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

rbghongade · Aug 19, 2019

Great work Klaus!
Can we plot semilog and logarithmic charts? I have done it but in a crude manner!

klaus · Aug 19, 2019

Can we plot semilog and logarithmic charts?

Sorry, not in this version.

aminoacid · Aug 25, 2019

Can it be used to display real-time data (Dynamic Graph) ?

klaus · Aug 25, 2019

No.
But you can use the xChart class.

klaus · Dec 14, 2019

The xGraph class and b4xlib have been updated to version 1.1 amending the bug reported HERE.

rgarnett1955 · Dec 15, 2019

Amin Ismail said:
Can it be used to display real-time data (Dynamic Graph) ?

You can you xGraph for displaying realtime data that has a slow sample rate i.e >= 0.5 sample per second. I use it for plotting mains power voltage frequency etc at an update rate of 2 seconds. I make the x axis range -2 Hours and reverse the data.The latest data is then shown at the right hand side of the graph. The CPU load with 3600 samples is negligible.

The reason I used xGraph was that it had an inbuilt cursor and was simple to use. It also provides for multiple y axis ranges on the same graph space. It does exactly what I need.

The first code snippet is the initialisation. I have left the test data in, but you could initialise the arrays to whatever you like.

B4X:

Private Sub InitGraphX1
    Private i As Int
 
    xGraph1.CurveYName(0) = "Voltage RMS"
    xGraph1.SetScaleManu(0, 220, 270)
    xGraph1.CurveYName(1) = "Frequency Hz"
    xGraph1.SetScaleManu(1, 48.5, 51.5)
 
    xGraph1.CurvesToDisplay.Initialize2(Array As Int(0, 1))
 
    Private x0 = -120 * 30 As Int
    Samples = NWServ.NO_SAMPLES
    xGraph1.NbSamples = Samples + 1
    For i = 0 To Samples
        xGraph1.CurveX(i) = (i + x0) / 30
        xGraph1.CurveY(0, i) = 1 * SinD(i * 0.1) + 247
        xGraph1.CurveY(1, i) = 0.1 * CosD(i * 0.1)
    Next
    xGraph1.DrawGraph
End Sub

This next snippet is all you need to do to update the graph with realtime data.

B4X:

    ptrOut = ptrIn

   For i = 0 To Main.Samples - 1
       If ptrOut = NO_SAMPLES Then
           ptrOut = 0
       End If
      
       Main.xGraph1.CurveY(0, i) = arrayVrms(ptrOut)
       Main.xGraph1.CurveY(1, i) = arrayFreq(ptrOut)
      
       Main.xGraph2.CurveY(0, i) = arraySupplykW(ptrOut)
       Main.xGraph2.CurveY(1, i) = arraySolarkW(ptrOut)
       Main.xGraph2.CurveY(2, i) = arrayQuality(ptrOut)
       Main.xGraph2.CurveY(3, i) = arrayLoadkW(ptrOut)
       ptrOut = ptrOut + 1
   Next
   Main.xGraph1.DrawGraph
   Main.xGraph2.DrawGraph
h

Too easy!!

In this code NO_SAMPLES is a constant of 3600. (2 hours of 2 second data)

I have uploaded the project so you can see the layout for the graphs.

Best regards

Rob

PS I had a seniors moment and got the code for right hand origin wrong. I have updated it, but I haven't bothered changing the zip file because the Layout is still the same.

rgarnett1955 · Dec 16, 2019

klaus said:
The xGraph Class and B4XLib allows graphic analysis of signals.

The graph holds a given number of curves (10 by default) with a given number of samples (10000 by default) these values can be defined in the Designer.
All curves have the same number of samples with the same X signal.

What can be done:
- Draw up to 4 curves on the same graph.
- Show values when moving the cursor on the graph.
- Zooming, either with the cursor or setting in the code.
- Different scale modes.
- Different methods on curves.
-- Copy a curve to another location.
-- Add a value to a curve.
-- Multiply a curve by a value.
-- Add two curves and save the result in another curve.
-- Multiply two curves and save the result in another curve.
-- Calculate the integral of a curve and save the result in another curve.
-- Calculate the derivative of a curve and save the result in another curve.

Attached the xGraphDemo.zip file contains three demo program using the xGraph.b4xlib library,
the xGraph.b4xlib library file, the xGraph.bas file and the xGraph.xml file.

The xGraph library needs the XUI, iXUI, or jXUI libraries.
The xGraphDemo programs need the XUI Views.b4xlib library.

EDIT: 2019.12.14 Version 1.1
Amended bug reported HERE

View attachment 83217

xGraph

Author: Klaus CHRISTL (klaus)
Version: 1.1

xGraph

Functions:

CalcAddValue (CurveIndex As Int, Value As Double, ZoomedPartOnly As Boolean)
Adds a value to the given cuve
ZoomedPartOnly = True calculates only the zoomed part if the curve is zoomed

CalcDerivative (SourceIndex As Int, DestinationIndex As Int, ZoomedPartOnly As Boolean)
Calculates the derivative of the source curve and copies the result in the destination curve
ZoomedPartOnly = True calculates only the zoomed part if the curve is zoomed

CalcDevide2Curves (SourceIndex1 As Int, SourceIndex2 As Int, DestinationIndex As Int, ZoomedPartOnly As Boolean)
Devides two curves and copies the result in the destination curve
Curve(DestinationIndex) = Curve(SourceIndex1) / Curve(SourceIndex2)
ZoomedPartOnly = True calculates only the zoomed part if the curve is zoomed

CalcIntegral (SourceIndex As Int, DestinationIndex As Int, InitilalCondition As Double, ZoomedPartOnly As Boolean)
Calculates the integral of the source curve and copies the result in the destination curve
ZoomedPartOnly = True calculates only the zoomed part if the curve is zoomed

CalcMeanValue (CurveIndex As Int, ZoomedPartOnly As Boolean) As Double
Returns the mean value of the given curve
ZoomedPartOnly = True calculates only the zoomed part if the curve is zoomed

CalcMultiplyByValue (CurveIndex As Int, Value As Double, ZoomedPartOnly As Boolean)
Multiplies the curve by the given value
ZoomedPartOnly = True calculates only the zoomed part if the curve is zoomed

CalcMutiply2Curves (SourceIndex1 As Int, SourceIndex2 As Int, DestinationIndex As Int, ZoomedPartOnly As Boolean)
Multiplies two curves and copies the result in the destination curve
Curve(DestinationIndex) = Curve(SourceIndex1) * Curve(SourceIndex2)
ZoomedPartOnly = True calculates only the zoomed part if the curve is zoomed

CalcSubtract2Curves (SourceIndex1 As Int, SourceIndex2 As Int, DestinationIndex As Int, ZoomedPartOnly As Boolean)
Substracts two curves and copies the result in the destination curve
Curve(DestinationIndex) = Curve(SourceIndex1) - Curve(SourceIndex2)
ZoomedPartOnly = True calculates only the zoomed part if the curve is zoomed

CalcSum2Curves (SourceIndex1 As Int, SourceIndex2 As Int, DestinationIndex As Int, ZoomedPartOnly As Boolean)
Adds two curves and copies the result in the destination curve
Curve(DestinationIndex) = Curve(SourceIndex1) + Curve(SourceIndex2)
ZoomedPartOnly = True calculates only the zoomed part if the curve is zoomed

CopyCurve (SourceIndex As Int, DestinationIndex As Int)
Copies the curve with SourceIndex to the DestinationIndex curve.

DrawGraph
Draws a graph

GetScaleAuto (CurveIndex As Int) As ScaleValues
Gets the automatic scale for the given curve

GetScaleManu (CurveIndex As Int) As ScaleValues
Gets the manual scale for the given curve

NumberFormat3 (Number As Double, MaxDigits As Int) As String
Formats numbers with a fixed number of digits and scientific notation

SetCurveName (CurveIndex As Int, Name As String, UpdateGraph As Boolean)
Sets the a new name for the curve with the given index
UpdateGraph = True redraws the graph

SetCurveUnit (CurveIndex As Int, Unit As String, UpdateGraph As Boolean)
Sets a new unit for the curve with the given index
UpdateGraph = True redraws the graph

SetSameScale (SameScaleCurveIndex As Int)
Sets the scale of curve SameScaleCurveIndex for all curves

SetScaleManu (CurveIndex As Int, MinVal As Double, MaxVal As Double)
Sets a manual scale for a given curve

SetZoomIndexes (BeginIndex As Int, EndIndex As Int)
Sets the begin and end indexes for zoom diaplay

SetZoomMode
Sets the zooming mode
The user selects with the curor the left limit and then the right limit

Properties:

AutomaticYScales
Gets or sets the automatic scales mode
True displays automatic Y sacales for all curves
False displays the manual scales

CurvesToDisplay
Gets or sets the curves to display

DisplayCurveIndex
Gets or sets the DisplayCurveIndex property
True displays the curve index before the curve name
Example: 3 : Speed

DisplayCurveUnit
Gets or sets the DisplayCurveUnit property
True displays the curve unit after the curve name
Example: Speed [m/s]

GraphColor
Gets or sets the graph background color

GridColor
Gets or sets the graph grid color

GridFrameColor
Gets or sets the graph grid frame color

NbMaxCurves
Gets or sets the max number of curves

NbMaxSamples
Gets or sets the max number of samples

NbSamples
Gets or sets the current number of samples

NbXIntervals
Gets or sets the number of x axis intervals

NbYIntervals
Gets or sets the number of y axis intervals

OuterFrame
Gets or sets the graph outer frame property
True = draws an outer frame around the graph

OuterFrameColor
Gets or sets the graph outer frame color

ScaleXValues
Gets or sets the ScaleValues property
it is a string with the different scale values separated by an exclamation mark.
it must begin with 1! and end with !10
Example: the default property 1!2!2.5!5!10
These values can be selected in the Designer: 1!2!2.5!5!10|1!1.2!1.5!1.8!2!2.5!3!4!5!6!7!8!9!10

ScaleYValues
Gets or sets the ScaleValues property
used for automatic scales
it is a string with the different scale values separated by the exclamation mark.
it must begin with 1! and end with !10
Example: the default property 1!2!2.5!5!10
These values can be selected in the Designer: 1!2!2.5!5!10|1!1.2!1.5!1.8!2!2.5!3!4!5!6!7!8!9!10

Snapshot
Returns a B4XBitmap object of the graph (read only)

Title
Gets or sets the graph title

XAxisName
Gets or sets the x axis name

XAxisUnit
Gets or sets the x axis uni

Hi Klause

If you ever get a chance do you think that you could add the following feature to xGraph, (probably applies to xChart as well):

- Do not plot values that are set to "not a number" (NaN) Matlab does this and its handy for prefilling a graph buffer before valid data is received or when a displayed calc goes bad. Gaps in the trace a better than trying to plot infinity or - infinity.

Best regards

Rob

klaus · Dec 16, 2019

I could add two new properties GraphWithMissingSamples and MissingSampleValue.

GraphWithMissingSamples, when set to True, tests for missing samples. When set to False avoids wasting time to check for missing sample values.
Two different DrawCurves routines.

MissingSampleValue = a specific value representing a missing sample. Default value = 1000000000

It would look like this:

mahyara · May 5, 2020

Hi can we change the red color of plot & scales and legend? since I only saw background and grid color.

klaus · May 6, 2020

No, not currently.
The xGraph object can contain up to 10 curves.
But only 4 out of the 10 can be displayed at the same time.
The colors for these 4 curves are defined internaly.
Then it depends on what color to change?
One color for each of the 10 curves or the colors for the 4 visible curves.

mahyara · May 6, 2020

Thanks for your reply, I wanted to change the scale, curve colors or editing the legend I mean instead of "0:" which comes before curve name like Temperature not 0:Temperature, generally I meant some graphical modifications.

klaus · May 6, 2020

You can disable the curve number with:

B4X:

xGraph1.DisplayCurveIndex = False

If you use the xGraph.bas module you can set the CurveColor array as Public like this:

B4X:

Public CurveColor(4) As Int

I will set it to Public in the next update.

...generally I meant some graphical modifications

What kind of graphical modifications?

mahyara · May 6, 2020

klaus said:
You can disable the curve number with:

B4X:

xGraph1.DisplayCurveIndex = False

If you use the xGraph.bas module you can set the CurveColor array as Public like this:

B4X:

Public CurveColor(4) As Int

I will set it to Public in the next update.

What kind of graphical modifications?

Thanks for the hints they were great and improved my plot. Just sometimes even on your example, when I zoom the window also becomes half width as shown on the attachment. Is it normal or me again making mistakes? and is there a touch focus type i mean with two fingers getting near each other zooming in and when fingers getting far zooming out?

mahyara · May 7, 2020

I used BAS and could do changes I wanted to do just I dont know how to change Width (ratio of curve to graph: distance shown with arrow to maximize area used for curve)

klaus · May 7, 2020

Just sometimes even on your example, when I zoom the window also becomes half width as shown ...

This is normal and it's due to the automatic scale.
Depending on the difference between the first and last value and a given scale the number of divisions changes.
And, as I want to keep the with of the divisions constant, the length of the graph is different.
Many years ago I had written a graphic analysis program in VB. The graphs could be saved as images and transfered to Word with square beeing either 1cm or 5mm.

and is there a touch focus type i mean with two fingers getting near

No, and the zoom function works only on the X axis.

mahyara · May 7, 2020

klaus said:
This is normal and it's due to the automatic scale.
Depending on the difference between the first and last value and a given scale the number of divisions changes.
And, as I want to keep the with of the divisions constant, the length of the graph is different.
Many years ago I had written a graphic analysis program in VB. The graphs could be saved as images and transfered to Word with square beeing either 1cm or 5mm.

No, and the zoom function works only on the X axis.

How about this: how can I decrease this gap between graph panel (minimizing the distance shown as Width in upper photo I posted)

klaus · May 7, 2020

It would need to redesign the drawing function.

mahyara · May 8, 2020

klaus said:
It would need to redesign the drawing function.

Whatever I did I could not make it in a way that whenever I zoom the window is not scaled again (decreasing graph size) do you have any example to give me so that I know how to resolve this problem.

klaus · Jun 4, 2020

Sorry for answering only today, I missed your post.
To do what you want would need to write another routine to draw the graphs.

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

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