[magick-users] Chopping, swapping, and glueing back together

[David Harmon]

On Fri, 01 Jun 2007 09:09:10 +1000, "Anthony Thyssen" wrote:
>Hmmm  making cross1.jpg a negated rose,  and cross2.jpg a normal rose
>image....
>
>   convert \( rose: -negate -crop 50%x100% +swap +append \) \
>           \( rose:         -crop 50%x100% +swap +append \) \
>           -append x:

But you eliminated my (attempted) rescaling.

convert ( rose: -crop 50%x100% +repage -resize 900x1800 -gravity center
-crop 900x600+0+0 +repage +swap +append ) ( rose: -crop 50%x100%
+repage -resize 900x1800 -gravity center -crop 900x600+0+0 +repage +swap
+append ) -append parx.jpg

Same kind of unwanted result in the lower half, and the message:
   convert: no such image `ROSE'.

(I am doing the resizing because I want a fixed output size 1800x1200 
to print on 6"x4" paper at 300 pixels/inch.  The originals are all
different sizes and aspect ratio, and I want to fit as much as possible
cropped from the center of each half of each L/R pair.  Perhaps there is
a better set of IM command options to achieve that.)

I was getting the same behavior regardless of which of my sample 
images I started from, so I didn't think it mattered.  But these are
representative
  cross1.jpg = http://i14.tinypic.com/66t6fjr.jpg
  cross2.jpg = http://i10.tinypic.com/664lh76.jpg

Thanks for the help.