QT 图片旋转--QTransform 沿中间旋转

最新推荐文章于 2024-11-25 08:58:56 发布

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本文介绍了一个使用Qt实现带有阴影效果的旋转动画的示例。通过创建自定义QWidget并利用QGraphicsDropShadowEffect和QTimeLine，实现了图片的动态旋转效果。文中详细展示了如何设置场景、添加图片项及动画控制。

#ifndef shadow_H_
#define shadow_H_
#include <QtGui/QtGui>
#include <QtCore/QtCore>

class ShadowWidget : public QWidget
{
   Q_OBJECT
public:
   ShadowWidget(QWidget *parent =0)
   {
       //setWindowFlags(Qt::FramelessWindowHint);
       QGraphicsDropShadowEffect *fEffect = new QGraphicsDropShadowEffect;
       //fEffect->setColor(QColor(255,0,0));
       QVBoxLayout *layout = new QVBoxLayout(this);
       QGraphicsScene *scene = new QGraphicsScene;
       scene->setSceneRect(QRect(0,0,900,600));
       fPixmap= new QGraphicsPixmapItem;
       fPixmap->setPos(200,200);
       QPixmap *pix = new QPixmap("1.jpg");
       fPixmap->setPixmap(*pix);
       //fPixmap->setGraphicsEffect(fEffect);
       QTransform *tran = new QTransform;
       tran->rotate(80,Qt::YAxis);
       //fPixmap->setTransform(*tran);
       //fPixmap->setTransformOriginPoint(QPointF(pix->size().width()/2,pix->size().height()/2));
       //fPixmap->setTransformOriginPoint(100,100);
       scene->addItem(fPixmap);
       QGraphicsView *view = new QGraphicsView(scene);
       layout->addWidget(view);
       QPushButton * animButton = new QPushButton(tr("Start"));
       layout->addWidget(animButton);
       connect(animButton,SIGNAL(clicked()),this,SLOT(performAnimation()));
       //setGraphicsEffect(fEffect);
       resize(900,600);
       fTimeLine = NULL;
   }

private slots:
   void performAnimation()
   {
       if(!fTimeLine)
       {
           fTimeLine = new QTimeLine;
           fTimeLine->setDuration(1000);
           fTimeLine->setFrameRange(1,10);
           connect(fTimeLine,SIGNAL(frameChanged(int)),this,SLOT(performRotateAnimation(int )));
       }

       fTimeLine->start();
   }

   void performRotateAnimation(int frame)
   {
       qreal angle = 90*(frame)/10.0;
       QTransform tran;
       tran.translate(150,0);
       //fPixmap->setTransformOriginPoint(0,0);
       tran.rotate(angle,Qt::YAxis);
       fPixmap->setTransform(tran);
       QTransform t;
       t.translate(-150,0);
       fPixmap->setTransform(t,true);
   }
private:
   QGraphicsPixmapItem *fPixmap;
   QTimeLine *fTimeLine ;
};
#endif