1

I am trying to make an eBook cover via ImageMagick, to be incorporated in a larger project after it works.

I want to get to geometry and gravity later, but at present I have two relevant images:

  1. A 1000x1600 JPEG background, which I lightened via GIMP enough so that it has no black or near-black pixels, and

  2. An 800x70 PNG author name with a single piece of text saved as black text against a transparent background.

(At present the 800x70 image is generated by Pango, and there may strictly be more options than compositing images; I expect it is possible to create a title and author name via Pango and circumvent image compositing. However, I would like to know that in addition to, and not instead of, a basic invocation for image compositing that would place a PNG with alpha over a JPEG, and be able to control its position with -gravity and -geometry.)

I am trying to go off of ImageMagick's layering examples, and have tried a few variations of the following:

convert -size 1000x1600 -geometry +0+0 \
  -composite background.jpg -gravity center -geometry +0+0 \
  -composite author.png -gravity center -geometry +0+0 \
  result.jpg

What I get from this is an 800x70 solid black image, which I would expect to be what you get when taking transparency from a PNG like the author name to make a JPEG.

What should I be doing to (for now at least) get to the point where I have a 1000x1600 result image equal to the background with the author name placed on it in some intelligible place?

Thanks

  • N.B. I tried removing the '-geometry +0+0' arguments. It seemed to produce the same result. – Christos Hayward Oct 27 '17 at 14:49
1

Two issues:

  • You shouldn't need the convert command for this operation.

  • Your images are backwards in the command (the first image is the image to overlay on the second i.e. author then background).

This should give the results you want:

composite author.png -gravity center -geometry +0+0 \
background.jpg -gravity center -geometry +0+0 result.jpg

Arguably, you likely don't even need the second gravity/geometry combo:

composite author.png -gravity center -geometry +0+0 background.jpg result.jpg

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.