A fill tool for bitmaps

Hi guys,
I would like to create a fill tool just like the fill tool in Microsoft paint. How would I go about doing it?
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Mike TomlinsonMiddle School Assistant TeacherCommented:
Here is one way to do it.  I originally used recursion in the fill routine, but it seemed to cause stack overflows if the region was too big.

Public Class Form1
    Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

    Public Sub New()

        'This call is required by the Windows Form Designer.

        'Add any initialization after the InitializeComponent() call

    End Sub

    'Form overrides dispose to clean up the component list.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
            End If
        End If
    End Sub

    'Required by the Windows Form Designer
    Private components As System.ComponentModel.IContainer

    'NOTE: The following procedure is required by the Windows Form Designer
    'It can be modified using the Windows Form Designer.  
    'Do not modify it using the code editor.
    Friend WithEvents Button1 As System.Windows.Forms.Button
    Friend WithEvents PictureBox1 As System.Windows.Forms.PictureBox
    Friend WithEvents ColorDialog1 As System.Windows.Forms.ColorDialog
    Friend WithEvents Button3 As System.Windows.Forms.Button
    Friend WithEvents OpenFileDialog1 As System.Windows.Forms.OpenFileDialog
    <System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
        Me.Button1 = New System.Windows.Forms.Button
        Me.PictureBox1 = New System.Windows.Forms.PictureBox
        Me.ColorDialog1 = New System.Windows.Forms.ColorDialog
        Me.Button3 = New System.Windows.Forms.Button
        Me.OpenFileDialog1 = New System.Windows.Forms.OpenFileDialog
        Me.Button1.BackColor = System.Drawing.Color.Red
        Me.Button1.Location = New System.Drawing.Point(8, 48)
        Me.Button1.Name = "Button1"
        Me.Button1.Size = New System.Drawing.Size(64, 32)
        Me.Button1.TabIndex = 0
        Me.Button1.Text = "Color"
        Me.PictureBox1.Anchor = CType((((System.Windows.Forms.AnchorStyles.Top Or System.Windows.Forms.AnchorStyles.Bottom) _
                    Or System.Windows.Forms.AnchorStyles.Left) _
                    Or System.Windows.Forms.AnchorStyles.Right), System.Windows.Forms.AnchorStyles)
        Me.PictureBox1.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle
        Me.PictureBox1.Location = New System.Drawing.Point(80, 8)
        Me.PictureBox1.Name = "PictureBox1"
        Me.PictureBox1.Size = New System.Drawing.Size(200, 248)
        Me.PictureBox1.TabIndex = 1
        Me.PictureBox1.TabStop = False
        Me.Button3.Location = New System.Drawing.Point(8, 8)
        Me.Button3.Name = "Button3"
        Me.Button3.Size = New System.Drawing.Size(64, 32)
        Me.Button3.TabIndex = 3
        Me.Button3.Text = "Image"
        Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Name = "Form1"
        Me.Text = "Form1"

    End Sub

#End Region

    Private stk As New Stack

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        If ColorDialog1.ShowDialog = DialogResult.OK Then
            Button1.BackColor = ColorDialog1.Color
        End If
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        If OpenFileDialog1.ShowDialog = DialogResult.OK Then
                PictureBox1.Image = Image.FromFile(OpenFileDialog1.FileName)
            Catch ex As Exception
                MessageBox.Show(ex.Message, "Error Loading Image", MessageBoxButtons.OK, MessageBoxIcon.Error)
            End Try
        End If
    End Sub

    Private Sub PictureBox1_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles PictureBox1.MouseDown
        If Not (PictureBox1.Image Is Nothing) Then
            If e.X < PictureBox1.Image.Width AndAlso e.Y < PictureBox1.Image.Height Then
                Cursor.Current = Cursors.WaitCursor

                Dim bmp As New Bitmap(PictureBox1.Image)
                If Not bmp.GetPixel(e.X, e.Y).Equals(Button1.BackColor) Then
                    fillRegion(bmp, Button1.BackColor, bmp.GetPixel(e.X, e.Y), e.X, e.Y)
                    PictureBox1.Image = bmp
                End If

                Cursor.Current = Cursors.Default
            End If
        End If
    End Sub

    Private Sub fillRegion(ByVal bmp As Bitmap, ByVal fillColor As Color, ByVal replaceColor As Color, ByVal x As Integer, ByVal y As Integer)
        Dim p As Point
        stk.Push(New Point(x, y))
        While stk.Count > 0
            p = CType(stk.Pop(), Point)
            x = p.X
            y = p.Y
            If x >= 0 AndAlso x < bmp.Width AndAlso y >= 0 AndAlso y < bmp.Height Then
                If bmp.GetPixel(x, y).Equals(replaceColor) Then
                    bmp.SetPixel(x, y, fillColor)

                    If y - 1 >= 0 AndAlso bmp.GetPixel(x, y - 1).Equals(replaceColor) Then
                        stk.Push(New Point(x, y - 1))
                    End If

                    If x + 1 < bmp.Width AndAlso bmp.GetPixel(x + 1, y).Equals(replaceColor) Then
                        stk.Push(New Point(x + 1, y))
                    End If

                    If y + 1 < bmp.Height AndAlso bmp.GetPixel(x, y + 1).Equals(replaceColor) Then
                        stk.Push(New Point(x, y + 1))
                    End If

                    If x - 1 >= 0 AndAlso bmp.GetPixel(x - 1, y).Equals(replaceColor) Then
                        stk.Push(New Point(x - 1, y))
                    End If
                End If
            End If
        End While
    End Sub

End Class

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