diff --git a/wms_usher.sh b/wms_usher.sh
index da4e502..4144f9a 100755
--- a/wms_usher.sh
+++ b/wms_usher.sh
@@ -22,7 +22,8 @@ SH=$((RH - 2 * BW))
 usage() {
     cat<<EOF
 usage:
-wms_usher.sh [ -n, -s, -e, -o, -r, -l, -d, -u, -w, -W, -h, -H ]
+wms_usher.sh [ -c, -f, -n, -s, -e, -o, -r, -l, -d, -u, -w, -W, -h, -H ]
+-c) centered
 -f) fullsize
 -n) half north
 -s) half south
@@ -52,14 +53,14 @@ south() {
     x=0
     y=$((SH / 2 + BW))
     w=$SW
-    h=$((SH / 2))
+    h=$((SH / 2 - BW))
 }
 
 # half est value
 est() {
     x=$((SW / 2 + BW))
     y=0
-    w=$((SW / 2))
+    w=$((SW / 2 - BW))
     h=$SH
 }
 
@@ -71,7 +72,18 @@ west() {
     h=$SH
 }
 
-# fulsize function
+# centered function.
+center() {
+    # windows width.
+    ww=$((SW * WP / 100))
+    # windows height.
+    wh=$((SH * WP / 100))
+    x=$(((SW - ww) / 2))
+    y=$(((SH - wh) / 2))
+    wtp $x $y $ww $wh $FW
+}
+
+    # fulsize function
 fullsize() {
     # original size and position.
     osp=$(atomx WM_FS $FW)
@@ -98,6 +110,9 @@ fullsize() {
 }
 
 case $FLAG in
+    -c)
+	center
+	;;
     -f)
 	fullsize
 	;;