barrier/GRAVE_MODIFIER_SETUP.md

Grave Modifier Setup for Barrier

Overview

This implementation adds support for using the grave key (`) as a hotkey modifier in Barrier, similar to Control, Alt, and Shift.

Required Setup

1. Code Changes

The following code changes have been implemented:

• XWindowsUtil.cpp: Added case XK_grave: return kKeyModifierBitGrave; to getModifierBitForKeySym()
• XWindowsKeyState.cpp: Added fallback mapping for grave modifier to Mod4 in updateKeysymMapXKB()
• key_types.cpp: Already included grave modifier in kModifierNameMap

2. X11 Modifier Mapping (REQUIRED)

The grave key must be mapped to an X11 modifier for hotkeys to work. Run this command:

xmodmap -e "add mod4 = grave"

3. Make it Permanent

To make the X11 mapping persistent across reboots, add this line to ~/.xsessionrc:

echo 'xmodmap -e "add mod4 = grave"' >> ~/.xsessionrc

Usage

Once setup is complete, you can use grave modifier hotkeys in your Barrier configuration:

keystroke(Grave+1) = switchToScreen(screen1,960,540)
keystroke(Grave+2) = switchToScreen(screen2,960,540)

Verification

To verify the setup:

1. Check modifier mapping: xmodmap -pm
   • Should show grave (0x31) in the mod4 line
2. Test hotkeys: Press and hold grave, then press a number key
3. Check Barrier logs for successful hotkey registration

Troubleshooting

• If hotkeys don't work, verify grave is mapped to mod4: xmodmap -pm
• If mapping is lost after reboot, ensure ~/.xsessionrc contains the xmodmap command
• Restart Barrier server after making X11 mapping changes