#!/bin/bash

# Detects the width of running window with name given as first
# argument (xprop name '$1') and creates an XPM icon of that width,
# 1px height, and transparent.  Outputs an <icon>-tag for use in
# xmobar to display the generated XPM icon.
#
# Run script from xmobar and trayer:
# `Run Com "/where/ever/padding-icon.sh" ["panel"] "trayerpad" 10`
# and use `%trayerpad%` in your template.
# or, if you're using for instance stalonetray:
# `Run Com "/where/ever/padding-icon.sh" ["stalonetray"] "tray" 10`

# Very heavily based on Jonas Camillus Jeppensen code
# https://codeberg.org/xmobar/xmobar/issues/239#issuecomment-233206552

# Function to create a transparent Wx1 px XPM icon
create_xpm_icon () {
timestamp=$(date)
pixels=$(for i in `seq $1`; do echo -n "."; done)

cat << EOF > "$2"
/* XPM *
static char * trayer_pad_xpm[] = {
/* This XPM icon is used for padding in xmobar to */
/* leave room for trayer-srg. It is dynamically   */
/* updated by by trayer-pad-icon.sh which is run  */
/* by xmobar.                                     */
/* Created: ${timestamp} */
/* <w/cols>  <h/rows>  <colors>  <chars per pixel> */
"$1 1 1 1",
/* Colors (none: transparent) */
". c none",
/* Pixels */
"$pixels"
};
EOF
}

# panel window name
pname=${1:-panel}

# Width of the trayer window
width=$(xprop -name $pname | grep 'program specified minimum size' | cut -d ' ' -f 5)

# Icon file name
iconfile="/tmp/$pname-padding-${width:-0}px.xpm"

# If the desired icon does not exist create it
if [ ! -f $iconfile ]
then
    create_xpm_icon $width $iconfile
fi

# Output the icon tag for xmobar
echo "<icon=${iconfile}/>"