monochrome: whole output image is black

[cwong]

I use the following command to convert image to black and white:
"C:\Program Files\ImageMagick-7.0.8-Q16\magick.exe" convert input.png -monochrome output.png

Most of the output images are good.
However, I found that with the following input image, the whole output image is black.

Input image:


Output image:


Magick version:
7.0.8 on Windows 10

Please advise. Thanks a lot.

Best Regards,
Clive

[fmw42]

See https://imagemagick.org/discourse-serve ... =3&t=37192 -- similar issue

[magick]

Thanks for the problem report. We can reproduce it and will have a patch to fix it in GIT master branch @ https://github.com/ImageMagick/ImageMagick later today. The patch will be available in the beta releases of ImageMagick @ https://www.imagemagick.org/download/beta/ by sometime tomorrow.

[cwong]

Thank you so much! Looking forward the beta release.

[cwong]

Thanks for the beta release and I have tried it.
(ImageMagick-7.0.9-8~beta20191205-Q16-x64-static.exe)

Unfortunately, for the above image, the problem still persists (The whole output image is still black).
Other images do not have this problem. (relate to major color is orange... ?)

Would you please help? Thanks a lot!

Best Regards,
Clive