Use mktemp for tempfile and allow out-of-aspect resizing

generate-icns.sh

@@ -21,7 +21,7 @@ for SIZE in $((DIMS[0] - WIDESORT[0])) $((DIMS[0] + WIDESORT[0])); do
   (( SIZE > 0 && (SIZE & (SIZE - 1)) == 0 )) && RESIZE=${SIZE}
 done
 
-set -x
-convert "${1}" -resize ${RESIZE}x${RESIZE} /tmp/tmp.png
-png2icns ${1/%png/icns} /tmp/tmp.png
-rm /tmp/tmp.png
+TEMPFILE=$(mktemp)
+convert "${1}" -resize ${RESIZE}x${RESIZE}\! ${TEMPFILE}
+png2icns ${1/%png/icns} ${TEMPFILE}
+rm ${TEMPFILE}