Another Simple-Plot Example

[<fic...@gm...>]

Hello everyone,

I tried to find another simple example for loading z-values, but I 
didn't find one. It would be great if someone would be so kind to mail a 
small example, that creates a plot just like the one in the "simple 
plot"-example, but with precomputed z-values.
I'm also not sure which subclass of Plot3D is best for this purpose.
The background of my question is, that I'm using the CImg-library (maybe 
someone knows this lib) for the image processing algorithms and I want 
to display some 2D image data as 3D plots. Here is an extract of what I 
tried so far (I used a lot of the simpleplot example here):

The header file:

#ifndef FSURFACEPLOT_H_
#define FSURFACEPLOT_H_

#include <math.h>
#include <qapplication.h>
#include <qwt3d_surfaceplot.h>
#include <qwt3d_function.h>
#include "CImg.h" 

using namespace Qwt3D;

class FSurfacePlot : public SurfacePlot
{
public:
    FSurfacePlot(cimg_library::CImg<>& data);
};
 
#endif 

And the source file:

#include "FSurfacePlot.h"

  FSurfacePlot::FSurfacePlot(cimg_library::CImg<>& data)
  {
    setTitle("Time-space image");

    int columns = data.dimx();
    int rows = data.dimy();
    double** newdata = new double* [columns];
    for( int i = 0; i < columns; ++i)
        newdata[i] = new double[rows];
          
    for(int i = 0; i < columns; i++)
    {
        for(int j = 0; j < rows; j++)
        {
            newdata[i][j] = data(i,j);
        }
    }

    loadFromData(newdata,columns,rows,1,columns,1,rows);

    setRotation(30,0,15);
    setScale(1,1,1);
    setShift(0.15,0,0);
    setZoom(0.9);

    for (unsigned i=0; i!=coordinates()->axes.size(); ++i)
    {
      coordinates()->axes[i].setMajors(7);
      coordinates()->axes[i].setMinors(4);
    }


    coordinates()->axes[X1].setLabelString("x-axis");
    coordinates()->axes[Y1].setLabelString("y-axis");
    //coordinates()->axes[Z1].setLabelString(QChar(0x38f)); // Omega - 
see http://www.unicode.org/charts/

    setCoordinateStyle(BOX);

    updateData();
    updateGL();
  }

Everything compiles without errors, but when the widget is shown, I just 
see a black window with a wireframe box, whose colors are changing in a 
weird way.
Maybe you can tell me, where I'm thinking wrong or give me some other 
clues!?

Best regards!
Florian