Steema Central

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    // Methods gets called whenever data is available
    public void UpdateChannelData(string seriesName, double[] data)
    {
      var series = _oscilloscopeDataSeries[seriesName];

      if (this.EnableAccumulation)
      {
          // TODO: I want to draw the new set of data while keeping all past series data visualized in the chart.
          // I do not need the complete data and properties of all last series in memory, but just the graphics...
          // Since this method gets called very often (every 30ms) I can not add a new series with approx. 8000 values
          // each time. Is there some way to draw the updated series, without erasing the old series?
      }
      else
      {
        // simple: just reset old values and update the series with incoming data
        series.Delete(0, series.Count);
        series.Add(data);
       }

Code: Select all

    void OnAfterDraw(object sender, Graphics3D g)
    {
      if (_enableAccumulationMode)
      {
        // 1) render current frame to accumulation buffer
        using (Graphics gfx = Graphics.FromImage(_accumulationBuffer[0]))
        {
          g.BackBuffer.Render(gfx);
        }

        // 2) combine current frame with accumulation buffer
        unsafe
        {
          int width = _accumulationBuffer[0].Width;
          int height = _accumulationBuffer[0].Height;
          var srcData =
            _accumulationBuffer[0].LockBits(Rectangle.FromLTRB(0, 0, width, height), ImageLockMode.ReadOnly, PixelFormat.Format32bppArgb);
          var dstData =
            _accumulationBuffer[1].LockBits(Rectangle.FromLTRB(0, 0, width, height), ImageLockMode.ReadWrite, PixelFormat.Format32bppArgb);

          int* srcPtr = (int*)srcData.Scan0;
          int* dstPtr = (int*)dstData.Scan0;

          HashSet<int> colorLut = new HashSet<int>();
          foreach (var series in _osciDataChannels.Values)
          {
            colorLut.Add(series.Color.ToArgb());
          }

          for (int idx = 0; idx < height * width; idx++, srcPtr++, dstPtr++)
          {
            int srcValue = *srcPtr;
            if (colorLut.Contains(srcValue))
            {
              *dstPtr = srcValue;
            }
          }
          
          _accumulationBuffer[0].UnlockBits(srcData);
          _accumulationBuffer[1].UnlockBits(dstData);
        }

        // 3) draw combined frame on top
        g.Draw(0, 0, _accumulationBuffer[1]);
      }
    }