Real-time scatter plots

[User (Legacy)]

Hello,

I'm attempting to create a scatter plot which updates in real-time as data

arrives.  I've prototype the following code to update the chart once per

second:

Dim bufferSize As Integer = 5

Chart1.OpenData(SoftwareFX.ChartFX.COD.Values, 1, bufferSize)

Chart1.OpenData(SoftwareFX.ChartFX.COD.XValues, 1, bufferSize)

'Chart1.RealTimeSettings.BufferSize = 100

Dim i As Integer

Dim ran As New Random()

For i = 0 To bufferSize - 1

    Chart1.Value(0, i) = ran.Next(-20, 20)

    Chart1.XValue(0, i) = ran.Next(-20, 20)

    Chart1.Update( )

    Application.DoEvents()

    System.Threading.Thread.Sleep(1000)

Next

Chart1.CloseData(SoftwareFX.ChartFX.COD.Values)

Chart1.CloseData(SoftwareFX.ChartFX.COD.XValues)

This sample does not update the chart until the CloseData functions are

called.

If I uncomment the line which specifies RealTimeSettings then I get the

following run time exception:

         OpenData call with COD.XValues required

Any suggestions?

thanks,

Jason Davis

[Software FX]

Your code is right but the timing in which it is executing is not real-time.

The chart will redraw when you yield control, while you are in a loop

setting values you have the CPU for yourself and the Chart window won't be

painted until you yield control of the CPU.

You could add a DoEvents() call inside your loop to force a refresh but I

don't think this is what you want to do.

Normally, you use a real-time chart when you DON'T have all the data at

once, if you have all the data at once, as you have in your example then it

is not really a real-time chart.

Check out the real-time samples for more details, in the example, a timer is

used to indicate a new value is available, in a real-case scenario, this

timer could poll some data source or device, or instead of a timer you cod

add data as a response from an event sent by the entity in charge of

collecting the real-time data.

--

FP

Software FX, Inc.