LockBitmap

'Code originally from http://www.codeproject.com/Tips/240428/Work-with-bitmap-faster-with-Csharp
Imports System.Drawing
Imports System.Drawing.Imaging
Imports System.Runtime.InteropServices
Public Class LockBitmap
    Private source As Bitmap = Nothing
    Private Iptr As IntPtr = IntPtr.Zero
    Private bitmapData As BitmapData = Nothing
    Public Property Pixels() As Byte()
        Get
            Return m_Pixels
        End Get
        Set(value As Byte())
            m_Pixels = value
        End Set
    End Property
    Private m_Pixels As Byte()
    Public Property Depth() As Integer
        Get
            Return m_Depth
        End Get
        Private Set(value As Integer)
            m_Depth = value
        End Set
    End Property
    Private m_Depth As Integer
    Public Property Width() As Integer
        Get
            Return m_Width
        End Get
        Private Set(value As Integer)
            m_Width = value
        End Set
    End Property
    Private m_Width As Integer
    Public Property Height() As Integer
        Get
            Return m_Height
        End Get
        Private Set(value As Integer)
            m_Height = value
        End Set
    End Property
    Private m_Height As Integer
    Public Sub New(source As Bitmap)
        Me.source = source
    End Sub
    Public Sub LockBits()
        Try
            Width = source.Width
            Height = source.Height
            Dim PixelCount As Integer = Width * Height
            Dim rect As New Rectangle(0, 0, Width, Height)
            Depth = System.Drawing.Bitmap.GetPixelFormatSize(source.PixelFormat)
            If Depth <> 8 AndAlso Depth <> 24 AndAlso Depth <> 32 _
            Then Throw New ArgumentException("Only 8, 24 and 32 bpp images are supported.")
            bitmapData = source.LockBits(rect, ImageLockMode.ReadWrite, source.PixelFormat)
            Dim [step] As Integer = Depth / 8
            Pixels = New Byte(PixelCount * [step] - 1) {}
            Iptr = bitmapData.Scan0
            Marshal.Copy(Iptr, Pixels, 0, Pixels.Length)
        Catch ex As Exception
            Throw ex
        End Try
    End Sub
    Public Sub UnlockBits()
        Try
            Marshal.Copy(Pixels, 0, Iptr, Pixels.Length)
            source.UnlockBits(bitmapData)
        Catch ex As Exception
            Throw ex
        End Try
    End Sub
    Public Function GetPixel(x As Integer, y As Integer) As Color
        Dim clr As Color = Color.Empty
        Dim cCount As Integer = Depth / 8
        Dim i As Integer = ((y * Width) + x) * cCount
        If i > Pixels.Length - cCount Then Throw New IndexOutOfRangeException()
        If Depth = 32 Then
            Dim b As Byte = Pixels(i)
            Dim g As Byte = Pixels(i + 1)
            Dim r As Byte = Pixels(i + 2)
            Dim a As Byte = Pixels(i + 3)
            clr = Color.FromArgb(a, r, g, b)
        End If
        If Depth = 24 Then
            Dim b As Byte = Pixels(i)
            Dim g As Byte = Pixels(i + 1)
            Dim r As Byte = Pixels(i + 2)
            clr = Color.FromArgb(r, g, b)
        End If
        If Depth = 8 Then
            Dim c As Byte = Pixels(i)
            clr = Color.FromArgb(c, c, c)
        End If
        Return clr
    End Function
    Public Sub SetPixel(x As Integer, y As Integer, color As Color)
        Dim cCount As Integer = Depth / 8
        Dim i As Integer = ((y * Width) + x) * cCount
        If Depth = 32 Then
            Pixels(i) = color.B
            Pixels(i + 1) = color.G
            Pixels(i + 2) = color.R
            Pixels(i + 3) = color.A
        End If
        If Depth = 24 Then
            Pixels(i) = color.B
            Pixels(i + 1) = color.G
            Pixels(i + 2) = color.R
        End If
        If Depth = 8 Then Pixels(i) = color.B
    End Sub
End Class