qcustomplot 绘图 4

关注点：

设置背景、增加文字图层、第二坐标显示控制、设置label显示位置

    auto customPlot  = plot;
    customPlot->axisRect()->setBackground(QPixmap("./solarpanels.jpg"));
    customPlot->addGraph();
    customPlot->graph()->setLineStyle(QCPGraph::lsLine);
    QPen pen;
    pen.setColor(QColor(255, 200, 20, 200));
    pen.setStyle(Qt::DashLine);
    pen.setWidthF(2.5);
    customPlot->graph()->setPen(pen);
    customPlot->graph()->setBrush(QBrush(QColor(255,200,20,70)));
    customPlot->graph()->setScatterStyle(QCPScatterStyle(QPixmap("./sun.png")));
    // set graph name, will show up in legend next to icon:
    customPlot->graph()->setName("Data from Photovoltaic\nenergy barometer 2011");
    // set data:
    QVector<double> year, value;
    year  << 2005 << 2006 << 2007 << 2008  << 2009  << 2010 << 2011;
    value << 2.17 << 3.42 << 4.94 << 10.38 << 15.86 << 29.33 << 52.1;
    customPlot->graph()->setData(year, value);

    // set title of plot:
    customPlot->plotLayout()->insertRow(0);
    customPlot->plotLayout()->addElement(0, 0, new QCPTextElement(customPlot, "Regenerative Energies", QFont("sans", 12, QFont::Bold)));
    // axis configurations:
    customPlot->xAxis->setLabel("Year");
    customPlot->yAxis->setLabel("Installed Gigawatts of\nphotovoltaic in the European Union");
//    customPlot->xAxis2->setVisible(true);
//    customPlot->yAxis2->setVisible(true);
//    customPlot->xAxis2->setTickLabels(false);
//    customPlot->yAxis2->setTickLabels(false);
//    customPlot->xAxis2->setTicks(false);
//    customPlot->yAxis2->setTicks(false);
//    customPlot->xAxis2->setSubTicks(false);
//    customPlot->yAxis2->setSubTicks(false);
    customPlot->xAxis->setRange(2004.5, 2011.5);
    customPlot->yAxis->setRange(0, 52);
    // setup legend:
    customPlot->legend->setFont(QFont(font().family(), 7));
    customPlot->legend->setIconSize(50, 20);
    customPlot->legend->setVisible(true);
    customPlot->axisRect()->insetLayout()->setInsetAlignment(0, Qt::AlignLeft | Qt::AlignTop);