[2005] Splitting an image into sections

[Troy Lundin]

I want to be able to split an image into equal parts (8x8), so an image of size 64x64 will be split into 64 pieces. Each piece is 8x8. Then I want to compare each piece to find out which of them is identical, pixel-wise.

I can not figure out how to split the image. Any ideas?
Thanks, Troy.

[Atheist]

Dim OriginalBitmap As New Bitmap("c:\64by64.bmp")
Dim bmpList As New List(Of Bitmap)
        For x As Integer = 0 To 56 Step 8
            For y As Integer = 0 To 56 Step 8
                Dim b As Bitmap = OriginalBitmap.Clone(New Rectangle(x, y, 8, 8), Imaging.PixelFormat.DontCare)
                bmpList.Add(b)
            Next
        Next

This will split a 64x64 image into 8x8 parts. The splitted parts are added to a List(of Bitmap)

[Troy Lundin]

Alright, thank you for that.

I have been trying to compare each bitmap in the list to find out which ones are the same. I tried to compare them by pixels but that takes a long time. Is there another way to do this?

[Atheist]

Instead of comparing all pixels at once, try comparing just a couple of them first (say..the pixel in each corner, that'll only make 4 pixels), and if they match, then you compare all pixels. This will shorten the time alot.

[Troy Lundin]

I am using a method that is similar to that. Basically I start checking pixels and as soon as they don't match, then I know the tiles don't match.

The part I am having trouble with is keeping track of which tiles are equal.

Say I have a simple image with 4 different colors in it. Red, Green, Blue, White. Each color takes up the size of a tile (8x8). I want to be able to show text like so:

RRGWGRBG
GGRWBRGR
WGRBRGWB
BGRWRGBG
GRBGRBGR
GGRWBRGR
WGRBRGWB
BGRWRGBG

Where each letter is a different tile. Similar tiles are shown with similar letters. I do not know how else to explain it.

I guess each different tile in the image will get a different letter and similar tiles will get a similar letter. Sorry if this is confusing.

[Troy Lundin]

I have tried using Lists(Of Bitmap) and even two dimensional arrays but cannot figure it out. Any help would be great. Thanks.