Legacy ImageMagick Discussions Archive

Following up on an issue discussed at this LINK. Using IM 7.0.7-6 on Windows 10, creating a 640x480 built-in "logo:", and using "-chop" to remove some percentages with this command...
The output specs show an image which is 608 pixels wide as expected, but it's 479 pixels high. It should chop nothing in the "0%" direction and remain 480 pixels, but it chops one row anyway.

Also, when using "-chop" with an inline FX expression to set the percentages to chop, the command fails to chop either width or height. Running this command...
... describes an output image of 640x480, same as the input. It should chop 3% from the width and 7% from the height, but it doesn't chop anything at all.

This issue remains with version 7.0.7-7 Q16 HDRI using Windows 10 64. This command...
Produces this output...

I think IM tries to chop at least one pixel in either dimension as a minimum. If you wanted 0 pixel chop, that would be a no-op and why bother calling -chop? Trying to chop 0 pixels in one dimension does not make sense to me. That means that one whole row or column is not going to be chopped since the one dimension is 0. So again a no-op situation.

Have I misunderstood some other situation where this makes more sense? Or are you just looking for it to do nothing if either dimension is 0%, which you could do by a conditional test beforehand.

"-chop WxH" should remove W columns, and also remove H rows. This might be zero columns, and 5 rows. Zero does make sense.
In v6.9.5-3, this produces the expected output:

Thanks, snibgo. I stand corrected. I was misinterpreting what W and H mean in -chop.

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.