Improve fixed width/height/size hit testing

Zhao Yuhang

2024-05-23 6002cd46a2c5a1c2c4afdbf8e491e76f68b9bfd8

 src/core/contexts/win32windowcontext.cpp

@@ -81,6 +81,8 @@

    static void setInternalWindowFrameMargins(QWindow *window, const QMargins &margins) {
        const QVariant marginsVar = QVariant::fromValue(margins);

        // TODO: Add comments
        window->setProperty("_q_windowsCustomMargins", marginsVar);
#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
        if (QPlatformWindow *platformWindow = window->handle()) {
@@ -124,6 +126,36 @@
                       SWP_NOACTIVATE | SWP_NOSIZE | SWP_NOZORDER | SWP_NOOWNERZORDER);
    }

    static inline bool isFullScreen(HWND hwnd) {
        RECT windowRect{};
        ::GetWindowRect(hwnd, &windowRect);
        // Compare to the full area of the screen, not the work area.
        return (windowRect == getMonitorForWindow(hwnd).rcMonitor);
    }

    static inline bool isMaximized(HWND hwnd) {
        return ::IsZoomed(hwnd);
    }

    static inline bool isMinimized(HWND hwnd) {
        return ::IsIconic(hwnd);
    }

    static inline bool isWindowNoState(HWND hwnd) {
#if 0
        WINDOWPLACEMENT wp{};
        wp.length = sizeof(wp);
        ::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
    }

    static inline void bringWindowToFront(HWND hwnd) {
        HWND oldForegroundWindow = ::GetForegroundWindow();
        if (!oldForegroundWindow) {
@@ -135,7 +167,7 @@
        if (!::IsWindowVisible(hwnd)) {
            ::ShowWindow(hwnd, SW_SHOW);
        }
        if (IsMinimized(hwnd)) {
        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.
@@ -170,28 +202,6 @@
        ::SetActiveWindow(hwnd);
        // Throw us on the active monitor.
        moveWindowToMonitor(hwnd, activeMonitor);
    }

    static inline bool isFullScreen(HWND hwnd) {
        RECT windowRect{};
        ::GetWindowRect(hwnd, &windowRect);
        // Compare to the full area of the screen, not the work area.
        return (windowRect == getMonitorForWindow(hwnd).rcMonitor);
    }

    static inline bool isWindowNoState(HWND hwnd) {
#if 0
        WINDOWPLACEMENT wp{};
        wp.length = sizeof(wp);
        ::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
    }

    static void syncPaintEventWithDwm() {
@@ -250,7 +260,7 @@
            return true;
        }

        const bool maxOrFull = IsMaximized(hWnd) || isFullScreen(hWnd);
        const bool maxOrFull = isMaximized(hWnd) || isFullScreen(hWnd);
        ::EnableMenuItem(hMenu, SC_CLOSE, (MF_BYCOMMAND | MFS_ENABLED));
        ::EnableMenuItem(hMenu, SC_MAXIMIZE,
                         (MF_BYCOMMAND | ((maxOrFull || fixedSize) ? MFS_DISABLED : MFS_ENABLED)));
@@ -821,6 +831,12 @@
        if (key == QStringLiteral("border-thickness")) {
            return m_windowId
                       ? int(getWindowFrameBorderThickness(reinterpret_cast<HWND>(m_windowId)))
                       : 0;
        }

        if (key == QStringLiteral("title-bar-height")) {
            return m_windowId
                       ? int(getTitleBarHeight(reinterpret_cast<HWND>(m_windowId)))
                       : 0;
        }
        return AbstractWindowContext::windowAttribute(key);
@@ -1567,12 +1583,21 @@
                QPoint qtScenePos = QHighDpi::fromNativeLocalPosition(point2qpoint(nativeLocalPos),
                                                                      m_windowHandle.data());

                int frameSize = getResizeBorderThickness(hWnd);

                bool isFixedWidth = isHostWidthFixed();
                bool isFixedHeight = isHostHeightFixed();
                bool isFixedSize = isHostSizeFixed();
                bool isTitleBar = isInTitleBarDraggableArea(qtScenePos);
                bool isInLeftBorder = nativeLocalPos.x <= frameSize;
                bool isInTopBorder = nativeLocalPos.y <= frameSize;
                bool isInRightBorder = nativeLocalPos.x > clientWidth - frameSize;
                bool isInBottomBorder = nativeLocalPos.y > clientHeight - frameSize;
                bool isInTitleBar = isInTitleBarDraggableArea(qtScenePos);
                WindowAgentBase::SystemButton sysButtonType = WindowAgentBase::Unknown;
                bool isInCaptionButtons = isInSystemButtons(qtScenePos, &sysButtonType);
                bool dontOverrideCursor = false; // ### TODO

                WindowAgentBase::SystemButton sysButtonType = WindowAgentBase::Unknown;
                if (!isFixedSize && isInSystemButtons(qtScenePos, &sysButtonType)) {
                if (isInCaptionButtons) {
                    // 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;
@@ -1582,29 +1607,41 @@
                    // window is not maximized/fullscreen/minimized, of course).
                    if (isWindowNoState(hWnd)) {
                        static constexpr const quint8 kBorderSize = 2;
                        bool isTop = (nativeLocalPos.y <= kBorderSize);
                        bool isTop = nativeLocalPos.y <= kBorderSize;
                        bool isLeft = nativeLocalPos.x <= kBorderSize;
                        bool isRight = (nativeLocalPos.x >= (clientWidth - kBorderSize));
                        bool isRight = nativeLocalPos.x > clientWidth - kBorderSize;
                        if (isTop || isLeft || isRight) {
                            if (dontOverrideCursor) {
                            if (isFixedSize || 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);
                                *result = isInTitleBar ? HTCAPTION : HTCLIENT;
                            } else {
                                if (isTop) {
                                    if (isLeft) {
                                        *result = HTTOPLEFT;
                                        if (isFixedWidth) {
                                            *result = HTTOP;
                                        } else if (isFixedHeight) {
                                            *result = HTLEFT;
                                        } else {
                                            *result = HTTOPLEFT;
                                        }
                                    } else if (isRight) {
                                        *result = HTTOPRIGHT;
                                        if (isFixedWidth) {
                                            *result = HTTOP;
                                        } else if (isFixedHeight) {
                                            *result = HTRIGHT;
                                        } else {
                                            *result = HTTOPRIGHT;
                                        }
                                    } else {
                                        *result = HTTOP;
                                        *result = isFixedHeight ? HTBORDER : HTTOP;
                                    }
                                } else {
                                    if (isLeft) {
                                        *result = HTLEFT;
                                    if (isFixedWidth) {
                                        *result = HTBORDER;
                                    } else {
                                        *result = HTRIGHT;
                                        *result = isLeft ? HTLEFT : HTRIGHT;
                                    }
                                }
                            }
@@ -1646,10 +1683,8 @@
                // 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 max = isMaximized(hWnd);
                bool full = isFullScreen(hWnd);
                int frameSize = getResizeBorderThickness(hWnd);
                bool isTop = (nativeLocalPos.y < frameSize);

                if (isSystemBorderEnabled()) {
                    // This will handle the left, right and bottom parts of the frame
@@ -1661,8 +1696,48 @@
                        // 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);
                        *result = HTNOWHERE; // Make sure we can know we don't set any value explicitly later.
                        if (originalHitTestResult == HTCAPTION) {
                        } else if (isFixedSize || dontOverrideCursor) {
                            *result = HTBORDER;
                        } else if (isFixedWidth || isFixedHeight) {
                            if (originalHitTestResult == HTTOPLEFT) {
                                if (isFixedWidth) {
                                    *result = HTTOP;
                                } else {
                                    *result = HTLEFT;
                                }
                            } else if (originalHitTestResult == HTTOPRIGHT) {
                                if (isFixedWidth) {
                                    *result = HTTOP;
                                } else {
                                    *result = HTRIGHT;
                                }
                            } else if (originalHitTestResult == HTBOTTOMRIGHT) {
                                if (isFixedWidth) {
                                    *result = HTBOTTOM;
                                } else {
                                    *result = HTRIGHT;
                                }
                            } else if (originalHitTestResult == HTBOTTOMLEFT) {
                                if (isFixedWidth) {
                                    *result = HTBOTTOM;
                                } else {
                                    *result = HTLEFT;
                                }
                            } else if (originalHitTestResult == HTLEFT || originalHitTestResult == HTRIGHT) {
                                if (isFixedWidth) {
                                    *result = HTBORDER;
                                }
                            } else if (originalHitTestResult == HTTOP || originalHitTestResult == HTBOTTOM) {
                                if (isFixedHeight) {
                                    *result = HTBORDER;
                                }
                            }
                        }
                        if (*result == HTNOWHERE) {
                            *result = originalHitTestResult;
                        }
                        return true;
                    }
                    if (full) {
@@ -1670,7 +1745,7 @@
                        return true;
                    }
                    if (max) {
                        *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                        *result = isInTitleBar ? HTCAPTION : HTCLIENT;
                        return true;
                    }
                    // At this point, we know that the cursor is inside the client area,
@@ -1678,16 +1753,24 @@
                    // 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) {
                    if (isInTopBorder) {
                        // 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);
                        *result = [&]() {
                            if (isFixedSize || isFixedHeight || dontOverrideCursor || (isFixedWidth && (isInLeftBorder || isInRightBorder))) {
                                if (isInTitleBar) {
                                    return HTCAPTION;
                                } else {
                                    return HTCLIENT;
                                }
                            } else {
                                return HTTOP;
                            }
                        }();
                        return true;
                    }
                    if (isTitleBar) {
                    if (isInTitleBar) {
                        *result = HTCAPTION;
                        return true;
                    }
@@ -1698,58 +1781,86 @@
                        *result = HTCLIENT;
                        return true;
                    }
                    if (max) {
                        *result = (isTitleBar ? HTCAPTION : HTCLIENT);
                    if (max || isFixedSize || dontOverrideCursor) {
                        *result = isInTitleBar ? 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 scaledFrameSize = std::round(qreal(frameSize) * scaleFactor);
                        const bool isLeft = (nativeLocalPos.x < scaledFrameSize);
                        const bool isRight = (nativeLocalPos.x >= (clientWidth - scaledFrameSize));
                        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 (isFixedWidth || isFixedHeight) {
                        if (isInLeftBorder && isInTopBorder) {
                            if (isFixedWidth) {
                                *result = HTTOP;
                            } else {
                                *result = HTLEFT;
                            }
                        } else if (isInRightBorder && isInTopBorder) {
                            if (isFixedWidth) {
                                *result = HTTOP;
                            } else {
                                *result = HTRIGHT;
                            }
                        } else if (isInRightBorder && isInBottomBorder) {
                            if (isFixedWidth) {
                                *result = HTBOTTOM;
                            } else {
                                *result = HTRIGHT;
                            }
                        } else if (isInLeftBorder && isInBottomBorder) {
                            if (isFixedWidth) {
                                *result = HTBOTTOM;
                            } else {
                                *result = HTLEFT;
                            }
                        } else if (isInLeftBorder || isInRightBorder) {
                            if (isFixedWidth) {
                                *result = HTCLIENT;
                            } else {
                                *result = isInLeftBorder ? HTLEFT : HTRIGHT;
                            }
                        } else if (isInTopBorder || isInBottomBorder) {
                            if (isFixedHeight) {
                                *result = HTCLIENT;
                            } else {
                                *result = isInTopBorder ? HTTOP : HTBOTTOM;
                            }
                        } else {
                            *result = HTCLIENT;
                        }
                        if (isTop) {
                            if (isLeft) {
                        return true;
                    } else {
                        if (isInTopBorder) {
                            if (isInLeftBorder) {
                                *result = HTTOPLEFT;
                                return true;
                            }
                            if (isRight) {
                            if (isInRightBorder) {
                                *result = HTTOPRIGHT;
                                return true;
                            }
                            *result = HTTOP;
                            return true;
                        }
                        if (isBottom) {
                            if (isLeft) {
                        if (isInBottomBorder) {
                            if (isInLeftBorder) {
                                *result = HTBOTTOMLEFT;
                                return true;
                            }
                            if (isRight) {
                            if (isInRightBorder) {
                                *result = HTBOTTOMRIGHT;
                                return true;
                            }
                            *result = HTBOTTOM;
                            return true;
                        }
                        if (isLeft) {
                        if (isInLeftBorder) {
                            *result = HTLEFT;
                            return true;
                        }
                        if (isRight) {
                        if (isInRightBorder) {
                            *result = HTRIGHT;
                            return true;
                        }
                    }
                    if (isTitleBar) {
                    if (isInTitleBar) {
                        *result = HTCAPTION;
                        return true;
                    }
@@ -1942,9 +2053,9 @@
            // that's also how most applications customize their title bars on Windows. It's
            // totally OK but since we want to preserve as much original frame as possible,
            // we can't use that solution.
            const LRESULT hitTestResult = ::DefWindowProcW(hWnd, WM_NCCALCSIZE, wParam, lParam);
            if ((hitTestResult != HTERROR) && (hitTestResult != HTNOWHERE)) {
                *result = hitTestResult;
            const LRESULT originalResult = ::DefWindowProcW(hWnd, WM_NCCALCSIZE, wParam, lParam);
            if (originalResult != 0) {
                *result = originalResult;
                return true;
            }
            // Re-apply the original top from before the size of the default frame was
@@ -1958,7 +2069,7 @@
            clientRect->top = originalTop;
        }

        const bool max = IsMaximized(hWnd);
        const bool max = isMaximized(hWnd);
        const bool full = isFullScreen(hWnd);
        // 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
@@ -2073,7 +2184,7 @@
            return {GET_X_LPARAM(lParam), GET_Y_LPARAM(lParam)};
        };
        const auto getNativeGlobalPosFromKeyboard = [hWnd]() -> POINT {
            const bool maxOrFull = IsMaximized(hWnd) || isFullScreen(hWnd);
            const bool maxOrFull = isMaximized(hWnd) || isFullScreen(hWnd);
            const quint32 frameSize = getResizeBorderThickness(hWnd);
            const quint32 horizontalOffset =
                ((maxOrFull || !isSystemBorderEnabled()) ? 0 : frameSize);