##// END OF EJS Templates
Manage the scroll of the tab QScrollArea during a drag&drop operation
Manage the scroll of the tab QScrollArea during a drag&drop operation

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r843:8d32ce09be20
r843:8d32ce09be20
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DragDropHelper.cpp
248 lines | 7.4 KiB | text/x-c | CppLexer
/ gui / src / DragDropHelper.cpp
#include "DragDropHelper.h"
#include "Visualization/VisualizationDragWidget.h"
#include "SqpApplication.h"
#include <QDragMoveEvent>
#include <QDragEnterEvent>
#include <QScrollBar>
#include <QScrollArea>
#include <QVBoxLayout>
#include <QTimer>
#include <QDir>
const QString DragDropHelper::MIME_TYPE_GRAPH = "scqlop/graph";
const QString DragDropHelper::MIME_TYPE_ZONE = "scqlop/zone";
const int SCROLL_SPEED = 5;
const int SCROLL_ZONE_SIZE = 50;
struct DragDropScroller::DragDropScrollerPrivate {
QList<QScrollArea*> m_scrollAreas;
QScrollArea* m_currentScrollArea = nullptr;
std::unique_ptr<QTimer> m_timer = nullptr;
enum class ScrollDirection {up, down, unknown};
ScrollDirection m_direction = ScrollDirection::unknown;
explicit DragDropScrollerPrivate()
: m_timer{std::make_unique<QTimer>()}
{
m_timer->setInterval(0);
}
};
DragDropScroller::DragDropScroller(QObject* parent)
: QObject{parent}, impl{spimpl::make_unique_impl<DragDropScrollerPrivate>()}
{
connect(impl->m_timer.get(), &QTimer::timeout, this, &DragDropScroller::onTimer);
}
void DragDropScroller::addScrollArea(QScrollArea* scrollArea)
{
impl->m_scrollAreas << scrollArea;
scrollArea->viewport()->setAcceptDrops(true);
}
void DragDropScroller::removeScrollArea(QScrollArea* scrollArea)
{
impl->m_scrollAreas.removeAll(scrollArea);
scrollArea->viewport()->setAcceptDrops(false);
}
bool DragDropScroller::eventFilter(QObject *obj, QEvent *event)
{
if (event->type() == QEvent::DragMove)
{
auto w = static_cast<QWidget*>(obj);
if (impl->m_currentScrollArea && impl->m_currentScrollArea->isAncestorOf(w))
{
auto moveEvent = static_cast<QDragMoveEvent*>(event);
auto pos = moveEvent->pos();
if (impl->m_currentScrollArea->viewport() != w)
{
auto globalPos = w->mapToGlobal(moveEvent->pos());
pos = impl->m_currentScrollArea->viewport()->mapFromGlobal(globalPos);
}
auto isInTopZone = pos.y() > impl->m_currentScrollArea->viewport()->size().height() - SCROLL_ZONE_SIZE;
auto isInBottomZone = pos.y() < SCROLL_ZONE_SIZE;
if (!isInTopZone && !isInBottomZone)
{
impl->m_direction = DragDropScrollerPrivate::ScrollDirection::unknown;
impl->m_timer->stop();
}
else if (!impl->m_timer->isActive())
{
impl->m_direction = isInTopZone ? DragDropScrollerPrivate::ScrollDirection::up : DragDropScrollerPrivate::ScrollDirection::down;
impl->m_timer->start();
}
}
}
else if (event->type() == QEvent::DragEnter)
{
auto w = static_cast<QWidget*>(obj);
for (auto scrollArea : impl-> m_scrollAreas)
{
if (impl->m_currentScrollArea != scrollArea && scrollArea->isAncestorOf(w))
{
auto enterEvent = static_cast<QDragEnterEvent*>(event);
enterEvent->acceptProposedAction();
enterEvent->setDropAction(Qt::IgnoreAction);
impl->m_currentScrollArea = scrollArea;
break;
}
}
}
else if (event->type() == QEvent::DragLeave)
{
auto w = static_cast<QWidget*>(obj);
if (impl->m_currentScrollArea)
{
if (!QRect(QPoint(), impl->m_currentScrollArea->size()).contains(impl->m_currentScrollArea->mapFromGlobal(QCursor::pos())))
{
impl->m_currentScrollArea = nullptr;
impl->m_direction = DragDropScrollerPrivate::ScrollDirection::unknown;
impl->m_timer->stop();
}
}
}
else if (event->type() == QEvent::Drop)
{
auto w = static_cast<QWidget*>(obj);
if (impl->m_currentScrollArea)
{
impl->m_currentScrollArea = nullptr;
impl->m_direction = DragDropScrollerPrivate::ScrollDirection::unknown;
impl->m_timer->stop();
}
}
return false;
}
void DragDropScroller::onTimer()
{
if (impl->m_currentScrollArea)
{
auto mvt = 0;
switch (impl->m_direction)
{
case DragDropScrollerPrivate::ScrollDirection::up:
mvt = SCROLL_SPEED;
break;
case DragDropScrollerPrivate::ScrollDirection::down:
mvt = -SCROLL_SPEED;
break;
default:
break;
}
impl->m_currentScrollArea->verticalScrollBar()->setValue(impl->m_currentScrollArea->verticalScrollBar()->value() + mvt);
}
}
struct DragDropHelper::DragDropHelperPrivate {
VisualizationDragWidget* m_currentDragWidget = nullptr;
std::unique_ptr<QWidget> m_placeHolder = nullptr;
std::unique_ptr<DragDropScroller> m_dragDropScroller = nullptr;
QString m_imageTempUrl; //Temporary file for image url generated by the drag & drop. Not using QTemporaryFile to have a name which is not generated.
explicit DragDropHelperPrivate()
: m_placeHolder{std::make_unique<QWidget>()},
m_dragDropScroller{std::make_unique<DragDropScroller>()}
{
m_placeHolder->setStyleSheet("background-color: #BBD5EE; border:2px solid #2A7FD4");
sqpApp->installEventFilter(m_dragDropScroller.get());
m_imageTempUrl = QDir::temp().absoluteFilePath("Scqlop_graph.png");
}
void preparePlaceHolder() const
{
if (m_currentDragWidget)
{
m_placeHolder->setMinimumSize(m_currentDragWidget->size());
m_placeHolder->setSizePolicy(m_currentDragWidget->sizePolicy());
}
else
{
m_placeHolder->setMinimumSize(200, 200);
}
}
};
DragDropHelper::DragDropHelper() :
impl{spimpl::make_unique_impl<DragDropHelperPrivate>()}
{
}
DragDropHelper::~DragDropHelper()
{
QFile::remove(impl->m_imageTempUrl);
}
void DragDropHelper::setCurrentDragWidget(VisualizationDragWidget *dragWidget)
{
impl->m_currentDragWidget = dragWidget;
}
VisualizationDragWidget *DragDropHelper::getCurrentDragWidget() const
{
return impl->m_currentDragWidget;
}
QWidget& DragDropHelper::placeHolder() const
{
return *impl->m_placeHolder;
}
void DragDropHelper::insertPlaceHolder(QVBoxLayout *layout, int index)
{
removePlaceHolder();
impl->preparePlaceHolder();
layout->insertWidget(index, impl->m_placeHolder.get());
impl->m_placeHolder->show();
}
void DragDropHelper::removePlaceHolder()
{
auto parentWidget = impl->m_placeHolder->parentWidget();
if (parentWidget)
{
parentWidget->layout()->removeWidget(impl->m_placeHolder.get());
impl->m_placeHolder->setParent(nullptr);
impl->m_placeHolder->hide();
}
}
bool DragDropHelper::isPlaceHolderSet() const
{
return impl->m_placeHolder->parentWidget();
}
void DragDropHelper::addDragDropScrollArea(QScrollArea *scrollArea)
{
impl->m_dragDropScroller->addScrollArea(scrollArea);
}
void DragDropHelper::removeDragDropScrollArea(QScrollArea *scrollArea)
{
impl->m_dragDropScroller->removeScrollArea(scrollArea);
}
QUrl DragDropHelper::imageTemporaryUrl(const QImage& image) const
{
image.save(impl->m_imageTempUrl);
return QUrl::fromLocalFile(impl->m_imageTempUrl);
}