A simple Plot doesn't work in Qt5

[8Observer8]

Hi,

A simple Plot doesn't work in Qt5. Please, help me!

SimplePlotInQt5.pro

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 
SOURCES += \
    main.cpp \
    plotwindow.cpp
 
HEADERS += \
    plotwindow.h
 
QWT_LOCATION = c:/Qwt-6.1.0
INCLUDEPATH += $${QWT_LOCATION}/include
LIBS = -L$${QWT_LOCATION}/lib \
     -lqwt

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

SOURCES += \
    main.cpp \
    plotwindow.cpp

HEADERS += \
    plotwindow.h

QWT_LOCATION = c:/Qwt-6.1.0
INCLUDEPATH += $${QWT_LOCATION}/include
LIBS = -L$${QWT_LOCATION}/lib \
     -lqwt

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plotwindow.h

#ifndef PLOTHWINDOW_H
#define PLOTWINDOW_H
 
#include <QMainWindow>
 
class PlotWindow : public QMainWindow
{
    Q_OBJECT
public:
    explicit PlotWindow(QWidget *parent = 0);
 
signals:
 
public slots:
 
};
 
#endif // PLOTWINDOW_H

#ifndef PLOTHWINDOW_H
#define PLOTWINDOW_H

#include <QMainWindow>

class PlotWindow : public QMainWindow
{
    Q_OBJECT
public:
    explicit PlotWindow(QWidget *parent = 0);

signals:

public slots:

};

#endif // PLOTWINDOW_H

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plotwindow.cpp

#include "plotwindow.h"
#include <qwt_plot.h>
#include <qwt_legend.h>
#include <qwt_plot_grid.h>
#include <qwt_plot_curve.h>
#include <qwt_symbol.h>
#include <QHBoxLayout>
#include <QWidget>
 
PlotWindow::PlotWindow(QWidget *parent) :
    QMainWindow(parent)
{
    QwtPlot *plot = new QwtPlot;
 
    plot->setTitle(tr("Simple Plot"));
    plot->setCanvasBackground(Qt::white);
    plot->setAxisScale(QwtPlot::yLeft, 0.0, 100);
    plot->insertLegend(new QwtLegend);
 
    QwtPlotGrid *grid = new QwtPlotGrid;
    grid->attach(plot);
 
    QwtPlotCurve *curve = new QwtPlotCurve;
    curve->setTitle(tr("Points"));
    curve->setPen(QPen(Qt::blue, 4));
    curve->setRenderHint(QwtPlotItem::RenderAntialiased, true);
 
    QwtSymbol *symbol = new QwtSymbol(QwtSymbol::Ellipse, QBrush(Qt::yellow),
                                      QPen(Qt::red, 2), QSize(8, 8));
    curve->setSymbol(symbol);
 
    QPolygonF points;
    points << QPointF(0.0, 0.0) << QPointF(200.0, 20.0) << QPointF(400, 40) <<
              QPointF(600.0, 40) << QPointF(1000.0, 100.0);
 
    curve->setSamples(points);
    curve->attach(plot);
 
    QHBoxLayout *mainLayout = new QHBoxLayout;
    mainLayout->addWidget(plot);
 
    QWidget *window = new QWidget;
    window->setLayout(mainLayout);
 
    setCentralWidget(window);
 
    this->setWindowTitle(tr("Simple Plot"));
    this->resize(600, 400);
}

#include "plotwindow.h"
#include <qwt_plot.h>
#include <qwt_legend.h>
#include <qwt_plot_grid.h>
#include <qwt_plot_curve.h>
#include <qwt_symbol.h>
#include <QHBoxLayout>
#include <QWidget>

PlotWindow::PlotWindow(QWidget *parent) :
    QMainWindow(parent)
{
    QwtPlot *plot = new QwtPlot;

    plot->setTitle(tr("Simple Plot"));
    plot->setCanvasBackground(Qt::white);
    plot->setAxisScale(QwtPlot::yLeft, 0.0, 100);
    plot->insertLegend(new QwtLegend);

    QwtPlotGrid *grid = new QwtPlotGrid;
    grid->attach(plot);

    QwtPlotCurve *curve = new QwtPlotCurve;
    curve->setTitle(tr("Points"));
    curve->setPen(QPen(Qt::blue, 4));
    curve->setRenderHint(QwtPlotItem::RenderAntialiased, true);

    QwtSymbol *symbol = new QwtSymbol(QwtSymbol::Ellipse, QBrush(Qt::yellow),
                                      QPen(Qt::red, 2), QSize(8, 8));
    curve->setSymbol(symbol);

    QPolygonF points;
    points << QPointF(0.0, 0.0) << QPointF(200.0, 20.0) << QPointF(400, 40) <<
              QPointF(600.0, 40) << QPointF(1000.0, 100.0);

    curve->setSamples(points);
    curve->attach(plot);

    QHBoxLayout *mainLayout = new QHBoxLayout;
    mainLayout->addWidget(plot);

    QWidget *window = new QWidget;
    window->setLayout(mainLayout);

    setCentralWidget(window);

    this->setWindowTitle(tr("Simple Plot"));
    this->resize(600, 400);
}

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main.cpp

#include <QApplication>
#include "plotwindow.h"
 
int main(int argc, char **argv)
{
    QApplication app(argc, argv);
 
    PlotWindow gw;
    gw.show();
 
    return app.exec();
}

#include <QApplication>
#include "plotwindow.h"

int main(int argc, char **argv)
{
    QApplication app(argc, argv);

    PlotWindow gw;
    gw.show();

    return app.exec();
}

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Output

QWidget: Must construct a QApplication before a QPaintDevice
Invalid parameter passed to C runtime function.
Invalid parameter passed to C runtime function.

[Cah]

Looks like you are using the release version of the lib in a debug app

In the pro file try

LIBS += -L$${QWT_LOCATION}/lib -lqwtd

note the -lqwtd instead of -lqwt

[8Observer8]

Looks like you are using the release version of the lib in a debug app

In the pro file try

LIBS += -L$${QWT_LOCATION}/lib -lqwtd

note the -lqwtd instead of -lqwt

Yes, It works! Thank you very much

[Uwe]

To avoid issues like this: http://qwt.sourceforge.net/qwtinstal...PILEANDLINKAPP

Uwe