How to display the times in various time zones from the LXDE Panel

I normally check the time in the time zone of family, friends and colleagues who live in various places around the World before I call or message them. In KDE Plasma on my laptop it is possible to configure the digital clock widget to display the times in a list of time zones of my choice when I hover the mouse pointer over the widget. However, my family’s PC has Lubuntu 18.04 installed, which uses LXDE, and the digital clock on the LXDE Panel does not have that ability. Therefore I installed the GUI utility gworldclock in Lubuntu 18.04:

$ sudo apt-get install gworldclock

I added it to the ‘Application Launch and Task Bar’ plugin on the LXDE Panel, and a clock icon is now displayed on the Panel.

gworldclock icon on Application Launch and Task Bar on LXDE Panel

When I click the clock icon, a window opens on the Desktop and displays the date and time at each of the World locations I configured in gworldclock (‘Options’ > ‘Add Timezone’). Excellent, and almost as convenient as the World time feature in the Digital Clock widget in KDE Plasma 5.

gworldclock window default size

I have configured gworldclock to display a list of ten additional time zones when I click on the clock icon on the Application Launch and Task Bar on the Panel. However, the size of the pop-up gworldclock window was relatively small; only six of the eleven time zones were visible, so I had to use the window’s scroll bar in order to view some of the configured time zone entries. I therefore made some changes in LXDE in order to display a larger gworldclock window showing all eleven time zones. This is how I did it.

1. I installed wmctrl:

$ sudo apt-get install wmctrl

2. I created a hidden Bash script ~/.gworldclockfitzcarraldo.sh containing the following:

#!/bin/bash
gworldclock &
sleep 0.5s
wmctrl -F gworldclock -r gworldclock -e 0,500,300,300,340

and made it executable:

$ chmod +x ~/.gworldclockfitzcarraldo.sh

See man wmctrl for the meaning of the options in the above-mentioned Bash script.

3. I created the Desktop Configuration File ~/.local/share/applications/gworldclockfitzcarraldo.desktop containing the following:

[Desktop Entry]
Comment=See the time in other timezones
Name=gworldclock
GenericName=World Clock
Encoding=UTF-8
Comment[fr]=Voir l'heure dans d'autres fuseaux horaires
Exec=/home/fitzcarraldo/.gworldclockfitzcarraldo.sh
Terminal=false
Type=Application
Icon=gworldclock
Categories=Utility;Clock;HamRadio

4. I edited the file ~/.config/lxpanel/Lubuntu/panels/panel and added an entry for the new Desktop Configuration File to the end of list for the Application Launch and Task Bar, as shown in the following excerpt from the file:

Plugin {
  type=launchtaskbar
  Config {
    Button {
      id=pcmanfm.desktop
    }
    Button {
      id=firefox.desktop
    }
    Button {
      id=google-chrome.desktop
    }
    Button {
      id=gedit.desktop
    }
    Button {
      id=lxterminal.desktop
    }
    Button {
      id=galculator.desktop
    }
    Button {
      id=gworldclockfitzcarraldo.desktop
    }
  }
}

Then I logged out and back in again. Now, when I click on the clock icon on the Panel, the gworldclock window opens at the location and size specified by the wmctrl command in the Bash script I created.

gworldclock window resized by the Bash script