Remove hot-switch

Sine Striker

2023-12-20 995dc0b4d52e66adac84812dedf32785a65bce83

 src/core/contexts/win32windowcontext.cpp

@@ -79,16 +79,6 @@
    // Original Qt window proc function
    static WNDPROC g_qtWindowProc = nullptr;

    // ### FIXME FIXME FIXME
    // ### FIXME: Tell the user to call in the documentation, instead of automatically
    // calling it directly.
    // ### FIXME FIXME FIXME
    static const struct QWK_Hook {
        QWK_Hook() {
            qApp->setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
        }
    } g_hook{};

    struct DynamicApis {
        static const DynamicApis &instance() {
            static const DynamicApis inst{};
@@ -114,6 +104,7 @@
        DYNAMIC_API_DECLARE(DwmIsCompositionEnabled);
        DYNAMIC_API_DECLARE(DwmGetCompositionTimingInfo);
        DYNAMIC_API_DECLARE(DwmGetWindowAttribute);
        DYNAMIC_API_DECLARE(DwmSetWindowAttribute);
        DYNAMIC_API_DECLARE(GetDpiForWindow);
        DYNAMIC_API_DECLARE(GetSystemMetricsForDpi);
        DYNAMIC_API_DECLARE(GetDpiForMonitor);
@@ -140,6 +131,7 @@
            DYNAMIC_API_RESOLVE(dwmapi, DwmIsCompositionEnabled);
            DYNAMIC_API_RESOLVE(dwmapi, DwmGetCompositionTimingInfo);
            DYNAMIC_API_RESOLVE(dwmapi, DwmGetWindowAttribute);
            DYNAMIC_API_RESOLVE(dwmapi, DwmSetWindowAttribute);

            QSystemLibrary winmm(QStringLiteral("winmm"));
            DYNAMIC_API_RESOLVE(winmm, timeGetDevCaps);
@@ -387,16 +379,7 @@
               getSystemMetricsForDpi(SM_CXPADDEDBORDER, dpi);
    }

    static void updateInternalWindowFrameMargins(HWND hwnd, QWindow *window) {
        const auto margins = [hwnd]() -> QMargins {
            const auto titleBarHeight = int(getTitleBarHeight(hwnd));
            if (isWin10OrGreater()) {
                return {0, -titleBarHeight, 0, 0};
            } else {
                const auto frameSize = int(getResizeBorderThickness(hwnd));
                return {-frameSize, -titleBarHeight, -frameSize, -frameSize};
            }
        }();
    static void setInternalWindowFrameMargins(QWindow *window, const QMargins &margins) {
        const QVariant marginsVar = QVariant::fromValue(margins);
        window->setProperty("_q_windowsCustomMargins", marginsVar);
#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
@@ -422,16 +405,83 @@
        monitorInfo.cbSize = sizeof(monitorInfo);
        ::GetMonitorInfoW(monitor, &monitorInfo);
        return monitorInfo;
    };
    }

    static inline void moveToDesktopCenter(HWND hwnd) {
        const auto monitorInfo = getMonitorForWindow(hwnd);
    static inline void moveWindowToDesktopCenter(HWND hwnd) {
        MONITORINFOEXW monitorInfo = getMonitorForWindow(hwnd);
        RECT windowRect{};
        ::GetWindowRect(hwnd, &windowRect);
        const auto newX = (RECT_WIDTH(monitorInfo.rcMonitor) - RECT_WIDTH(windowRect)) / 2;
        const auto newY = (RECT_HEIGHT(monitorInfo.rcMonitor) - RECT_HEIGHT(windowRect)) / 2;
        const auto newX = monitorInfo.rcMonitor.left +
                          (RECT_WIDTH(monitorInfo.rcMonitor) - RECT_WIDTH(windowRect)) / 2;
        const auto newY = monitorInfo.rcMonitor.top +
                          (RECT_HEIGHT(monitorInfo.rcMonitor) - RECT_HEIGHT(windowRect)) / 2;
        ::SetWindowPos(hwnd, nullptr, newX, newY, 0, 0,
                       SWP_NOACTIVATE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOOWNERZORDER);
    }

    static inline void moveWindowToMonitor(HWND hwnd, const MONITORINFOEXW &activeMonitor) {
        RECT currentMonitorRect = getMonitorForWindow(hwnd).rcMonitor;
        RECT activeMonitorRect = activeMonitor.rcMonitor;
        // We are in the same monitor, nothing to adjust here.
        if (currentMonitorRect == activeMonitorRect) {
            return;
        }
        RECT currentWindowRect{};
        ::GetWindowRect(hwnd, &currentWindowRect);
        auto newWindowX =
            activeMonitorRect.left + (currentWindowRect.left - currentMonitorRect.left);
        auto newWindowY = activeMonitorRect.top + (currentWindowRect.top - currentMonitorRect.top);
        ::SetWindowPos(hwnd, nullptr, newWindowX, newWindowY, RECT_WIDTH(currentWindowRect),
                       RECT_HEIGHT(currentWindowRect),
                       SWP_NOACTIVATE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOOWNERZORDER);
    }

    static inline void bringWindowToFront(HWND hwnd) {
        HWND oldForegroundWindow = ::GetForegroundWindow();
        if (!oldForegroundWindow) {
            // The foreground window can be NULL, it's not an API error.
            return;
        }
        MONITORINFOEXW activeMonitor = getMonitorForWindow(oldForegroundWindow);
        // We need to show the window first, otherwise we won't be able to bring it to front.
        if (!::IsWindowVisible(hwnd)) {
            ::ShowWindow(hwnd, SW_SHOW);
        }
        if (IsMinimized(hwnd)) {
            // Restore the window if it is minimized.
            ::ShowWindow(hwnd, SW_RESTORE);
            // Once we've been restored, throw us on the active monitor.
            moveWindowToMonitor(hwnd, activeMonitor);
            // When the window is restored, it will always become the foreground window.
            // So return early here, we don't need the following code to bring it to front.
            return;
        }
        // OK, our window is not minimized, so now we will try to bring it to front manually.
        // First try to send a message to the current foreground window to check whether
        // it is currently hanging or not.
        if (!::SendMessageTimeoutW(oldForegroundWindow, WM_NULL, 0, 0,
                                   SMTO_BLOCK | SMTO_ABORTIFHUNG | SMTO_NOTIMEOUTIFNOTHUNG, 1000,
                                   nullptr)) {
            // The foreground window hangs, can't activate current window.
            return;
        }
        DWORD windowThreadProcessId = ::GetWindowThreadProcessId(oldForegroundWindow, nullptr);
        DWORD currentThreadId = ::GetCurrentThreadId();
        // We won't be able to change a window's Z order if it's not our own window,
        // so we use this small technique to pretend the foreground window is ours.
        ::AttachThreadInput(windowThreadProcessId, currentThreadId, TRUE);

        [[maybe_unused]] const auto &cleaner =
            qScopeGuard([windowThreadProcessId, currentThreadId]() {
                ::AttachThreadInput(windowThreadProcessId, currentThreadId, FALSE); //
            });

        ::BringWindowToTop(hwnd);
        // Activate the window too. This will force us to the virtual desktop this
        // window is on, if it's on another virtual desktop.
        ::SetActiveWindow(hwnd);
        // Throw us on the active monitor.
        moveWindowToMonitor(hwnd, activeMonitor);
    }

    static inline bool isFullScreen(HWND hwnd) {
@@ -448,6 +498,9 @@
        ::GetWindowPlacement(hwnd, &wp);
        return ((wp.showCmd == SW_NORMAL) || (wp.showCmd == SW_RESTORE));
#else
        if (isFullScreen(hwnd)) {
            return false;
        }
        const auto style = static_cast<DWORD>(::GetWindowLongPtrW(hwnd, GWL_STYLE));
        return (!(style & (WS_MINIMIZE | WS_MAXIMIZE)));
#endif
@@ -767,18 +820,52 @@
        return ::CallWindowProcW(g_qtWindowProc, hWnd, message, wParam, lParam);
    }

    static inline void addManagedWindow(QWindow *window, HWND hWnd, Win32WindowContext *ctx) {
        const auto margins = [hWnd]() -> QMargins {
            const auto titleBarHeight = int(getTitleBarHeight(hWnd));
            if (isWin10OrGreater()) {
                return {0, -titleBarHeight, 0, 0};
            } else {
                const auto frameSize = int(getResizeBorderThickness(hWnd));
                return {-frameSize, -titleBarHeight, -frameSize, -frameSize};
            }
        }();

        // Inform Qt we want and have set custom margins
        setInternalWindowFrameMargins(window, margins);

        // Store original window proc
        if (!g_qtWindowProc) {
            g_qtWindowProc = reinterpret_cast<WNDPROC>(::GetWindowLongPtrW(hWnd, GWLP_WNDPROC));
        }

        // Hook window proc
        ::SetWindowLongPtrW(hWnd, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(QWKHookedWndProc));

        // Install global native event filter
        WindowsNativeEventFilter::install();

        // Save window handle mapping
        g_wndProcHash->insert(hWnd, ctx);
    }

    static inline void removeManagedWindow(HWND hWnd) {
        // Remove window handle mapping
        if (!g_wndProcHash->remove(hWnd))
            return;

        // Remove event filter if the all windows has been destroyed
        if (g_wndProcHash->empty()) {
            WindowsNativeEventFilter::uninstall();
        }
    }

    Win32WindowContext::Win32WindowContext() : AbstractWindowContext() {
    }

    Win32WindowContext::~Win32WindowContext() {
        // Remove window handle mapping
        if (auto hWnd = reinterpret_cast<HWND>(windowId); hWnd) {
            g_wndProcHash->remove(hWnd);

            // Remove event filter if the all windows has been destroyed
            if (g_wndProcHash->empty()) {
                WindowsNativeEventFilter::uninstall();
            }
        if (windowId) {
            removeManagedWindow(reinterpret_cast<HWND>(windowId));
        }
    }

@@ -789,16 +876,51 @@
    void Win32WindowContext::virtual_hook(int id, void *data) {
        switch (id) {
            case CentralizeHook: {
                const auto hwnd = reinterpret_cast<HWND>(m_windowHandle->winId());
                moveToDesktopCenter(hwnd);
                if (!windowId)
                    return;
                const auto hwnd = reinterpret_cast<HWND>(windowId);
                moveWindowToDesktopCenter(hwnd);
                return;
            }

            case RaiseWindowHook: {
                if (!windowId)
                    return;
                const auto hwnd = reinterpret_cast<HWND>(windowId);
                bringWindowToFront(hwnd);
                return;
            }

            case ShowSystemMenuHook: {
                if (!windowId)
                    return;
                const auto &pos = *static_cast<const QPoint *>(data);
                auto hWnd = reinterpret_cast<HWND>(m_windowHandle->winId());
                showSystemMenu2(hWnd, qpoint2point(pos), false,
                auto hWnd = reinterpret_cast<HWND>(windowId);
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
                const QPoint nativeGlobalPos =
                    QHighDpi::toNativeGlobalPosition(pos, m_windowHandle);
#else
                const QPoint nativeGlobalPos = QHighDpi::toNativePixels(pos, m_windowHandle);
#endif
                showSystemMenu2(hWnd, qpoint2point(nativeGlobalPos), false,
                                m_delegate->isHostSizeFixed(m_host));
                return;
            }

            case WindowAttributeChangedHook: {
                auto args = static_cast<void **>(data);
                const auto &key = *static_cast<const QString *>(args[0]);
                const auto &newVar = *static_cast<const QVariant *>(args[1]);
                const auto &oldVar = *static_cast<const QVariant *>(args[2]);

                if (key == QStringLiteral("no-frame-shadow")) {
                    if (newVar.toBool()) {
                        // TODO: set off
                    } else {
                        // TODO: set on
                    }
                }

                return;
            }

@@ -813,11 +935,14 @@
            }

            case DrawWindows10BorderHook: {
                if (!windowId)
                    return;

                auto args = static_cast<void **>(data);
                auto &painter = *static_cast<QPainter *>(args[0]);
                const auto &rect = *static_cast<const QRect *>(args[1]);
                const auto &region = *static_cast<const QRegion *>(args[2]);
                const auto hwnd = reinterpret_cast<HWND>(m_windowHandle->winId());
                const auto hwnd = reinterpret_cast<HWND>(windowId);

                QPen pen;
                pen.setWidth(getWindowFrameBorderThickness(hwnd) * 2);
@@ -840,7 +965,7 @@
                }
                painter.save();

                // ### TODO: do we need to enable or disable it?
                // We needs anti-aliasing to give us better result.
                painter.setRenderHint(QPainter::Antialiasing);

                painter.setPen(pen);
@@ -849,12 +974,11 @@
                    QPoint{m_windowHandle->width(), 0}
                });
                painter.restore();
                return;
            }

            default: {
                // unreachable
            default:
                break;
            }
        }
        AbstractWindowContext::virtual_hook(id, data);
    }
@@ -867,32 +991,36 @@
        return getWindowFrameBorderThickness(reinterpret_cast<HWND>(windowId));
    }

    bool Win32WindowContext::setupHost() {
    void Win32WindowContext::winIdChanged() {
        // If the original window id is valid, remove all resources related
        if (windowId) {
            removeManagedWindow(reinterpret_cast<HWND>(windowId));
            windowId = 0;
        }

        if (!m_windowHandle) {
            return;
        }

        // Install window hook
        auto winId = m_windowHandle->winId();
        auto hWnd = reinterpret_cast<HWND>(winId);

        // Inform Qt we want and have set custom margins
        updateInternalWindowFrameMargins(hWnd, m_windowHandle);

        // Store original window proc
        if (!g_qtWindowProc) {
            g_qtWindowProc = reinterpret_cast<WNDPROC>(::GetWindowLongPtrW(hWnd, GWLP_WNDPROC));
#if QT_VERSION < QT_VERSION_CHECK(6, 5, 0)
        for (const auto attr : {
                 _DWMWA_USE_IMMERSIVE_DARK_MODE_BEFORE_20H1,
                 _DWMWA_USE_IMMERSIVE_DARK_MODE,
             }) {
            const BOOL enable = TRUE;
            DynamicApis::instance().pDwmSetWindowAttribute(hWnd, attr, &enable, sizeof(enable));
        }
#endif

        // Hook window proc
        ::SetWindowLongPtrW(hWnd, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(QWKHookedWndProc));
        // Add managed window
        addManagedWindow(m_windowHandle, hWnd, this);

        // Install global native event filter
        WindowsNativeEventFilter::install();

        // Cache window ID
        // Cache win id
        windowId = winId;

        // Save window handle mapping
        g_wndProcHash->insert(hWnd, this);

        return true;
    }

    bool Win32WindowContext::windowProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam,
@@ -1153,7 +1281,54 @@
                const WindowPart currentWindowPart = lastHitTestResult;
                if (message == WM_NCMOUSEMOVE) {
                    if (currentWindowPart != WindowPart::ChromeButton) {
                        m_delegate->resetQtGrabbedControl();
                        // https://github.com/qt/qtbase/blob/e26a87f1ecc40bc8c6aa5b889fce67410a57a702/src/widgets/kernel/qwidgetwindow.cpp#L472
                        // When the mouse press event arrives, QWidgetWindow will implicitly grab
                        // the top widget right under the mouse, and set `qt_button_down` to this
                        // widget. At this time, no other widgets will accept the mouse event until
                        // QWidgetWindow receives the mouse release event, then set `qt_button_down`
                        // to null.

                        // Imagine the following situation, now the main window has a pop-up menu,
                        // the focus is not on the main window, if we click outside the pop-up menu,
                        // the menu will close, which seems to be completely fine. But if we close
                        // the menu by clicking on the title bar draggable area, then other widgets
                        // won't accept the mouse message afterwards.

                        // Here's the reason.
                        // When the mouse is placed in the draggable area of the title bar, there
                        // are two situations.

                        // 1. If the focus is on the main window, and the last result of
                        // WM_NCHITTEST is HTCAPTION, the mouse click event in the title bar is
                        // taken over by Windows and Qt does not receive the mouse click event.

                        // 2. If the main window has a pop-up menu, it is completely different. When
                        // the mouse is pressed on the title bar, Windows sends the WM_LBUTTONDOWN
                        // message to the window plane of the pop-up menu, the menu is closed, but
                        // Qt will continue to forward the event to the QWidget under the mouse, and
                        // the event will be processed by QWidgetWindow, causing the title bar
                        // widget to be implicitly grabbed. After the menu is closed, Windows
                        // immediately sends WM_NCHITTEST, because the mouse is in the title bar
                        // draggable area, the result is HTCAPTION, so when the mouse is released,
                        // Windows sends WM_NCLBUTTONUP, which is a non-client message, and it
                        // will be ignored by Qt. As a consequence, QWidgetWindow can't receive a
                        // mouse release message in the client area, so the grab remains, and other
                        // widgets cannot receive mouse events.

                        // Since we didn't watch the menu window, we cannot capture any mouse
                        // press events sent by Windows, so we cannot solve this problem by
                        // recording mouse events. Fortunately, we found that the main window will
                        // receive a WM_NCMOUSEMOVE message immediately after the menu is closed, so
                        // we just manually send a mouse release event when this message arrives and
                        // set qt_button_down to null. Don't worry, when receiving WM_NCMOUSEMOVE,
                        // there shouldn't be any control in the state of being grabbed.

                        // In the native window, although QWidgetWindow handles the forwarded mouse
                        // press event when the menu is closed, since the native title bar is not a
                        // QWidget, no widget will be grabbed, and `qt_button_down` remains empty,
                        // the above problems would not arise.

                        m_delegate->resetQtGrabbedControl(m_host);
                        if (mouseLeaveBlocked) {
                            emulateClientAreaMessage(hWnd, message, wParam, lParam,
                                                     WM_NCMOUSELEAVE);
@@ -1215,7 +1390,9 @@
                        // window from client area, which means we will get previous window part as
                        // HTCLIENT if the mouse leaves window from client area and enters window
                        // from non-client area, but it has no bad effect.
                        m_delegate->resetQtGrabbedControl();

                        // Why do we need to call this function here?
                        m_delegate->resetQtGrabbedControl(m_host);
                    }
                }
                break;
@@ -1235,9 +1412,9 @@
                    // If wParam is TRUE, the window is being shown.
                    // If lParam is zero, the message was sent because of a call to the ShowWindow
                    // function.
                    if (wParam && lParam == 0) {
                    if (wParam && !lParam) {
                        centered = true;
                        moveToDesktopCenter(hWnd);
                        moveWindowToDesktopCenter(hWnd);
                    }
                }
                break;
@@ -1324,7 +1501,6 @@
                // Terminal does, however, later I found that if we choose a proper
                // color, our homemade top border can almost have exactly the same
                // appearance with the system's one.

                [[maybe_unused]] const auto &hitTestRecorder = qScopeGuard([this, result]() {
                    lastHitTestResult = getHitWindowPart(int(*result)); //
                });
@@ -1447,7 +1623,7 @@
                        *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                        return true;
                    }
                    // At this point, we know that the cursor is inside the client area
                    // 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
@@ -1540,9 +1716,10 @@
                // the client area as a whole will shift to the left, which looks very abnormal if
                // we don't repaint it. This exception disappears if we add SWP_NOCOPYBITS flag.
                // But I don't know what caused the problem, or why this would solve it.
                static constexpr const auto kBadWindowPosFlag =
                    SWP_NOSIZE | SWP_NOMOVE | SWP_NOZORDER | SWP_NOACTIVATE | SWP_FRAMECHANGED;
                const auto windowPos = reinterpret_cast<LPWINDOWPOS>(lParam);
                if (windowPos->flags ==
                    (SWP_NOSIZE | SWP_NOMOVE | SWP_NOZORDER | SWP_NOACTIVATE | SWP_FRAMECHANGED)) {
                if (windowPos->flags == kBadWindowPosFlag) {
                    windowPos->flags |= SWP_NOCOPYBITS;
                }
                break;