add test_comp.sh

test_comp.sh

@@ -0,0 +1,32 @@
+#!/bin/sh
+
+if [ $# -ne 1 ]; then
+	echo "usage: $0 image"
+	exit
+fi
+
+echo "converting image to pdf, trying all compressions imagemagick has to offer"
+echo "if, as a result, Zip/FlateDecode should NOT be the lossless compression with the lowest size ratio, contact me j [dot] schauer [at] email [dot] de"
+echo "also, send me the image in question"
+echo
+
+imsize=`stat -c "%s" "$1"`
+
+for a in `convert -list compress`; do
+	echo "encode:\t$a"
+	convert "$1" -compress $a "`basename $1 .jpg`.pdf"
+	pdfimages "`basename $1 .jpg`.pdf" "`basename $1 .jpg`"
+	/bin/echo -ne "diff:\t"
+	diff=`compare -metric AE "$1" "\`basename $1 .jpg\`-000.ppm" null: 2>&1`
+	if [ "$diff" != "0" ]; then
+		echo "lossy"
+	else
+		echo "lossless"
+	fi
+	/bin/echo -ne "size:\t"
+	pdfsize=`stat -c "%s" "\`basename $1 .jpg\`.pdf"`
+	echo "scale=1;$pdfsize/$imsize" | bc
+	/bin/echo -ne "pdf:\t"
+	grep --max-count=1 --text /Filter "`basename $1 .jpg`.pdf"
+	echo
+done