QCustomPlot介绍及实例

        QCustomPlot 是一个小巧好用的 QT 图表插件。用来画曲线图、趋势图、坐标图、柱状图等类似二维图的库。实现大部分的2维图形绘制。使用时，我们在程序中写完相关调用的代码后，只需将 QCunstomPlot.cpp 和 QCustomPlot.h 两个文件加入工程，正常编译即可，有GPL的授权，支持跨平台的C/C++语言 。

        QCustomPlot给我们提供了非常方便的加载数据的接口：setData() 和 addData()。

        QCustomPlot采用了大量的技术比如自适应采样和文本对象缓存为了减少replot的时间。然而一些特性比如半透明的填充,反锯齿和粗线条都可能导致低效率。如果你在你的程序中注意到了这些。这有一些提示关于如何跳高Replot的性能。

        下面给出常用的统计图和K线图的示例：

  customPlot->plotLayout()->clear();   QCPAxisRect *wideAxisRect = new QCPAxisRect(customPlot);  wideAxisRect->setupFullAxesBox(true);  wideAxisRect->axis(QCPAxis::atRight, 0)->setTickLabels(true);  wideAxisRect->addAxis(QCPAxis::atLeft)->setTickLabelColor(QColor("#6050F8"));   QCPLayoutGrid *subLayout = new QCPLayoutGrid;  customPlot->plotLayout()->addElement(0, 0, wideAxisRect);   customPlot->plotLayout()->addElement(1, 0, subLayout);   QCPAxisRect *subRectLeft = new QCPAxisRect(customPlot, false);   QCPAxisRect *subRectRight = new QCPAxisRect(customPlot, false);  subLayout->addElement(0, 0, subRectLeft);  subLayout->addElement(0, 1, subRectRight);  subRectRight->setMaximumSize(150, 150);   subRectRight->setMinimumSize(150, 150);   subRectLeft->addAxes(QCPAxis::atBottom | QCPAxis::atLeft);  subRectRight->addAxes(QCPAxis::atBottom | QCPAxis::atRight);  subRectLeft->axis(QCPAxis::atLeft)->ticker()->setTickCount(2);  subRectRight->axis(QCPAxis::atRight)->ticker()->setTickCount(2);  subRectRight->axis(QCPAxis::atBottom)->ticker()->setTickCount(2);  subRectLeft->axis(QCPAxis::atBottom)->grid()->setVisible(true);  QCPMarginGroup *marginGroup = new QCPMarginGroup(customPlot);  subRectLeft->setMarginGroup(QCP::msLeft, marginGroup);  subRectRight->setMarginGroup(QCP::msRight, marginGroup);  wideAxisRect->setMarginGroup(QCP::msLeft | QCP::msRight, marginGroup);  foreach (QCPAxisRect *rect, customPlot->axisRects())  {    foreach (QCPAxis *axis, rect->axes())    {      axis->setLayer("axes");      axis->grid()->setLayer("grid");    }  }    QVector<QCPGraphData> dataCos(21), dataGauss(50), dataRandom(100);  QVector<double> x3, y3;  qsrand(3);  for (int i=0; i<dataCos.size(); ++i)  {    dataCos[i].key = i/(double)(dataCos.size()-1)*10-5.0;    dataCos[i].value = qCos(dataCos[i].key);  }  for (int i=0; i<dataGauss.size(); ++i)  {    dataGauss[i].key = i/(double)dataGauss.size()*10-5.0;    dataGauss[i].value = qExp(-dataGauss[i].key*dataGauss[i].key*0.2)*1000;  }  for (int i=0; i<dataRandom.size(); ++i)  {    dataRandom[i].key = i/(double)dataRandom.size()*10;    dataRandom[i].value = qrand()/(double)RAND_MAX-0.5+dataRandom[qMax(0, i-1)].value;  }  x3 << 1 << 2 << 3 << 4;  y3 << 2 << 2.5 << 4 << 1.5;    QCPGraph *mainGraphCos = customPlot->addGraph(wideAxisRect->axis(QCPAxis::atBottom), wideAxisRect->axis(QCPAxis::atLeft));  mainGraphCos->data()->set(dataCos);  mainGraphCos->valueAxis()->setRange(-1, 1);  mainGraphCos->rescaleKeyAxis();  mainGraphCos->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCircle, QPen(Qt::black), QBrush(Qt::white), 6));  mainGraphCos->setPen(QPen(QColor(120, 120, 120), 2));  QCPGraph *mainGraphGauss = customPlot->addGraph(wideAxisRect->axis(QCPAxis::atBottom), wideAxisRect->axis(QCPAxis::atLeft, 1));  mainGraphGauss->data()->set(dataGauss);  mainGraphGauss->setPen(QPen(QColor("#8070B8"), 2));  mainGraphGauss->setBrush(QColor(110, 170, 110, 30));  mainGraphCos->setChannelFillGraph(mainGraphGauss);  mainGraphCos->setBrush(QColor(255, 161, 0, 50));  mainGraphGauss->valueAxis()->setRange(0, 1000);  mainGraphGauss->rescaleKeyAxis();    QCPGraph *subGraphRandom = customPlot->addGraph(subRectLeft->axis(QCPAxis::atBottom), subRectLeft->axis(QCPAxis::atLeft));  subGraphRandom->data()->set(dataRandom);  subGraphRandom->setLineStyle(QCPGraph::lsImpulse);  subGraphRandom->setPen(QPen(QColor("#FFA100"), 1.5));  subGraphRandom->rescaleAxes();    QCPBars *subBars = new QCPBars(subRectRight->axis(QCPAxis::atBottom), subRectRight->axis(QCPAxis::atRight));  subBars->setWidth(3/(double)x3.size());  subBars->setData(x3, y3);  subBars->setPen(QPen(Qt::black));  subBars->setAntialiased(false);  subBars->setAntialiasedFill(false);  subBars->setBrush(QColor("#705BE8"));  subBars->keyAxis()->setSubTicks(false);  subBars->rescaleAxes();   QSharedPointer<QCPAxisTickerFixed> intTicker(new QCPAxisTickerFixed);  intTicker->setTickStep(1.0);  intTicker->setScaleStrategy(QCPAxisTickerFixed::ssMultiples);  subBars->keyAxis()->setTicker(intTicker);

统计图效果如图1-1所示：

                                                 图1-1 统计图

K线图代码：

customPlot->legend->setVisible(true); int n = 500;QVector<double> time(n), value1(n), value2(n);QDateTime start = QDateTime(QDate(2014, 6, 11));start.setTimeSpec(Qt::UTC);double startTime = start.toTime_t();double binSize = 3600*24; value1[0] = 60;value2[0] = 20;qsrand(9);for (int i=1; i<n; ++i){  time[i] = startTime + 3600*i;  value1[i] = value1[i-1] + (qrand()/(double)RAND_MAX-0.5)*10;  value2[i] = value2[i-1] + (qrand()/(double)RAND_MAX-0.5)*3;} QCPFinancial *candlesticks = new QCPFinancial(customPlot->xAxis, customPlot->yAxis);candlesticks->setName("Candlestick");candlesticks->setChartStyle(QCPFinancial::csCandlestick);candlesticks->data()->set(QCPFinancial::timeSeriesToOhlc(time, value1, binSize, startTime));candlesticks->setWidth(binSize*0.9);candlesticks->setTwoColored(true);candlesticks->setBrushPositive(QColor(245, 245, 245));candlesticks->setBrushNegative(QColor(40, 40, 40));candlesticks->setPenPositive(QPen(QColor(0, 0, 0)));candlesticks->setPenNegative(QPen(QColor(0, 0, 0))); QCPFinancial *ohlc = new QCPFinancial(customPlot->xAxis, customPlot->yAxis);ohlc->setName("OHLC");ohlc->setChartStyle(QCPFinancial::csOhlc);ohlc->data()->set(QCPFinancial::timeSeriesToOhlc(time, value2, binSize/3.0, startTime)); ohlc->setWidth(binSize*0.2);ohlc->setTwoColored(true); QCPAxisRect *volumeAxisRect = new QCPAxisRect(customPlot);customPlot->plotLayout()->addElement(1, 0, volumeAxisRect);volumeAxisRect->setMaximumSize(QSize(QWIDGETSIZE_MAX, 100));volumeAxisRect->axis(QCPAxis::atBottom)->setLayer("axes");volumeAxisRect->axis(QCPAxis::atBottom)->grid()->setLayer("grid");// bring bottom and main axis rect closer together:customPlot->plotLayout()->setRowSpacing(0);volumeAxisRect->setAutoMargins(QCP::msLeft|QCP::msRight|QCP::msBottom);volumeAxisRect->setMargins(QMargins(0, 0, 0, 0));// create two bar plottables, for positive (green) and negative (red) volume bars:customPlot->setAutoAddPlottableToLegend(false);QCPBars *volumePos = new QCPBars(volumeAxisRect->axis(QCPAxis::atBottom), volumeAxisRect->axis(QCPAxis::atLeft));QCPBars *volumeNeg = new QCPBars(volumeAxisRect->axis(QCPAxis::atBottom), volumeAxisRect->axis(QCPAxis::atLeft));for (int i=0; i<n/5; ++i){  int v = qrand()%20000+qrand()%20000+qrand()%20000-10000*3;  (v < 0 ? volumeNeg : volumePos)->addData(startTime+3600*5.0*i, qAbs(v)); volumePos->setWidth(3600*4);volumePos->setPen(Qt::NoPen);volumePos->setBrush(QColor(100, 180, 110));volumeNeg->setWidth(3600*4);volumeNeg->setPen(Qt::NoPen);volumeNeg->setBrush(QColor(180, 90, 90)); // interconnect x axis ranges of main and bottom axis rects:connect(customPlot->xAxis, SIGNAL(rangeChanged(QCPRange)), volumeAxisRect->axis(QCPAxis::atBottom), SLOT(setRange(QCPRange)));connect(volumeAxisRect->axis(QCPAxis::atBottom), SIGNAL(rangeChanged(QCPRange)), customPlot->xAxis, SLOT(setRange(QCPRange)));// configure axes of both main and bottom axis rect:QSharedPointer<QCPAxisTickerDateTime> dateTimeTicker(new QCPAxisTickerDateTime);dateTimeTicker->setDateTimeSpec(Qt::UTC);dateTimeTicker->setDateTimeFormat("dd. MMMM");volumeAxisRect->axis(QCPAxis::atBottom)->setTicker(dateTimeTicker);volumeAxisRect->axis(QCPAxis::atBottom)->setTickLabelRotation(15);customPlot->xAxis->setBasePen(Qt::NoPen);customPlot->xAxis->setTickLabels(false);customPlot->xAxis->setTicks(false); customPlot->xAxis->setTicker(dateTimeTicker);customPlot->rescaleAxes();customPlot->xAxis->scaleRange(1.025, customPlot->xAxis->range().center());customPlot->yAxis->scaleRange(1.1, customPlot->yAxis->range().center()); QCPMarginGroup *group = new QCPMarginGroup(customPlot);customPlot->axisRect()->setMarginGroup(QCP::msLeft|QCP::msRight, group);volumeAxisRect->setMarginGroup(QCP::msLeft|QCP::msRight, group);

K线图如图1-2所示：

                                                                   图1-2 K线图

其它绘图效果如下所示：