Image to array

[krtxmrtz]

I want to copy the image in a picturebox to a 1D array of integers where each elment would be a pixel colour.

I'm wondering whether it's best to use .Net methods which partly I have yet to learn or rather stick to the API functions I was using in VB6, such as in this example provided to me by a forum user:

Public Function RetDIBDataLong(PictureObject As Object, Optional Return2DArray As Boolean) As Long()
Dim BM As BITMAP, bmi As BITMAPINFO, lngImageData() As Long
  'The PictureObject must be an object with both a HDC and Image property
  'such as a PictureBox, UserControl or Form

    Dim hDC As Long, bReleaseDC As Boolean, hHandle As Long
    
    If TypeOf PictureObject Is StdPicture Then
        hHandle = PictureObject.Handle
        bReleaseDC = True
    Else
        hHandle = PictureObject.Picture
        hDC = PictureObject.hDC
    End If
    If GetObjectA(hHandle, 24, BM) = 0& Then Exit Function
    
    
  bmi.bmHeader.bmWidth = BM.bmWidth
  bmi.bmHeader.bmHeight = BM.bmHeight
  bmi.bmHeader.bmSize = 40
  bmi.bmHeader.bmPlanes = 1
  bmi.bmHeader.bmBitCount = 32

  If bReleaseDC Then hDC = GetDC(GetDesktopWindow)
  
  If Return2DArray Then
    ReDim lngImageData(BM.bmWidth - 1, BM.bmHeight - 1)
    GetDIBits hDC, hHandle, 0, BM.bmHeight, lngImageData(0, 0), bmi, 0
  Else
    ReDim lngImageData(BM.bmWidth * BM.bmHeight - 1)
    GetDIBits hDC, hHandle, 0, BM.bmHeight, lngImageData(0), bmi, 0
  End If
  
  If bReleaseDC Then ReleaseDC GetDesktopWindow, hDC
  RetDIBDataLong = lngImageData
End Function

At any rate, I've been using .Net only for a short time and I still get lost in the new graphics methods. I need something like,

Dim imgArray as Integer() = SomeFunction(PictureBox1.Image)

[jmcilhinney]

If you were to use GetPixel in a loop then it would be very slow, so that's probably not the way to go. I'm not sure whether what you have got there would be the best option in VB.NET or not. I think that there might be a thread in the CodeBank that deals with reading pixel colours quickly.

[Mc_VB]

there might be a thread in the CodeBank that deals with reading pixel colours quickly.

Probably the most and the best examples of that type come from contributor boop boops , his examples use the InteropServices.Marshal.LockBits( ) method.

Search for lockbits and it pulls up quite a few posts.

[Mc_VB]

Here's one
http://www.vbforums.com/showthread.p...light=lockbits

[Sitten Spynne]

If you do this in C# there are numerous examples, because it has access to "unsafe code" which is a scary way to say "it can access pointers".

If you do this in VB, your best bet is to use the example Mc_VB posted. It does as close to what C# does as it can, with an extra copy of the pixel data that is a penalty VB cannot avoid.

[krtxmrtz]

Here's one
http://www.vbforums.com/showthread.p...light=lockbits

Thanks, this looks very much like what I was after, I'm going to start playing around with it.

[krtxmrtz]

If you do this in C# there are numerous examples, because it has access to "unsafe code" which is a scary way to say "it can access pointers".

If you do this in VB, your best bet is to use the example Mc_VB posted. It does as close to what C# does as it can, with an extra copy of the pixel data that is a penalty VB cannot avoid.

Thanks for the suggestion but my knowledge of C# is still inaproppriate to say the least.

[krtxmrtz]

Here's one
http://www.vbforums.com/showthread.p...light=lockbits

I got it to work in no time. Very easy to use and fast as lightning!