compare images

hi all i got a question, i tried lots of things but i cant find any answers. how can i compare a picture in a picture box with something on the screen at given coordinates, im looking for something like this:

VB Code:

Option Explicit
 
Public Sub CompareIMG()
Dim intX As Integer
Dim intY As Integer
 
Dim blnMatch As Boolean     'True if pictures match
 
    If intX > 200 Then      'Check within given coordinates
        intX = 0
        intY = intY + 1
    Else
        Do Until blnMatch = True
            'Here is what i dont get, i hope it will be short like this:
            Compare picImage With (intX, intY), blnMatch
            
            intX = intX + 1
        Loop
    End If
        
End Sub

but it will probably will be very different :mad:
I hope anyone knows how to do something like this

Bye, Koen

This is an old project I made for comparing pictures.. I hope it helps you

(I removed this old version of the PicComp Project, download the current one that is posted below.)

Is it just me, or does that code only compare the size of the images?

If you have a good look at the code you will notice the comment "'Compare the Colors of Each Byte". This is the loop which compares the two images byte by byte, so no it's not just comparing file sizes :thumb:

I see, but this still happens:

And it's because the byte arrays are empty, the line to populate them fails:

VB Code:

Debug.Print GetBitmapBits(Pic1, bmHeight * bmWidthBytes, Bytes1(0, 0))

Returns a 0.

Sorry... I have two versions of the project and unfortunatelly I attached the oldest of them.

Here is the real thing. :)

thanks all for replys, i now have an idea how to do it but how can i compare an image with something on the screen, at given coordinates?

Search the forums to see how to get a screenshot... So that might help you get the image in that point and then compare it.

i remember i could do something i wanted with colors, it made a spiral from the middle of the screen untill it finds the color. i was thinking of something sort like. i shall add a crappy bit of code, its very old from the time when i couldnt really program. here it is:

VB Code:

On Error Resume Next
 
Righto = False
 
DoCheck
 
DoEvents
 
If Righto = True Then Exit Sub
 
Dim i
 
For i = 1 To Outwards
 
BigX = BigX + 4
 
lilX = lilX + 4
 
DoCheck
 
DoEvents
 
If Righto = True Then Exit Sub
 
Next
 
For i = 1 To Outwards
 
BigY = BigY + 4
 
lilY = lilY + 4
 
DoCheck
 
DoEvents
 
If Righto = True Then Exit Sub
 
Next
 
Outwards = Outwards + 2
 
For i = 1 To Outwards
 
BigX = BigX - 4
 
lilX = lilX - 4
 
DoCheck
 
DoEvents
 
If Righto = True Then Exit Sub
 
Next
 
For i = 1 To Outwards
 
BigY = BigY - 4
 
lilY = lilY - 4
 
DoCheck
 
DoEvents
 
If Righto = True Then Exit Sub
 
Next 
 
Outwards = Outwards + 2
 
If Outwards > 70 Then
 
BigX = closeX
 
BigY = closeY
 
lilY = Sample.Height \ 2
 
lilX = Sample.Width \ 2
 
Outwards = 0
 
Picture1.Cls
 
End If

pretty crappy huh? it needs some coding to be done but it might be useful.

Koen

I'd just use getpixel, store the color values in some arrays, and do a comparison - but I guess that's rather slow ?

Yea, GetPixel is really slow for some reason, I tried it on a 128x128 image and it took 94ms.

if i used that it will really take ages, because i have to compare over 10,000 images (257x42) but i still do have a question,if i make a screenshot, there is more on the picture then i want. i just want to compare a small piece of the screenshot with my pictures. how can i do something like this?

Koen

Tec-Nico your Piccomp app works great with bmp, gif, jpg etc. But if you load icons into the images you get Subscript out of range in:

ReDim Bytes1(0 To Bm1.bmWidthBytes - 1, 0 To Bm1.bmHeight - 1)

Because it can't dimension the array. Any ideas why it can't find the height and width.

I am not quite sure... But it could be that you would need to use different API and even structures.

Look it up in the API Forums..