[ferret_users] Re: producing eps and png from postscript

[Hein Zelle <hein.zelle@xxxxxxxxxxxxx>]

Dear Ferret users,


a small update on this thread, with my latest solution (been working
reliably for years now).  

to generate eps, I generate a ps file with Fprint, then I use 

   cat ferret_file.ps | ps2eps -B  > plot.eps

This converts and crops reliably and generates valid eps files.  The
tool is available in the ps2eps package (Ubuntu/Debian).
Alternatively these days I go straight to png via a much faster (all
in memory) process:

gs -dSAFER -dNOPAUSE -r300  -dDEVICEWIDTHPOINTS=864  \
   -dDEVICEHEIGHTPOINTS=864 -sDEVICE=ppmraw -q -sOutputFile=- \
   -f ferret_file.ps -c showpage -c quit \
   | pnmcrop | convert pnm:- PNG:${tmppng}

where ferret_file.ps is the output of Fprint, and ${tmppng} is a
temporary png output file. I write the output under /dev/shm to keep
the file in memory.  I then antialias and scale this (huge) pngfile with

convert -antialias -scale 35% -rotate 270 -type Palette \
	${tmppng} PNG8:output.png

The above requires ghostscript to be installed (gs) as well as pnmcrop
which is part of the netpbm package.  Finally it uses convert from
imagemagick.  

The step with /dev/shm can be avoided by piping the temporary png
file straight to the last convert command, but I want to create 2
sizes of png file, so I need the intermediate file. The gs device width
and height can be increased further if cropping problems with the page
margins occur.


Kind regards,
     Hein


-- 

Dr. Hein Zelle
Senior consultant meteorology & oceanography
BMT ARGOSS

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#!/bin/bash

inputfn="metafile.plt"
outputfn="output.ps"
myname=`basename $0`
convert="ps2eps -B"
# makepng="convert +antialias -density 300 -rotate 270"
# makethumb="convert +antialias -density 37 -rotate 270"
makesmall="convert -antialias -scale 35% -rotate 270 -type Palette"
makethumb="convert -antialias -scale 12% -rotate 270 -type Palette"
background=0
thumbnail=0
rotate=270

# where to copy the metafile to 
tmpname=/dev/shm/fprint_metafile_$$.tmp
tmpps=/dev/shm/ferret-tmp-ps-$$.ps
tmppng=/dev/shm/ferret-tmp-png-$$.png

# make a subroutine to process a file.
# this makes it possible to continue in the background and exit the script.
# the input filename is passed in $1
process_file()
{
    if [ $myname = "bwprint" -o $myname = "rbwprint" ] ; then
	# echo -n "Fprint -l ps -R -o $outputfn $1 ... "
	# Fprint -l ps -R -o $tmpps $1
	echo -n gksm2ps -l ps -R -d cps -a -o $tmpps $1 ...
	gksm2ps -l ps -R -d cps -a -o $tmpps $1
    else
	# echo -n "Fprint -l cps -R -o $outputfn $1 ... "
	# Fprint -l cps -R -o $tmpps $1
	echo -n gksm2ps -l cps -R -d cps -a -o $tmpps $1 ...
	gksm2ps -l cps -R -d cps -a -o $tmpps $1
    fi
    echo "done."
    rm -v $1
    
    # get a basename for the file wether it's called .eps or .png
    basename=$(basename $(basename $outputfn .eps) .png)
    pngbase=${basename}.png
    pngfile=`dirname $outputfn`/${pngbase}

    # Hein Zelle, 27-12-2010
    # add a fixed papersize of 12"x12".  This is roughly the long side
    # of an A4 sheet, squared.  (1 point = 1/72 inch)
    # this prevents margin problems and legends getting clipped during
    # the postscript rendering, hopefully.

    echo "trimming postscript, converting to PNG"
    echo "gs -dSAFER -dNOPAUSE -r300 -dDEVICEWIDTHPOINTS=864 -dDEVICEHEIGHTPOINTS=864 -sDEVICE=ppmraw -q -sOutputFile=- -f $tmpps -c showpage -c quit | pnmcrop | convert pnm:- PNG:${tmppng}"
    gs -dSAFER -dNOPAUSE -r300  -dDEVICEWIDTHPOINTS=864 -dDEVICEHEIGHTPOINTS=864 -sDEVICE=ppmraw -q -sOutputFile=- -f $tmpps -c showpage -c quit | pnmcrop | convert pnm:- PNG:${tmppng}

    echo "$makesmall $tmppng PNG8:${pngfile}"
    $makesmall $tmppng PNG8:${pngfile}
    
    if [ "$thumbnail" = "1" ] ; then
	thumbdir=`dirname $outputfn`/thumbnails
	thumbfile=${thumbdir}/${pngbase}
	
        # make thumbnails directory if needed
	if [ ! -d $thumbdir ] ; then
	    mkdir $thumbdir
	fi
	
        # make the thumbnail
	echo "$makethumb $pngfile PNG8:${thumbfile} ... "
	$makethumb $tmppng PNG8:${thumbfile}
    fi

    # clean up
    echo "cleaning up temporary files under /dev/shm"
    rm -v $tmpps $tmppng
    
    echo "processing of $outputfn done."
}

# main script starts here

if [ "$1" = "-h" -o "$1" = "--help" ] ; then
	echo ""
	echo "Usage: $myname [-t] [-b] [-r angle] [input.plt] <output.png>"
        echo "    Input is optional, 'metafile.plt' assumed by default."
        echo "    If no arguments are given, values are requested interactively."
	echo "    -t generates a thumbnail in thumbnails/ directory"
	echo "    -b runs postscript processing in the background"
	echo "    -r rotates the final picture by angle degrees (default 270)"
	echo ""
        echo "DO NOT CHANGE THE ORDER OF -t, -b, -r !"
	echo ""
	echo "Converts a Ferret metafile to PNG with a proper boundingbox."

	echo $myname | egrep -q "^r"
	if [ "$?" = "0" ] ; then 
		echo "Input metafile is removed after processing."
	fi

	echo ""
	exit 0
fi

# check for --thumbnail or -t option
# remove the $1 argument (shift) and continue normally
if [ "$1" = "--thumbnail" -o "$1" = "-t" ] ; then
    thumbnail="1"
    shift 1
fi

if [ "$1" = "--background" -o "$1" = "-b" ] ; then
    background="1"
    shift 1
fi

if [ "$1" = "--rotate" -o "$1" = "-r" ] ; then
    rotate="$2"
    shift 2
fi

if [ "$1" = "" ] ; then
	# no arguments, ask interactively
	echo -n "enter input filename [metafile.plt] ? "
	read tmpin
	if [ $tmpin != "" ] ; then 
	    inputfn=$tmpin
	fi

	echo -n "enter output filename [output.eps] ? "
	read tmpout
	if [ $tmpout != "" ] ; then
	    outputfn=$tmpout
	fi
else
	if [ "$2" = "" ] ; then
		# one argument
		outputfn=$1
	else
		# two arguments (or more)
		inputfn=$1
		outputfn=$2
	fi
fi

# run in the background if requested
# check if inputfn exists before continuing.

if [ ! -f $inputfn ] ; then
    echo "$0: ${inputfn}: no such metafile found."
    exit 1
fi

if [ "$background" = "1" ] ; then
    echo "processing $inputfn in the background."
    cp $inputfn $tmpname
    (process_file $tmpname) &
else
    echo "processing $inputfn in the foreground."
    cp $inputfn $tmpname
    (process_file $tmpname)
fi

# remove the original metafile if requested (program name starts with r)
echo $myname | egrep -q "^r"
if [ "$?" = "0" ] ; then 
    rm -v $inputfn
fi

# done - script exits here