Steema Central

I'm creating an 'Oscilloscopic' ECG system which requires that datapoints be transparent when the second and subsequent screen scans are made. The problem is described fully in the post on oscilloscopic emulation.

The solution (which was recommended by you) works very well in regular Dot.Net, but does not work when running under Xamarin.Android. (As shown in the screenshot above, a line is drawn between the two relevant data points (Arrowed in red))

The problem seems to be that "chart.Series[0][PressureGraphCursor + 1].Color = System.Drawing.Color.Transparent;" is ignored.

Can you suggest a solution?

Many thanks,

Andy Pybus

The working (PC) version is:

private void UpdateGraphs()
{
short val;
if (Pressure_Data.TryDequeue(out val)) //If data points are available...
{
//PRESSURE GRAPH
if (InputPressure.Count > PressureGraph.Axes.Bottom.Maximum) //If we've accumulated at least 1 scan...
{
InputPressure[PressureGraphCursor].Y = val * VARIABLESCALEFACTOR;
InputPressure[PressureGraphCursor].Color = InputPressure.Color;
InputPressure[PressureGraphCursor + 1].Color = Color.Transparent;
}
else
{
InputPressure.Add(val * VARIABLESCALEFACTOR);
}
PressureGraphCursor++;
PressureGraphCursor = (PressureGraphCursor < PressureGraph.Axes.Bottom.Maximum) ? PressureGraphCursor : 0;
}
if ((PressureGraphCursor % SIGNALFREQUENCY == 0) && (Mode == OpMode.File) && (PlotTimer.IsRunning)) GetNextDORecord();
//FFT GRAPH
if (FftGraphIsAvailable) DisplayCurrentFFT();
}

The Xamarin.android version is:

void UpdateGraphs(Steema.TeeChart.TChart chart)
{
chart.AutoRepaint = false;
short val;
if (Pressure_Data.TryDequeue(out val)) //If data points are available...
{
//PRESSURE GRAPH
if (chart.Series[0].Count > PressureGraph.Axes.Bottom.Maximum) //If we've accumulated at least 1 scan...
{
chart.Series[0][PressureGraphCursor].Y = val * VARIABLESCALEFACTOR;
chart.Series[0][PressureGraphCursor].Color = chart.Series[0].Color;
chart.Series[0][PressureGraphCursor + 1].Color = System.Drawing.Color.Transparent;
}
else
{
chart.Series[0].Add(val * VARIABLESCALEFACTOR);
}
PressureGraphCursor++;
PressureGraphCursor = (PressureGraphCursor < PressureGraph.Axes.Bottom.Maximum) ? PressureGraphCursor : 0;
}
chart.AutoRepaint = true;
chart.Chart.Invalidate();
}

OOPs - I forgot to specify:

fastLine1.TreatNulls = Steema.TeeChart.Styles.TreatNullsStyle.DoNotPaint; - This fixes the problem!