Problem with the QwtPlot

cp · 28th February 2014, 02:45

Hi,
When I use the QwtPlot,I have a problem with it.If I set the size(width or height) of the plot larger than 32767,and I set the scale div of axis equal with the size(width or height) of plot.There will appear a black area in the bottom of the plot.Why?? Here is some code and picture in forrow.

Qt Code:

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QwtPlot *plot = new QwtPlot();
    plot->enableAxis(QwtPlot::xBottom,false);
    QwtScaleDiv div;
    QwtLinearScaleEngine *linearEngine=new QwtLinearScaleEngine();
    div=linearEngine->divideScale(0,33000,50,0,10);
    plot->setAxisScaleDiv(QwtPlot::yLeft,div);
    plot->setFixedSize(200,33000);
    plot->replot()
;

QwtPlot *plot = new QwtPlot();
    plot->enableAxis(QwtPlot::xBottom,false);
    QwtScaleDiv div;
    QwtLinearScaleEngine *linearEngine=new QwtLinearScaleEngine();
    div=linearEngine->divideScale(0,33000,50,0,10);
    plot->setAxisScaleDiv(QwtPlot::yLeft,div);
    plot->setFixedSize(200,33000);
    plot->replot()
;

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plot.jpg
Thanks for you help!