QwtPlot更新自定义轴(QwtPlot updating custom axis)

 使用Qwt我必须使用自定义x轴制作绘图，我可以在程序执行时更改缩放标签。 为了做到这一点，我从QwtScaleDraw重载了label ，如下所示： 
 
 H-文件： 
 
class TimeScaleDraw : public QwtScaleDraw
{
public:
    TimeScaleDraw();
    virtual QwtText label(double) const;
    void setTimeScale(double factor, QString unit);
private:
    double factor;
    QString unit;
};
 
 CPP-文件： 
 
TimeScaleDraw::TimeScaleDraw()
{
    factor = 1.0;
    unit = "s";
}

QwtText TimeScaleDraw::label(double val) const
{
    return QwtText(QString::number(val*factor) + unit);
}

void TimeScaleDraw::setTimeScale(double factor, QString unit)
{
    this->factor = factor;
    this->unit = unit;
}
 
 如果我从我的Qt窗口构造函数中调用方法setTimeScale(2.0, "sec) ，这可以正常工作。但是如果我尝试调用方法，例如按下按钮，那么它什么都没做？我试过调用replot()和updateAxes()但这没有任何改变。 
 
 有什么建议么？ 

Using Qwt I have to make a plot with a custom x-axis, where I can change the scale labels under program execution. In order to do so i have overloaded label from QwtScaleDraw like this:
 
H-file:
 
class TimeScaleDraw : public QwtScaleDraw
{
public:
    TimeScaleDraw();
    virtual QwtText label(double) const;
    void setTimeScale(double factor, QString unit);
private:
    double factor;
    QString unit;
};
 
Cpp-file:
 
TimeScaleDraw::TimeScaleDraw()
{
    factor = 1.0;
    unit = "s";
}

QwtText TimeScaleDraw::label(double val) const
{
    return QwtText(QString::number(val*factor) + unit);
}

void TimeScaleDraw::setTimeScale(double factor, QString unit)
{
    this->factor = factor;
    this->unit = unit;
}
 
This works fine if i call the method setTimeScale(2.0, "sec) from my Qt window constructor. But if i try to call the method when eg. a button is pushed, then it does not do anything? I have tried by calling replot() and updateAxes() but this changes nothing.
 
Any suggestions?

原文：https://stackoverflow.com/questions/35841496