compton-trans: add a 'get' option.

bin/compton-trans

@@ -32,7 +32,7 @@ wprefix=
 window=
 opacity=
 cur=
-delete=
+action=
 treeout=
 wid=
 topmost=
@@ -48,15 +48,16 @@ while test $# -gt 0; do
   LASTIND=1
 
   # Read options
-  while getopts ':scdn:w:o:' option "$@"; do
+  while getopts ':scdgn:w:o:' option "$@"; do
     case "$option" in
       s) wprefix=''; window='' ;;
       c)
         active=$(xprop -root -notype _NET_ACTIVE_WINDOW \
           | sed 's/^.*\(0x\S*\).*$/\1/')
         wprefix='-id'; window=$active
       ;;
-      d) delete=1 ;;
+      d) action='delete' ;;
+      g) action='get' ;;
       n) wprefix='-name'; window=$OPTARG ;;
       w) wprefix='-id'; window=$OPTARG ;;
       o) opacity=$OPTARG ;;
@@ -81,7 +82,7 @@ done
 opacity=$(echo "$opacity" | sed 's/%//g' | xargs)
 
 # Validate opacity value
-if test -z "$delete" && ! echo "$opacity" | grep -q '^[+-]\?[0-9]\+$'; then
+if test -z "$action" && ! echo "$opacity" | grep -q '^[+-]\?[0-9]\+$'; then
   echo "Invalid opacity specified: $opacity."
   exit 1
 fi
@@ -140,17 +141,25 @@ if test -z "$topmost"; then
 fi
 
 # Remove the opacity property.
-if test -n "$delete"; then
+if test x"$action" = x'delete'; then
   xprop -id "$topmost" -remove _NET_WM_WINDOW_OPACITY
   exit 0
 fi
 
+# Get current opacity.
+cur=$(xprop -id "$topmost" -notype _NET_WM_WINDOW_OPACITY \
+  | sed 's/^.*\b\([0-9]\+\).*$\|^.*$/\1/')
+test -z "$cur" && cur=0xffffffff
+cur=$((cur * 100 / 0xffffffff))
+
+# Output current opacity.
+if test x"$action" = x'get'; then
+  echo "$cur"
+  exit 0
+fi
+
 # Calculate the desired opacity
 if echo "$opacity" | grep -q '^[+-]'; then
-  cur=$(xprop -id "$topmost" -notype _NET_WM_WINDOW_OPACITY \
-    | sed 's/^.*\b\([0-9]\+\).*$\|^.*$/\1/')
-  test -z "$cur" && cur=0xffffffff
-  cur=$((cur * 100 / 0xffffffff))
   opacity=$(($cur + $opacity))
 fi