Chen Yulin's Blog

Objective

I use a hyprland plugin called hyprscroller to emulate the scroll functionality of PaperWM.
However, I can’t get whether I am in row mode or column mode, so I want to show the mode status on my waybar.

Related issue: https://github.com/dawsers/hyprscroller/issues/57

Implementation

I wrote two shell script under ~/.config/waybar/

• scroller_mode_listener.sh, responsible for listening the IPC message of hyprscroller and store that information in a tmp file. This script can be executed in hyprland config file using exec-once

  #!/bin/bash
  
  MODE_FILE="/tmp/hyprland_scroller_mode"
  
  function handle {
    if [[ ${1:0:8} == "scroller" ]]; then
      if [[ ${1:10:9} == "mode, row" ]]; then
          echo "Row" > "$MODE_FILE"
      elif [[ ${1:10:12} == "mode, column" ]]; then
          echo "Column" > "$MODE_FILE"
      #else
          #echo "" > "$MODE_FILE"
      fi
      hyprctl dispatch submap reset && pkill -SIGRTMIN+8 waybar # update the widget on waybar
    fi
  }
  
  # Initialize the mode file
  echo "" > "$MODE_FILE"
  
  socat - "UNIX-CONNECT:$XDG_RUNTIME_DIR/hypr/$HYPRLAND_INSTANCE_SIGNATURE/.socket2.sock" | while read -r line; do handle "$line"; done

• scroller_mode_reader.sh, responsible for reading the tmp file and return the json value to waybar to change the shown icon.

  #!/bin/bash
  
  MODE_FILE="/tmp/hyprland_scroller_mode"
  
  current_mode=$(cat "$MODE_FILE")
  
  if [[ "$current_mode" == "Row" ]]; then
      icon="Row"
      percent=0
      class="mode-row"
  elif [[ "$current_mode" == "Column" ]]; then
      icon="Column"
      percent=100
      class="mode-column"
  else
      icon="Row"
      percent=0
      class=""
  fi
  
  echo "{\"text\":\"$icon\", \"tooltip\":\"Scroller Mode: $current_mode\", \"class\":\"$class\",\"percentage\": $percent}"

Then add the custom module to waybar in config file (we use signal to update the module):

"custom/scroller-mode": {
    "exec": "~/.config/waybar/scroller_mode_reader.sh",
    "return-type": "json",
    "interval": "once",
    "signal": 8,
    "on-click": "hyprctl dispatch submap reset && pkill -SIGRTMIN+8 waybar",
    "format": "{icon}",
    "format-icons": ["", ""],
}

Also remember to add the module to the bar:

"modules-right": ["custom/scroller-mode", "cpu", "memory", "temperature","battery","clock","custom/power"],

Then everything is done