detectChanges.ps1

#
# Runs ImageMagick tool to find changed images
# reference folder - folder with reference images
# diff folder - folder where diff images are generated
#
# USAGE:
#       powershell -File detectChanges.ps1 [-magick PathToImageMagick] [-diff PathToImageDiffFolder] [-reference PathToReferenceFolder]
#
#       powershell -File detectChanges.ps1
#
# or you can open and run this script from Windows PowerShell ISE
#
# requirement:
#   - powershell
#   - running powershell scripts is allowed:
#     Set-ExecutionPolicy RemoteSigned (or Unrestricted)
#
#     in Windows Vista, Win7 and above you can change the setting
#     only by running powershell with administrative rights
#
#     you have to change both 32 and 64 bit settings because they are separate, details:
#     http://blog.unixwiz.net/2010/05/powershell-surprise-in-windows-7.html
#
#
$magickFolder="D:/win_/ImageMagick-6.7.2-8/"
$referenceFolder = "./reference/"
$diffFolder = "./diff/"
$imgMask = "./shots/*.png"
$copy2reference = $false #$true #if reference file does not exist - copy tested file

#------------------ read command line
$option = ""
foreach ($nm in $args) {
    switch ($nm) {
        "-magick" { # folder with ImageMagick
            $option = "magickFolder"
        }
        "-diff" { # folder to store image difference files
            $option = "diffFolder"
        }
        "-reference" { #folder with reference images
            $option = "referenceFolder"
        }
        "-copyReference" { #copy file to reference folder if necessary
            $option = "copyReference"
        }
        default { #image mask to process
            switch ($option) {
                "copyReference" {
                    $copy2reference = $nm -eq "true"
                }
                "magickFolder" {
                    $magickFolder = $nm
                    if (!$magickFolder.EndsWith('/')) {$magickFolder += '/'}
                }
                "referenceFolder" {
                    $referenceFolder = $nm
                    if (!$referenceFolder.EndsWith('/')) {$referenceFolder += '/'}
                }
                "diffFolder" {
                    $diffFolder = $nm
                    if (!$diffFolder.EndsWith('/')) {$diffFolder += '/'}
                }
                default {
                    $imgMask = $nm
                }
            }
            $option = ""
        }
    }
}

#Clean diff folder
$diffFiles = $diffFolder + "*.png"
Remove-Item $diffFiles

foreach ($fl in get-childitem $imgMask) {
    $in = $referenceFolder + $fl.name
    if (Test-Path $in) { #file exists
        Write-Host $fl.FullName
        $diff = $diffFolder + "diff-" + $fl.name
        $cmd = $magickFolder + "compare.exe"

        #redirect STDERR to STDIN
        $res = & $cmd -metric AE $fl.FullName $in $diff 2>&1
        if ($res.Exception.Message -eq 0) { #OK
            #Write-Host '--------- OK---- ' $fl.name
            Remove-Item $diff
        } else { #FAIL
            #Write-Host '============= FAIL === ' $fl.name
        }
    } else { #reference file doesn't exist
        Write-Host $fl.name " - reference file doesn't exist"
        if ($copy2reference) {
            Write-Host "--- Copy " $fl.name " as the reference"
            Copy-Item $fl $in
        }
    }
}