Lesson 28: Mastering Ellipse & Circle Drawing in VB2022

Private Sub BtnDrawEllipse_Click(sender As Object, e As EventArgs) Handles BtnDrawEllipse.Click
    ' Create graphics object
    Dim g As Graphics = Me.CreateGraphics()
    
    ' Create a pen for the border
    Dim borderPen As New Pen(Color.Blue, 3)
    
    ' Create a brush for filling
    Dim fillBrush As New SolidBrush(Color.LightSkyBlue)
    
    ' Define ellipse position and size
    Dim rect As New Rectangle(50, 50, 200, 150)
    
    ' Draw the ellipse border
    g.DrawEllipse(borderPen, rect)
    
    ' Fill the ellipse
    g.FillEllipse(fillBrush, rect)
    
    ' Clean up resources
    borderPen.Dispose()
    fillBrush.Dispose()
    g.Dispose()
End Sub

Private Sub BtnDrawCircle_Click(sender As Object, e As EventArgs) Handles BtnDrawCircle.Click
    Dim g As Graphics = Me.CreateGraphics()
    
    ' Create a pen for the border
    Dim borderPen As New Pen(Color.DarkGreen, 4)
    
    ' Create a brush for filling
    Dim fillBrush As New SolidBrush(Color.LightGreen)
    
    ' Define circle position and size (width = height)
    Dim rect As New Rectangle(100, 50, 150, 150)
    
    ' Draw the circle border
    g.DrawEllipse(borderPen, rect)
    
    ' Fill the circle
    g.FillEllipse(fillBrush, rect)
    
    ' Clean up resources
    borderPen.Dispose()
    fillBrush.Dispose()
    g.Dispose()
End Sub

Private Sub BtnConcentric_Click(sender As Object, e As EventArgs) Handles BtnConcentric.Click
    Dim g As Graphics = Me.CreateGraphics()
    Dim centerX As Integer = 200
    Dim centerY As Integer = 150
    
    For radius As Integer = 20 To 100 Step 20
        ' Create a pen with varying color intensity
        Dim myPen As New Pen(Color.FromArgb(0, 0, 200 - radius * 2), 2)
        
        ' Calculate top-left position
        Dim x As Integer = centerX - radius
        Dim y As Integer = centerY - radius
        
        ' Draw the circle
        g.DrawEllipse(myPen, x, y, radius * 2, radius * 2)
        
        ' Clean up pen
        myPen.Dispose()
    Next
    
    g.Dispose()
End Sub

Private Sub BtnPattern_Click(sender As Object, e As EventArgs) Handles BtnPattern.Click
    Dim g As Graphics = Me.CreateGraphics()
    Dim rand As New Random()
    
    ' Clear the form
    g.Clear(Me.BackColor)
    
    ' Draw 4x4 grid of ellipses
    For row As Integer = 0 To 3
        For col As Integer = 0 To 3
            Dim x As Integer = 30 + col * 100
            Dim y As Integer = 30 + row * 100
            Dim width As Integer = 80 + rand.Next(-20, 20)
            Dim height As Integer = 60 + rand.Next(-15, 15)
            
            ' Create random color
            Dim color As Color = Color.FromArgb(rand.Next(256), rand.Next(256), rand.Next(256))
            
            ' Create pen and brush
            Dim myPen As New Pen(Color.Black, 2)
            Dim myBrush As New SolidBrush(color)
            
            ' Create rectangle
            Dim rect As New Rectangle(x, y, width, height)
            
            ' Draw filled ellipse
            g.FillEllipse(myBrush, rect)
            
            ' Draw border
            g.DrawEllipse(myPen, rect)
            
            ' Clean up
            myPen.Dispose()
            myBrush.Dispose()
        Next
    Next
    
    g.Dispose()
End Sub

Private Sub BtnGradient_Click(sender As Object, e As EventArgs) Handles BtnGradient.Click
    Dim g As Graphics = Me.CreateGraphics()
    
    ' Create a custom pen
    Dim myPen As New Pen(Color.Purple, 4)
    myPen.DashStyle = Drawing.Drawing2D.DashStyle.DashDot
    
    ' Create gradient brush
    Dim gradBrush As New Drawing2D.LinearGradientBrush(
        New Point(50, 50),
        New Point(250, 200),
        Color.Yellow,
        Color.Orange)
    
    ' Define ellipse
    Dim rect As New Rectangle(50, 50, 200, 150)
    
    ' Draw filled ellipse
    g.FillEllipse(gradBrush, rect)
    
    ' Draw border
    g.DrawEllipse(myPen, rect)
    
    ' Clean up
    myPen.Dispose()
    gradBrush.Dispose()
    g.Dispose()
End Sub