DragDropScroller.cpp
125 lines
| 4.4 KiB
| text/x-c
|
CppLexer
| r885 | #include "DragAndDrop/DragDropScroller.h" | |||
| #include <QDragEnterEvent> | ||||
| #include <QDragMoveEvent> | ||||
| #include <QScrollBar> | ||||
| #include <QTimer> | ||||
| 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) { | ||||
| 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) { | ||||
| 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); | ||||
| } | ||||
| } | ||||
