Add host interface

Sine Striker

2023-12-05 3cfe15a9c3db0993d8b8fef5d148625840e5a75c

 src/core/contexts/win32windowcontext.cpp

@@ -6,6 +6,7 @@
#include <QtCore/QAbstractNativeEventFilter>
#include <QtCore/QCoreApplication>
#include <QtCore/QOperatingSystemVersion>
#include <QtCore/QScopeGuard>

#include <QtCore/private/qsystemlibrary_p.h>
#include <QtGui/private/qhighdpiscaling_p.h>
@@ -27,6 +28,7 @@

    struct DynamicApis {
        decltype(&::DwmFlush) pDwmFlush = nullptr;
        decltype(&::DwmIsCompositionEnabled) pDwmIsCompositionEnabled = nullptr;
        decltype(&::GetDpiForWindow) pGetDpiForWindow = nullptr;
        decltype(&::GetSystemMetricsForDpi) pGetSystemMetricsForDpi = nullptr;
        decltype(&::GetDpiForMonitor) pGetDpiForMonitor = nullptr;
@@ -44,6 +46,8 @@

            QSystemLibrary dwmapi(QStringLiteral("dwmapi.dll"));
            pDwmFlush = reinterpret_cast<decltype(pDwmFlush)>(dwmapi.resolve("DwmFlush"));
            pDwmIsCompositionEnabled = reinterpret_cast<decltype(pDwmIsCompositionEnabled)>(
                dwmapi.resolve("DwmIsCompositionEnabled"));
        }

        ~DynamicApis() = default;
@@ -137,6 +141,12 @@
        return hwnd2str(reinterpret_cast<WId>(hwnd));
    }

    static inline bool isWin8OrGreater() {
        static const bool result =
            QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows8;
        return result;
    }

    static inline bool isWin8Point1OrGreater() {
        static const bool result =
            QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows8_1;
@@ -147,6 +157,28 @@
        static const bool result =
            QOperatingSystemVersion::current() >= QOperatingSystemVersion::Windows10;
        return result;
    }

    static inline bool isDwmCompositionEnabled() {
        if (isWin8OrGreater()) {
            return true;
        }
        const DynamicApis &apis = DynamicApis::instance();
        if (!apis.pDwmIsCompositionEnabled) {
            return false;
        }
        BOOL enabled = FALSE;
        return SUCCEEDED(apis.pDwmIsCompositionEnabled(&enabled)) && enabled;
    }

    static inline void triggerFrameChange(HWND hwnd) {
        Q_ASSERT(hwnd);
        if (!hwnd) {
            return;
        }
        ::SetWindowPos(hwnd, nullptr, 0, 0, 0, 0,
                       SWP_NOACTIVATE | SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOOWNERZORDER |
                           SWP_FRAMECHANGED);
    }

    static inline quint32 getDpiForWindow(HWND hwnd) {
@@ -213,6 +245,22 @@
        return (windowRect == mi.value_or(MONITORINFOEXW{}).rcMonitor);
    }

    static inline bool isWindowNoState(HWND hwnd) {
        Q_ASSERT(hwnd);
        if (!hwnd) {
            return false;
        }
#if 0
        WINDOWPLACEMENT wp{};
        wp.length = sizeof(wp);
        ::GetWindowPlacement(hwnd, &wp);
        return ((wp.showCmd == SW_NORMAL) || (wp.showCmd == SW_RESTORE));
#else
        const auto style = static_cast<DWORD>(::GetWindowLongPtrW(hwnd, GWL_STYLE));
        return (!(style & (WS_MINIMIZE | WS_MAXIMIZE)));
#endif
    }

    static inline QPoint fromNativeLocalPosition(const QWindow *window, const QPoint &point) {
        Q_ASSERT(window);
        if (!window) {
@@ -249,7 +297,7 @@
            case HTBORDER:
                return Win32WindowContext::FixedBorder;
            default:
                break;
                break; // unreachable
        }
        return Win32WindowContext::Outside;
    }
@@ -315,11 +363,11 @@

        static inline void install() {
            instance = new WindowsNativeEventFilter();
            qApp->installNativeEventFilter(instance);
            installNativeEventFilter(instance);
        }

        static inline void uninstall() {
            qApp->removeNativeEventFilter(instance);
            removeNativeEventFilter(instance);
            delete instance;
            instance = nullptr;
        }
@@ -407,8 +455,8 @@
        return ::CallWindowProcW(g_qtWindowProc, hWnd, message, wParam, lParam);
    }

    Win32WindowContext::Win32WindowContext(QWindow *window, WindowItemDelegate *delegate)
        : AbstractWindowContext(window, delegate) {
    Win32WindowContext::Win32WindowContext(QObject *host, WindowItemDelegate *delegate)
        : AbstractWindowContext(host, delegate) {
    }

    Win32WindowContext::~Win32WindowContext() {
@@ -424,9 +472,12 @@
    }

    bool Win32WindowContext::setup() {
        auto winId = m_windowHandle->winId();
        if (!m_windowHandle) {
            return false;
        }

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

        // Store original window proc
@@ -994,9 +1045,348 @@
                *result = wParam == FALSE ? FALSE : WVR_REDRAW;
                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，虽然看起来效果还不错，但对于此项目而言，代码和窗口结构过于复
                // 杂，因此我没有采用此方案。然而，对于具体的软件项目而言，其做法也
                // 不失为一个优秀的解决方案，毕竟其在大多数条件下的表现都还可以。
                //
                // 和1.x的做法不同，现在的2.x选择了保留窗口三边，去除整个窗口顶部，
                // 好处是保留了系统的原生边框，外观较好，且与系统结合紧密，而且resize
                // 的表现也有很大改善，缺点是需要自行绘制顶部边框线。原本以为只能像
                // Windows Terminal那样在WM_PAINT里搞黑魔法，但后来发现，其实只
                // 要颜色相近，我们自行绘制一根实线也几乎能以假乱真，而且这样也不会
                // 破坏Qt自己的绘制系统，能做到不依赖黑魔法就能实现像Windows Terminal
                // 那样外观和功能都比较完美的自定义边框。

                // 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.
                //
                // Unlike the 1.x code, we choose to preserve the three edges of the
                // window in 2.x, and get rid of the whole top part of the window.
                // There are quite some advantages such as the appearance looks much
                // better and due to we have the original system window frame, our
                // window can behave just like a normal Win32 window even if we now
                // doesn't have a title bar at all. Most importantly, the flicker and
                // jitter during window resizing is totally gone now. The disadvantage
                // is we have to draw a top frame border ourselves. Previously I thought
                // we have to do the black magic in WM_PAINT just like what Windows
                // 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)); //
                });

                POINT nativeGlobalPos{GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)};
                POINT nativeLocalPos = nativeGlobalPos;
                ::ScreenToClient(hWnd, &nativeLocalPos);

                RECT clientRect{0, 0, 0, 0};
                ::GetClientRect(hWnd, &clientRect);
                auto clientWidth = RECT_WIDTH(clientRect);
                auto clientHeight = RECT_HEIGHT(clientRect);

                QPoint qtScenePos = fromNativeLocalPosition(
                    m_windowHandle, QPoint(nativeLocalPos.x, nativeLocalPos.y));

                bool isFixedSize = /*isWindowFixedSize()*/ false; // ### FIXME
                bool isTitleBar = isInTitleBarDraggableArea(qtScenePos);
                bool dontOverrideCursor = false;                  // ### TODO

                CoreWindowAgent::SystemButton sysButtonType = CoreWindowAgent::Unknown;
                if (!isFixedSize && isInSystemButtons(qtScenePos, &sysButtonType)) {
                    // Firstly, we set the hit test result to a default value to be able to detect
                    // whether we have changed it or not afterwards.
                    *result = HTNOWHERE;
                    // Even if the mouse is inside the chrome button area now, we should still allow
                    // the user to be able to resize the window with the top or right window border,
                    // this is also the normal behavior of a native Win32 window (but only when the
                    // window is not maximized/fullscreen/minimized, of course).
                    if (isWindowNoState(hWnd)) {
                        static constexpr const int kBorderSize = 2;
                        bool isTop = (nativeLocalPos.y <= kBorderSize);
                        bool isRight = (nativeLocalPos.x >= (clientWidth - kBorderSize));
                        if (isTop || isRight) {
                            if (dontOverrideCursor) {
                                // The user doesn't want the window to be resized, so we tell
                                // Windows we are in the client area so that the controls beneath
                                // the mouse cursor can still be hovered or clicked.
                                *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                            } else {
                                if (isTop && isRight) {
                                    *result = HTTOPRIGHT;
                                } else if (isTop) {
                                    *result = HTTOP;
                                } else {
                                    *result = HTRIGHT;
                                }
                            }
                        }
                    }
                    if (*result == HTNOWHERE) {
                        // OK, we are now really inside one of the chrome buttons, tell Windows the
                        // exact role of our button. The Snap Layout feature introduced in Windows
                        // 11 won't work without this.
                        switch (sysButtonType) {
                            case CoreWindowAgent::WindowIcon:
                                *result = HTSYSMENU;
                                break;
                            case CoreWindowAgent::Help:
                                *result = HTHELP;
                                break;
                            case CoreWindowAgent::Minimize:
                                *result = HTREDUCE;
                                break;
                            case CoreWindowAgent::Maximize:
                                *result = HTZOOM;
                                break;
                            case CoreWindowAgent::Close:
                                *result = HTCLOSE;
                                break;
                            case CoreWindowAgent::Unknown:
                                break;
                            default:
                                break; // unreachable
                        }
                    }
                    if (*result == HTNOWHERE) {
                        // OK, it seems we are not inside the window resize area, nor inside the
                        // chrome buttons, tell Windows we are in the client area to let Qt handle
                        // this event.
                        *result = HTCLIENT;
                    }
                    return true;
                }
                // OK, we are not inside any chrome buttons, try to find out which part of the
                // window are we hitting.

                bool max = IsMaximized(hWnd);
                bool full = isFullScreen(hWnd);
                int frameSize = getResizeBorderThickness(hWnd);
                bool isTop = (nativeLocalPos.y < frameSize);

                if (isWin10OrGreater()) {
                    // This will handle the left, right and bottom parts of the frame
                    // because we didn't change them.
                    LRESULT originalHitTestResult = ::DefWindowProcW(hWnd, WM_NCHITTEST, 0, lParam);
                    if (originalHitTestResult != HTCLIENT) {
                        // Even if the window is not resizable, we still can't return HTCLIENT here
                        // because when we enter this code path, it means the mouse cursor is
                        // outside the window, that is, the three transparent window resize area.
                        // Returning HTCLIENT will confuse Windows, we can't put our controls there
                        // anyway.
                        *result = ((isFixedSize || dontOverrideCursor) ? HTBORDER
                                                                       : originalHitTestResult);
                        return true;
                    }
                    if (full) {
                        *result = HTCLIENT;
                        return true;
                    }
                    if (max) {
                        *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                        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 (isTop) {
                        // Return HTCLIENT instead of HTBORDER here, because the mouse is
                        // inside our homemade title bar now, return HTCLIENT to let our
                        // title bar can still capture mouse events.
                        *result = ((isFixedSize || dontOverrideCursor)
                                       ? (isTitleBar ? HTCAPTION : HTCLIENT)
                                       : HTTOP);
                        return true;
                    }
                    if (isTitleBar) {
                        *result = HTCAPTION;
                        return true;
                    }
                    *result = HTCLIENT;
                } else {
                    if (full) {
                        *result = HTCLIENT;
                        return true;
                    }
                    if (max) {
                        *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                        return true;
                    }
                    if (!isFixedSize) {
                        const bool isBottom = (nativeLocalPos.y >= (clientHeight - frameSize));
                        // Make the border a little wider to let the user easy to resize on corners.
                        const auto scaleFactor = ((isTop || isBottom) ? qreal(2) : qreal(1));
                        const int scaledFrameSizeX = std::round(qreal(frameSize) * scaleFactor);
                        const bool isLeft = (nativeLocalPos.x < scaledFrameSizeX);
                        const bool isRight = (nativeLocalPos.x >= (clientWidth - scaledFrameSizeX));
                        if (dontOverrideCursor && (isTop || isBottom || isLeft || isRight)) {
                            // Return HTCLIENT instead of HTBORDER here, because the mouse is
                            // inside the window now, return HTCLIENT to let the controls
                            // inside our window can still capture mouse events.
                            *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                            return true;
                        }
                        if (isTop) {
                            if (isLeft) {
                                *result = HTTOPLEFT;
                                return true;
                            }
                            if (isRight) {
                                *result = HTTOPRIGHT;
                                return true;
                            }
                            *result = HTTOP;
                            return true;
                        }
                        if (isBottom) {
                            if (isLeft) {
                                *result = HTBOTTOMLEFT;
                                return true;
                            }
                            if (isRight) {
                                *result = HTBOTTOMRIGHT;
                                return true;
                            }
                            *result = HTBOTTOM;
                            return true;
                        }
                        if (isLeft) {
                            *result = HTLEFT;
                            return true;
                        }
                        if (isRight) {
                            *result = HTRIGHT;
                            return true;
                        }
                    }
                    if (isTitleBar) {
                        *result = HTCAPTION;
                        return true;
                    }
                    *result = HTCLIENT;
                }
                return true;
            }
            default:
                break;
        }
        if (!isWin10OrGreater()) {
            switch (message) {
                case WM_NCUAHDRAWCAPTION:
                case WM_NCUAHDRAWFRAME: {
                    // These undocumented messages are sent to draw themed window
                    // borders. Block them to prevent drawing borders over the client
                    // area.
                    *result = FALSE;
                    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 (!isDwmCompositionEnabled()) {
                        // 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 = FALSE;
                        return true;
                    } else {
                        break;
                    }
                }
                case WM_NCACTIVATE: {
                    if (isDwmCompositionEnabled()) {
                        // 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" here, otherwise the window won't respond to the
                        // window activation state change.
                        *result = ::DefWindowProcW(hWnd, WM_NCACTIVATE, wParam, -1);
                    } else {
                        if (wParam == FALSE) {
                            *result = TRUE;
                        } else {
                            *result = FALSE;
                        }
                    }
                    return true;
                }
                case WM_SETICON:
                case WM_SETTEXT: {
                    // Disable painting while these messages are handled to prevent them
                    // from drawing a window caption over the client area.
                    const auto oldStyle = static_cast<DWORD>(::GetWindowLongPtrW(hWnd, GWL_STYLE));
                    // Prevent Windows from drawing the default title bar by temporarily
                    // toggling the WS_VISIBLE style.
                    const DWORD newStyle = (oldStyle & ~WS_VISIBLE);
                    ::SetWindowLongPtrW(hWnd, GWL_STYLE, static_cast<LONG_PTR>(newStyle));
                    triggerFrameChange(hWnd);
                    const LRESULT originalResult = ::DefWindowProcW(hWnd, message, wParam, lParam);
                    ::SetWindowLongPtrW(hWnd, GWL_STYLE, static_cast<LONG_PTR>(oldStyle));
                    triggerFrameChange(hWnd);
                    *result = originalResult;
                    return true;
                }
                default:
                    break;
            }
        }
        return false;
    }