Image automatic crop

[jguinch]

Today, I had to automate the crop of several image files, by detecting the area used by the picture.
The goal is to remove the white borders of the image.

I searched on the forum, but didn't find what I need. Please, make your suggestions if you have an easy way...

So, here is the function :

expandcollapse popup

#include <GDIPlus.au3>

_GDIPlus_Startup()
_ImageAutoCrop(@ScriptDir & "\source.png", @ScriptDir & "\destination.png")

Func _ImageAutoCrop($sSrcImage, $sDstImage = "")
    If Not FileExists($sSrcImage) Then Return SetError(1, 0, 0)
    If $sDstImage = "" Then $sDstImage = $sSrcImage
    Local $hImage = _GDIPlus_ImageLoadFromFile($sSrcImage)
    Local $CoordsY = _GetImageCropSize($hImage)
    If @error Then Return SetError(2, 0, 0)
    Local $hClone = _GDIPlus_ImageClone($hImage)
    _GDIPlus_ImageRotateFlip($hClone, 1)
    Local $CoordsX = _GetImageCropSize($hClone)
    _GDIPlus_ImageDispose($hClone)
    Local $hCrop = _GDIPlus_BitmapCloneArea($hImage, $CoordsX[0], $CoordsY[0], $CoordsX[1], $CoordsY[1])
    _GDIPlus_ImageDispose($hImage)
    Local $bRes = _GDIPlus_ImageSaveToFile($hCrop, $sDstImage)
    _GDIPlus_ImageDispose($hCrop)
    Return $bRes
EndFunc


Func _GetImageCropSize($hImage)
    Local $iWidth = _GDIPlus_ImageGetWidth($hImage)
    Local $iHeight = _GDIPlus_ImageGetHeight($hImage)
    Local $hClone = _GDIPlus_ImageClone($hImage)
    Local $tBitmapData  = _GDIPlus_BitmapLockBits($hClone, 0, 0, $iWidth, $iHeight)
    Local $iScan0 = DllStructGetData($tBitmapData , "Scan0")
    Local $v_BufferA = DllStructCreate("byte[" & $iHeight * $iWidth * 4 & "]", $iScan0) ; Create DLL structure for all pixels
    Local $AllPixels = StringRegExpReplace(DllStructGetData($v_BufferA, 1), "^0x", "")
    Local $aPixels = StringRegExp($AllPixels, ".{" & 8 * $iWidth & "}", 3)
    Local $iYStart, $iYEnd

    For $i = 0 To UBound($aPixels) - 1
        If Not $iYStart And StringRegExp($aPixels[$i], "[^F]") Then
            $iYStart = $i
            ExitLoop
        EndIf
    Next
    If Not $iYStart Then SetError(1, 0, 0)

    For $i = UBound($aPixels) - 1 To 0 Step -1
        If Not $iYEnd And StringRegExp($aPixels[$i], "[^F]") Then
            $iYEnd = $i
            ExitLoop
        EndIf
    Next

    _GDIPlus_BitmapUnlockBits($hClone, $tBitmapData ) ; releases the locked region
    _GDIPlus_ImageDispose($hClone)

    Local $aReturn = [$iYStart, $iYEnd - $iYStart]
    Return $aReturn
EndFunc