How to copy, paste and flip horizontally and vertically many images?

Question

Basically, I have 500+ images which I need to modify in exactly the same way. I have images like this .

And I need to copy the left side of the image, more precisely the rectangle which dimensions are 645x999 pixels, paste it, flip it diagonally and move it on the right side. I could do this manually with any image editor but I want to know if I can make a program (preferably in c++), or enter a command that can do this for me. I wish to obtain this , any advice would be of great help.

Thank you.

Answer 1

The following netpbm commands show how to do this for a single file

cat cwxAr.png | pngtopnm | pamcut -width 670 -height 999 | pnmtopng > il.png
cat il.png | pngtopnm | pnmflip -tb | pnmflip -lr | pnmtopng > ir.png
cat il.png | pngtopnm > il.pnm
cat ir.png | pngtopnm > ir.pnm
pnmcat -lr il.pnm ir.pnm | pnmtopng > i.png

note - to obtain the output image that is given in the example the width is 670 pixels, not 645.

This should generate intermediate images il.png

ir.png

and a final picture i.png

To do this for a series of files the following script would work, where the variable flist is set to the list of files to be processed

#!/bin/bash -f

flist=( cwxAr-0 cwxAr-1 cwxAr-2 )
outpref=( cwxAr-out )
nout=0
for f in ${flist[*]} ; do
 fout=`printf "%s-%4.4d.png" ${outpref} ${nout}`
 echo "Reading "${f}", writing ",${fout}
 cat ${f}.png   | pngtopnm | pamcut -width 670 -height 999 | pnmtopng > il.png
 cat il.png | pngtopnm | pnmflip -tb | pnmflip -lr | pnmtopng > ir.png
 cat ir.png | pngtopnm > ir.pnm
 cat il.png | pngtopnm > il.pnm
 pnmcat -lr il.pnm ir.pnm | pnmtopng > ${fout}
 nout=$(( nout +1 ))
done