QSvgRenderer *renderer = new QSvgRenderer(QLatin1String("SvgCardDeck.svg"));
QGraphicsSvgItem *black = new QGraphicsSvgItem();
QGraphicsSvgItem *red = new QGraphicsSvgItem();
black->setSharedRenderer(renderer);
black->setElementId(QLatin1String("black_joker"));
red->setSharedRenderer(renderer);
red->setElementId(QLatin1String("red_joker"));

QSvgGenerator generator;
generator.setFileName(path);
generator.setSize(QSize(200, 200));
generator.setViewBox(QRect(0, 0, 200, 200));
generator.setTitle(tr("SVG Generator Example Drawing"));
generator.setDescription(tr("An SVG drawing created by the SVG Generator "
                       "Example provided with Qt."));

// 无需在paintEvent函数中
QPainter painter;
painter.begin(&generator);
// 此处绘制的内容就是保存为svg文件的内容
...
painter.end();

void SVGShow3Widget::on_pushButton_saveAs_clicked()
{
    QString filePath = QFileDialog::getSaveFileName(0, "打开文件", ".", "SVG(*.svg)");
    if(filePath.isEmpty())
    {
        return;
    }
    QSvgGenerator svgGenerator;
    svgGenerator.setFileName(filePath);
    svgGenerator.setSize(QSize(rect().width(), rect().height()));
    svgGenerator.setViewBox(rect());
    svgGenerator.setTitle("测试QSvgGenerator");
    svgGenerator.setDescription("另存为绘制测试");
    QPainter painter;
    painter.begin(&svgGenerator);
    painter.setPen(Qt::red);
    painter.drawPixmap(rect(), _pixmapSvg);
    painter.drawText(rect(), "红胖子测试Svg");
    painter.end();
}

#ifndef SVGSHOW2WIDGET_H
#define SVGSHOW2WIDGET_H
#include <QWidget>
#include <QSvgRenderer>
namespace Ui {
class SVGShow2Widget;
}
class SVGShow2Widget : public QWidget
{
    Q_OBJECT
public:
    explicit SVGShow2Widget(QWidget *parent = 0);
    ~SVGShow2Widget();
protected:
    void paintEvent(QPaintEvent *event);
private slots:
    void on_pushButton_openFile_clicked();
    void on_pushButton_load_clicked();
private:
    Ui::SVGShow2Widget *ui;
    QPixmap _pixmap;
    QPixmap _pixmapSvg;
    QSvgRenderer *_pSvgRenderer;
};
#endif // SVGSHOW2WIDGET_H
SVGShow2Widget.cpp
#include "SVGShow2Widget.h"
#include "ui_SVGShow2Widget.h"
#include <QFileDialog>
#include <QPainter>
#include <QDebug>
SVGShow2Widget::SVGShow2Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::SVGShow2Widget),
    _pSvgRenderer(0)
{
    ui->setupUi(this);
    QString version = "v1.0.0";
    setWindowTitle(QString("使用QSvgRenderer加载svgDemo %1 (作者：红模仿(红胖子) QQ：21497936 博客地址: blog.csdn.net/qq21497936").arg(version));
    _pixmap.load(":/images/1.png");
    _pSvgRenderer = new QSvgRenderer(this);
    _pSvgRenderer->load(QString(":/images/2.svg"));
}
SVGShow2Widget::~SVGShow2Widget()
{
    delete ui;
}
void SVGShow2Widget::paintEvent(QPaintEvent *event)
{
    QPainter painter(this);
    painter.drawPixmap(ui->label_png->geometry(), _pixmap);
    _pixmapSvg = QPixmap(ui->label_svg->width(), ui->label_svg->height());
    _pixmapSvg.fill(Qt::white);
    QPainter painter2(&_pixmapSvg);
    _pSvgRenderer->render(&painter2, _pixmapSvg.rect());
    painter.drawPixmap(ui->label_svg->geometry(), _pixmapSvg);
}
void SVGShow2Widget::on_pushButton_openFile_clicked()
{
    QString filePath = QFileDialog::getOpenFileName(0, "打开文件", ".", "SVG(*.svg)");
    if(filePath.isEmpty())
    {
        return;
    }
    ui->lineEdit_path->setText(filePath);
}
void SVGShow2Widget::on_pushButton_load_clicked()
{
    _pSvgRenderer->load(ui->lineEdit_path->text());
    update();
}

#ifndef MYSVGWIDGET_H
#define MYSVGWIDGET_H
#include <QWidget>
#include <QSvgWidget>
#include <QSvgRenderer>
namespace Ui {
class MySvgWidget;
}
class MySvgWidget : public QWidget
{
    Q_OBJECT
public:
    explicit MySvgWidget(QWidget *parent = 0);
    ~MySvgWidget();
public:
    void load(const QString &file);
protected:
    void resizeEvent(QResizeEvent *event);
private:
    Ui::MySvgWidget *ui;
private:
    QString _filePath;
    QSvgWidget *_pSvgWidget;
    QSvgRenderer *_pSvgRenderer;
};
#endif // MYSVGWIDGET_H

#include "MySvgWidget.h"
#include "ui_MySvgWidget.h"
#include <QDebug>
MySvgWidget::MySvgWidget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::MySvgWidget),
    _pSvgWidget(0),
    _pSvgRenderer(0)
{
    ui->setupUi(this);
    _pSvgWidget = new QSvgWidget(this);
    _pSvgRenderer = _pSvgWidget->renderer();
}
MySvgWidget::~MySvgWidget()
{
    delete ui;
}
void MySvgWidget::load(const QString &file)
{
    _filePath = file;
    _pSvgWidget->load(_filePath);
    _pSvgWidget->repaint();
    update();
}
void MySvgWidget::resizeEvent(QResizeEvent *event)
{
    if(_pSvgWidget)
    {
        _pSvgWidget->setGeometry(rect());
    }
}