B4J Library [B4X] [XUI] xGraph Class and b4xlib

For i = 0 To Samples - 1
        TimeVelocity(i) = xGraph1.CurveY(TimeVelIndex, i)
    Next

#Region  Project Attributes
    #ApplicationLabel: B4A XGraph Integral
    #VersionCode: 1
    #VersionName:
    'SupportedOrientations possible values: unspecified, landscape or portrait.
    #SupportedOrientations: unspecified
    #CanInstallToExternalStorage: False
#End Region

#Region  Activity Attributes
    #FullScreen: False
    #IncludeTitle: False
#End Region

Sub Process_Globals
    'These global variables will be declared once when the application starts.
    'These variables can be accessed from all modules.
    Private xui As XUI
    Private Samples As Int
End Sub

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    Private xGraph1 As xGraph
    Private FFT As xFFT
    Private TimeAccelleration(256), TimeVelocity(256) As Double
    Private FFTMagAccelleration(), FFTMagVelocity() As Double
    Private SineAmplitude, SineCyclesNumber, Omega As Double
    Private TimeAccIndex = 0 As Int
    Private TimeVelIndex = 2 As Int
    Private FFTAccIndex = 1 As Int
    Private FFTVelIndex = 3 As Int
End Sub

Sub Activity_Create(FirstTime As Boolean)
    Activity.LoadLayout("Layout")
    FFT.Initialize
    
    InitGraph
End Sub

Sub Activity_Resume

End Sub

Sub Activity_Pause (UserClosed As Boolean)

End Sub

Private Sub InitGraph
    Private i As Int
    
    xGraph1.CurveYName(TimeAccIndex) = "Time Acceleration"
    xGraph1.CurveYUnit(TimeAccIndex) = "m/s^2"
    xGraph1.CurveYName(TimeVelIndex) = "Time Velocity"
    xGraph1.CurveYUnit(TimeVelIndex) = "m/s"
    xGraph1.CurveYName(FFTAccIndex) = "FFT Acceleration"
    xGraph1.CurveYUnit(FFTAccIndex) = "m/s^2"
    xGraph1.CurveYName(3) = "FFT Velocity"
    xGraph1.CurveYUnit(3) = "m/s"
    
    xGraph1.CurvesToDisplay.Initialize2(Array As Int(0, 1, 2, 3))

    Samples = 256
    xGraph1.NbSamples = Samples
    
    ' number of sines in the time window (256 samples)
    ' you can play with NumberOfSines
    ' setting an integer number gives 1 frequency peak.
    ' with the values below you can see in the graph that:
    ' the frequency peak is at 9, which is the SineCyclesNumber
    ' the amplitude of the peak is 10, which is the SineAmplitude.
    ' setting a non integer value for the SineCyclesNumber will lower  the amplitude a bit and 'spread' the peak
'    SineCyclesNumber = 9.0
    SineCyclesNumber = 100.0
    SineAmplitude = 10
    Omega = 360 * SineCyclesNumber / Samples
    For i = 0 To Samples - 1
        TimeAccelleration(i) = SineAmplitude * CosD(i * Omega)
        xGraph1.CurveY(TimeAccIndex, i) = TimeAccelleration(i)
        xGraph1.CurveX(i) = i
    Next
    
    xGraph1.CalcIntegral(TimeAccIndex, TimeVelIndex, 0, False)

    For i = 0 To Samples - 1
        TimeVelocity(i) = xGraph1.CurveY(TimeVelIndex, i)
    Next
    
'    FFTMagAccelleration = FFT.Forward(TimeAccelleration)
    FFTMagVelocity = FFT.Forward(TimeVelocity)
    
    For i = 0 To Samples / 2 - 1
'        xGraph1.CurveY(FFTAccIndex, i) = FFTMagAccelleration(i)
        xGraph1.CurveY(FFTVelIndex, i) = FFTMagVelocity(i)
    Next
    

    xGraph1.CurveYName(TimeVelIndex) = "Time Velocity"
    xGraph1.CurveYUnit(TimeVelIndex) = "m/s"
    xGraph1.DrawCurves(Array As Int(FFTVelIndex))
End Sub

main.bas

dim datax() as double = array(1,...1000000000) 'manage data in main.bas, not directly operate data in xgraph
dim datay1() as double = func(datax)
dim datay2() as double = func(datay1)

Graph.CurveX = datax  'reference, can just define dim curvex() as double in xgraph I think
Graph.CurveY(0) = datay1  'how to define CurveY in xGraph? dim curvey(10, ?) as double??
Graph.CurveY(1) = datay2

Graph.DrawGraph

    Public CurveX(1000) As Double
    Public CurveY(10, 1000) As Double