imagemagickimagemagick-convert

How to stop gravity option screwing up imagemagick parenthesised inputs?

I've been battling with this error (bug?) in imagemagick:

% convert \
> \( logo: -crop 100x100+300+300 -gravity west \) \
> \( logo: -crop 100x100+300+300 -gravity west \) \
> +append out.png
convert: geometry does not contain image ("100x100+300+490") `LOGO' @ warning/transform.c/CropImage/599.

Where does the number 490 come from??

ImageMagick's example image logo: is 640x480px. The crop geometry 100x100+300+300 is clearly entirely within the 640x480 bounds of logo:.

Of course the output I am expecting is the side-by-side of two identical 100x100+300+300 crops from logo:

enter image description here

But I am getting this funky error instead. If a previous parenthesised input image has a -gravity switch, then subsequent parenthesised inputs have their crop geometries warped in different ways:

% convert \( logo: -gravity east \) \( logo: -crop 10x10+630+470 \) +append  out.png
convert: geometry does not contain image ("10x10+0+705") `LOGO' @ warning/transform.c/CropImage/599.

How can I prevent any -gravity switches in parenthesised input images from affecting other parenthesised inputs?

Solution

  • Three suggestions...

    First, the "-gravity" setting should be before the operation that uses it.

    After the operation that the uses the "-gravity" setting put just "+gravity" to end the setting.

    If you use "-respect-parenthesis" before the parentheses, then the "-gravity" settings you make inside the parentheses won't continue to be in effect after them. You can use "+respect-parenthesis" to end that setting.