QGraphicsItem旋转效果实现

#include "MyItem.h" #include <QStyle> MyItem::MyItem(qreal wid,qreal hgt) { m_width=wid;m_height=hgt; m_Rotation=0; setZValue(0); setAcceptDrops(true); setFlags(ItemIsSelectable | ItemIsMovable); m_pm=NULL; paintPic(); } QString MyItem::Cardinate(){ QPointF lt=this->mapToScene(-m_width/2,-m_height/2); QPointF lb=this->mapToScene(-m_width/2,m_height/2); QPointF rt=this->mapToScene(m_width/2,-m_height/2); QPointF rb=this->mapToScene(m_width/2,m_height/2); QString _lt=QString("Left-Top:")+"("+QString::number(lt.x())+","+QString::number(lt.y())+");\n"; QString _lb=QString("Left-Bottom:")+"("+QString::number(lb.x())+","+QString::number(lb.y())+");\n"; QString _rt=QString("Right-Top:")+"("+QString::number(rt.x())+","+QString::number(rt.y())+");\n"; QString _rb=QString("Right-Bottom:")+"("+QString::number(rb.x())+","+QString::number(rb.y())+");\n"; return QString(_lt+_lb+_rt+_rb); } void MyItem::paintPic(){ m_pm=new QPixmap(m_width/2,m_height/2); QPainter painter(m_pm); painter.setPen(Qt::gray); m_pm->fill(); painter.drawText(10,10,"TEST_TOO"); painter.drawRect(1,1,m_width/2-2,m_height/2-2); } QRectF MyItem::boundingRect()const{ qreal max=(m_width>m_height)?m_width:m_height; return QRectF(-(max+1)/2,-(max+1)/2,max,max);//每个item都有自己的一个坐标系， //这个设置相当于把item相对于自身的坐标系的原点（0,0）放到自己的正中央。 } QPainterPath MyItem::shape()const{ QPainterPath path; path.addRect(QRectF(-m_width/2,-m_height/2,m_width,m_height)); return path; } void MyItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget){ //Q_UNUSED(option); Q_UNUSED(widget); painter->rotate(m_Rotation); painter->drawText(0,0,QString("This is a test!")); //painter->rotate(-m_Rotation); painter->drawRect(QRectF(-m_width/2+2,-m_height/2+2,m_width-4,m_height-4)); painter->drawPixmap(-m_width/4,-m_height/4,m_pm->width(),m_pm->height(),*m_pm); if(option->state & QStyle::State_Selected){ painter->setPen(QPen(Qt::red,2,Qt::DotLine)); painter->drawRect(QRectF(-m_width/2,-m_height/2,m_width,m_height)); } update(); } void MyItem::Rotate(){ m_Rotation+=90; if(m_Rotation==360)m_Rotation=0; }