Configuring Multi-Monitor Setup in Niri

https://github.com/YaLTeR/niri/wiki/Configuration:-Outputs 

Step 1: Identify Your Monitors

Use niri msg outputs to get information about your connected monitors, including their names and logical sizes:

niri msg outputs

Look for the Logical size values in the output - you’ll need these for positioning.

Step 2: Configure Monitor Layout

Edit your niri config file to set up the monitor arrangement. Use the monitor names from the previous command.

Example Configuration: This setup places an external monitor (DP-3) above a laptop monitor (eDP-1):

output "eDP-1" {
    scale 2.5
    transform "normal"
    position x=0 y=1080
}

output "DP-3" {
    scale 2.0
    transform "normal"
    position x=0 y=0
}

Configuration Breakdown:

• scale: Adjusts the display scaling (higher = larger UI elements)
• transform: Display rotation ("normal", "90", "180", "270")
• position:
  • x=0 y=0 places the monitor at the top-left origin
  • x=0 y=1080 places the monitor 1080 pixels below the origin

Layout Logic:

• DP-3 (external): positioned at y=0 (top)
• eDP-1 (laptop): positioned at y=1080 (bottom, below the external monitor)
• Both monitors aligned at x=0 (left edge)

Tip: Adjust the y position values based on the actual logical height of your top monitor to ensure proper alignment.