File indexing completed on 2024-05-19 13:14:18

 /*
  * breezewindowmanager.cpp
  * pass some window mouse press/release/move event actions to window manager
  * Largely inspired from BeSpin style
  *
  * SPDX-FileCopyrightText: 2007 Thomas Luebking <thomas.luebking@web.de>
  * SPDX-FileCopyrightText: 2014 Hugo Pereira Da Costa <hugo.pereira@free.fr>
  *
  * SPDX-License-Identifier: GPL-2.0-or-later OR MIT
  */
 
 #include "breezewindowmanager.h"
 #include "breezehelper.h"
 #include "breezepropertynames.h"
 
 #include <QComboBox>
 #include <QDialog>
 #include <QDockWidget>
 #include <QGraphicsView>
 #include <QGroupBox>
 #include <QLabel>
 #include <QListView>
 #include <QMainWindow>
 #include <QMdiSubWindow>
 #include <QMenuBar>
 #include <QMouseEvent>
 #include <QProgressBar>
 #include <QScreen>
 #include <QScrollBar>
 #include <QStatusBar>
 #include <QStyle>
 #include <QStyleOptionGroupBox>
 #include <QTabBar>
 #include <QTabWidget>
 #include <QToolBar>
 #include <QToolButton>
 #include <QTreeView>
 
 #include <QTextStream>
 
 // needed to deal with device pixel ratio
 #include <QWindow>
 
 #if BREEZE_HAVE_QTQUICK
 // needed to enable dragging from QQuickWindows
 #include <QQuickRenderControl>
 #include <QQuickWindow>
 #endif
 
 namespace Util
 {
 template<class T>
 inline T makeT(std::initializer_list<typename T::key_type> &&reference)
 {
     return T(std::move(reference));
 }
 }
 
 namespace Breeze
 {
 //* provide application-wise event filter
 /**
 it us used to unlock dragging and make sure event look is properly restored
 after a drag has occurred
 */
 class AppEventFilter : public QObject
 {
 public:
     //* constructor
     explicit AppEventFilter(WindowManager *parent)
         : QObject(parent)
         , _parent(parent)
     {
     }
 
     //* event filter
     bool eventFilter(QObject *object, QEvent *event) override
     {
         if (event->type() == QEvent::MouseButtonRelease) {
             // stop drag timer
             if (_parent->_dragTimer.isActive()) {
                 _parent->resetDrag();
             }
 
             // unlock
             if (_parent->isLocked()) {
                 _parent->setLocked(false);
             }
         }
 
         if (!_parent->enabled()) {
             return false;
         }
 
         /*
         if a drag is in progress, the widget will not receive any event
         we trigger on the first MouseMove or MousePress events that are received
         by any widget in the application to detect that the drag is finished
         */
         if (_parent->_dragInProgress && _parent->_target && (event->type() == QEvent::MouseMove || event->type() == QEvent::MouseButtonPress)) {
             return appMouseEvent(object, event);
         }
 
         return false;
     }
 
 protected:
     //* application-wise event.
     /** needed to catch end of XMoveResize events */
     bool appMouseEvent(QObject *, QEvent *event)
     {
         Q_UNUSED(event);
 
         /*
         post some mouseRelease event to the target, in order to counter balance
         the mouse press that triggered the drag. Note that it triggers a resetDrag
         */
         QMouseEvent mouseEvent(QEvent::MouseButtonRelease, _parent->_dragPoint, Qt::LeftButton, Qt::LeftButton, Qt::NoModifier);
         qApp->sendEvent(_parent->_target.data(), &mouseEvent);
 
         return false;
     }
 
 private:
     //* parent
     WindowManager *_parent = nullptr;
 };
 
 //_____________________________________________________________
 WindowManager::WindowManager(QObject *parent)
     : QObject(parent)
 {
     // install application wise event filter
     _appEventFilter = new AppEventFilter(this);
     qApp->installEventFilter(_appEventFilter);
 }
 
 //_____________________________________________________________
 void WindowManager::initialize()
 {
     setEnabled(StyleConfigData::windowDragMode() != StyleConfigData::WD_NONE);
     setDragMode(StyleConfigData::windowDragMode());
     setDragDistance(QApplication::startDragDistance());
     setDragDelay(QApplication::startDragTime());
 
     initializeWhiteList();
     initializeBlackList();
 }
 
 //_____________________________________________________________
 void WindowManager::registerWidget(QWidget *widget)
 {
     if (isBlackListed(widget) || isDragable(widget) || widget->inherits("QQuickWidget")) {
         /*
         install filter for dragable widgets.
         also install filter for blacklisted widgets
         to be able to catch the relevant events and prevent
         the drag to happen
         */
         widget->removeEventFilter(this);
         widget->installEventFilter(this);
     }
 }
 
 #if BREEZE_HAVE_QTQUICK
 //_____________________________________________________________
 void WindowManager::registerQuickItem(QQuickItem *item)
 {
     if (!item) {
         return;
     }
 
     if (auto window = item->window()) {
         auto contentItem = window->contentItem();
         contentItem->setAcceptedMouseButtons(Qt::LeftButton);
         contentItem->removeEventFilter(this);
         contentItem->installEventFilter(this);
     }
 }
 #endif
 
 //_____________________________________________________________
 void WindowManager::unregisterWidget(QWidget *widget)
 {
     if (widget) {
         widget->removeEventFilter(this);
     }
 }
 
 //_____________________________________________________________
 void WindowManager::initializeWhiteList()
 {
     _whiteList = Util::makeT<ExceptionSet>({ExceptionId(QStringLiteral("MplayerWindow")),
                                             ExceptionId(QStringLiteral("ViewSliders@kmix")),
                                             ExceptionId(QStringLiteral("Sidebar_Widget@konqueror"))});
 
     foreach (const QString &exception, StyleConfigData::windowDragWhiteList()) {
         ExceptionId id(exception);
         if (!id.className().isEmpty()) {
             _whiteList.insert(ExceptionId(exception));
         }
     }
 }
 
 //_____________________________________________________________
 void WindowManager::initializeBlackList()
 {
     _blackList = Util::makeT<ExceptionSet>(
         {ExceptionId(QStringLiteral("CustomTrackView@kdenlive")), ExceptionId(QStringLiteral("MuseScore")), ExceptionId(QStringLiteral("KGameCanvasWidget"))});
 
     foreach (const QString &exception, StyleConfigData::windowDragBlackList()) {
         ExceptionId id(exception);
         if (!id.className().isEmpty()) {
             _blackList.insert(ExceptionId(exception));
         }
     }
 }
 
 //_____________________________________________________________
 bool WindowManager::eventFilter(QObject *object, QEvent *event)
 {
     if (!enabled()) {
         return false;
     }
 
     switch (event->type()) {
     case QEvent::MouseButtonPress:
         return mousePressEvent(object, event);
         break;
 
     case QEvent::MouseMove:
         if (object == _target.data()
 #if BREEZE_HAVE_QTQUICK
             || object == _quickTarget.data()
 #endif
         ) {
             return mouseMoveEvent(object, event);
         }
         break;
 
     case QEvent::MouseButtonRelease:
         if (_target
 #if BREEZE_HAVE_QTQUICK
             || _quickTarget
 #endif
         ) {
             return mouseReleaseEvent(object, event);
         }
         break;
 
     default:
         break;
     }
 
     return false;
 }
 
 //_____________________________________________________________
 void WindowManager::timerEvent(QTimerEvent *event)
 {
     if (event->timerId() == _dragTimer.timerId()) {
         _dragTimer.stop();
         setLocked(false);
         if (_target) {
             startDrag(_target.data()->window()->windowHandle());
         }
 #if BREEZE_HAVE_QTQUICK
         else if (_quickTarget) {
             _quickTarget.data()->ungrabMouse();
             startDrag(_quickTarget.data()->window());
         }
 #endif
         resetDrag();
     } else {
         return QObject::timerEvent(event);
     }
 }
 
 //_____________________________________________________________
 bool WindowManager::mousePressEvent(QObject *object, QEvent *event)
 {
     // cast event and check buttons/modifiers
     auto mouseEvent = static_cast<QMouseEvent *>(event);
     if (mouseEvent->source() != Qt::MouseEventNotSynthesized) {
         return false;
     }
     if (!(mouseEvent->modifiers() == Qt::NoModifier && mouseEvent->button() == Qt::LeftButton)) {
         return false;
     }
 
     // If we are in a QQuickWidget we don't want to ever do dragging from a qwidget in the
     // hyerarchy, but only from an internal item, if any. If any event handler will manage
     // the event, we don't want the drag to start
     if (object->inherits("QQuickWidget")) {
         _eventInQQuickWidget = true;
         event->setAccepted(false);
         return false;
     } else {
         _eventInQQuickWidget = false;
     }
 
     // check lock
     if (isLocked()) {
         return false;
     } else {
         setLocked(true);
     }
 
 #if BREEZE_HAVE_QTQUICK
     // check QQuickItem - we can immediately start drag, because QQuickWindow's contentItem
     // only receives mouse events that weren't handled by children
     if (auto item = qobject_cast<QQuickItem *>(object)) {
         _quickTarget = item;
         _dragPoint = mouseEvent->pos();
         _globalDragPoint = mouseEvent->globalPos();
 
         if (_dragTimer.isActive()) {
             _dragTimer.stop();
         }
         _dragTimer.start(_dragDelay, this);
 
         return true;
     }
 #endif
 
     if (_eventInQQuickWidget) {
         event->setAccepted(true);
         return false;
     }
     _eventInQQuickWidget = false;
 
     // cast to widget
     auto widget = static_cast<QWidget *>(object);
 
     // check if widget can be dragged from current position
     if (isBlackListed(widget) || !canDrag(widget)) {
         return false;
     }
 
     // retrieve widget's child at event position
     auto position(mouseEvent->pos());
     auto child = widget->childAt(position);
     if (!canDrag(widget, child, position)) {
         return false;
     }
 
     // save target and drag point
     _target = widget;
     _dragPoint = position;
     _globalDragPoint = mouseEvent->globalPos();
     _dragAboutToStart = true;
 
     // send a move event to the current child with same position
     // if received, it is caught to actually start the drag
     auto localPoint(_dragPoint);
     if (child) {
         localPoint = child->mapFrom(widget, localPoint);
     } else {
         child = widget;
     }
     QMouseEvent localMouseEvent(QEvent::MouseMove, localPoint, Qt::LeftButton, Qt::LeftButton, Qt::NoModifier);
     qApp->sendEvent(child, &localMouseEvent);
 
     // never eat event
     return false;
 }
 
 //_____________________________________________________________
 bool WindowManager::mouseMoveEvent(QObject *object, QEvent *event)
 {
     Q_UNUSED(object);
 
     // stop timer
     if (_dragTimer.isActive()) {
         _dragTimer.stop();
     }
 
     // cast event and check drag distance
     auto mouseEvent = static_cast<QMouseEvent *>(event);
     if (mouseEvent->source() != Qt::MouseEventNotSynthesized) {
         return false;
     }
     if (!_dragInProgress) {
         if (_dragAboutToStart) {
             if (mouseEvent->pos() == _dragPoint) {
                 // start timer,
                 _dragAboutToStart = false;
                 if (_dragTimer.isActive()) {
                     _dragTimer.stop();
                 }
                 _dragTimer.start(_dragDelay, this);
 
             } else {
                 resetDrag();
             }
 
         } else if (QPoint(mouseEvent->globalPos() - _globalDragPoint).manhattanLength() >= _dragDistance) {
             _dragTimer.start(0, this);
         }
 
         return true;
 
     } else {
         return false;
     }
 }
 
 //_____________________________________________________________
 bool WindowManager::mouseReleaseEvent(QObject *object, QEvent *event)
 {
     Q_UNUSED(object);
     Q_UNUSED(event);
     resetDrag();
     return false;
 }
 
 //_____________________________________________________________
 bool WindowManager::isDragable(QWidget *widget)
 {
     // check widget
     if (!widget) {
         return false;
     }
 
     // accepted default types
     if ((qobject_cast<QDialog *>(widget) && widget->isWindow()) || (qobject_cast<QMainWindow *>(widget) && widget->isWindow())
         || qobject_cast<QGroupBox *>(widget)) {
         return true;
     }
 
     // more accepted types, provided they are not dock widget titles
     if ((qobject_cast<QMenuBar *>(widget) || qobject_cast<QTabBar *>(widget) || qobject_cast<QStatusBar *>(widget) || qobject_cast<QToolBar *>(widget))
         && !isDockWidgetTitle(widget)) {
         return true;
     }
 
     if (widget->inherits("KScreenSaver") && widget->inherits("KCModule")) {
         return true;
     }
 
     if (isWhiteListed(widget)) {
         return true;
     }
 
     // flat toolbuttons
     if (auto toolButton = qobject_cast<QToolButton *>(widget)) {
         if (toolButton->autoRaise()) {
             return true;
         }
     }
 
     // viewports
     /*
     one needs to check that
     1/ the widget parent is a scrollarea
     2/ it matches its parent viewport
     3/ the parent is not blacklisted
     */
     if (auto listView = qobject_cast<QListView *>(widget->parentWidget())) {
         if (listView->viewport() == widget && !isBlackListed(listView)) {
             return true;
         }
     }
 
     if (auto treeView = qobject_cast<QTreeView *>(widget->parentWidget())) {
         if (treeView->viewport() == widget && !isBlackListed(treeView)) {
             return true;
         }
     }
 
     /*
     catch labels in status bars.
     this is because of kstatusbar
     who captures buttonPress/release events
     */
     if (auto label = qobject_cast<QLabel *>(widget)) {
         if (label->textInteractionFlags().testFlag(Qt::TextSelectableByMouse)) {
             return false;
         }
 
         QWidget *parent = label->parentWidget();
         while (parent) {
             if (qobject_cast<QStatusBar *>(parent)) {
                 return true;
             }
             parent = parent->parentWidget();
         }
     }
 
     return false;
 }
 
 //_____________________________________________________________
 bool WindowManager::isBlackListed(QWidget *widget)
 {
     // check against noAnimations property
     const auto propertyValue(widget->property(PropertyNames::noWindowGrab));
     if (propertyValue.isValid() && propertyValue.toBool()) {
         return true;
     }
 
     // list-based blacklisted widgets
     const auto appName(qApp->applicationName());
     foreach (const ExceptionId &id, _blackList) {
         if (!id.appName().isEmpty() && id.appName() != appName) {
             continue;
         }
         if (id.className() == QStringLiteral("*") && !id.appName().isEmpty()) {
             // if application name matches and all classes are selected
             // disable the grabbing entirely
             setEnabled(false);
             return true;
         }
         if (widget->inherits(id.className().toLatin1().data())) {
             return true;
         }
     }
 
     return false;
 }
 
 //_____________________________________________________________
 bool WindowManager::isWhiteListed(QWidget *widget) const
 {
     const auto appName(qApp->applicationName());
     foreach (const ExceptionId &id, _whiteList) {
         if (!(id.appName().isEmpty() || id.appName() == appName)) {
             continue;
         }
         if (widget->inherits(id.className().toLatin1().data())) {
             return true;
         }
     }
 
     return false;
 }
 
 //_____________________________________________________________
 bool WindowManager::canDrag(QWidget *widget)
 {
     // check if enabled
     if (!enabled()) {
         return false;
     }
 
     // assume isDragable widget is already passed
     // check some special cases where drag should not be effective
 
     // check mouse grabber
     if (QWidget::mouseGrabber()) {
         return false;
     }
 
     /*
     check cursor shape.
     Assume that a changed cursor means that some action is in progress
     and should prevent the drag
     */
     if (widget->cursor().shape() != Qt::ArrowCursor) {
         return false;
     }
 
     // accept
     return true;
 }
 
 //_____________________________________________________________
 bool WindowManager::canDrag(QWidget *widget, QWidget *child, const QPoint &position)
 {
     // retrieve child at given position and check cursor again
     if (child && child->cursor().shape() != Qt::ArrowCursor) {
         return false;
     }
 
     /*
     check against children from which drag should never be enabled,
     even if mousePress/Move has been passed to the parent
     */
     if (child && (qobject_cast<QComboBox *>(child) || qobject_cast<QProgressBar *>(child) || qobject_cast<QScrollBar *>(child))) {
         return false;
     }
 
     // tool buttons
     if (auto toolButton = qobject_cast<QToolButton *>(widget)) {
         if (dragMode() == StyleConfigData::WD_MINIMAL && !qobject_cast<QToolBar *>(widget->parentWidget())) {
             return false;
         }
         return toolButton->autoRaise() && !toolButton->isEnabled();
     }
 
     // check menubar
     if (auto menuBar = qobject_cast<QMenuBar *>(widget)) {
         // do not drag from menubars embedded in Mdi windows
         if (findParent<QMdiSubWindow *>(widget)) {
             return false;
         }
 
         // check if there is an active action
         if (menuBar->activeAction() && menuBar->activeAction()->isEnabled()) {
             return false;
         }
 
         // check if action at position exists and is enabled
         if (auto action = menuBar->actionAt(position)) {
             if (action->isSeparator()) {
                 return true;
             }
             if (action->isEnabled()) {
                 return false;
             }
         }
 
         // return true in all other cases
         return true;
     }
 
     /*
     in MINIMAL mode, anything that has not been already accepted
     and does not come from a toolbar is rejected
     */
     if (dragMode() == StyleConfigData::WD_MINIMAL) {
         if (qobject_cast<QToolBar *>(widget)) {
             return true;
         } else {
             return false;
         }
     }
 
     /* following checks are relevant only for WD_FULL mode */
 
     // tabbar. Make sure no tab is under the cursor
     if (auto tabBar = qobject_cast<QTabBar *>(widget)) {
         return tabBar->tabAt(position) == -1;
     }
 
     /*
     check groupboxes
     prevent drag if unchecking grouboxes
     */
     if (auto groupBox = qobject_cast<QGroupBox *>(widget)) {
         // non checkable group boxes are always ok
         if (!groupBox->isCheckable()) {
             return true;
         }
 
         // gather options to retrieve checkbox subcontrol rect
         QStyleOptionGroupBox opt;
         opt.initFrom(groupBox);
         if (groupBox->isFlat()) {
             opt.features |= QStyleOptionFrame::Flat;
         }
         opt.lineWidth = 1;
         opt.midLineWidth = 0;
         opt.text = groupBox->title();
         opt.textAlignment = groupBox->alignment();
         opt.subControls = (QStyle::SC_GroupBoxFrame | QStyle::SC_GroupBoxCheckBox);
         if (!groupBox->title().isEmpty()) {
             opt.subControls |= QStyle::SC_GroupBoxLabel;
         }
 
         opt.state |= (groupBox->isChecked() ? QStyle::State_On : QStyle::State_Off);
 
         // check against groupbox checkbox
         if (groupBox->style()->subControlRect(QStyle::CC_GroupBox, &opt, QStyle::SC_GroupBoxCheckBox, groupBox).contains(position)) {
             return false;
         }
 
         // check against groupbox label
         if (!groupBox->title().isEmpty()
             && groupBox->style()->subControlRect(QStyle::CC_GroupBox, &opt, QStyle::SC_GroupBoxLabel, groupBox).contains(position)) {
             return false;
         }
 
         return true;
     }
 
     // labels
     if (auto label = qobject_cast<QLabel *>(widget)) {
         if (label->textInteractionFlags().testFlag(Qt::TextSelectableByMouse)) {
             return false;
         }
     }
 
     // abstract item views
     QAbstractItemView *itemView(nullptr);
     if ((itemView = qobject_cast<QListView *>(widget->parentWidget())) || (itemView = qobject_cast<QTreeView *>(widget->parentWidget()))) {
         if (widget == itemView->viewport()) {
             // QListView
             if (itemView->frameShape() != QFrame::NoFrame) {
                 return false;
             } else if (itemView->selectionMode() != QAbstractItemView::NoSelection && itemView->selectionMode() != QAbstractItemView::SingleSelection
                        && itemView->model() && itemView->model()->rowCount()) {
                 return false;
             } else if (itemView->model() && itemView->indexAt(position).isValid()) {
                 return false;
             }
         }
 
     } else if ((itemView = qobject_cast<QAbstractItemView *>(widget->parentWidget()))) {
         if (widget == itemView->viewport()) {
             // QAbstractItemView
             if (itemView->frameShape() != QFrame::NoFrame) {
                 return false;
             } else if (itemView->indexAt(position).isValid()) {
                 return false;
             }
         }
 
     } else if (auto graphicsView = qobject_cast<QGraphicsView *>(widget->parentWidget())) {
         if (widget == graphicsView->viewport()) {
             // QGraphicsView
             if (graphicsView->frameShape() != QFrame::NoFrame) {
                 return false;
             } else if (graphicsView->dragMode() != QGraphicsView::NoDrag) {
                 return false;
             } else if (graphicsView->itemAt(position)) {
                 return false;
             }
         }
     }
 
     return true;
 }
 
 //____________________________________________________________
 void WindowManager::resetDrag()
 {
     _target.clear();
 #if BREEZE_HAVE_QTQUICK
     _quickTarget.clear();
 #endif
     if (_dragTimer.isActive()) {
         _dragTimer.stop();
     }
     _dragPoint = QPoint();
     _globalDragPoint = QPoint();
     _dragAboutToStart = false;
     _dragInProgress = false;
 }
 
 //____________________________________________________________
 void WindowManager::startDrag(QWindow *window)
 {
     if (!(enabled() && window)) {
         return;
     }
     if (QWidget::mouseGrabber()) {
         return;
     }
 
 #if BREEZE_HAVE_QTQUICK
     if (_quickTarget) {
         if (QQuickWindow *qw = qobject_cast<QQuickWindow *>(window)) {
             QWindow *renderWindow = QQuickRenderControl::renderWindowFor(qw);
             if (renderWindow) {
                 _dragInProgress = renderWindow->startSystemMove();
             } else {
                 _dragInProgress = window->startSystemMove();
             }
         }
     } else
 #endif
     {
         _dragInProgress = window->startSystemMove();
     }
 }
 
 //____________________________________________________________
 bool WindowManager::isDockWidgetTitle(const QWidget *widget) const
 {
     if (!widget) {
         return false;
     }
     if (auto dockWidget = qobject_cast<const QDockWidget *>(widget->parent())) {
         return widget == dockWidget->titleBarWidget();
 
     } else {
         return false;
     }
 }
 
 }