreen()) {
@@ -77,7 +90,7 @@ void FLWindow::setupUi()
     });
 
     m_closeButton = new QPushButton(m_titleBarWidget);
-	m_closeButton->setText(QStringLiteral("Close"));
+    m_closeButton->setText(QStringLiteral("Close"));
     m_closeButton->setObjectName(QStringLiteral("CloseButton"));
     connect(m_closeButton, &QPushButton::clicked, this, &QWidget::close);
 
@@ -88,7 +101,7 @@ void FLWindow::setupUi()
     titleBarLayout->addWidget(m_minimizeButton);
     titleBarLayout->addWidget(m_maximizeButton);
     titleBarLayout->addWidget(m_closeButton);
-	titleBarLayout->addStretch();
+    titleBarLayout->addStretch();
     m_titleBarWidget->setLayout(titleBarLayout);
 
     const auto mainLayout = new QVBoxLayout(this);

examples/minimal/flwindow.h

@@ -1,6 +1,7 @@
 #pragma once
 
 #include <QWidget>
+#include "framelesshelper.h"
 
 class QPushButton;
 
@@ -13,12 +14,16 @@ public:
 
 protected:
 	void showEvent(QShowEvent *event) override;
+#ifdef Q_OS_WIN
+	bool nativeEvent(const QByteArray &eventType, void *message, long *result) override;
+#endif // Q_OS_WIN
 
 private:
 	void initFramelessWindow();
 	void setupUi();
 
 private:
+	__flh_ns::FramelessHelper *m_flsHelper = nullptr;
 	QWidget *m_titleBarWidget = nullptr;
     QPushButton *m_minimizeButton = nullptr;
     QPushButton *m_maximizeButton = nullptr;

framelesshelper.cpp

@@ -28,8 +28,18 @@
 #include <QtGui/qevent.h>
 #include <QtGui/qwindow.h>
 #include <QtGui/qscreen.h>
+#include <QtGui/qguiapplication.h>
+#if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
+#include <QtGui/qpa/qplatformnativeinterface.h>
+#else
+#include <QtGui/qpa/qplatformwindow_p.h>
+#endif
+
 #include "framelesswindowsmanager.h"
 #include "utilities.h"
+#ifdef Q_OS_WIN
+#include "framelesshelper_windows.h"
+#endif
 
 FRAMELESSHELPER_BEGIN_NAMESPACE
 
@@ -52,24 +62,44 @@ FramelessHelper::FramelessHelper(QWindow *window)
  */
 void FramelessHelper::install()
 {
+    if (!QCoreApplication::testAttribute(Qt::AA_DontCreateNativeWidgetSiblings)) {
+        QCoreApplication::setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
+    }
+
     QRect origRect = m_window->geometry();
     m_origWindowFlags = m_window->flags();
 
 #ifdef Q_OS_MAC
     m_window->setFlags(Qt::Window);
-#else
+#endif // Q_OS_MAC
+
+#ifdef Q_OS_LINUX
     m_window->setFlags(m_origWindowFlags | Qt::FramelessWindowHint);
-#endif
+#endif // Q_OS_LINUX
+
+#ifdef Q_OS_WIN
+    // On Windows, Qt::FramelessWindowHint cant not be set.
+    m_window->setFlags(m_origWindowFlags & ~Qt::FramelessWindowHint);
+#endif // Q_OS_WIN
 
     m_window->setGeometry(origRect);
     resizeWindow(origRect.size());
 
+#ifndef Q_OS_WIN
     m_window->installEventFilter(this);
+#endif
 
 #ifdef Q_OS_MAC
     Utilities::setMacWindowHook(m_window);
     Utilities::setMacWindowFrameless(m_window);
 #endif
+
+#ifdef Q_OS_WIN
+    updateQtFrameMargins(true);
+    const WId winId = m_window->winId();
+    Utilities::updateFrameMargins(winId, !true);
+    Utilities::triggerFrameChange(winId);
+#endif // Q_OS_WIN
 }
 
 /*!
@@ -81,11 +111,20 @@ void FramelessHelper::uninstall()
     m_origWindowFlags = Qt::WindowFlags();
     resizeWindow(QSize());
 
+#ifndef Q_OS_WIN
     m_window->removeEventFilter(this);
+#endif
 
 #ifdef Q_OS_MAC
     Utilities::unsetMacWindowHook(m_window);
 #endif
+
+#ifdef Q_OS_WIN
+    updateQtFrameMargins(false);
+    const WId winId = m_window->winId();
+    Utilities::updateFrameMargins(winId, !false);
+    Utilities::triggerFrameChange(winId);
+#endif // Q_OS_WIN
 }
 
 /*!
@@ -371,14 +410,36 @@ bool FramelessHelper::isHitTestVisible(QObject *obj)
     return m_HTVObjects.contains(obj);
 }
 
+/*!
+    Get position and area of hit test visible widget relative to top-level window.
+ */
 QRect FramelessHelper::getHTVObjectRect(QObject *obj)
 {
-    const QPoint originPoint = m_window->mapFromGlobal(
+    if (!obj) {
-        Utilities::mapOriginPointToWindow(obj).toPoint());
+        return {};
+    }
+
+    if (!obj->isWidgetType() && !obj->inherits("QQuickItem")) {
+        qWarning() << obj << "is not a QWidget or a QQuickItem.";
+        return {};
+    }
+
+    // Get local position of descendant widget relative to top-level window,
+    QPointF localPos = {obj->property("x").toReal(), obj->property("y").toReal()};
+    for (QObject *p = obj->parent(); p; p = p->parent()) {
+        // If parent is nullptr, the QWidget is a window.
+        if (p->parent() == nullptr)
+            break;
+        // Top-level window of QQuickItem is a QWindow. 
+        if (p->isWindowType())
+            break;
+        localPos += {p->property("x").toReal(), p->property("y").toReal()};
+    }
+
     const int width = obj->property("width").toInt();
     const int height = obj->property("height").toInt();
 
-    return QRect(originPoint, QSize(width, height));
+    return QRect(localPos.toPoint(), QSize(width, height));
 }
 
 bool FramelessHelper::eventFilter(QObject *object, QEvent *event)
@@ -509,4 +570,609 @@ void FramelessHelper::handleResizeHandlerDblClicked()
     }
 }
 
+#ifdef Q_OS_WIN
+static inline bool shouldHaveWindowFrame()
+{
+    if (Utilities::shouldUseNativeTitleBar()) {
+        // We have to use the original window frame unconditionally if we
+        // want to use the native title bar.
+        return true;
+    }
+    const bool should = qEnvironmentVariableIsSet(Constants::kPreserveNativeFrameFlag);
+    const bool force = qEnvironmentVariableIsSet(Constants::kForcePreserveNativeFrameFlag);
+    if (should || force) {
+        if (force) {
+            return true;
+        }
+        if (should) {
+            // If you preserve the window frame on Win7~8.1,
+            // the window will have a terrible appearance.
+            return Utilities::isWin10OrGreater();
+        }
+    }
+    return false;
+}
+
+Q_DECLARE_METATYPE(QMargins)
+void FramelessHelper::updateQtFrameMargins(const bool enable)
+{
+    const bool useCustomFrameMargin = (enable && (m_window->windowState() != Qt::WindowMaximized)
+                                         && (m_window->windowState() != Qt::WindowFullScreen));
+    const int resizeBorderThickness = useCustomFrameMargin ? this->resizeBorderThickness() : 0;
+    const int titleBarHeight = enable ? this->titleBarHeight() : 0;
+    const QMargins margins = {-resizeBorderThickness, -titleBarHeight, -resizeBorderThickness, -resizeBorderThickness}; // left, top, right, bottom
+    const QVariant marginsVar = QVariant::fromValue(margins);
+    m_window->setProperty("_q_windowsCustomMargins", marginsVar);
+#if (QT_VERSION < QT_VERSION_CHECK(6, 0, 0))
+    QPlatformWindow *platformWindow = m_window->handle();
+    if (platformWindow) {
+        QGuiApplication::platformNativeInterface()->setWindowProperty(platformWindow, QStringLiteral("WindowsCustomMargins"), marginsVar);
+    } else {
+        qWarning() << "Failed to retrieve the platform window.";
+    }
+#else
+    auto *platformWindow = dynamic_cast<QNativeInterface::Private::QWindowsWindow *>(
+        m_window->handle());
+    if (platformWindow) {
+        platformWindow->setCustomMargins(margins);
+    } else {
+        qWarning() << "Failed to retrieve the platform window.";
+    }
+#endif
+}
+
+/*!
+    This function works like a eventFilter, return \c true means the event has been handled.
+ */
+#if (QT_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+bool FramelessHelper::handleNativeEvent(QWindow *window, const QByteArray &eventType, void *message, qintptr *result)
+#else
+bool FramelessHelper::handleNativeEvent(QWindow *window, const QByteArray &eventType, void *message, long *result)
+#endif
+{
+    if ((eventType != QByteArrayLiteral("windows_generic_MSG")) || !message || !result) {
+        return false;
+    }
+
+#if (QT_VERSION == QT_VERSION_CHECK(5, 11, 1))
+    // Work-around a bug caused by typo which only exists in Qt 5.11.1
+    const auto msg = *reinterpret_cast<MSG **>(message);
+#else
+    const auto msg = static_cast<LPMSG>(message);
+#endif
+
+    if (!msg->hwnd) {
+        // Why sometimes the window handle is null? Is it designed to be?
+        // Anyway, we should skip it in this case.
+        return false;
+    }
+
+    if (!window)
+        return false;
+
+    // 所有从 Qt 获得的值必须乘以放大倍速，所有传给 Qt 的值必须除以放大倍数。
+    // TODO: 全屏情况下 hitTestVisible 区域的计算有问题。很可能是全屏时，边框剪切造成的按钮位置偏移。
+    qreal scaleFactor = m_window->screen()->devicePixelRatio();
+
+    switch (msg->message) {
+    case WM_NCCALCSIZE: {
+        // 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
+        // 围的，lParam里存放的就是新客户区的几何区域，默认是整个窗口的大小，正常
+        // 的程序需要修改这个参数，告知系统窗口的客户区和非客户区的范围（一般来说可
+        // 以完全交给Windows，让其自行处理，使用默认的客户区和非客户区），因此如果
+        // 我们不修改lParam，就可以使客户区充满整个窗口，从而去掉标题栏和窗口边框
+        // （因为这些东西都被客户区给盖住了。但边框阴影也会因此而丢失，不过我们会使
+        // 用其他方式将其带回，请参考其他消息的处理，此处不过多提及）。但有个情况要
+        // 特别注意，那就是窗口最大化后，窗口的实际尺寸会比屏幕的尺寸大一点，从而使
+        // 用户看不到窗口的边界，这样用户就不能在窗口最大化后调整窗口的大小了（虽然
+        // 这个做法听起来特别奇怪，但Windows确实就是这样做的），因此如果我们要自行
+        // 处理窗口的非客户区，就要在窗口最大化后，将窗口边框的宽度和高度（一般是相
+        // 等的）从客户区裁剪掉，否则我们窗口所显示的内容就会超出屏幕边界，显示不全。
+        // 如果用户开启了任务栏自动隐藏，在窗口最大化后，还要考虑任务栏的位置。因为
+        // 如果窗口最大化后，其尺寸和屏幕尺寸相等（因为任务栏隐藏了，所以窗口最大化
+        // 后其实是充满了整个屏幕，变相的全屏了），Windows会认为窗口已经进入全屏的
+        // 状态，从而导致自动隐藏的任务栏无法弹出。要避免这个状况，就要使窗口的尺寸
+        // 小于屏幕尺寸。我下面的做法参考了火狐、Chromium和Windows Terminal
+        // 如果没有开启任务栏自动隐藏，是不存在这个问题的，所以要先进行判断。
+        // 一般情况下，*result设置为0（相当于DefWindowProc的返回值为0）就可以了，
+        // 根据MSDN的说法，返回0意为此消息已经被程序自行处理了，让Windows跳过此消
+        // 息，否则Windows会添加对此消息的默认处理，对于当前这个消息而言，就意味着
+        // 标题栏和窗口边框又会回来，这当然不是我们想要的结果。根据MSDN，当wParam
+        // 为FALSE时，只能返回0，但当其为TRUE时，可以返回0，也可以返回一个WVR_常
+        // 量。根据Chromium的注释，当存在非客户区时，如果返回WVR_REDRAW会导致子
+        // 窗口/子控件出现奇怪的bug（自绘控件错位），并且Lucas在Windows 10
+        // 上成功复现，说明这个bug至今都没有解决。我查阅了大量资料，发现唯一的解决
+        // 方案就是返回0。但如果不存在非客户区，且wParam为TRUE，最好返回
+        // WVR_REDRAW，否则窗口在调整大小可能会产生严重的闪烁现象。
+        // 虽然对大多数消息来说，返回0都代表让Windows忽略此消息，但实际上不同消息
+        // 能接受的返回值是不一样的，请注意自行查阅MSDN。
+
+        // Sent when the size and position of a window's client area must be
+        // calculated. By processing this message, an application can
+        // control the content of the window's client area when the size or
+        // position of the window changes. If wParam is TRUE, lParam points
+        // to an NCCALCSIZE_PARAMS structure that contains information an
+        // application can use to calculate the new size and position of the
+        // client rectangle. If wParam is FALSE, lParam points to a RECT
+        // structure. On entry, the structure contains the proposed window
+        // rectangle for the window. On exit, the structure should contain
+        // the screen coordinates of the corresponding window client area.
+        // The client area is the window's content area, the non-client area
+        // is the area which is provided by the system, such as the title
+        // bar, the four window borders, the frame shadow, the menu bar, the
+        // status bar, the scroll bar, etc. But for Qt, it draws most of the
+        // window area (client + non-client) itself. We now know that the
+        // title bar and the window frame is in the non-client area and we
+        // can set the scope of the client area in this message, so we can
+        // remove the title bar and the window frame by let the non-client
+        // area be covered by the client area (because we can't really get
+        // rid of the non-client area, it will always be there, all we can
+        // do is to hide it) , which means we should let the client area's
+        // size the same with the whole window's size. So there is no room
+        // for the non-client area and then the user won't be able to see it
+        // again. But how to achieve this? Very easy, just leave lParam (the
+        // re-calculated client area) untouched. But of course you can
+        // modify lParam, then the non-client area will be seen and the
+        // window borders and the window frame will show up. However, things
+        // are quite different when you try to modify the top margin of the
+        // client area. DWM will always draw the whole title bar no matter
+        // what margin value you set for the top, unless you don't modify it
+        // and remove the whole top area (the title bar + the one pixel
+        // height window border). This can be confirmed in Windows
+        // Terminal's source code, you can also try yourself to verify
+        // it. So things will become quite complicated if you want to
+        // preserve the four window borders. So we just remove the whole
+        // window frame, otherwise the code will become much more complex.
+
+        if (Utilities::shouldUseNativeTitleBar()) {
+            break;
+        }
+
+        if (msg->wParam == FALSE) {
+            *result = 0;
+            return true;
+        }
+
+        const auto clientRect = &(reinterpret_cast<LPNCCALCSIZE_PARAMS>(msg->lParam)->rgrc[0]);
+
+        resizeWindow(QSize(
+            qRound((clientRect->right - clientRect->left) / scaleFactor),
+            qRound((clientRect->bottom - clientRect->top) / scaleFactor)
+        ));
+
+        if (shouldHaveWindowFrame()) {
+            // Store the original top before the default window proc
+            // applies the default frame.
+            const LONG originalTop = clientRect->top;
+            // Apply the default frame
+            const LRESULT ret = DefWindowProcW(msg->hwnd, WM_NCCALCSIZE, TRUE, msg->lParam);
+            if (ret != 0) {
+                *result = ret;
+                return true;
+            }
+            // Re-apply the original top from before the size of the
+            // default frame was applied.
+            clientRect->top = originalTop;
+        }
+        bool nonClientAreaExists = false;
+        // We don't need this correction when we're fullscreen. We will
+        // have the WS_POPUP size, so we don't have to worry about
+        // borders, and the default frame will be fine.
+        if (IsMaximized(msg->hwnd) && (window->windowState() != Qt::WindowFullScreen)) {
+            // When a window is maximized, its size is actually a little bit more
+            // than the monitor's work area. The window is positioned and sized in
+            // such a way that the resize handles are outside of the monitor and
+            // then the window is clipped to the monitor so that the resize handle
+            // do not appear because you don't need them (because you can't resize
+            // a window when it's maximized unless you restore it).
+            const int resizeBorderThickness = qRound(this->resizeBorderThickness() * scaleFactor);
+            clientRect->top += resizeBorderThickness;
+            if (!shouldHaveWindowFrame()) {
+                clientRect->bottom -= resizeBorderThickness;
+                clientRect->left += resizeBorderThickness;
+                clientRect->right -= resizeBorderThickness;
+            }
+            nonClientAreaExists = true;
+        }
+        // Attempt to detect if there's an autohide taskbar, and if
+        // there is, reduce our size a bit on the side with the taskbar,
+        // so the user can still mouse-over the taskbar to reveal it.
+        // Make sure to use MONITOR_DEFAULTTONEAREST, so that this will
+        // still find the right monitor even when we're restoring from
+        // minimized.
+        if (IsMaximized(msg->hwnd) || (window->windowState() == Qt::WindowFullScreen)) {
+            APPBARDATA abd;
+            SecureZeroMemory(&abd, sizeof(abd));
+            abd.cbSize = sizeof(abd);
+            const UINT taskbarState = SHAppBarMessage(ABM_GETSTATE, &abd);
+            // First, check if we have an auto-hide taskbar at all:
+            if (taskbarState & ABS_AUTOHIDE) {
+                bool top = false, bottom = false, left = false, right = false;
+                // Due to ABM_GETAUTOHIDEBAREX only exists from Win8.1,
+                // we have to use another way to judge this if we are
+                // running on Windows 7 or Windows 8.
+                if (Utilities::isWin8Point1OrGreater()) {
+                    MONITORINFO monitorInfo;
+                    SecureZeroMemory(&monitorInfo, sizeof(monitorInfo));
+                    monitorInfo.cbSize = sizeof(monitorInfo);
+                    const HMONITOR monitor = MonitorFromWindow(msg->hwnd, MONITOR_DEFAULTTONEAREST);
+                    if (!monitor) {
+                        qWarning() << Utilities::getSystemErrorMessage(QStringLiteral("MonitorFromWindow"));
+                        break;
+                    }
+                    if (GetMonitorInfoW(monitor, &monitorInfo) == FALSE) {
+                        qWarning() << Utilities::getSystemErrorMessage(QStringLiteral("GetMonitorInfoW"));
+                        break;
+                    }
+                    // This helper can be used to determine if there's a
+                    // auto-hide taskbar on the given edge of the monitor
+                    // we're currently on.
+                    const auto hasAutohideTaskbar = [&monitorInfo](const UINT edge) -> bool {
+                        APPBARDATA _abd;
+                        SecureZeroMemory(&_abd, sizeof(_abd));
+                        _abd.cbSize = sizeof(_abd);
+                        _abd.uEdge = edge;
+                        _abd.rc = monitorInfo.rcMonitor;
+                        const auto hTaskbar = reinterpret_cast<HWND>(SHAppBarMessage(ABM_GETAUTOHIDEBAREX, &_abd));
+                        return (hTaskbar != nullptr);
+                    };
+                    top = hasAutohideTaskbar(ABE_TOP);
+                    bottom = hasAutohideTaskbar(ABE_BOTTOM);
+                    left = hasAutohideTaskbar(ABE_LEFT);
+                    right = hasAutohideTaskbar(ABE_RIGHT);
+                } else {
+                    // The following code is copied from Mozilla Firefox,
+                    // with some modifications.
+                    int edge = -1;
+                    APPBARDATA _abd;
+                    SecureZeroMemory(&_abd, sizeof(_abd));
+                    _abd.cbSize = sizeof(_abd);
+                    _abd.hWnd = FindWindowW(L"Shell_TrayWnd", nullptr);
+                    if (_abd.hWnd) {
+                        const HMONITOR windowMonitor = MonitorFromWindow(msg->hwnd, MONITOR_DEFAULTTONEAREST);
+                        if (!windowMonitor) {
+                            qWarning() << Utilities::getSystemErrorMessage(QStringLiteral("MonitorFromWindow"));
+                            break;
+                        }
+                        const HMONITOR taskbarMonitor = MonitorFromWindow(_abd.hWnd, MONITOR_DEFAULTTOPRIMARY);
+                        if (!taskbarMonitor) {
+                            qWarning() << Utilities::getSystemErrorMessage(QStringLiteral("MonitorFromWindow"));
+                            break;
+                        }
+                        if (taskbarMonitor == windowMonitor) {
+                            SHAppBarMessage(ABM_GETTASKBARPOS, &_abd);
+                            edge = _abd.uEdge;
+                        }
+                    } else {
+                        qWarning() << "Failed to retrieve the task bar window handle.";
+                        break;
+                    }
+                    top = (edge == ABE_TOP);
+                    bottom = (edge == ABE_BOTTOM);
+                    left = (edge == ABE_LEFT);
+                    right = (edge == ABE_RIGHT);
+                }
+                // If there's a taskbar on any side of the monitor, reduce
+                // our size a little bit on that edge.
+                // Note to future code archeologists:
+                // This doesn't seem to work for fullscreen on the primary
+                // display. However, testing a bunch of other apps with
+                // fullscreen modes and an auto-hiding taskbar has
+                // shown that _none_ of them reveal the taskbar from
+                // fullscreen mode. This includes Edge, Firefox, Chrome,
+                // Sublime Text, PowerPoint - none seemed to support this.
+                // This does however work fine for maximized.
+                if (top) {
+                    // Peculiarly, when we're fullscreen,
+                    clientRect->top += kAutoHideTaskbarThickness;
+                    nonClientAreaExists = true;
+                } else if (bottom) {
+                    clientRect->bottom -= kAutoHideTaskbarThickness;
+                    nonClientAreaExists = true;
+                } else if (left) {
+                    clientRect->left += kAutoHideTaskbarThickness;
+                    nonClientAreaExists = true;
+                } else if (right) {
+                    clientRect->right -= kAutoHideTaskbarThickness;
+                    nonClientAreaExists = true;
+                }
+            }
+        }
+#if 0
+        // Fix the flickering issue while resizing.
+        // "clientRect->right += 1;" also works.
+        // This small technique is known to have two draw backs:
+        // (1) Qt's coordinate system will be confused because the canvas size
+        // doesn't match the client area size so you will get some warnings
+        // from Qt and you should also be careful when you try to draw something
+        // manually through QPainter or in Qt Quick, be aware of the coordinate
+        // mismatch issue when you calculate position yourself.
+        // (2) Qt's window system will take some wrong actions when the window
+        // is being resized. For example, the window size will become 1px smaller
+        // or bigger everytime when resize() is called because the client area size
+        // is not correct. It confuses QPA's internal logic.
+        clientRect->bottom += 1;
+#endif
+        // If the window bounds change, we're going to relayout and repaint
+        // anyway. Returning WVR_REDRAW avoids an extra paint before that of
+        // the old client pixels in the (now wrong) location, and thus makes
+        // actions like resizing a window from the left edge look slightly
+        // less broken.
+        //
+        // We cannot return WVR_REDRAW when there is nonclient area, or
+        // Windows exhibits bugs where client pixels and child HWNDs are
+        // mispositioned by the width/height of the upper-left nonclient
+        // area.
+        *result = nonClientAreaExists ? 0 : WVR_REDRAW;
+        return true;
+    }
+    // These undocumented messages are sent to draw themed window
+    // borders. Block them to prevent drawing borders over the client
+    // area.
+    case WM_NCUAHDRAWCAPTION:
+    case WM_NCUAHDRAWFRAME: {
+        if (shouldHaveWindowFrame()) {
+            break;
+        } else {
+            *result = 0;
+            return true;
+        }
+    }
+    case WM_NCPAINT: {
+        // 边框阴影处于非客户区的范围，因此如果直接阻止非客户区的绘制，会导致边框阴影丢失
+
+        if (!Utilities::isDwmCompositionAvailable() && !shouldHaveWindowFrame()) {
+            // Only block WM_NCPAINT when DWM composition is disabled. If
+            // it's blocked when DWM composition is enabled, the frame
+            // shadow won't be drawn.
+            *result = 0;
+            return true;
+        } else {
+            break;
+        }
+    }
+    case WM_NCACTIVATE: {
+        if (shouldHaveWindowFrame()) {
+            break;
+        } else {
+            if (Utilities::isDwmCompositionAvailable()) {
+                // DefWindowProc won't repaint the window border if lParam
+                // (normally a HRGN) is -1. See the following link's "lParam"
+                // section:
+                // https://docs.microsoft.com/en-us/windows/win32/winmsg/wm-ncactivate
+                // Don't use "*result = 0" otherwise the window won't respond
+                // to the window active state change.
+                *result = DefWindowProcW(msg->hwnd, WM_NCACTIVATE, msg->wParam, -1);
+            } else {
+                if (msg->wParam == FALSE) {
+                    *result = TRUE;
+                } else {
+                    *result = FALSE;
+                }
+            }
+            return true;
+        }
+    }
+    case WM_NCHITTEST: {
+        // 原生Win32窗口只有顶边是在窗口内部resize的，其余三边都是在窗口
+        // 外部进行resize的，其原理是，WS_THICKFRAME这个窗口样式会在窗
+        // 口的左、右和底边添加三个透明的resize区域，这三个区域在正常状态
+        // 下是完全不可见的，它们由DWM负责绘制和控制。这些区域的宽度等于
+        // (SM_CXSIZEFRAME + SM_CXPADDEDBORDER)，高度等于
+        // (SM_CYSIZEFRAME + SM_CXPADDEDBORDER)，在100%缩放时，均等
+        // 于8像素。它们属于窗口区域的一部分，但不属于客户区，而是属于非客
+        // 户区，因此GetWindowRect获取的区域中是包含这三个resize区域的，
+        // 而GetClientRect获取的区域是不包含它们的。当把
+        // DWMWA_EXTENDED_FRAME_BOUNDS作为参数调用
+        // DwmGetWindowAttribute时，也能获取到一个窗口大小，这个大小介
+        // 于前面两者之间，暂时不知道这个数据的意义及其作用。我们在
+        // WM_NCCALCSIZE消息的处理中，已经把整个窗口都设置为客户区了，也
+        // 就是说，我们的窗口已经没有非客户区了，因此那三个透明的resize区
+        // 域，此刻也已经成为窗口客户区的一部分了，从而变得不透明了。所以
+        // 现在的resize，看起来像是在窗口内部resize，是因为原本透明的地方
+        // 现在变得不透明了，实际上，单纯从范围上来看，现在我们resize的地方，
+        // 就是普通窗口的边框外部，那三个透明区域的范围。
+        // 因此，如果我们把边框完全去掉（就是我们正在做的事情），resize就
+        // 会看起来是在内部进行，这个问题通过常规方法非常难以解决。我测试过
+        // QQ和钉钉的窗口，它们的窗口就是在外部resize，但实际上它们是通过
+        // 把窗口实际的内容，嵌入到一个完全透明的但尺寸要大一圈的窗口中实现
+        // 的，虽然看起来效果还行，但在我看来不是正途。而且我之所以能发现，
+        // 也是由于这种方法在很多情况下会露馅，比如窗口未响应卡住或贴边的时
+        // 候，能明显看到窗口周围多出来一圈边界。我曾经尝试再把那三个区域弄
+        // 透明，但无一例外都会破坏DWM绘制的边框阴影，因此只好作罢。
+
+        // As you may have found, if you use this code, the resize areas
+        // will be inside the frameless window, however, a normal Win32
+        // window can be resized outside of it. Here is the reason: the
+        // WS_THICKFRAME window style will cause a window has three
+        // transparent areas beside the window's left, right and bottom
+        // edge. Their width or height is eight pixels if the window is not
+        // scaled. In most cases, they are totally invisible. It's DWM's
+        // responsibility to draw and control them. They exist to let the
+        // user resize the window, visually outside of it. They are in the
+        // window area, but not the client area, so they are in the
+        // non-client area actually. But we have turned the whole window
+        // area into client area in WM_NCCALCSIZE, so the three transparent
+        // resize areas also become a part of the client area and thus they
+        // become visible. When we resize the window, it looks like we are
+        // resizing inside of it, however, that's because the transparent
+        // resize areas are visible now, we ARE resizing outside of the
+        // window actually. But I don't know how to make them become
+        // transparent again without breaking the frame shadow drawn by DWM.
+        // If you really want to solve it, you can try to embed your window
+        // into a larger transparent window and draw the frame shadow
+        // yourself. As what we have said in WM_NCCALCSIZE, you can only
+        // remove the top area of the window, this will let us be able to
+        // resize outside of the window and don't need much process in this
+        // message, it looks like a perfect plan, however, the top border is
+        // missing due to the whole top area is removed, and it's very hard
+        // to bring it back because we have to use a trick in WM_PAINT
+        // (learned from Windows Terminal), but no matter what we do in
+        // WM_PAINT, it will always break the backing store mechanism of Qt,
+        // so actually we can't do it. And it's very difficult to do such
+        // things in NativeEventFilters as well. What's worse, if we really
+        // do this, the four window borders will become white and they look
+        // horrible in dark mode. This solution only supports Windows 10
+        // because the border width on Win10 is only one pixel, however it's
+        // eight pixels on Windows 7 so preserving the three window borders
+        // looks terrible on old systems. I'm testing this solution in
+        // another branch, if you are interested in it, you can give it a
+        // try.
+
+        if (Utilities::shouldUseNativeTitleBar()) {
+            break;
+        }
+
+        POINT winLocalMouse = {GET_X_LPARAM(msg->lParam), GET_Y_LPARAM(msg->lParam)};
+        if (ScreenToClient(msg->hwnd, &winLocalMouse) == FALSE) {
+            qWarning() << Utilities::getSystemErrorMessage(QStringLiteral("ScreenToClient"));
+            break;
+        }
+        const QPointF localMouse = {static_cast<qreal>(winLocalMouse.x), static_cast<qreal>(winLocalMouse.y)};
+        RECT clientRect = {0, 0, 0, 0};
+        if (GetClientRect(msg->hwnd, &clientRect) == FALSE) {
+            qWarning() << Utilities::getSystemErrorMessage(QStringLiteral("GetClientRect"));
+            break;
+        }
+        const LONG windowWidth = clientRect.right;
+        const int resizeBorderThickness = qRound(this->resizeBorderThickness() * scaleFactor);
+        const int titleBarHeight = qRound(this->titleBarHeight() * scaleFactor);
+
+        bool isTitleBar = isInTitlebarArea(QPoint(qRound(localMouse.x() / scaleFactor), qRound(localMouse.y() / scaleFactor)));
+
+        /*
+        if (IsMaximized(msg->hwnd) || (window->windowState() == Qt::WindowFullScreen)) {
+            isTitleBar = (localMouse.y() >= 0) && (localMouse.y() <= titleBarHeight)
+                    && (localMouse.x() >= 0) && (localMouse.x() <= windowWidth)
+                    && !Utilities::isHitTestVisibleInChrome(window);
+        }
+        if (window->windowState() == Qt::WindowNoState) {
+            isTitleBar = (localMouse.y() > resizeBorderThickness) && (localMouse.y() <= titleBarHeight)
+                    && (localMouse.x() > resizeBorderThickness) && (localMouse.x() < (windowWidth - resizeBorderThickness))
+                    && !Utilities::isHitTestVisibleInChrome(window);
+        }
+        */
+
+        const bool isTop = localMouse.y() <= resizeBorderThickness;
+        if (shouldHaveWindowFrame()) {
+            // This will handle the left, right and bottom parts of the frame
+            // because we didn't change them.
+            const LRESULT originalRet = DefWindowProcW(msg->hwnd, WM_NCHITTEST, 0, msg->lParam);
+            if (originalRet != HTCLIENT) {
+                *result = originalRet;
+                return true;
+            }
+            // At this point, we know that the cursor is inside the client area
+            // so it has to be either the little border at the top of our custom
+            // title bar or the drag bar. Apparently, it must be the drag bar or
+            // the little border at the top which the user can use to move or
+            // resize the window.
+            if (!IsMaximized(msg->hwnd) && isTop) {
+                *result = HTTOP;
+                return true;
+            }
+            if (isTitleBar) {
+                *result = HTCAPTION;
+                return true;
+            }
+            *result = HTCLIENT;
+            return true;
+        } else {
+            const LRESULT hitTestResult = [
+                clientRect, msg, isTitleBar, &localMouse, 
+                resizeBorderThickness, windowWidth, isTop,
+                window, scaleFactor] {
+                if (IsMaximized(msg->hwnd)) {
+                    if (isTitleBar) {
+                        return HTCAPTION;
+                    }
+                    return HTCLIENT;
+                }
+                const LONG windowHeight = clientRect.bottom;
+                const bool isBottom = (localMouse.y() >= (windowHeight - resizeBorderThickness));
+                // Make the border a little wider to let the user easy to resize on corners.
+                const qreal factor = (isTop || isBottom) ? 2.0 : 1.0;
+                const bool isLeft = (localMouse.x() <= qRound(static_cast<qreal>(resizeBorderThickness) * factor));
+                const bool isRight = (localMouse.x() >= (windowWidth - qRound(static_cast<qreal>(resizeBorderThickness) * factor)));
+                const bool fixedSize = Utilities::isWindowFixedSize(window);
+                const auto getBorderValue = [fixedSize](int value) -> int {
+                    return fixedSize ? HTCLIENT : value;
+                };
+                if (isTop) {
+                    if (isLeft) {
+                        return getBorderValue(HTTOPLEFT);
+                    }
+                    if (isRight) {
+                        return getBorderValue(HTTOPRIGHT);
+                    }
+                    return getBorderValue(HTTOP);
+                }
+                if (isBottom) {
+                    if (isLeft) {
+                        return getBorderValue(HTBOTTOMLEFT);
+                    }
+                    if (isRight) {
+                        return getBorderValue(HTBOTTOMRIGHT);
+                    }
+                    return getBorderValue(HTBOTTOM);
+                }
+                if (isLeft) {
+                    return getBorderValue(HTLEFT);
+                }
+                if (isRight) {
+                    return getBorderValue(HTRIGHT);
+                }
+                if (isTitleBar) {
+                    return HTCAPTION;
+                }
+                return HTCLIENT;
+            }();
+            *result = hitTestResult;
+            return true;
+        }
+    }
+    case WM_SETICON:
+    case WM_SETTEXT: {
+        if (Utilities::shouldUseNativeTitleBar()) {
+            break;
+        }
+
+        // Disable painting while these messages are handled to prevent them
+        // from drawing a window caption over the client area.
+        const LONG_PTR oldStyle = GetWindowLongPtrW(msg->hwnd, GWL_STYLE);
+        // Prevent Windows from drawing the default title bar by temporarily
+        // toggling the WS_VISIBLE style.
+        if (SetWindowLongPtrW(msg->hwnd, GWL_STYLE, static_cast<LONG_PTR>(oldStyle & ~WS_VISIBLE)) == 0) {
+            qWarning() << Utilities::getSystemErrorMessage(QStringLiteral("SetWindowLongPtrW"));
+            break;
+        }
+        const auto winId = reinterpret_cast<WId>(msg->hwnd);
+        Utilities::triggerFrameChange(winId);
+        const LRESULT ret = DefWindowProcW(msg->hwnd, msg->message, msg->wParam, msg->lParam);
+        if (SetWindowLongPtrW(msg->hwnd, GWL_STYLE, oldStyle) == 0) {
+            qWarning() << Utilities::getSystemErrorMessage(QStringLiteral("SetWindowLongPtrW"));
+            break;
+        }
+        Utilities::triggerFrameChange(winId);
+        *result = ret;
+        return true;
+    }
+    case WM_SIZE: {
+        const bool normal = (msg->wParam == SIZE_RESTORED);
+        const bool max = (msg->wParam == SIZE_MAXIMIZED);
+        const bool full = (window->windowState() == Qt::WindowFullScreen);
+        if (normal || max || full) {
+            Utilities::updateFrameMargins(reinterpret_cast<WId>(msg->hwnd), (max || full));
+            updateQtFrameMargins(true);
+        }
+    } break;
+    default:
+        break;
+    }
+    return false;
+}
+#endif // Q_OS_WIN
+
 FRAMELESSHELPER_END_NAMESPACE

framelesshelper.h

@@ -89,6 +89,19 @@ public:
     bool isHitTestVisible(QObject *obj);
     QRect getHTVObjectRect(QObject *obj);
 
+#ifdef Q_OS_WIN
+#if (QT_VERSION >= QT_VERSION_CHECK(6, 0, 0))
+    bool handleNativeEvent(QWindow *window, const QByteArray &eventType, void *message, qintptr *result);
+#else
+    bool handleNativeEvent(QWindow *window, const QByteArray &eventType, void *message, long *result);
+#endif
+#endif // Q_OS_WIN
+
+private:
+#ifdef Q_OS_WIN
+    void updateQtFrameMargins(const bool enable);
+#endif // Q_OS_WIN
+
 protected:
     bool eventFilter(QObject *object, QEvent *event) override;
     void handleResizeHandlerDblClicked();