Keymap configuration

RMK supports configuring the default keymap at the compile time. Keymap in RMK is a 3-D matrix of KeyAction, which represent the keyboard's action after you trigger a physical key. The 3 dimensions are the number of columns, rows and layers.

RMK provides both Rust code or config ways to set your default keymap.

Define default keymap in keyboard.toml

Please check this section in keyboard configuration doc.

Define default keymap in Rust source file

The default keymap could also be defined at a Rust source file, There are keymap.rss in example folder, such as this, which could be a good example of defining keymaps using Rust in RMK:

#![allow(unused)]
fn main() {
// https://github.com/HaoboGu/rmk/blob/main/examples/use_rust/nrf52840_ble/src/keymap.rs
use rmk::action::KeyAction;
use rmk::{a, k, layer, mo};
pub(crate) const COL: usize = 14;
pub(crate) const ROW: usize = 5;
pub(crate) const NUM_LAYER: usize = 2;

#[rustfmt::skip]
pub fn get_default_keymap() -> [[[KeyAction; COL]; ROW]; NUM_LAYER] {
    [
        layer!([
            [k!(Grave), k!(Kc1), k!(Kc2), k!(Kc3), k!(Kc4), k!(Kc5), k!(Kc6), k!(Kc7), k!(Kc8), k!(Kc9), k!(Kc0), k!(Minus), k!(Equal), k!(Backspace)],
            [k!(Tab), k!(Q), k!(W), k!(E), k!(R), k!(T), k!(Y), k!(U), k!(I), k!(O), k!(P), k!(LeftBracket), k!(RightBracket), k!(Backslash)],
            [k!(Escape), k!(A), k!(S), k!(D), k!(F), k!(G), k!(H), k!(J), k!(K), k!(L), k!(Semicolon), k!(Quote), a!(No), k!(Enter)],
            [k!(LShift), k!(Z), k!(X), k!(C), k!(V), k!(B), k!(N), k!(M), k!(Comma), k!(Dot), k!(Slash), a!(No), a!(No), k!(RShift)],
            [k!(LCtrl), k!(LGui), k!(LAlt), a!(No), a!(No), k!(Space), a!(No), a!(No), a!(No), mo!(1), k!(RAlt), a!(No), k!(RGui), k!(RCtrl)]
        ]),
        layer!([
            [k!(Grave), k!(F1), k!(F2), k!(F3), k!(F4), k!(F5), k!(F6), k!(F7), k!(F8), k!(F9), k!(F10), k!(F11), k!(F12), k!(Delete)],
            [a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No)],
            [k!(CapsLock), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No)],
            [a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), k!(UP)],
            [a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), a!(No), k!(Left), a!(No), k!(Down), k!(Right)]
        ]),
    ]
}

}

First of all, the keyboard matrix's basic info(number of rows, cols and layers) is defined as consts:

#![allow(unused)]
fn main() {
pub(crate) const COL: usize = 14;
pub(crate) const ROW: usize = 5;
pub(crate) const NUM_LAYER: usize = 2;
}

Then, the keymap is defined as a static 3-D matrix of KeyAction:

#![allow(unused)]
fn main() {
// You should define a function that returns defualt keymap by yourself
pub fn get_default_keymap() -> [[[KeyAction; COL]; ROW]; NUM_LAYER] {
    ...
}
}

A keymap in RMK is a 3-level hierarchy: layer - row - column. Each keymap is a slice of layers whose length is NUM_LAYER. Each layer is a slice of rows whose length is ROW, and each row is a slice of KeyActions whose length is COL.

RMK provides a bunch of macros which simplify the keymap definition a lot. You can check all available macros in RMK doc. For example, layer! macro is used to define a layer. k! macro is used to define a normal key in the keymap. If there is no actual key at a position, you can use a!(No) to represent KeyAction::No.