Question

版本：qwt 6.0.1 我试图为Spectrum开发对数缩放。我使用简单的线来启用缩放plotspectrum-＆gt; setAxisScaleEngine（QwtPlot :: yLeft，new QwtLog10ScaleEngine）;

问题：未绘制数据，因此绘图为空，编译器返回以下错误：“QwtLog10ScaleEngine'之前的预期类型说明符” 任何帮助都会受到赞赏这是我的代码：

class SpectrumPlot : public QWidget
{
Q_OBJECT
public:
PlotSpektrum();
private:
QHBoxLayout*    m_SpectrumLayout;
QwtPlot*        m_SpectrumPlot;
QwtPlotCurve*   m_SpectrumCurve;
QwtPlotMarker*  m_Marker;

};

SpectrumPlot::SpectrumPlot()
{
m_SpectrumLayout = new QHBoxLayout();
m_SpectrumPlot = new QwtPlot();
m_SpectrumCurve = new QwtPlotCurve();
QwPlotGrid* pGrid = new QwtPlotGrid();
QPen GridPen;
GridPen.setColor(Qt::green);
GridPen.setWidthF(0.7);
GridPen.setStyle(Qt::DashLine);
QPen SpectrumPen;
SpectrumPen.setColor(Qt::white);

pGrid->setRenderHint(QwtPlotItem::RenderAntialiased);
pGrid->setPen(GridPen);
pGrid->enableXMin(true);
pGrid->attach(m_SpectrumPlot);
m_SpectrumPlot->setTitle("Spectrum");
m_SpectrumPlot->setCanvasBackground(QBrush(Qt::black));
m_SpectrumPlot->setAutoDelete(true);
m_SpectrumPlot->setAxisTitle(QwtPlot::xBottom, "Frequency Hz");
m_SpectrumPlot->setAxisScale(QwtPlot::xBottom, 100, nNyquistFrequency);
m_SpectrumPlot->setAxisScale(QwtPlot::yLeft, 0, 150);
m_SpectrumPlot->setAxisScaleEngine(QwtPlot::xBottom, new QwtLog10ScaleEngine());
m_SpectrumLayout->addWidget(m_SpectrumPlot);

this->setLayout(m_SpectrumLayout);
}

Answer 1

我认为你应该使用：

new QwtLogScaleEngine(10)

QwtScaleEngine的手册并未显示任何名为QwtLog10ScaleEngine的课程。

QwtLog10ScaleEngine＆＃39;之前的预期类型说明符？

1 个答案: