Qt：读写SVG

//绘制SVG图形：

 SvgView::SvgView(const QString &file, QWidget *parent)
     : QWidget(parent)
 {
     doc = new QSvgRenderer(file, this);  //QSvgRenderer将SVG图形绘制到绘图设备上
     connect(doc, SIGNAL(repaintNeeded()),  //文档需要更新时发出，通常用来实现动画效果
             this, SLOT(update()));
 }

 void SvgView::paintEvent(QPaintEvent *)
 {
     QPainter p(this);
     p.setViewport(0, 0, width(), height());
     doc->render(&p);
 }

 QSize SvgView::sizeHint() const
 {
     if (doc)
         return doc->defaultSize();
     return QWidget::sizeHint();
 }

 void SvgView::wheelEvent(QWheelEvent *e)
 {
     const double diff = 0.1;
     QSize size = doc->defaultSize();
     int width  = size.width();
     int height = size.height();
     if (e->delta() > 0) {      //此函数已废弃，用pixelDelta() / angleDelta() instead.
         width = int(this->width()+this->width()*diff);
         height = int(this->height()+this->height()*diff);
     } else {
         width  = int(this->width()-this->width()*diff);
         height = int(this->height()-this->height()*diff);
     }
     resize(width, height);
 }
 //    void MyWidget::wheelEvent(QWheelEvent *event)
 //    {
 //        QPoint numPixels = event->pixelDelta();
 //        QPoint numDegrees = event->angleDelta() / 8;

 //        if (!numPixels.isNull()) {
 //            scrollWithPixels(numPixels);
 //        } else if (!numDegrees.isNull()) {
 //            QPoint numSteps = numDegrees / 15;
 //            scrollWithDegrees(numSteps);
 //        }

 //        event->accept();
 //    }

//生成SVG图形：

 #include
 #include
 #include

 int main(int argc, char *argv[])
 {
     QApplication app(argc, argv);

     QSvgGenerator svgGen;
     svgGen.setFileName("test.svg");

     QRectF rectangle(10.0, 20.0, 80.0, 60.0);
     QPainter painter;
     painter.begin(&svgGen);
     QPen pen(Qt::red);
     painter.setPen(pen);
     painter.drawEllipse(rectangle);
     rectangle.moveRight(100);
     painter.drawRect(rectangle);

     rectangle.moveRight(100);
     QRectF source(0.0, 0.0, 70.0, 40.0);
     QImage image("Greenstone.bmp");
     painter.drawImage(rectangle, image, source);

     painter.end();

     return 0;
 }