Add:doc:added errors and usage messages to navit_svg2png script (#369)

To know how to use the script you had to inspect the script code.
Error messages and help/usage messages added.

1 files changed, 36 insertions, 0 deletions

diff --git a/navit/icons/navit_svg2png b/navit/icons/navit_svg2png
index 675207561..668613a61 100755
--- a/navit/icons/navit_svg2png
+++ b/navit/icons/navit_svg2png
@@ -1,5 +1,14 @@
 #!/bin/sh
 
+exitwithhelp()
+{
+	echo "Usage: navit_svg2png <conversion_tool> <output_png_filename> [<width_px> <height_px>]"
+	echo "The input filename is the same than the output png one with svg or svgz extension"
+	echo "Possible conversion tools: ksvgtopng, ksvgtopng4, rsvg-convert, inkscape and convert"
+	echo "width_px and height_px arguments can be omitted if output png size is specified in the filename, like this: imagename_WIDTH_HEIGHT.png (ex. myPng_100_100.png)"
+	exit
+}
+
 svgtopng()
 {
 	case $svgtopng in
@@ -15,6 +24,10 @@ svgtopng()
 	*convert)
 		$svgtopng -alpha on -background none $3 -resize $1x$2 $4
 		;;
+	*)
+		echo "Error: unknown conversion tool"
+		exitwithhelp    # unknown conversion tool
+		;;
 	esac
 }
 
@@ -26,8 +39,27 @@ svgtopng=$1
 png=$2
 w=$3
 h=$4
+
+# if -h or --help arg is passed, print help and exit
+case "$1" in
+	'-h'|'--help'|'')
+		exitwithhelp
+		;;
+esac
+
+# args num must be == 2 or == 4
+if [ "$#" -ne 2 ] && [ "$#" -ne 4 ];
+then
+	echo "Error: wrong number of arguments"
+	exitwithhelp
+fi
+
 case "$png" in
 	*_[1-9]*_[1-9]*.png)
+		if [ "$#" -ne 2 ]; then
+			echo "Error: output png size is specified by filename and by arguments, plese use only one"
+			exitwithhelp    # png size musn't be specifed, only in filename
+		fi
 		svg=${png%_*_*.png};
 		h=${png##*_}
 		w=${png%_$h}
@@ -35,6 +67,10 @@ case "$png" in
 		w=${w##*_}
 		;;
 	*)
+		if [ "$#" -ne 4 ]; then
+			echo "Error: please, specify output png size"
+			exitwithhelp    # filename doesn't specify png size, must be done with args 3 and 4
+		fi
 		svg=${png%.png}
 		;;
 esac