Compare two pictures in binary-- true/false

[joystickus]

Greetings, Dear Members!

Foreword: I am completely new to any kind of programming and this is my first experience both with AutoIt and programming.

Overall task I need: to compare a certain area of the screen with a given template for two states -- identical or not.

Here my thoughts: I made a template in a lossless format 24-bit bmp (size 12*27px). Then I can make a script to capture the same area from the screen to a temp file next to the template. And then I can compare them in their binary data and to see if it is identical of not. (When done by hands -- it gives pure picture with no mistakes.)

In more details as I see it: I need to get the binary data of the template to a variable, then to capture the same area from the screen, to save it to a temp file and to get the binary data of the temp file to another variable. Then to compare those variables and go forward by one of the two ways depending on whether they are identical of not.

Skipping a step would be to get the binary data to a second variable (from the screen) directly from the buffer when the area is captured.

And here's a problem: I didn't manage to find the way in AutoIt to get the binary data of the *.bmp file to a variable and/or from the buffer.

Can you please give me a hint of the operators I need to use to do that simple task?

Thank you for your attention.

[Zedna]

Search this forum. This was answered many times already.

[Blue_Drache]

Do you have an example of the picture you're wanting to compare? Perhaps a live area? Honestly, a 12x27 area is only used for one of two things, though... and to me ... what you're asking for smells like an anti-captcha script.

[joystickus]

2Zedna

Unfortunately I didn't manage to find anything like this in the forum. There are examples of comparing pictures pixel by pixel but I assumed that's not exactly what I need. I need it more simple -- to find out how to put binaries of the files into variables.

2Blue_Drache

No, it's not anti-captcha. I want to use it as a trigger to making a click in two or more areas in the screen. Meaning if the picture in the given area is for example a green circle then click in the area one, if it's not then click in the area two.

[joystickus]

Update:

I found half a solution -- comparing an MD5 sum. For my templates they're all unique and they do match nicely to the MD5's of screenshots.

Only now I don't understand why in the script it doesn't work.

If _IdenticalImages("2c.bmp","2d.bmp") Then
    MsgBox(64,"Info","Match")
Else
    MsgBox(64,"Info","Don't match")
EndIf
Func _IdenticalImages($file1,$file2)
    If _MD5ForFile($file1) = _MD5ForFile($file2) Then
        Return True
    Else
        Return False
    EndIf
EndFunc

And it gives an error message:

Line 8

If _MD5ForFile($file1) = _MD5ForFile($file2) Then

If ^ ERROR

Error: Unknown function name.

Edited October 18, 2011 by joystickus

[guinness]

Of course it would where is the function _MD5ForFile? Is this your own function or trancexx's?

I would advise to read the Help file about Functions before you continue, because it will help you for the future.

Edited October 18, 2011 by guinness

[joystickus]

Got it! Thanks to everyone for help and remarks!

The solution was in the part I missed:

expandcollapse popup

Func _MD5ForFile($sFile)
    Local $a_hCall = DllCall("kernel32.dll", "hwnd", "CreateFileW", _
            "wstr", $sFile, _
            "dword", 0x80000000, _ ; GENERIC_READ
            "dword", 1, _ ; FILE_SHARE_READ
            "ptr", 0, _
            "dword", 3, _ ; OPEN_EXISTING
            "dword", 0, _ ; SECURITY_ANONYMOUS
            "ptr", 0)
    If @error Or $a_hCall[0] = -1 Then
        Return SetError(1, 0, "")
    EndIf
    Local $hFile = $a_hCall[0]
    $a_hCall = DllCall("kernel32.dll", "ptr", "CreateFileMappingW", _
            "hwnd", $hFile, _
            "dword", 0, _ ; default security descriptor
            "dword", 2, _ ; PAGE_READONLY
            "dword", 0, _
            "dword", 0, _
            "ptr", 0)
    If @error Or Not $a_hCall[0] Then
        DllCall("kernel32.dll", "int", "CloseHandle", "hwnd", $hFile)
        Return SetError(2, 0, "")
    EndIf
    DllCall("kernel32.dll", "int", "CloseHandle", "hwnd", $hFile)
    Local $hFileMappingObject = $a_hCall[0]
    $a_hCall = DllCall("kernel32.dll", "ptr", "MapViewOfFile", _
            "hwnd", $hFileMappingObject, _
            "dword", 4, _ ; FILE_MAP_READ
            "dword", 0, _
            "dword", 0, _
            "dword", 0)
    If @error Or Not $a_hCall[0] Then
        DllCall("kernel32.dll", "int", "CloseHandle", "hwnd", $hFileMappingObject)
        Return SetError(3, 0, "")
    EndIf
    Local $pFile = $a_hCall[0]
    Local $iBufferSize = FileGetSize($sFile)
    Local $tMD5_CTX = DllStructCreate("dword i[2];" & _
            "dword buf[4];" & _
            "ubyte in[64];" & _
            "ubyte digest[16]")
    DllCall("advapi32.dll", "none", "MD5Init", "ptr", DllStructGetPtr($tMD5_CTX))
    If @error Then
        DllCall("kernel32.dll", "int", "UnmapViewOfFile", "ptr", $pFile)
        DllCall("kernel32.dll", "int", "CloseHandle", "hwnd", $hFileMappingObject)
        Return SetError(4, 0, "")
    EndIf
    DllCall("advapi32.dll", "none", "MD5Update", _
            "ptr", DllStructGetPtr($tMD5_CTX), _
            "ptr", $pFile, _
            "dword", $iBufferSize)
    If @error Then
        DllCall("kernel32.dll", "int", "UnmapViewOfFile", "ptr", $pFile)
        DllCall("kernel32.dll", "int", "CloseHandle", "hwnd", $hFileMappingObject)
        Return SetError(5, 0, "")
    EndIf
    DllCall("advapi32.dll", "none", "MD5Final", "ptr", DllStructGetPtr($tMD5_CTX))
    If @error Then
        DllCall("kernel32.dll", "int", "UnmapViewOfFile", "ptr", $pFile)
        DllCall("kernel32.dll", "int", "CloseHandle", "hwnd", $hFileMappingObject)
        Return SetError(6, 0, "")
    EndIf
    DllCall("kernel32.dll", "int", "UnmapViewOfFile", "ptr", $pFile)
    DllCall("kernel32.dll", "int", "CloseHandle", "hwnd", $hFileMappingObject)
    Local $sMD5 = Hex(DllStructGetData($tMD5_CTX, "digest"))
    Return SetError(0, 0, $sMD5)
EndFunc   ;==>_MD5ForFile

I didn't understand a single word in it, but once called it does what's needed.