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1 vote
6k views

Hi,

i have a SciChartSurface with DateTimeAxis as xAxis and a NumericAxis as yAxis.
The fifo capacity is 500 points.

Now what i want to archieve is that when i zoom in that the visible range updates in a matter that its moving with the fifo and not to be frozen and at some point in time see how the data points are discarded.
I already implemented a CustomRubberBandZoomModifier which disables autoranging on Zoom and enables it after Zoom to Extents.

How could i archieve this like shown in the attached image?

Thank you already in advance.

  • Armin Wild asked 7 months ago
  • last active 6 months ago
1 vote
7k views

I am working on a multithreaded application where the acquisition and chart display run on different threads. I am attempting to collect samples and plot only when I have 100 samples available to have less resource consumption and keep the application responsive. However, when I change the number of samples in the block, my FIFO capacity seems to change, allowing significantly less amount of samples than the ones I need. The current FIFO capacity should allow for at least 16 mins worth of data, but it only shows less than a second

If I set the block size to 1 (single sample appending) I obtain the results I need, but I am seeing performance issues in other areas of the program, hence the need of appending in blocks.

See the attachments for more clarity. Any suggestions?

EDIT: Adding code

private void DisplayNPD()
        {
            XyDataSeries<float, float> npdRawDataSeries = new XyDataSeries<float, float>();
            int fifoSize = 1000000;
            npdRawDataSeries.FifoCapacity = fifoSize;
            npdRawData_RS.DataSeries = npdRawDataSeries;

            double npdRaw = 0;
            bool successfulDequeue = false;
            int samplesQueued = 0;
            int samplesInBlock = 100;
            float[] rawSamples = new float[samplesInBlock];
            float[] time = new float[samplesInBlock];

            while (!ImagingSession.terminateThreads)
            {
                if (ImagingSession.laserOnOff && !graphRestarted)
                {
                    int npdElementsInQueue = npdDisplayQueue.Count;
                    if (npdElementsInQueue > 0)
                        successfulDequeue = npdDisplayQueue.TryDequeue(out npdRaw);

                    if (successfulDequeue)
                    {
                        currentTime = graphStopwatch.ElapsedMilliseconds * 0.001;
                        time[samplesQueued] = (float) currentTime;
                        rawSamples[samplesQueued] = (float) (npdRaw * 1000);

                        samplesQueued++;
                        if (samplesQueued == samplesInBlock)
                        {
                            using (npdRawDataSeries.SuspendUpdates())
                                npdRawDataSeries.Append(time, rawSamples);
                            samplesQueued = 0;

                            if (currentTime > upperLimit)
                            {
                                lowerLimit = upperLimit;
                                upperLimit += xAxisWidth;
                                AdjustXAxis(currentHorizontalScale);
                            }
                        }
                    }
                }
            }
        }
1 vote
6k views

I get data in real time and I only care about the Y values.
I want to define a range of values on the X axis that will be fixed (but if I want I can change it from time to time)
For example: define that the range will be from 0 to 1000 and all the information that arrives will be displayed only in this range. And when I pass the 1000 points it will simply “push” the older points aside.
For example: the point located at X=2 will move to X=1, 1 will move to 0 and 0 will leave the graph…
During the program I want of course to give the user the possibility to change this range if he wants.
The optimal way for me was to define a range of the X axis and when I do Append(), add only Y values so that they enter the next place on the X axis in order…
Is there an option in the API to set this? If not, how is it recommended to do it?

1 vote
3k views

Hi.

We want to use your Android Chart library in our project. I’m getting familiar with it and I don’t totally gets how to implement Scrolling Realtime (FIFO) Line Chart.

What we want to do: our copmany wants an app that will represent the data on the line charts from their sensors. I need real-time (FIFO) representation from 1 to 16 charts in RecyclerView.

The guide here doesn’t cover the whole implementation (for example, we add data to XyDataSeries, but where to add these series to surface is not indicated). And link to github is not working also.

Do you have some example code or documentation regarding it?

1 vote
11k views

I evaluating Scichart for our application and have been testing the Realtime FIFO example.

I have made the following modifications to the example
– Increased number of samples added per timer tick
– Replaced a sin wave with a recording of FPS
– Swapped to DX10 render surface
– Changed Plot Theme
– Added Plot Modifiers for manipulation

When FIFO is enabled and more than 5052 points are added unusual behavior occurs, the line seems to slide backwards and faster than the plot does and there are lines connecting the start and end of the plot.

I have recorded a video that compares running with FIFO enabled vs FIFO disabled.

https://youtu.be/SKi1zRDhq60

I forgot to add that I can get a similar but slightly different glitch by taking the example straight from the example browser and increasing the FIFO length to 10000, see attached image.

  • Hugoagogo asked 8 years ago
  • last active 8 years ago
1 vote
16k views

Hello,

I have been working with an application that plots real-time serial data using a FIFO buffer. I have started programming around the ECG-Monitor example as this is exactly what I am creating.

I have a device that broadcasts real-time ECG data via Bluetooth (HC-05), to be exact. I have paired the device and opened a SerialPort in my program to receive the data. My sampling rate is 256 Hz.

When I used a text file to simulate ECG data, it works perfectly well. However, when I use real-time data, there is a delay in charting that increases as the time increases. An easier way to understand this is, the chart continues plotting for a significant period of time even after I have switched off my hardware device.

I have then come to the conclusion that my data is being received at the rate that I want it to, but the plotting gets delayed at an increasing rate as the time increases.

I am currently using the Direct-X rendering type as this gives me a very smooth plot. I receive the data via SerialPort, write to an array and then to the FIFO buffer.

I’m attaching my code for the same.

namespace SciChart.Examples.Examples.SeeFeaturedApplication.ECGMonitor
{
    public class ECGMonitorViewModel : BaseViewModel
    {
    private Timer _timer;
    private IXyDataSeries<double, double> _series0;
    public static double[] _sourceData = new double[50000];
    private int _currentIndex = 0;
    private int _totalIndex = 0;
    private DoubleRange _yVisibleRange;
    private bool _isBeat;
    private int _heartRate;
    private bool _lastBeat;
    private DateTime _lastBeatTime;
    private ICommand _startCommand;
    private ICommand _stopCommand;
    private const double WindowSize = 5.0;
    private const int TimerInterval = 40;
    public static int counter = 0;
    public static SerialPort mySerialPort=new SerialPort("COM3",9600);

    public ECGMonitorViewModel()
    {
        mySerialPort.Open();
        ECGMonitorViewModel.mySerialPort.WriteLine("A");
        ECGMonitorViewModel.mySerialPort.WriteLine("F");

        _series0 = new XyDataSeries<double, double>() { FifoCapacity = 2460, AcceptsUnsortedData = true };

        YVisibleRange = new DoubleRange(-20, 500);
        _startCommand = new ActionCommand(OnExampleEnter);
        _stopCommand = new ActionCommand(OnExampleExit);
    }

    public ICommand StartCommand
    {
        get
        {
            return _startCommand;
        }
    }

    public ICommand StopCommand
    {
        get
        {
            return _stopCommand;
        }
    }

    public IXyDataSeries<double, double> EcgDataSeries
    {
        get
        {
            return _series0;
        }
        set
        {
            _series0 = value;
            OnPropertyChanged("EcgDataSeries");
        }
    }

    public DoubleRange YVisibleRange
    {
        get
        {
            return _yVisibleRange;
        }
        set
        {
            _yVisibleRange = value;
            OnPropertyChanged("YVisibleRange");
        }
    }

    public bool IsBeat
    {
        get
        {
            return _isBeat;
        }
        set
        {
            if (_isBeat != value)
            {
                _isBeat = value;
                OnPropertyChanged("IsBeat");
            }
        }
    }

    public int HeartRate
    {
        get { return _heartRate; }
        set
        {
            _heartRate = value;
            OnPropertyChanged("HeartRate");
        }
    }

    public void OnExampleExit()
    {
        if (_timer != null)
        {
            _timer.Stop();
            _timer.Elapsed -= TimerElapsed;
            _timer = null;
        }
    }

    public void OnExampleEnter()
    {
        _timer = new Timer(TimerInterval) { AutoReset = true };
        _timer.Elapsed += TimerElapsed;
        _timer.Start();
    }

    private void TimerElapsed(object sender, EventArgs e)
    {
        lock (this)
        {
            for (int i = 0; i < 10; i++)
            {
                AppendPoint(250);
            }

            if ((DateTime.Now - _lastBeatTime).TotalMilliseconds < 120) return;

            IsBeat = _series0.YValues[_series0.Count - 3] > 120 ||
                     _series0.YValues[_series0.Count - 5] > 120 ||
                     _series0.YValues[_series0.Count - 8] > 120;

            if (IsBeat && !_lastBeat)
            {
                HeartRate = (int)(60.0 / (DateTime.Now - _lastBeatTime).TotalSeconds);
                _lastBeatTime = DateTime.Now;
            }
        }
    }

    private void AppendPoint(double sampleRate)
    {
        if (_currentIndex >= _sourceData.Length)
        {
            _currentIndex = 0;
        }

        double voltage = _sourceData[_currentIndex];
        double time = _totalIndex / sampleRate %10;

        if(time==0.00)
        {
            voltage = double.NaN;
        }

        _series0.Append(time, voltage);

        _lastBeat = IsBeat;
        _currentIndex++;
        _totalIndex++;
    }

    public static void mySerialPort_DataReceived(object sender, SerialDataReceivedEventArgs e)
    {
        while (mySerialPort.BytesToRead > 0)
        {
            int b;
            b = mySerialPort.ReadByte();
            _sourceData[counter] = b;
            counter++;
        }
    }
}
}

namespace SciChart.Examples.Examples.SeeFeaturedApplication.ECGMonitor
{
    public partial class ECGMonitorView : UserControl
    {
        public ECGMonitorView()
        {
            InitializeComponent();
            ECGMonitorViewModel.mySerialPort.DataReceived += new SerialDataReceivedEventHandler(ECGMonitorViewModel.mySerialPort_DataReceived);
        }
    }
}

The xaml code is as follows,

<UserControl
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
         xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
         xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
         xmlns:local="clr-namespace:SciChart.Examples.Examples.SeeFeaturedApplication.ECGMonitor"
         xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
         xmlns:s="http://schemas.abtsoftware.co.uk/scichart"
         xmlns:s3D="http://schemas.abtsoftware.co.uk/scichart3D" xmlns:XamlRasterizer="clr-namespace:SciChart.Drawing.XamlRasterizer;assembly=SciChart.Drawing" x:Class="SciChart.Examples.Examples.SeeFeaturedApplication.ECGMonitor.ECGMonitorView"
         d:DesignHeight="400"
         d:DesignWidth="600"
         mc:Ignorable="d">

<UserControl.Resources>

    <Style TargetType="{x:Type s:RenderSurfaceBase}">
        <Setter Property="Effect">
            <Setter.Value>
                <DropShadowEffect BlurRadius="5"
                                  ShadowDepth="0"
                                  Color="#FFB3E8F6" />
            </Setter.Value>
        </Setter>
    </Style>

    <local:BeatToScaleConverter x:Key="BeatToScaleConverter" />
</UserControl.Resources>

<i:Interaction.Triggers>
    <i:EventTrigger EventName="Loaded">
        <i:InvokeCommandAction Command="{Binding StartCommand}" />
    </i:EventTrigger>
    <i:EventTrigger EventName="Unoaded">
        <i:InvokeCommandAction Command="{Binding StopCommand}" />
    </i:EventTrigger>
</i:Interaction.Triggers>

<Grid>

    <s:SciChartSurface RenderPriority="Low" MaxFrameRate="25" AutoRangeOnStartup="False">

        <s:SciChartSurface.RenderableSeries>
            <s:FastLineRenderableSeries DataSeries="{Binding EcgDataSeries}"
                Stroke="#FFB3E8F6"                                      
                StrokeThickness="2" />
        </s:SciChartSurface.RenderableSeries>

        <s:SciChartSurface.YAxis>
            <s:NumericAxis AxisTitle="Voltage (mV)"
                DrawMinorGridLines="True"
                MaxAutoTicks="5"
                VisibleRange="{Binding YVisibleRange, Mode=TwoWay}" />
        </s:SciChartSurface.YAxis>

        <s:SciChartSurface.XAxis>
            <s:NumericAxis AxisTitle="Seconds (s)" TextFormatting="0.000s" VisibleRange="0, 10" AutoRange="Never"/>
        </s:SciChartSurface.XAxis>

        <s:SciChartSurface.RenderSurface>
            <s3D:Direct3D10RenderSurface/>
        </s:SciChartSurface.RenderSurface>

    </s:SciChartSurface>

    <StackPanel Margin="30,30" Orientation="Horizontal">
        <StackPanel.Effect>
            <DropShadowEffect BlurRadius="5"
                ShadowDepth="0"
                Color="#FFB3E8F6" />
        </StackPanel.Effect>

        <Grid HorizontalAlignment="Left" VerticalAlignment="Top">
            <Canvas x:Name="layer1"
                Width="20"
                Height="20"
                Margin="12,34,10,0">
                <Canvas.RenderTransform>
                    <ScaleTransform CenterX="-6"
                        CenterY="-6"
                        ScaleX="{Binding IsBeat, Converter={StaticResource BeatToScaleConverter}}"
                        ScaleY="{Binding IsBeat, Converter={StaticResource BeatToScaleConverter}}" />
                </Canvas.RenderTransform>
                <Path Data="m 0 0 c -4 -4 -8.866933 -10.79431 -10 -15 0 0 0 -5 5 -5 5 0 5 5 5 5 0 0 0 -5 5 -5 5 0 5.242535 4.02986 5 5 -1 4 -6 11 -10 15 z" Fill="#FFB0E6F4" />
            </Canvas>
        </Grid>

        <TextBlock HorizontalAlignment="Left"
            VerticalAlignment="Top"
            FontFamily="ArialBlack"
            FontSize="36"
            FontWeight="Bold"
            Foreground="#FFB0E6F4"
            Text="{Binding HeartRate}" />
        <TextBlock HorizontalAlignment="Left"
            VerticalAlignment="Top"
            FontFamily="ArialBlack"
            FontSize="36"
            FontWeight="Bold"
            Foreground="#FFB0E6F4"
            Text="BPM" />

    </StackPanel>

    <TextBlock Margin="5"
        HorizontalAlignment="Left"
        VerticalAlignment="Bottom"
        FontSize="9"
        FontStyle="Italic"
        Foreground="#FFB0E6F4"/>

</Grid>

I’ve attached pictures of what my program currently does. I have also attached a file with sample data in case anybody wants to test the program. I have also tried building in release mode and that doesn’t help, either.

The only issue is the delay in plotting of real-time data. Otherwise, the graphing and rendering is really smooth. As I am a complete beginner to this, can somebody help with me with what I might have done wrong?

Thanks a ton,

Jaivignesh Jayakumar

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