Multi curves plotting issue

[fallen]

Hi!

I am making a program plotting more than a curve in one QwtPlot. This program is plotting real time data and allows the user to set the size of aquisition, so the number of plots in a curve. Resizing the curves works perfectly but I have some issues printing the curves, only the last one has the correct number of plots.

For example I ask 20 points per curve and I have 3 curves. The last curve I created will print 20 points, the second will print 10 and the first will print less.
Here is the snapshot: http://www.box.net/shared/q09jvw1yco

In the code I am regularly updating each curve before replotting in a timer:

setRawData (d_x, d_y, nCurPlotsY); //nCurPlotsY the current nb of plots

setRawData (d_x, d_y, nCurPlotsY); //nCurPlotsY the current nb of plots

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Any ideas?

Cheers,

ben

[Uwe]

...but I have some issues printing the curves, only the last one has the correct number of plots.

You mean points ?

For example I ask 20 points per curve and I have 3 curves. The last curve I created will print 20 points, the second will print 10 and the first will print less. Here is the snapshot: ...

Showing 3 curves - one with 20 points, the second with 10 and the third with less.

So what exactly is the problem ?

Uwe

[fallen]

...but I have some issues printing the curves, only the last one has the correct number of plots.

You mean points ?

Yeah of course... sorry for the mistake.

For example I ask 20 points per curve and I have 3 curves. The last curve I created will print 20 points, the second will print 10 and the first will print less.

So I want 20 points on each curve.
Each curve is really attached to the plot with the same number of points, but doesn't show those points (except the last curve created).

[Uwe]

Without knowing your code it's hard to say what you are doing wrong.

Uwe

[fallen]

Ok here is the code concerning the creation and modifications of the curves, I tried to extract the most important parts.

Definition of the plot:

class DataPlot
    : public QwtPlot
{
    Q_OBJECT
 
    public:
        void newCurve (QString, QString); //create a new curve
        void updateCurves (); //update all curves (called by a thread)
 
    private:
        std::vector <Curve*> curves; //vector of curves
};

class DataPlot
    : public QwtPlot
{
    Q_OBJECT

    public:
        void newCurve (QString, QString); //create a new curve
        void updateCurves (); //update all curves (called by a thread)

    private:
        std::vector <Curve*> curves; //vector of curves
};

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Definition of a curve:

class Curve
    : public QwtPlotCurve, QWidget
{
    public:
        void updaterX (Message&); //update X values
        void updaterY (Message&); //update Y values
 
        void updateNPoints (int); //update nb of points
        void reattach (); //reattach with the correct nb of points
 
    private:
 
        int nPoints; //nb of points asked
 
        int nCurPointsX; //current nb of values on X called in a thread
        int nCurPointsY; //current nb of values on Y called in a thread
 
        double d_x[MAX_PLOT_SIZE]; //values on X
        double d_y[MAX_PLOT_SIZE]; //values on Y
 
        QColor color; //curve color
        QwtSymbol symbol; //curve symbol
};

class Curve
    : public QwtPlotCurve, QWidget
{
    public:
        void updaterX (Message&); //update X values
        void updaterY (Message&); //update Y values

        void updateNPoints (int); //update nb of points
        void reattach (); //reattach with the correct nb of points

    private:

        int nPoints; //nb of points asked

        int nCurPointsX; //current nb of values on X called in a thread
        int nCurPointsY; //current nb of values on Y called in a thread

        double d_x[MAX_PLOT_SIZE]; //values on X
        double d_y[MAX_PLOT_SIZE]; //values on Y

        QColor color; //curve color
        QwtSymbol symbol; //curve symbol
};

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Interesting code in DataPlot:

//////////////////////////////////
// create a new curve
//////////////////////////////////
void
DataPlot::newCurve (QString _varX,
                               QString _varY)
{
    [...]
    //create a new curve
    curves.push_back (new Curve (_name, robot,
                                 nbCurves++, col,
                                 nbPlots, this)); 
 
    //attach the new curve to the plot   
    curves.back ()->attach (this);
    curves.back ()->setPen (col);
    [...]
}
 
//////////////////////////////////
// update the curves
//////////////////////////////////
void
DataPlot::updateCurves()
{
    [...] 
    //for each curve
    for (unsigned int i=0; i<curves.size (); i++)
    {
        [...]
        //reattach the curve with an updated number of points
        curves[i]->reattach (this);
    }
 
    // update the display
    replot ();
}

//////////////////////////////////
// create a new curve
//////////////////////////////////
void
DataPlot::newCurve (QString _varX,
                               QString _varY)
{
    [...]
    //create a new curve
    curves.push_back (new Curve (_name, robot,
                                 nbCurves++, col,
                                 nbPlots, this)); 

    //attach the new curve to the plot   
    curves.back ()->attach (this);
    curves.back ()->setPen (col);
    [...]
}

//////////////////////////////////
// update the curves
//////////////////////////////////
void
DataPlot::updateCurves()
{
    [...] 
    //for each curve
    for (unsigned int i=0; i<curves.size (); i++)
    {
        [...]
        //reattach the curve with an updated number of points
        curves[i]->reattach (this);
    }

    // update the display
    replot ();
}

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Interesting code in Curve:

////////////////////////////////////////////////////////////
// Constructor
////////////////////////////////////////////////////////////
Curve::Curve (const QString& s,
              QColor _color,
              int _nPoints,
              QWidget* _parent) :
    QwtPlotCurve (s),
    QWidget (_parent),
    s_error (false),
    id (_id),
    nPoints (_nPoints),
    nCurPointsX (0),
    nCurPointsY (0),
    color (_color),
    symbol (QwtSymbol::Cross,
            QBrush (),
            QPen (_color),
            QSize (5,5))
{
    //initiate values to 0
    for (int i = 0; i< MAX_PLOT_SIZE; i++)
    {
        d_x[i] = 0;
        d_y[i] = 0;
    }
 
    setSymbol (symbol);
}
 
////////////////////////////////////////////////////////////
// updates Y values
////////////////////////////////////////////////////////////
void
Curve::updaterY (Message &msg)
{
        //when we receive a correct message
        if (msg.value->type == DATA_DOUBLE)
        {
            //the following code allows a fluent printing of the
            //points, increasing 1 by 1 when more points are asked
            //or decreasing and keeping the last points when less 
            //points are requiered
 
            //if we have to decrease the size of the curve
            if (nCurPointsY > nPoints)
            {
                for (int i = (nCurPointsY - nPoints); i <= nCurPointsY; i++)
                    d_y[i-(nCurPointsY - nPoints)] = d_y[i];
 
                nCurPointsY = nPoints ;
            }
 
            //if we have to increase it
            if (nCurPointsY < nPoints)
            {
                nCurPointsY++;
            }
 
            //move the array to left
            else
            {
                for (int j = 1; j <= nCurPointsY; j++)
                    d_y[j-1] = d_y[j];
            }
 
           //add the new value in the end
            if (nCurPointsY >= 0)
                d_y[nCurPointsY-1] = msg.value->val;
}
 
////////////////////////////////////////////////////////////
// updates X values
////////////////////////////////////////////////////////////
void
Curve::updaterX (Message &msg)
{
   //same with X instead of Y....
   [...]
}
 
////////////////////////////////////////////////////////////
// reattach the curve with the correct nb of points
////////////////////////////////////////////////////////////
void
Curve::reattach ()
{
    setRawData (d_x, d_y, nCurPointsY);
}

////////////////////////////////////////////////////////////
// Constructor
////////////////////////////////////////////////////////////
Curve::Curve (const QString& s,
              QColor _color,
              int _nPoints,
              QWidget* _parent) :
    QwtPlotCurve (s),
    QWidget (_parent),
    s_error (false),
    id (_id),
    nPoints (_nPoints),
    nCurPointsX (0),
    nCurPointsY (0),
    color (_color),
    symbol (QwtSymbol::Cross,
            QBrush (),
            QPen (_color),
            QSize (5,5))
{
    //initiate values to 0
    for (int i = 0; i< MAX_PLOT_SIZE; i++)
    {
        d_x[i] = 0;
        d_y[i] = 0;
    }

    setSymbol (symbol);
}

////////////////////////////////////////////////////////////
// updates Y values
////////////////////////////////////////////////////////////
void
Curve::updaterY (Message &msg)
{
        //when we receive a correct message
        if (msg.value->type == DATA_DOUBLE)
        {
            //the following code allows a fluent printing of the
            //points, increasing 1 by 1 when more points are asked
            //or decreasing and keeping the last points when less 
            //points are requiered

            //if we have to decrease the size of the curve
            if (nCurPointsY > nPoints)
            {
                for (int i = (nCurPointsY - nPoints); i <= nCurPointsY; i++)
                    d_y[i-(nCurPointsY - nPoints)] = d_y[i];

                nCurPointsY = nPoints ;
            }
            
            //if we have to increase it
            if (nCurPointsY < nPoints)
            {
                nCurPointsY++;
            }

            //move the array to left
            else
            {
                for (int j = 1; j <= nCurPointsY; j++)
                    d_y[j-1] = d_y[j];
            }
            
           //add the new value in the end
            if (nCurPointsY >= 0)
                d_y[nCurPointsY-1] = msg.value->val;
}

////////////////////////////////////////////////////////////
// updates X values
////////////////////////////////////////////////////////////
void
Curve::updaterX (Message &msg)
{
   //same with X instead of Y....
   [...]
}

////////////////////////////////////////////////////////////
// reattach the curve with the correct nb of points
////////////////////////////////////////////////////////////
void
Curve::reattach ()
{
    setRawData (d_x, d_y, nCurPointsY);
}

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I hope this can help... thanks!

[Uwe]

The code looks o.k. to me.

So it's time to start your debugger and to check the number of points.

Uwe