FloatingDragPreview.cpp

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//============================================================================
//============================================================================

//============================================================================
//                                   INCLUDES
//============================================================================
#include "FloatingDragPreview.h"
#include <iostream>

#include <QEvent>
#include <QApplication>
#include <QPainter>
#include <QKeyEvent>

#include "DockWidget.h"
#include "DockAreaWidget.h"
#include "DockManager.h"
#include "DockContainerWidget.h"
#include "DockOverlay.h"

namespace ads
{

struct FloatingDragPreviewPrivate
{
        CFloatingDragPreview *_this;
        QWidget* Content;
        CDockAreaWidget* ContentSourceArea = nullptr;
        QPoint DragStartMousePosition;
        CDockManager* DockManager;
        CDockContainerWidget *DropContainer = nullptr;
        qreal WindowOpacity;
        bool Hidden = false;
        QPixmap ContentPreviewPixmap;
        bool Canceled = false;


        FloatingDragPreviewPrivate(CFloatingDragPreview *_public);
        void updateDropOverlays(const QPoint &GlobalPos);

        void setHidden(bool Value)
        {
                Hidden = Value;
                _this->update();
        }

        void cancelDragging()
        {
                Canceled = true;
                emit _this->draggingCanceled();
                DockManager->containerOverlay()->hideOverlay();
                DockManager->dockAreaOverlay()->hideOverlay();
                _this->close();
        }

        void createFloatingWidget();
};
// struct LedArrayPanelPrivate


//============================================================================
void FloatingDragPreviewPrivate::updateDropOverlays(const QPoint &GlobalPos)
{
        if (!_this->isVisible() || !DockManager)
        {
                return;
        }

        auto Containers = DockManager->dockContainers();
        CDockContainerWidget *TopContainer = nullptr;
        for (auto ContainerWidget : Containers)
        {
                if (!ContainerWidget->isVisible())
                {
                        continue;
                }

                QPoint MappedPos = ContainerWidget->mapFromGlobal(GlobalPos);
                if (ContainerWidget->rect().contains(MappedPos))
                {
                        if (!TopContainer || ContainerWidget->isInFrontOf(TopContainer))
                        {
                                TopContainer = ContainerWidget;
                        }
                }
        }

        DropContainer = TopContainer;
        auto ContainerOverlay = DockManager->containerOverlay();
        auto DockAreaOverlay = DockManager->dockAreaOverlay();
        auto DockDropArea = DockAreaOverlay->dropAreaUnderCursor();
        auto ContainerDropArea = ContainerOverlay->dropAreaUnderCursor();

        if (!TopContainer)
        {
                ContainerOverlay->hideOverlay();
                DockAreaOverlay->hideOverlay();
                if (CDockManager::testConfigFlag(CDockManager::DragPreviewIsDynamic))
                {
                        setHidden(false);
                }
                return;
        }

        int VisibleDockAreas = TopContainer->visibleDockAreaCount();
        ContainerOverlay->setAllowedAreas(
            VisibleDockAreas > 1 ? OuterDockAreas : AllDockAreas);
        auto DockArea = TopContainer->dockAreaAt(GlobalPos);
        if (DockArea && DockArea->isVisible() && VisibleDockAreas >= 0 && DockArea != ContentSourceArea)
        {
                DockAreaOverlay->enableDropPreview(true);
                DockAreaOverlay->setAllowedAreas(
                    (VisibleDockAreas == 1) ? NoDockWidgetArea : DockArea->allowedAreas());
                DockWidgetArea Area = DockAreaOverlay->showOverlay(DockArea);

                // A CenterDockWidgetArea for the dockAreaOverlay() indicates that
                // the mouse is in the title bar. If the ContainerArea is valid
                // then we ignore the dock area of the dockAreaOverlay() and disable
                // the drop preview
                if ((Area == CenterDockWidgetArea) && (ContainerDropArea != InvalidDockWidgetArea))
                {
                        DockAreaOverlay->enableDropPreview(false);
                        ContainerOverlay->enableDropPreview(true);
                }
                else
                {
                        ContainerOverlay->enableDropPreview(InvalidDockWidgetArea == Area);
                }
                ContainerOverlay->showOverlay(TopContainer);
        }
        else
        {
                DockAreaOverlay->hideOverlay();
                // If there is only one single visible dock area in a container, then
                // it does not make sense to show a dock overlay because the dock area
                // would be removed and inserted at the same position
                if (VisibleDockAreas == 1)
                {
                        ContainerOverlay->hideOverlay();
                }
                else
                {
                        ContainerOverlay->showOverlay(TopContainer);
                }


                if (DockArea == ContentSourceArea && InvalidDockWidgetArea == ContainerDropArea)
                {
                        DropContainer = nullptr;
                }
        }

        if (CDockManager::testConfigFlag(CDockManager::DragPreviewIsDynamic))
        {
                setHidden(DockDropArea != InvalidDockWidgetArea || ContainerDropArea != InvalidDockWidgetArea);
        }
}


//============================================================================
FloatingDragPreviewPrivate::FloatingDragPreviewPrivate(CFloatingDragPreview *_public) :
        _this(_public)
{

}


//============================================================================
void FloatingDragPreviewPrivate::createFloatingWidget()
{
        CDockWidget* DockWidget = qobject_cast<CDockWidget*>(Content);
        CDockAreaWidget* DockArea = qobject_cast<CDockAreaWidget*>(Content);

        CFloatingDockContainer* FloatingWidget = nullptr;

        if (DockWidget && DockWidget->features().testFlag(CDockWidget::DockWidgetFloatable))
        {
                FloatingWidget = new CFloatingDockContainer(DockWidget);
        }
        else if (DockArea && DockArea->features().testFlag(CDockWidget::DockWidgetFloatable))
        {
                FloatingWidget = new CFloatingDockContainer(DockArea);
        }

        if (FloatingWidget)
        {
                FloatingWidget->setGeometry(_this->geometry());
                FloatingWidget->show();
                if (!CDockManager::testConfigFlag(CDockManager::DragPreviewHasWindowFrame))
                {
                        QApplication::processEvents();
                        int FrameHeight = FloatingWidget->frameGeometry().height() - FloatingWidget->geometry().height();
                        QRect FixedGeometry = _this->geometry();
                        FixedGeometry.adjust(0, FrameHeight, 0, 0);
                        FloatingWidget->setGeometry(FixedGeometry);
                }
        }
}


//============================================================================
CFloatingDragPreview::CFloatingDragPreview(QWidget* Content, QWidget* parent) :
        QWidget(parent),
        d(new FloatingDragPreviewPrivate(this))
{
        d->Content = Content;
        setAttribute(Qt::WA_DeleteOnClose);
        if (CDockManager::testConfigFlag(CDockManager::DragPreviewHasWindowFrame))
        {
                setWindowFlags(
                        Qt::Window | Qt::WindowMaximizeButtonHint | Qt::WindowCloseButtonHint);
        }
        else
        {
                setWindowFlags(Qt::Tool | Qt::FramelessWindowHint);
                setAttribute(Qt::WA_NoSystemBackground);
                setAttribute(Qt::WA_TranslucentBackground);
        }

#ifdef Q_OS_LINUX
    auto Flags = windowFlags();
    Flags |= Qt::WindowStaysOnTopHint | Qt::X11BypassWindowManagerHint;
    setWindowFlags(Flags);
#endif

        setWindowOpacity(0.6);

        // Create a static image of the widget that should get undocked
        // This is like some kind preview image like it is uses in drag and drop
        // operations
        if (CDockManager::testConfigFlag(CDockManager::DragPreviewShowsContentPixmap))
        {
                d->ContentPreviewPixmap = QPixmap(Content->size());
                Content->render(&d->ContentPreviewPixmap);
        }

        connect(qApp, SIGNAL(applicationStateChanged(Qt::ApplicationState)),
                SLOT(onApplicationStateChanged(Qt::ApplicationState)));

        // The only safe way to receive escape key presses is to install an event
        // filter for the application object
        qApp->installEventFilter(this);
}


//============================================================================
CFloatingDragPreview::CFloatingDragPreview(CDockWidget* Content)
        : CFloatingDragPreview((QWidget*)Content, Content->dockManager())
{
        d->DockManager = Content->dockManager();
        if (Content->dockAreaWidget()->openDockWidgetsCount() == 1)
        {
                d->ContentSourceArea = Content->dockAreaWidget();
        }
        setWindowTitle(Content->windowTitle());
}


//============================================================================
CFloatingDragPreview::CFloatingDragPreview(CDockAreaWidget* Content)
        : CFloatingDragPreview((QWidget*)Content, Content->dockManager())
{
        d->DockManager = Content->dockManager();
        d->ContentSourceArea = Content;
        setWindowTitle(Content->currentDockWidget()->windowTitle());
}


//============================================================================
CFloatingDragPreview::~CFloatingDragPreview()
{
        delete d;
}


//============================================================================
void CFloatingDragPreview::moveFloating()
{
        int BorderSize = (frameSize().width() - size().width()) / 2;
        const QPoint moveToPos = QCursor::pos() - d->DragStartMousePosition
            - QPoint(BorderSize, 0);
        move(moveToPos);
        d->updateDropOverlays(QCursor::pos());
}


//============================================================================
void CFloatingDragPreview::startFloating(const QPoint &DragStartMousePos,
    const QSize &Size, eDragState DragState, QWidget *MouseEventHandler)
{
        Q_UNUSED(MouseEventHandler)
        Q_UNUSED(DragState)
        resize(Size);
        d->DragStartMousePosition = DragStartMousePos;
        moveFloating();
        show();

}


//============================================================================
void CFloatingDragPreview::finishDragging()
{
        ADS_PRINT("CFloatingDragPreview::finishDragging");
        auto DockDropArea = d->DockManager->dockAreaOverlay()->visibleDropAreaUnderCursor();
        auto ContainerDropArea = d->DockManager->containerOverlay()->visibleDropAreaUnderCursor();
        if (!d->DropContainer)
        {
                d->createFloatingWidget();
        }
        else if (DockDropArea != InvalidDockWidgetArea)
        {
                d->DropContainer->dropWidget(d->Content, DockDropArea, d->DropContainer->dockAreaAt(QCursor::pos()));
        }
        else if (ContainerDropArea != InvalidDockWidgetArea)
        {
                // If there is only one single dock area, and we drop into the center
                // then we tabify the dropped widget into the only visible dock area
                if (d->DropContainer->visibleDockAreaCount() <= 1 && CenterDockWidgetArea == ContainerDropArea)
                {
                        d->DropContainer->dropWidget(d->Content, ContainerDropArea, d->DropContainer->dockAreaAt(QCursor::pos()));
                }
                else
                {
                        d->DropContainer->dropWidget(d->Content, ContainerDropArea, nullptr);
                }
        }
        else
        {
                d->createFloatingWidget();
        }

        this->close();
        d->DockManager->containerOverlay()->hideOverlay();
        d->DockManager->dockAreaOverlay()->hideOverlay();
}


//============================================================================
void CFloatingDragPreview::paintEvent(QPaintEvent* event)
{
        Q_UNUSED(event);
        if (d->Hidden)
        {
                return;
        }

        QPainter painter(this);
        if (CDockManager::testConfigFlag(CDockManager::DragPreviewShowsContentPixmap))
        {
                painter.drawPixmap(QPoint(0, 0), d->ContentPreviewPixmap);
        }

        // If we do not have a window frame then we paint a QRubberBand like
        // frameless window
        if (!CDockManager::testConfigFlag(CDockManager::DragPreviewHasWindowFrame))
        {
                QColor Color = palette().color(QPalette::Active, QPalette::Highlight);
                QPen Pen = painter.pen();
                Pen.setColor(Color.darker(120));
                Pen.setStyle(Qt::SolidLine);
                Pen.setWidth(1);
                Pen.setCosmetic(true);
                painter.setPen(Pen);
                Color = Color.lighter(130);
                Color.setAlpha(64);
                painter.setBrush(Color);
                painter.drawRect(rect().adjusted(0, 0, -1, -1));
        }
}

//============================================================================
void CFloatingDragPreview::onApplicationStateChanged(Qt::ApplicationState state)
{
        if (state != Qt::ApplicationActive)
        {
                disconnect(qApp, SIGNAL(applicationStateChanged(Qt::ApplicationState)),
                        this, SLOT(onApplicationStateChanged(Qt::ApplicationState)));
                d->cancelDragging();
        }
}


//============================================================================
bool CFloatingDragPreview::eventFilter(QObject *watched, QEvent *event)
{
        Q_UNUSED(watched);
    if (!d->Canceled && event->type() == QEvent::KeyPress)
    {
        QKeyEvent* e = static_cast<QKeyEvent*>(event);
        if (e->key() == Qt::Key_Escape)
        {
            watched->removeEventFilter(this);
            d->cancelDragging();
        }
    }

    return false;
}



} // namespace ads

//---------------------------------------------------------------------------
// EOF FloatingDragPreview.cpp