possible bug -stereo IM 6.7.7.10 Q16 Mac OSX Snow Leopard

[fmw42]

I do not know if I am using the correct syntax or if this is a bug. But there is no change in the resulting image. I would have expected the left (red channel) image or the right (green channel) image to shifted +10 pixels (rolled?) in the output and the blue channel to be black.

Am I misunderstanding how -stereo works here?

# create a simplistic test pair.
convert logo: -colorspace gray logog.png
# stereo merge
composite -stereo +10 logog.png logog.png tmp.png
# examine resulting channels
convert tmp.png -separate tmp_%d.png

All three channels are the same. There is no shift between red and green channels.

[magick]

+10 should work but it doesn't. We'll add a patch soon. In the mean-time, try +10+10.

[fmw42]

+10 should work but it doesn't. We'll add a patch soon. In the mean-time, try +10+10.

OK, I think you mean +10+0.

incorrect gamma=(0/100000)
incorrect gamma=(0/100000)
composite: Ignoring incorrect gAMA value when sRGB is also present `logog.png' @ warning/png.c/MagickPNGWarningHandler/1754.

This is not urgent for me. I only submitted this because I was trying to answer a question on the forum about IM -stereo and realized that it was not working as I thought it should. But I had no real experience with it before.

If it is doing what I think (just a roll of the green image and possibly blackening of the blue), then a simple command line using -roll ought to produce the same results, if one blackens the blue channel (or duplicate the green into the blue to make it red-cyan rather than red-green). Is that correct?

[magick]

We're using ImageMagick 6.7.8.0. We're getting the expected stereo anaglyph image without any warnings. We're not sure why its failing for you. Our command:

• composite -stereo +10+10 logo: logo: tmp.png

[fmw42]

We're using ImageMagick 6.7.8.0. We're getting the expected stereo anaglyph image without any warnings. We're not sure why its failing for you. Our command:

• composite -stereo +10+10 logo: logo: tmp.png

Right I had a typo. But using +10+0, as I assume you meant, is putting the same result into the green and blue channels. Thus the result will be a red-cyan stereo (actually what the other user wanted). It would not be a red-green stereo as stated on the options page:

"The left side of the stereo pair is saved as the red channel of the output image. The right side is saved as the green channel. Red-green stereo glasses are required to properly view the stereo image."

Or am I misunderstanding something?

Do you want me to edit the options page to make it say red-cyan?

It should also mention that in

composite -stereo +X+Y image1 image2 result

image2 is put into the red channel, thus it is the left image
image1 is put into the green and blue channels, thus it is the right image.

Fred

P.S. I am also getting some odd warnings when running the -stereo command using logog.png (convert logo: -colorspace gray logog.png)


incorrect gamma=(0/100000)
incorrect gamma=(0/100000)
composite: Ignoring incorrect gAMA value when sRGB is also present `logog.png' @ warning/png.c/MagickPNGWarningHandler/1754.

[magick]

We corrected the web page, it will take 24-hours to update. You are welcome to make additional edits.