qTableWidgetItem and qwtPlot subclassing

[chinalski]

Hi to all,
I have problem on qTableWidgetItem subclassing.
I'm trying to display a qwtPlot (not a curve, only the axis) in the vertical header of a qTableWidget, using the tableWidget->setVerticalHeaderItem() function, because I need to have a lot of curves in the table widget, each one with his own plot, all of them in the same row, and a single axis scale in the vertical header of that row which is fixed when the scroll is used.

It seems to me that everything is okay in my code, but the plot in the header does not appear in the table widget header.
I tried to apply the qwtPlot-qTableWidgetItem in a normal cell in the table widget (not in the header), and the result is the same: nothing appears.

This is my simple subclassing: nothing is added, only the qwtPlot became also a qTableWidgetItem.

class MyPlot :  public QTableWidgetItem, public QwtPlot
{
public:
    MyPlot();
};
 
MyPlot::MyPlot() :
    QTableWidgetItem(), QwtPlot()
{
    ;
}

class MyPlot :  public QTableWidgetItem, public QwtPlot
{
public:
    MyPlot();
};

MyPlot::MyPlot() :
    QTableWidgetItem(), QwtPlot()
{
    ;
}

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And this is the code I use:

Viewgraph::Viewgraph(QWidget *parent)
    : QMainWindow(parent)
{
    int samplesNumber = 200;
    QVector <double> yData;
    QVector <double> xData;
    QVector <double> zeroData;
 
    MyPlot * axis = new MyPlot;
    QwtPlotCurve * zeroCurve = new QwtPlotCurve;
 
    QTableWidget * tableWidget = new QTableWidget;
    tableWidget->setRowCount(1);
    tableWidget->setColumnCount(11);
    tableWidget->setRowHeight(0, 300);
    tableWidget->setColumnWidth(0, 30);
 
    tableWidget->verticalHeader()->setResizeMode(QHeaderView::Fixed);
    tableWidget->verticalHeader()->resizeSection(0, 300);
 
    yData.resize(samplesNumber);
    xData.resize(samplesNumber);
    zeroData.resize(samplesNumber);
 
    for (int i = 0; i < samplesNumber; i++){
        yData[i] = sin((double) i/5);
        xData[i] = (double) i;
        zeroData[i] = (double) 0;
    }
 
    MyPlot * plot = new MyPlot;
    QwtPlotCurve * plotCurve = new QwtPlotCurve;
    tableWidget->setColumnWidth(1, 60);
 
    plot->enableAxis(QwtPlot::xBottom, false);
    plot->enableAxis(QwtPlot::yLeft, false);
    plot->setAxisScale(QwtPlot::yLeft, samplesNumber, 0, 0);
    plot->axisScaleDraw(QwtPlot::yLeft);
    plot->setAxisScale(QwtPlot::xBottom, -1, 1, 0);
    plotCurve->setOrientation(Qt::Horizontal);
    plotCurve->setSamples(yData, xData);
    plotCurve->setBaseline(0);
    plotCurve->attach(plot);
 
    tableWidget->setCellWidget(0,1,plot);
 
    axis->enableAxis(QwtPlot::xBottom, false);
    axis->setAxisScale(QwtPlot::xBottom, 0, 0, 0);
    axis->setAxisScale(QwtPlot::yLeft, samplesNumber, 0, 0);
    axis->axisScaleDraw(QwtPlot::yLeft);
    zeroCurve->setOrientation(Qt::Horizontal);
    zeroCurve->setPen(QColor(Qt::transparent));
    zeroCurve->setSamples(zeroData, xData);
    zeroCurve->attach(axis);
 
    //tableWidget->setCellWidget(0,0,axis);
    tableWidget->setVerticalHeaderItem(0, axis);
 
    tableWidget->show();
}

Viewgraph::Viewgraph(QWidget *parent)
    : QMainWindow(parent)
{
    int samplesNumber = 200;
    QVector <double> yData;
    QVector <double> xData;
    QVector <double> zeroData;

    MyPlot * axis = new MyPlot;
    QwtPlotCurve * zeroCurve = new QwtPlotCurve;

    QTableWidget * tableWidget = new QTableWidget;
    tableWidget->setRowCount(1);
    tableWidget->setColumnCount(11);
    tableWidget->setRowHeight(0, 300);
    tableWidget->setColumnWidth(0, 30);

    tableWidget->verticalHeader()->setResizeMode(QHeaderView::Fixed);
    tableWidget->verticalHeader()->resizeSection(0, 300);

    yData.resize(samplesNumber);
    xData.resize(samplesNumber);
    zeroData.resize(samplesNumber);

    for (int i = 0; i < samplesNumber; i++){
        yData[i] = sin((double) i/5);
        xData[i] = (double) i;
        zeroData[i] = (double) 0;
    }

    MyPlot * plot = new MyPlot;
    QwtPlotCurve * plotCurve = new QwtPlotCurve;
    tableWidget->setColumnWidth(1, 60);

    plot->enableAxis(QwtPlot::xBottom, false);
    plot->enableAxis(QwtPlot::yLeft, false);
    plot->setAxisScale(QwtPlot::yLeft, samplesNumber, 0, 0);
    plot->axisScaleDraw(QwtPlot::yLeft);
    plot->setAxisScale(QwtPlot::xBottom, -1, 1, 0);
    plotCurve->setOrientation(Qt::Horizontal);
    plotCurve->setSamples(yData, xData);
    plotCurve->setBaseline(0);
    plotCurve->attach(plot);

    tableWidget->setCellWidget(0,1,plot);

    axis->enableAxis(QwtPlot::xBottom, false);
    axis->setAxisScale(QwtPlot::xBottom, 0, 0, 0);
    axis->setAxisScale(QwtPlot::yLeft, samplesNumber, 0, 0);
    axis->axisScaleDraw(QwtPlot::yLeft);
    zeroCurve->setOrientation(Qt::Horizontal);
    zeroCurve->setPen(QColor(Qt::transparent));
    zeroCurve->setSamples(zeroData, xData);
    zeroCurve->attach(axis);

    //tableWidget->setCellWidget(0,0,axis);
    tableWidget->setVerticalHeaderItem(0, axis);

    tableWidget->show();
}

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If I was able to to put the "axis" plot in the vertical header my problem would be solved.
Something is wrong with my code or is it impossible for some reason?

And, if my way is not the right way, do you have some suggestion for a better mode?
Thank you very much to all,
Carlo

[Uwe]

Have you seen the plotmatrix example ?

Uwe

[chinalski]

Hi Uwe,
yes, I already knew the plotmatrix example, but it is not useful for my problem.
Plot matrix is a nethod to sort in a matrix some plots (let me say: complete plots, with curve and axis), but it is not related to scroll function.
What I need is:
- to have a single fixed vertical axis with scale on the left side of the window (with no curve drawn),
- more than one plot on the right side of the windows (each plot with no axis),
- the horizontal scroll bar which work only on the plots of the right side of the window (treated as a whole, as in a normal table widget), so that the vertical axis on the left side remain fix in his position.

Said in a simple way, I just need to put, in the vertical header, a qwtPlot.

[Uwe]

Said in a simple way, I just need to put, in the vertical header, a qwtPlot.

The simple way is a QHBoxLayout with a QwtScaleWidget and a QScrollArea. The scrollarea contains the plot widgets organized in a grid layout.

Using a QTableWidget introduces problems without any benefit.

Uwe

[chinalski]

Okay, I'll try what you suggest.
I'll let you know if I'm able to apply your solution.
carlo

[chinalski]

Thank you very much, Uwe,
everything is ok now.
I include my code, if this could be useful to someone.
c

#include <QTableWidget>
#include <math.h>
#include <QHeaderView>
#include <QHBoxLayout>
#include <QScrollArea>
#include <QScrollBar>
#include <QGridLayout>
 
#include "qwt_plot_curve.h"
#include "qwt_plot.h"
#include <qwt_scale_widget.h>
 
#include "viewgraph.h"
 
Viewgraph::Viewgraph(QWidget *parent)
    : QMainWindow(parent)
{
    QWidget * window = new QWidget;
    window->resize(600,400);
 
    QWidget * plotField = new QWidget(window);
    plotField->resize((50*20),600);
 
    QScrollArea * scrollArea = new QScrollArea(window);
    QScrollArea * scaleArea = new QScrollArea(window);
    scrollArea->move(100, 0);
    scrollArea->resize(500,350);
    scrollArea->setWidget(plotField);
    scaleArea->move(0,0);
    scaleArea->resize(100,350);
    scaleArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
 
    int samplesNumber = 200;
    QVector <double> yData[20];
    QVector <double> xData[20];
 
    QHBoxLayout *layout = new QHBoxLayout;
    layout->setSpacing(0);
 
    QwtPlot * scale = new QwtPlot(window);
    scale->resize(40,600);
    scale->setAxisScale(QwtPlot::yLeft, samplesNumber, 0, 50);
    scale->enableAxis(QwtPlot::xBottom, false);
 
    scaleArea->setWidget(scale);
 
    QScrollBar * plotScrollBar = new QScrollBar;
    QScrollBar * scaleScrollBar = new QScrollBar;
    plotScrollBar = scrollArea->verticalScrollBar();
    scaleScrollBar = scaleArea->verticalScrollBar();
 
    for (int j = 0; j < 20; j++) {
        yData[j].resize(samplesNumber);
        xData[j].resize(samplesNumber);
 
        for (int i = 0; i < samplesNumber; i++){
            yData[j][i] = sin((double) i/5);
            xData[j][i] = (double) i;
        }
 
        QwtPlot * plot = new QwtPlot;
        QwtPlotCurve * plotCurve = new QwtPlotCurve;
 
        plot->enableAxis(QwtPlot::xBottom, false);
        plot->enableAxis(QwtPlot::yLeft, false);
 
        plot->setAxisScale(QwtPlot::yLeft, samplesNumber, 0, 0);
        plot->axisScaleDraw(QwtPlot::yLeft);
 
        plot->setAxisScale(QwtPlot::xBottom, -1, 1, 0);
        plot->setMaximumWidth(50);
 
        plotCurve->setOrientation(Qt::Horizontal);
        plotCurve->setSamples(yData[j], xData[j]);
        plotCurve->setBaseline(0);
        plotCurve->attach(plot);
 
        layout->addWidget(plot);
    }
 
    QObject::connect(plotScrollBar, SIGNAL(valueChanged(int)),
            scaleScrollBar, SLOT(setValue(int)));
 
    plotField->setLayout(layout);
    window->show();
}

#include <QTableWidget>
#include <math.h>
#include <QHeaderView>
#include <QHBoxLayout>
#include <QScrollArea>
#include <QScrollBar>
#include <QGridLayout>

#include "qwt_plot_curve.h"
#include "qwt_plot.h"
#include <qwt_scale_widget.h>

#include "viewgraph.h"

Viewgraph::Viewgraph(QWidget *parent)
    : QMainWindow(parent)
{
    QWidget * window = new QWidget;
    window->resize(600,400);

    QWidget * plotField = new QWidget(window);
    plotField->resize((50*20),600);

    QScrollArea * scrollArea = new QScrollArea(window);
    QScrollArea * scaleArea = new QScrollArea(window);
    scrollArea->move(100, 0);
    scrollArea->resize(500,350);
    scrollArea->setWidget(plotField);
    scaleArea->move(0,0);
    scaleArea->resize(100,350);
    scaleArea->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);

    int samplesNumber = 200;
    QVector <double> yData[20];
    QVector <double> xData[20];

    QHBoxLayout *layout = new QHBoxLayout;
    layout->setSpacing(0);

    QwtPlot * scale = new QwtPlot(window);
    scale->resize(40,600);
    scale->setAxisScale(QwtPlot::yLeft, samplesNumber, 0, 50);
    scale->enableAxis(QwtPlot::xBottom, false);

    scaleArea->setWidget(scale);

    QScrollBar * plotScrollBar = new QScrollBar;
    QScrollBar * scaleScrollBar = new QScrollBar;
    plotScrollBar = scrollArea->verticalScrollBar();
    scaleScrollBar = scaleArea->verticalScrollBar();

    for (int j = 0; j < 20; j++) {
        yData[j].resize(samplesNumber);
        xData[j].resize(samplesNumber);

        for (int i = 0; i < samplesNumber; i++){
            yData[j][i] = sin((double) i/5);
            xData[j][i] = (double) i;
        }

        QwtPlot * plot = new QwtPlot;
        QwtPlotCurve * plotCurve = new QwtPlotCurve;

        plot->enableAxis(QwtPlot::xBottom, false);
        plot->enableAxis(QwtPlot::yLeft, false);

        plot->setAxisScale(QwtPlot::yLeft, samplesNumber, 0, 0);
        plot->axisScaleDraw(QwtPlot::yLeft);

        plot->setAxisScale(QwtPlot::xBottom, -1, 1, 0);
        plot->setMaximumWidth(50);

        plotCurve->setOrientation(Qt::Horizontal);
        plotCurve->setSamples(yData[j], xData[j]);
        plotCurve->setBaseline(0);
        plotCurve->attach(plot);

        layout->addWidget(plot);
    }

    QObject::connect(plotScrollBar, SIGNAL(valueChanged(int)),
            scaleScrollBar, SLOT(setValue(int)));

    plotField->setLayout(layout);
    window->show();
}

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