Getting no feedback from compare command.

[Bluehawk]

Hi all.

I tried a lot, but couldn't get any feedback from the code below.
The code seems to work ok because it doesn't give any error and creates the diff.png image.
But it doesn't give any feedback for debug.print
I''ve tried nearly every combination and and about to go nuts.
Can anybody help ?

PS. I'm using VBA under Access 2007

Code: Select all

Private Sub TestCompare()

Dim imgMagick
Dim strMsg As String

    Set imgMagick = CreateObject("ImageMagickObject.MagickImage.1")
    strMsg = imgMagick.Compare("-metric", "PSNR", "c:\test.jpg ", "c:\test2.jpg ", "c:\diff.png ")
    Debug.Print strMsg
    Set imgMagick = Nothing

End Sub

Thanks in advance...

[el_supremo]

The result from the compare command is not written to the standard output but to the error output (file descriptor 2). Can you capture the error output somehow (I'm not familiar with VBA)?

Pete

[Bluehawk]

I tried but it didn't work.

[fmw42]

in command line

compare -metric rmse image1 image2 null:

returns to terminal

[magick]

The compare metrics go to stderr. This permits you to pipe the output image:

• convert -metric rmse image.png reconstruct.png png:- | convert - ...

[Bluehawk]

Sorry but I didn't get it.
What exactly should I do to get the feedback ? Use convert after compare ?
And what does stderr mean ? (My English is not perfect)

[fmw42]

if you supply a third image, you will not get any messages, just the difference image. But if you specify null: for the third image, then you get the metric statistics.

PS what version of IM are you using? if old, perhaps you need to upgrade.

[Bluehawk]

Do you mean like this ?

Code: Select all

Private Sub TestCompare()

Dim imgMagick
Dim strMsg As String

    Set imgMagick = CreateObject("ImageMagickObject.MagickImage.1")
    strMsg = imgMagick.Compare("-metric", "PSNR", "c:\21.jpg", "c:\222.jpg")
    Debug.Print strMsg
    Set imgMagick = Nothing

End Sub

But I still get nothing. I'm using 6.6.1 Q16

[fmw42]

sorry I don't use API, just command line and don't use PC, but Mac. But I presume it would be:

strMsg = imgMagick.Compare("-metric", "PSNR", "c:\21.jpg", "c:\222.jpg", "null:")