Hi to all! Some time ago I downloaded Qwt. All OK. Compiling OK. Installing OK.
A troubles with using in project was resolved successfully. But I need a histogram.
Well, there is an example present in source code. Good. Building... OK.
Trying to start examples one by one.
bode - segmentation fault 
cpuplot - symbol lookup error: ./cpuplot: undefined symbol: _ZNK9QwtLegend4findEPK20QwtLegendItemManager ????
curvedemo1, curvedemo1 - segmentation fault 
data_plot - segmentation fault :-/
dials - ok :-D
event_filter - ok :-)
histogram - segmentation fault :-/
radio - ok :-D
realtime - segmentation fault :-/
simple - segmentation fault :-/
sliders - ok :-D
spectrogram - segmentation fault >:-/
sysinfo - ok :-)
So, it`s a pity, but I can`t see most interesting examples. Well. I`m trying to write a histogram for my project. Step by step I`m trying to understand what`s wrong with example "histogram". As I understood there are no class like QwtHistogram. So, in example I have
{
public:
explicit HistogramItem
(const QwtText &title
);
virtual ~HistogramItem();
void setColor
(const QColor &);
virtual QwtDoubleRect boundingRect() const;
virtual int rtti() const;
void setBaseline(double reference);
double baseline() const;
enum HistogramAttribute
{
Auto = 0,
Xfy = 1
};
void setHistogramAttribute(HistogramAttribute, bool on = true);
bool testHistogramAttribute(HistogramAttribute) const;
protected:
Qt
::Orientation o,
const QRect &) const;
private:
void init();
class PrivateData;
PrivateData *d_data;
};
class HistogramItem: public QwtPlotItem
{
public:
explicit HistogramItem(const QString &title = QString::null);
explicit HistogramItem(const QwtText &title);
virtual ~HistogramItem();
void setData(const QwtIntervalData &data);
const QwtIntervalData &data() const;
void setColor(const QColor &);
QColor color() const;
virtual QwtDoubleRect boundingRect() const;
virtual int rtti() const;
virtual void draw(QPainter *, const QwtScaleMap &xMap,
const QwtScaleMap &yMap, const QRect &) const;
void setBaseline(double reference);
double baseline() const;
enum HistogramAttribute
{
Auto = 0,
Xfy = 1
};
void setHistogramAttribute(HistogramAttribute, bool on = true);
bool testHistogramAttribute(HistogramAttribute) const;
protected:
virtual void drawBar(QPainter *,
Qt::Orientation o, const QRect &) const;
private:
void init();
class PrivateData;
PrivateData *d_data;
};
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I wrote a test as copy of example:
#include <stdlib.h>
#include <qapplication.h>
#include <qpen.h>
#include <qwt_plot.h>
#include <qwt_plot_grid.h>
#include <qwt_plot_marker.h>
#include <qwt_interval_data.h>
#include "histogram_item.h"
int main(int argc, char **argv)
{
plot
->setCanvasBackground
(QColor(Qt
::white));
plot->setTitle("Histogram");
grid->enableXMin(true);
grid->enableYMin(true);
grid
->setMajPen
(QPen(Qt
::black,
0, Qt
::DotLine));
grid
->setMinPen
(QPen(Qt
::gray,
0 , Qt
::DotLine));
grid->attach(plot);
HistogramItem *histogram = new HistogramItem();
histogram->setColor(Qt::darkCyan);
const int numValues = 20;
QwtArray<QwtDoubleInterval> intervals(numValues);
QwtArray<double> values(numValues);
double pos = 0.0;
for ( int i = 0; i < (int)intervals.size(); i++ )
{
const int width = 5 + rand() % 15;
const int value = rand() % 100;
values[i] = value;
pos += width;
}
histogram->attach(plot);
plot
->setAxisScale
(QwtPlot::yLeft,
0.0,
100.0);
plot
->setAxisScale
(QwtPlot::xBottom,
0.0, pos
);
plot->replot();
#if QT_VERSION < 0x040000
a.setMainWidget(&plot);
#endif
plot->resize(600,400);
plot->show();
return a.exec();
}
#include <stdlib.h>
#include <qapplication.h>
#include <qpen.h>
#include <qwt_plot.h>
#include <qwt_plot_grid.h>
#include <qwt_plot_marker.h>
#include <qwt_interval_data.h>
#include "histogram_item.h"
int main(int argc, char **argv)
{
QApplication a(argc, argv);
QwtPlot* plot = new QwtPlot(0);
plot->setCanvasBackground(QColor(Qt::white));
plot->setTitle("Histogram");
QwtPlotGrid *grid = new QwtPlotGrid;
grid->enableXMin(true);
grid->enableYMin(true);
grid->setMajPen(QPen(Qt::black, 0, Qt::DotLine));
grid->setMinPen(QPen(Qt::gray, 0 , Qt::DotLine));
grid->attach(plot);
HistogramItem *histogram = new HistogramItem();
histogram->setColor(Qt::darkCyan);
const int numValues = 20;
QwtArray<QwtDoubleInterval> intervals(numValues);
QwtArray<double> values(numValues);
double pos = 0.0;
for ( int i = 0; i < (int)intervals.size(); i++ )
{
const int width = 5 + rand() % 15;
const int value = rand() % 100;
intervals[i] = QwtDoubleInterval(pos, pos + double(width));
values[i] = value;
pos += width;
}
histogram->setData(QwtIntervalData(intervals, values));
histogram->attach(plot);
plot->setAxisScale(QwtPlot::yLeft, 0.0, 100.0);
plot->setAxisScale(QwtPlot::xBottom, 0.0, pos);
plot->replot();
#if QT_VERSION < 0x040000
a.setMainWidget(&plot);
#endif
plot->resize(600,400);
plot->show();
return a.exec();
}
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and got segmentation fault in return a.exec();
Can you help me? Were is problem may be? May be another way present to make histogram?
Thanks a lot everyone!
Qwt examples
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Originally Posted by DKL1972
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