QT 图片缩放

实现该功能主要通过对QGraphicsView进行重现，才能实现鼠标控制对图片的缩放和拖动 使用方法： 1.添加重写后的文件 SOURCES += \ interactive_view.cpp \ pixitem.cpp HEADERS += \ interactive_view.h \ pixitem.h 2.调用 QGraphics Scene *m_scene; InteractiveView *view ; //对整个界面进行重写 PixItem *m_pixItem; //对item进行重写 QPixmap *pixmap; view=new Intera ctiveView(ui->graphicsView); //重载重写之后graphicsView m_scene=new QGraphicsScene; //声明场景 view->resize(701, 479);//点击空白的窗口，程序会崩 m_scene->clear();//清除场景 //恢复到原来的尺寸 view->setTransformationAnchor(QGraphicsView::AnchorViewCenter); QMatrix q; q.setMatrix(1,view->matrix().m12(),view->matrix().m21(),1,view->matrix().dx(),view->matrix().dy()); view->setMatrix(q,false); pixmap = new QPixmap(filePath); m_pixItem = new PixItem(pixmap);//加载图片到单元 m_scene->addItem(m_pixItem);//在场景中添加单元 //设置场景的宽高和起点 view->setSceneRect(-pixmap->width()/2,-pixmap->height()/2,pixmap->width(),pixmap->height()); //在窗口中添加场景 view->setScene(m_scene); //对窗口进行缩放，填写参数为宽高缩放比例 view->scale(701.0/pixmap->width(),479.0/pixmap->height()); //显示窗口 view->show(); ctiveView(ui->graphicsView); //重载重写之后graphicsView m_scene=new QGraphicsScene; //声明场景 view->resize(701, 479);//点击空白的窗口，程序会崩 m_scene->clear();//清除场景 //恢复到原来的尺寸 view->setTransformationAnchor(QGraphicsView::AnchorViewCenter); QMatrix q; q.setMatrix(1,view->matrix().m12(),view->matrix().m21(),1,view->matrix().dx(),view->matrix().dy()); view->setMatrix(q,false); pixmap = new QPixmap(filePath); m_pixItem = new PixItem(pixmap);//加载图片到单元 m_scene->addItem(m_pixItem);//在场景中添加单元 //设置场景的宽高和起点 view->setSceneRect(-pixmap->width()/2,-pixmap->height()/2,pixmap->width(),pixmap->height()); //在窗口中添加场景 view->setScene(m_scene); //对窗口进行缩放，填写参数为宽高缩放比例 view->scale(701.0/pixmap->width(),479.0/pixmap->height()); //显示窗口 view->show();