Hi all,

I implemented my own QwtData which works with a ring buffer and is filled from a different thread than the plot.
Because the Plotter stops the plot with a QMutex before setting rawData
Qt Code: 
  1. curveList[a]->setRawData(dataList[a].x(), dataList[a].y(), dataList[a].size());
To copy to clipboard, switch view to plain text mode 
everything worked fine.


Qt Code: 
  1. void ValuePlotData::append(qint64 xValue, qint64 yValue)
  2. {
  3.                 if(currentValuecount == arraySize)
  4.                 {
  5.                         long newArraySize = arraySize*2;
  6.                         double * d_x_new = new double[newArraySize];
  7.                         double * d_y_new = new double[newArraySize];
  8.                         for(int i=0;i<arraySize;i++)
  9.                         {
  10.                                 d_x_new[i]=d_x[i];
  11.                                 d_y_new[i]=d_y[i];
  12.                         }
  13.                         delete [] d_x;
  14.                         delete [] d_y;
  15.                         d_x = d_x_new;
  16.                         d_y = d_y_new;
  17.                         arraySize = newArraySize;
  18.                 }
  19.                 d_x[currentValuecount] = xValue;
  20.                 d_y[currentValuecount] = yValue;
  21.                 currentValuecount++;
  22. }
To copy to clipboard, switch view to plain text mode 

Qt Code: 
  1. double ValuePlotData::x(size_t i) const
  2. {
  3.         return d_x[offset+(int)i];
  4. }
To copy to clipboard, switch view to plain text mode 

Now I had to use a zoomer for the plot and problems started.

Whenever I zoom in or out there is a chance of the program crashing with a "call to pure virtual method".
After getting post mortem debugging ready I found out, that a replot was issued and it died as I believe on Calling .x() method

I initialize the zoomer with AutoReplot(false) but still it seems to crash because of that.

How do you take care of concurrency issues with your plot, because I don't think it is wise to fill from the gui thread for many new values.

Thanks in advance, this has allready cost me several hours.

sun