Suppose I have serveral BMP image file, say 001.bmp, 002.bmp,..., 100.bmp. I want to convert these files to a single djvu file, whose first page is the content of 001.bmp, the second page is the content of 002.bmp...etc.
What is the best way (software) to do this task? I don't want to upload those image file to a server, since it takes too much time. On the other hand, I am not restricted to use BMP files, I can also work with PNG or JPG files.
Assuming you are on Linux. Install the djvulibre packages (on Debian/Ubuntu, it's apt install djvulibre-bin), cd to the path where you have your images and run the following:
for x in *.jpg; do c44 -dpi 300 $x; done
djvm -c ../result.djvu *.djvu
ddjvu -format=pdf myfile.djvu myfile.pdf
Sources:
On Windows you could follow these steps on cygwin, WSL or similar.
-percent 100 or similar option after -dpi 300, otherwise image quality in the resulting DJVU (and thus PDF) file may be quite bad.
For color pages:
pages=pg1.djvu
c44 -dpi 300 pg1.jpg pg1.djvu
For black/white:
for (( i = 2; i <= $N; i++ )); do
echo $i
convert pg$i.jpg pg$i.pbm
cjb2 pg$i.pbm pg$i.djvu
pages="$pages pg$i.djvu"
done
Join all pages:
djvm -c book.djvu $pages
If you want to use multiple cores while conversion, so it will be much much ... much faster :
$ CPU_N="6"; DPI="100"; for i in `ls *.JPG` ; do echo "$i --> ${i%.JPG}.djvu" ; c44 -dpi "$DPI" $i ${i%.JPG}.djvu & { while [[ $( ps aux | grep c44 | grep -v grep | wc -l ) -eq "$CPU_N" ]] ; do sleep 1 ; done ; }; done; { while [[ $( ps aux | grep c44 | grep -v grep | wc -l ) -ge 1 ]] ; do echo "wait.."; sleep 1 ; done ; }; echo "done"
CPU_N = a number of cores you want to use for conversion.
DPI = set dpi for djvu files.
Actually -dpi setting of c44 command doesnt do anything usefull, however it is another story.
