qt画出的图形无法显示出全部数据？

[weixin_38061848]

用qt做一个界面，目的是画出频谱图，使用qwt库，发现导入数据后，不同窗口大小显示的数据不一样，比如默认窗口大小显示大小如下拉长后显示如下放到最大时候显示如下代码如下：plot.h复制代码#include <qwt_plot.h>#include <qwt_plot_spectrogram.h>class Plot : public QwtPlot{    Q_OBJECTpublic:    Plot(QWidget * = NULL);    public slots:private:    QwtPlotSpectrogram *d_spectrogram;};plot.cpp复制代码#include <qprinter.h>#include <qprintdialog.h>#include <qnumeric.h>#include <qwt_color_map.h>#include <qwt_plot_spectrogram.h>#include <qwt_scale_widget.h>#include <qwt_scale_draw.h>#include <qwt_plot_zoomer.h>#include <qwt_plot_panner.h>#include <qwt_plot_layout.h>#include <qwt_plot_renderer.h>#include <qwt_matrix_raster_data.h>#include "plot.h"#include <QFile>#include<QtAlgorithms>class MyZoomer : public QwtPlotZoomer{public:    MyZoomer(QWidget *canvas) :        QwtPlotZoomer(canvas)    {        setTrackerMode(AlwaysOn);    }    virtual QwtText trackerTextF(const QPointF &pos) const    {        QColor bg(Qt::white);        //设置背景透明度        bg.setAlpha(20);        //QwtPlotZoomer::trackerTextF返回x,y的坐标轴的刻度数        QwtText text = QwtPlotZoomer::trackerTextF(pos);        text.setBackgroundBrush(QBrush(bg));        return text;    }};class SpectrogramData : public QwtMatrixRasterData{public:    SpectrogramData()    {        QFile data("H:/STUDY/Qtproject/spectromgramTest/est.bin");        if (data.open(QFile::ReadOnly))        {            QDataStream instream(&data);            QVector<double> rawData;            double *temp = new double[10000 * 300];            instream.readRawData((char*)temp, 10000 * 300 * sizeof(double));            for (int i = 0; i < 10000; i++)            {                for (int j = 0; j < 300; j++)                {                    rawData += temp[j * 10000 + i];                }            }            setValueMatrix(rawData, 300);        delete[] temp;            }        setInterval(Qt::XAxis, QwtInterval(0, 1));        setInterval(Qt::YAxis, QwtInterval(0,10));        setInterval(Qt::ZAxis, QwtInterval(0.0, 0.01));    }};class LinearColorMapRGB : public QwtLinearColorMap{public:    LinearColorMapRGB() :        //首尾颜色        QwtLinearColorMap(Qt::darkCyan, Qt::red, QwtColorMap::RGB)    {        addColorStop(0.0, Qt::black);        addColorStop(0.6, Qt::green);        addColorStop(0.75, Qt::white);    }};Plot::Plot(QWidget *parent) :QwtPlot(parent){    d_spectrogram = new QwtPlotSpectrogram();    // use system specific thread count    //设置线程数和缓存，影响不大    d_spectrogram->setRenderThreadCount(0);    d_spectrogram->setCachePolicy(QwtPlotRasterItem::PaintCache);    d_spectrogram->setData(new SpectrogramData());    d_spectrogram->attach(this);    //设置轮廓线的数量和层次（当值为多少时画一条轮廓线）    QList<double> contourLevels;    for ( double level =0.001; level <0.1; level += 0.002)        contourLevels += level;//不是相加，是在其后面添加元素    d_spectrogram->setContourLevels( contourLevels );    const QwtInterval zInterval = d_spectrogram->data()->interval(Qt::ZAxis);    // A color bar on the right axis    QwtScaleWidget *rightAxis = axisWidget(QwtPlot::yRight);    rightAxis->setTitle("Intensity");    //仅设置这个还不行    rightAxis->setColorBarEnabled(true);    setAxisScale(QwtPlot::yRight, zInterval.minValue(), zInterval.maxValue());    enableAxis(QwtPlot::yRight);//默认disabed    //设置画布对齐到所有坐标轴    plotLayout()->setAlignCanvasToScales(true);    //设置为RGBColorMap    d_spectrogram->setColorMap(new LinearColorMapRGB());    rightAxis->setColorMap(zInterval, new LinearColorMapRGB());    //设置显示模式    d_spectrogram->setDisplayMode(QwtPlotSpectrogram::ContourMode,true);    d_spectrogram->setDisplayMode( QwtPlotSpectrogram::ImageMode, false);    //设置鼠标操作    // LeftButton for the zooming    // MidButton for the panning    // RightButton: zoom out by 1    // Ctrl+RighButton: zoom out to full size    QwtPlotZoomer* zoomer = new MyZoomer(canvas());    //修改某一操作，比如一步返回到不放大状态    zoomer->setMousePattern(QwtEventPattern::MouseSelect2,        Qt::RightButton, Qt::ControlModifier);    zoomer->setMousePattern(QwtEventPattern::MouseSelect3,        Qt::RightButton);    const QColor c(Qt::red);    //设置RubberBandPen选择框笔触    zoomer->setRubberBandPen(c);    //设置TrackerPen笔触    zoomer->setTrackerPen(c);    QwtPlotPanner *panner = new QwtPlotPanner(canvas());    //移动绘图时候右边colorbar不需要自动改变刻度    panner->setAxisEnabled(QwtPlot::yRight, false);    panner->setMouseButton(Qt::MidButton);    // Avoid jumping when labels with more/less digits    // appear/disappear when scrolling vertically    const QFontMetrics fm(axisWidget(QwtPlot::yLeft)->font());    QwtScaleDraw *sd = axisScaleDraw(QwtPlot::yLeft);    sd->setMinimumExtent(fm.width("100.00"));}请问用什么办法使其显示出所有数据？困扰好久，感激不尽！