BitMap to Bytes - An Attempt

[KayJay]

Hi!

A lot of times it has been asked, yours truly inlcuded, how a Bitmap in an app can be serialized into a byte array. Given below is an attempt modifying an example from All-API Guide. Hope this provides a start to all of you. The array is now written to disk. But can be sent directly through Winsock for network tranfer.

'The Sending App, containing a PictureBox and a Command Button
'ScaleMode of the Form and the PictureBox set to Pixels
 
Private Const BI_RGB = 0&
Private Const DIB_RGB_COLORS = 0
Private Type BITMAPINFOHEADER
        biSize As Long
        biWidth As Long
        biHeight As Long
        biPlanes As Integer
        biBitCount As Integer
        biCompression As Long
        biSizeImage As Long
        biXPelsPerMeter As Long
        biYPelsPerMeter As Long
        biClrUsed As Long
        biClrImportant As Long
End Type
Private Type RGBQUAD
        rgbBlue As Byte
        rgbGreen As Byte
        rgbRed As Byte
        rgbReserved As Byte
End Type
Private Type BITMAPINFO
        bmiHeader As BITMAPINFOHEADER
        bmiColors As RGBQUAD
End Type
Private Declare Function CreateCompatibleDC Lib "gdi32" _
(ByVal hdc As Long) As Long
Private Declare Function CreateDIBSection Lib "gdi32" _
(ByVal hdc As Long, pBitmapInfo As BITMAPINFO, _
ByVal un As Long, ByVal lplpVoid As Long, _
ByVal handle As Long, ByVal dw As Long) As Long
Private Declare Function GetDIBits Lib "gdi32" _
(ByVal aHDC As Long, ByVal hBitmap As Long, ByVal nStartScan _
As Long, ByVal nNumScans As Long, lpBits As Any, _
lpBI As BITMAPINFO, ByVal wUsage As Long) As Long
Private Declare Function SelectObject Lib "gdi32" _
(ByVal hdc As Long, ByVal hObject As Long) As Long
Private Declare Function DeleteDC Lib "gdi32" _
(ByVal hdc As Long) As Long
Private Declare Function DeleteObject Lib "gdi32" _
(ByVal hObject As Long) As Long
Private Declare Function BitBlt Lib "gdi32" _
(ByVal hDestDC As Long, ByVal x As Long, ByVal y As Long, _
ByVal nWidth As Long, ByVal nHeight As Long, ByVal hSrcDC _
As Long, ByVal xSrc As Long, ByVal ySrc As Long, _
ByVal dwRop As Long) As Long
Private Declare Function GetDC Lib "user32" _
(ByVal hwnd As Long) As Long
Dim iBitmap As Long, iDC As Long
 
Private Sub Command1_Click()
    Dim bi24BitInfo As BITMAPINFO, bBytes() As Byte
    With bi24BitInfo.bmiHeader
        .biBitCount = 24
        .biCompression = BI_RGB
        .biPlanes = 1
        .biSize = Len(bi24BitInfo.bmiHeader)
        .biWidth = Picture1.Width
        .biHeight = Picture1.Height
    End With
    ReDim bBytes(1 To bi24BitInfo.bmiHeader.biWidth * _
    bi24BitInfo.bmiHeader.biHeight * 3) As Byte
 
    iDC = CreateCompatibleDC(0)
 
    iBitmap = CreateDIBSection(iDC, bi24BitInfo, _
    DIB_RGB_COLORS, ByVal 0&, ByVal 0&, ByVal 0&)
 
    SelectObject iDC, iBitmap
 
    BitBlt iDC, 0, 0, bi24BitInfo.bmiHeader.biWidth, _
    bi24BitInfo.bmiHeader.biHeight, Picture1.hdc, 0, 0, _
    vbSrcCopy
 
    GetDIBits iDC, iBitmap, 0, _
    bi24BitInfo.bmiHeader.biHeight, bBytes(1), _
    bi24BitInfo, DIB_RGB_COLORS
 
        Open App.Path & "\CloudsCopy.BMP" For Binary As #1
            Put #1, 1, CLng(Picture1.Width)
            Put #1, 5, CLng(Picture1.Height)
            Put #1, 9, bBytes
        Close #1
    DeleteDC iDC
    DeleteObject iBitmap
    Client.Show 'Run the client App. I used two forms in the same app
End Sub
 
Private Sub Form_Load()
Me.ScaleMode = vbPixels
With Picture1
    .ScaleMode = vbPixels
    .AutoRedraw = True
    .AutoSize = True
    .Picture = LoadPicture(App.Path & "\Clouds.bmp")
End With
End Sub
 
'The recieving App containing a pictureBox with a command button
'with the form and picturebox scalemode set to Pixels and
'autoredraw, autosize of the pictureBox set to true
 
Private Declare Function SetDIBitsToDevice Lib "gdi32" _
(ByVal hdc As Long, ByVal x As Long, ByVal y As Long, _
ByVal dx As Long, ByVal dy As Long, ByVal SrcX As Long, _
ByVal SrcY As Long, ByVal Scan As Long, ByVal NumScans _
As Long, Bits As Any, BitsInfo As BITMAPINFO, ByVal wUsage _
As Long) As Long
Private Const BI_RGB = 0&
Private Const DIB_RGB_COLORS = 0
Private Type BITMAPINFOHEADER
        biSize As Long
        biWidth As Long
        biHeight As Long
        biPlanes As Integer
        biBitCount As Integer
        biCompression As Long
        biSizeImage As Long
        biXPelsPerMeter As Long
        biYPelsPerMeter As Long
        biClrUsed As Long
        biClrImportant As Long
End Type
Private Type RGBQUAD
        rgbBlue As Byte
        rgbGreen As Byte
        rgbRed As Byte
        rgbReserved As Byte
End Type
Private Type BITMAPINFO
        bmiHeader As BITMAPINFOHEADER
        bmiColors As RGBQUAD
End Type
 
Private Sub Command1_Click()
Dim bi24BitInfo As BITMAPINFO, bmpWidth As Long, _
bmpHeight As Long
Dim bbBytes() As Byte
Open App.Path & "\CloudsCopy.BMP" For Binary As #1
    ReDim bbBytes(1 To (LOF(1) - 8))
        Get #1, 1, bmpWidth
        Get #1, 5, bmpHeight
        Get #1, 9, bbBytes
Close #1
 
    With bi24BitInfo.bmiHeader
        .biBitCount = 24
        .biCompression = BI_RGB
        .biPlanes = 1
        .biSize = Len(bi24BitInfo.bmiHeader)
        .biWidth = bmpWidth
        .biHeight = bmpHeight
    End With
        Picture1.Width = bmpWidth
        Picture1.Height = bmpHeight
    
    SetDIBitsToDevice Picture1.hdc, 0, 0, _
    bi24BitInfo.bmiHeader.biWidth, _
    bi24BitInfo.bmiHeader.biHeight, 0, 0, 0, _
    bi24BitInfo.bmiHeader.biHeight, bbBytes(1), _
    bi24BitInfo, DIB_RGB_COLORS
    
    Picture1.AutoSize = True
    Picture1.Refresh
End Sub
 
Private Sub Form_Load()
Me.ScaleMode = vbPixels
Picture1.ScaleMode = vbPixels
End Sub