Graphs in VB.Net - Visual Basic Graph Drawing Tutorial

Understanding Cartesian Coordinates vs. Window Forms in VB.Net

Graphs are an essential tool in mathematics and programming. In this tutorial, you'll learn how to draw graphs in VB.Net using the built-in System.Drawing library. We'll walk through the steps for creating a coordinate plane, plotting functions, and building your own simple Visual Basic graph control.

The Cartesian Plane is the usual graph surface we are taught in school. It consists of the x and y axes.

In Visual Basic, the Window's Form would represent something like a graph book; and this graph book is plotted or drawn on using code.

However, there is a subtle difference between the way we use graphs and the Visual Basic form:
The y-axis of the Visual Basic form is measured from the top and increases as you move downwards.

Figure: Cartesian graph compared to VB.Net Windows Form coordinate plane.

Setting Up the Coordinate Plane in VB.Net

Visual Basic .NET is a beginner-friendly language that still provides powerful tools for graphics programming. With just a few lines of code, you can:

Draw Cartesian graphs with x and y axes.
Plot mathematical functions (e.g., 'y = x^2').
Create simple charts and graphs for projects.
Work with the Paint event to refresh and update drawings.

Drawing on the Visual Basic Form

For drawing in Visual Basic.Net, we'll use the Windows Forms environment and the 'System.Drawing' namespace. This allows you to draw lines, shapes, and text directly on a form.
With Visual Basic.Net, drawing is usually done in the paint method of a window form or picture box.

Create a new Visual Basic Windows Forms Application project ; call it Dymetric_VB.
Create a new Visual Basic class file; call it Facet.
Type out the adjoining VB.Net code to see what the windows form looks like.

Note: This code creates the x and y axes - the basis for any VB.Net graph. We'll extend this code to build other graphing projects in VB.Net!

What You've Learnt on Graphs and VB.Net Windows Forms

In this tutorial, we've shown how to draw graphs in VB.Net using System.Drawing. Visual Basic makes it possible to create a coordinate plane on a Windows Form and plot functions, lines, and points. This Visual Basic graph tutorial serves as a step-by-step guide through the process.

By using the 'Paint' event, you can plot functions in VB.Net and create simple charts and graphs for school projects or professional applications. This example demonstrates how to implement a graph control in Visual Basic with code you can adapt.
Understanding how to work with graphs - both as mathematical models and as graphics on a VB.Net windows form-is essential for senior secondary students and aspiring developers.

Enhancing Your VB.Net Graphs

To make graphs more useful, you can:

Add gridlines for readability.
Label axes with numbers.
Create reusable graph drawing functions.
Extend to basic VB.Net charting controls if you need bar or line charts.

Key Takeaways on Graphs and VB.Net Windows Forms

With a little code, you can build custom graphs in Visual Basic. Whether you're plotting math functions, drawing coordinate planes, or experimenting with graphics, VB.Net makes it easy to get started.

This Visual Basic graph tutorial introduced you to:

Drawing axes with System.Drawing
Plotting functions like 'y = x^2'
Enhancing visuals with gridlines and labels

VB.Net Graph Code for Form Class

Public Class Dymetric
    Private cycle As New EllipticalRegion

    Private do_simulation As Boolean = False

    ' decide what course of action to take
    Public Sub decideAction(sender As Object, g As Graphics, click_check As Boolean)
        If do_simulation And click_check Then
            ' do animation
            cycle.play(sender, g)
            do_simulation = False
        Else
            ' Put ball on screen
            cycle.prep(sender, g)
            do_simulation = True
        End If
    End Sub
End Class

VB.Net Graph Code for Facet Class

Public Class Facet

    Dim screen_rect As Rectangle
    Dim response_btn As New Button()

    Public Sub formFeatures(control As Object)
        'Set window position, width and height
        screen_rect = Screen.PrimaryScreen.Bounds
        control.SetDesktopBounds(0, 0, screen_rect.Width, screen_rect.Height)

        ' Set a display text
        sender.Text = "usingMaths.com"

        ' Set a background colour
        sender.BackColor = System.Drawing.Color.Orange

        ' Set an icon image
        Dim path = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().CodeBase)
        path = New Uri(path).LocalPath
        Try
            sender.Icon = New Icon(path & "\usingMaths.ico")
        Catch ex As Exception
            ' Well, just go on and use default pic
        End Try
    End Sub

End Class

Important: Get the logo image(.ico) used in the code here and save it to the same folder(directory) as your code files.
For Visual Studio, this folder should be C:\Users\user_name\Documents\Visual Studio 20**\Projects\Dymetric_VB\Dymetric_VB\bin\Debug.

VB.Net Drawing Tutorial Reference

For a thorough explanation of drawing graphics in Visual Basic, please see the following links:

Drawing Graphics in Visual Basic - Step by step guide on using Visual Studio for Visual Basic graphics.

Graphics for Visual Basic 6.0 Users - largely apt for Visual Basic beginners; Knock your head out!!