BitmapBytesARGB32.vb

Imports System.Drawing.Imaging
Imports System.Runtime.InteropServices

Public Class BitmapBytesARGB32
    ' Provide public access to the picture's byte data.
    Public ImageBytes() As Byte
    Public RowSizeBytes As Integer
    Public Const PixelSizeBytes As Integer = 4                  ' 4 bytes/pixel.
    Public Const PixelSizeBits As Integer = PixelSizeBytes * 8  ' 32 bits per pixel.

    ' A reference to the Bitmap.
    Private m_Bitmap As Bitmap

    ' Save a reference to the bitmap.
    Public Sub New(ByVal bm As Bitmap)
        m_Bitmap = bm
    End Sub

    ' Bitmap data.
    Private m_BitmapData As BitmapData

    ' Lock the bitmap's data.
    Public Sub LockBitmap()
        ' Lock the bitmap data.
        Dim bounds As Rectangle = New Rectangle( _
            0, 0, m_Bitmap.Width, m_Bitmap.Height)
        m_BitmapData = m_Bitmap.LockBits(bounds, _
            Imaging.ImageLockMode.ReadWrite, _
            Imaging.PixelFormat.Format32bppArgb)
        RowSizeBytes = m_BitmapData.Stride

        ' Allocate room for the data.
        Dim total_size As Integer = m_BitmapData.Stride * m_BitmapData.Height
        ReDim ImageBytes(total_size)

        ' Copy the data into the ImageBytes array.
        Marshal.Copy(m_BitmapData.Scan0, ImageBytes, _
            0, total_size)
    End Sub

    ' Copy the data back into the Bitmap
    ' and release resources.
    Public Sub UnlockBitmap()
        ' Copy the data back into the bitmap.
        Dim total_size As Integer = m_BitmapData.Stride * m_BitmapData.Height
        Marshal.Copy(ImageBytes, 0, _
            m_BitmapData.Scan0, total_size)

        ' Unlock the bitmap.
        m_Bitmap.UnlockBits(m_BitmapData)

        ' Release resources.
        ImageBytes = Nothing
        m_BitmapData = Nothing
    End Sub
End Class