# -*- makefile -*-




# usage:  IN=`echo *.jpeg` make -f ~/mk/jpeg2djvu.mk -j 3

# The idea is to make this work on a debian install with the packages:
# psutils netpbm imagemagick djvulibre


IN := $(shell ls *.png)
PSS := $(IN:.png=.ps)

.PHONY: all

all: out.pdf

out.ps: $(PSS)
	psmerge -oout.ps $(PSS)

out.pdf: out.ps
	ps2pdf out.ps out.pdf

# Ordinary dither gives large files.  What you really want is some
# adaptive threshold algorithm (pamthreshold)., but the settings below
# don't work well.

DITHER=pamditherbw | pamtopnm
# DITHER=pamthreshold -dual=10x10  ## this doesn't work well with these settings
# DITHER=pgmtopbm -threshold 

# Dither to B&W.  This produces smaller files and seems ok for high res scans.
# %.ps: %.jpeg
#	cat $< | jpegtopnm | $(DITHER) | pnmtops -dpi 300 >$@	

%.ps: %.pnm
	pnmtops -dpi 300 <$< >$@

%.pnm: %.png
	convert $< $@