Converter

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

Public Class Converter
    Private Shared datapool() As Char = _
        CType("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789=/+ .".ToCharArray & Chr(10), Char())


    Public Shared Function ConvertTostring(ByVal img As Bitmap) As String

        Dim mList As New System.Text.StringBuilder
        Dim mDict As Dictionary(Of Color, String) = passCode(img)
        Dim pxf As PixelFormat = PixelFormat.Format32bppArgb
        Dim bmpData As BitmapData = img.LockBits(New Rectangle(0, 0, img.Width, img.Height), ImageLockMode.ReadWrite, pxf)
        Dim mPos As IntPtr = bmpData.Scan0 + (Math.Abs(bmpData.Stride) * 1) 'skip first row
        Dim mPixels As Integer = (Math.Abs(bmpData.Stride)) * img.Height - 1



        For i As Integer = 0 To mPixels - 1
            Dim currentByte(3) As Byte
            Marshal.Copy(mPos, currentByte, 0, 4)
            If currentByte(3) = 0 And currentByte(2) = 0 And currentByte(1) = 0 And currentByte(0) = 0 Then
                Exit For
            End If

            If mDict.ContainsKey(Color.FromArgb(currentByte(3), currentByte(2), currentByte(1), currentByte(0))) Then
                mList.Append(mDict.Item(Color.FromArgb(currentByte(3), currentByte(2), currentByte(1), currentByte(0))))
            End If

            mPos += 4  '<-- position

        Next

        img.UnlockBits(bmpData)
        Return mList.ToString
    End Function



    Private Shared Function passCode(ByVal img As Bitmap) As Dictionary(Of Color, String)
        Dim mDict As New Dictionary(Of Color, String)
        Dim pxf As PixelFormat = PixelFormat.Format32bppArgb 'Format32bppArgb
        Dim bmpData As BitmapData = img.LockBits(New Rectangle(0, 0, img.Width, img.Height), ImageLockMode.ReadWrite, pxf)
        'keep alpha

        Dim ptr As IntPtr = bmpData.Scan0
        For i As Integer = 0 To datapool.Length - 1
            Dim currentByte(3) As Byte
            Marshal.Copy(ptr, currentByte, 0, 4)
            mDict.Add(Color.FromArgb(currentByte(3), currentByte(2), currentByte(1), currentByte(0)), datapool(i))
            ptr += 4  '<-- position
        Next
        img.UnlockBits(bmpData)
        Return mDict
    End Function



    Public Shared Function ConvertToPixel(ByVal data As String, Optional ByVal mWidth As Integer = 500, Optional ByVal mHeight As Integer = 500) As Image
        list.Clear()

        'faster
        Dim mSB As New System.Text.StringBuilder : mSB.Append(data)

        Dim mDict As Dictionary(Of String, Color) = setdata()
        Dim mImage As Bitmap = New Bitmap(500, 500)

        Dim pxf As PixelFormat = PixelFormat.Format32bppArgb
        Dim bmpData As BitmapData = mImage.LockBits(New Rectangle(0, 0, mImage.Width, mImage.Height), ImageLockMode.ReadWrite, pxf)
        Dim dPos As IntPtr = bmpData.Scan0

        For i As Integer = 0 To mDict.Values.Count
            Dim hColor As Color = mDict.Values(i)
            Dim cHolder(3) As Byte
            cHolder(3) = hColor.A
            cHolder(2) = hColor.R
            cHolder(1) = hColor.G
            cHolder(0) = hColor.B
            Marshal.Copy(cHolder, 0, dPos, 4)
            dPos += 4
        Next

        'rescan
        Dim cPos As IntPtr = bmpData.Scan0 + (Math.Abs(bmpData.Stride) * 1) 'dragon broke dis.
        Dim xVal As Integer = 0

        For Each mCh As Char In mSB.ToString
            ' Small error, not needed.
            'If xVal = bmpData.Width Then
            '    cPos += Math.Abs(bmpData.Stride)
            '    xVal = 0
            ' End If
            Dim hColor As Color = mDict(mCh)
            Dim cBytes(3) As Byte
            cBytes(3) = hColor.A
            cBytes(2) = hColor.R
            cBytes(1) = hColor.G
            cBytes(0) = hColor.B
            Marshal.Copy(cBytes, 0, cPos, 4)
            cPos += 4
            xVal += 1
        Next
        mImage.UnlockBits(bmpData)
        Return mImage
    End Function


    Private Shared Function setdata() As Dictionary(Of String, Color)
        Dim mDict As New Dictionary(Of String, Color)
        For Each i As Char In datapool
            mDict.Add(i, Color.FromArgb(255, randomnumbers, randomnumbers, randomnumbers))
        Next
        Return mDict
    End Function

    Private Shared rand As New Random
    Private Shared list As New System.Text.StringBuilder
    Private Shared Function randomnumbers() As Integer
        Dim tmpvar As String = CStr(rand.Next(0, 255))
        If list.Length = 0 Then
            list.AppendLine(CStr(rand.Next(0, 255)))
        End If
        For i As Integer = 0 To list.Length - 1
            If tmpvar = list(i) Then
                randomnumbers()
            End If
        Next
        Return CInt(tmpvar)
    End Function
End Class