QGraphicsItem、QGraphicsView、QGraphicsScene封装

#include "MyItem.h" #include <QMenu> #include <QGraphicsSceneContextMenuEvent> #include <QAction> MyItem::MyItem() { brushColor = Qt::red; setFlag(QGraphicsItem::ItemIsFocusable); setFlag(QGraphicsItem::ItemIsMovable); //setAcceptHoverEvents(true); } QRectF MyItem::boundingRect() const { qreal adjust = 0.5; return QRectF(-10 - adjust, -10 - adjust, 20 + adjust, 20 + adjust); } void MyItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) { // qDebug("************MyItem::paint*****************"); // if(hasFocus()) { // painter->setPen(QPen(QColor(255,255,255,200))); // } else { // painter->setPen(QPen(QColor(100,100,100,100))); // } // painter->setBrush(brushColor); // painter->drawRect(-10, -10, 20, 20); painter->drawPixmap(-m_pix.width() / 2, -m_pix.height() / 2, m_pix); } // 鼠标按下事件处理函数，设置被点击的图形项获得焦点，并改变光标外观 void MyItem::mousePressEvent(QGraphicsSceneMouseEvent *event) { // qDebug("************MyItem::mousePressEvent*****************"); // setFocus(); // setCursor(Qt::ClosedHandCursor); setFocus(); setCursor(Qt::ClosedHandCursor); //stackBefore(this); topLevelItem(); setColor(QColor(255, 0, 0, 255)); setOpacity(0.8); if (event->button() == Qt::LeftButton) { if (event->modifiers() == Qt::ShiftModifier) { qDebug() << "Custom item left clicked with shift key."; // 选中 item setSelected(true); /*this->setZValue(1);*/ } // else if (event->modifiers() == Qt::AltModifier) { // qDebug() << "Custom item left clicked with alt key."; // // 重置 item 大小 // double radius = boundingRect().width() / 2.0; // QPointF topLeft = boundingRect().topLeft(); // m_centerPointF = QPointF(topLeft.x() + pos().x() + radius, topLeft.y() + pos().y() + radius); // QPointF pos = event->scenePos(); // qDebug() << boundingRect() << radius << this->pos() << pos << event->pos(); // double dist = sqrt(pow(m_centerPointF.x() - pos.x(), 2) + pow(m_centerPointF.y() - pos.y(), 2)); // if (dist / radius > 0.8) { // qDebug() << dist << radius << dist / radius; // m_bResizing = true; // } // else { // m_bResizing = false; // } // } // else { // qDebug() << "Custom item left clicked."; // QGraphicsItem::mousePressEvent(event); // event->accept(); // } } else if (event->button() == Qt::RightButton) { qDebug() << "Custom item right clicked."; event->ignore(); } } void MyItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event) { setOpacity(1); m_isMove = false;//标记鼠标左键已经抬起 if ((event->modifiers() == Qt::AltModifier) && m_bResizing) { m_bResizing = false; } else { QGraphicsItem::mouseReleaseEvent(event); } } // 键盘按下事件处理函数，判断是否是向下方向键，如果是，则向下移动图形项 void MyItem::keyPressEvent(QKeyEvent *event) { qDebug("************MyItem::keyPressEvent*****************"); if(event->key() == Qt::Key_Down) moveBy(0, 10); } // 悬停事件处理函数，设置光标外观和提示 void MyItem::hoverEnterEvent(QGraphicsSceneHoverEvent *event) { qDebug("************MyItem::hoverEnterEvent*****************"); setCursor(Qt::OpenHandCursor); setToolTip("I am item"); } void MyItem::hoverLeaveEvent(QGraphicsSceneHoverEvent *event) { // qDebug("************MyItem::hoverLeaveEvent*****************"); // setCursor(Qt::ArrowCursor); setOpacity(1); m_isMove = false;//标记鼠标左键已经抬起 if ((event->modifiers() == Qt::AltModifier) && m_bResizing) { m_bResizing = false; } else { QGraphicsItem::hoverLeaveEvent(event); } } // 右键菜单事件处理函数，为图形项添加一个右键菜单 void MyItem::contextMenuEvent(QGraphicsSceneContextMenuEvent *event) { QMenu menu; QAction *moveAction = menu.addAction("move back"); QAction *actAction = menu.addAction("test"); QAction *selectedAction = menu.exec(event->screenPos()); if(selectedAction == moveAction) { setPos(0, 0); } } void MyItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event) { // qDebug("************MyItem::mouseMoveEvent*****************"); // QGraphicsItem::mouseMoveEvent(event); this->setZValue(1); if ((event->modifiers() == Qt::AltModifier) && m_bResizing) { QPointF pos = event->scenePos(); double dist = sqrt(pow(m_centerPointF.x() - pos.x(), 2) + pow(m_centerPointF.y() - pos.y(), 2)); //setRect(m_centerPointF.x() - this->pos().x() - dist, m_centerPointF.y() - this->pos().y() - dist, dist * 2, dist * 2); } else if (event->modifiers() != Qt::AltModifier) { qDebug() << "Custom item moved."; QGraphicsItem::mouseMoveEvent(event); qDebug() << "moved" << pos(); } }