diff --git a/docs/docs/features/conditional-layers.md b/docs/docs/features/conditional-layers.md new file mode 100644 index 00000000..a685bcab --- /dev/null +++ b/docs/docs/features/conditional-layers.md @@ -0,0 +1,56 @@ +--- +title: Conditional Layers +--- + +Conditional layers support activating a particular layer (called the `then-layer`) when all layers +in a specified set (called the `if-layers`) are active. This feature generalizes what's commonly +known as tri-layer support, allowing activation of two layers (usually called "lower" and "raise") +to trigger a third (usually called "adjust"). + +Another way to think of this feature is as a simple combo system for layers, just like the usual +[combos for behaviors](combos.md). + +## Configuration + +Conditional layers are configured via a `conditional_layers` node in your `.keymap` file as follows: + +``` +/ { + conditional_layers { + compatible = "zmk,conditional-layers"; + tri_layer { + if-layers = <1 2>; + then-layer = <3>; + }; + }; +}; +``` + +Each conditional layer configuration may have whatever name you like, but it's helpful to choose +something self explanatory like `tri_layer`. The following properties are supported: + +- `if-layers` specifies a set of layer numbers, all of which must be active for the conditional + layer to trigger. +- `then-layer` specifies a layer number that should be activated if and only if all the layers + specified in the `if-layers` property are active. + +Therefore, in this example, layer 3 ("adjust") will be activated if and only if both layers 1 +("lower") and 2 ("raise") are active. + +:::tip +Since higher-numbered layers are processed first, a `then-layer` should generally have a higher +number than its associated `if-layers` so the `then-layer` can be accessed when active. +::: + +:::info +Activating a `then-layer` in one conditional layer configuration can trigger the `if-layers` +condition in another configuration, possibly repeatedly. +::: + +:::caution +When configured as a `then-layer`, a layer's activation status is entirely controlled by the +conditional layers feature. Even if the layer is activated for another reason (such as a [momentary +layer](../behaviors/layers.md#momentary-layer) behavior), it will be immediately deactivated if the +associated `then-layers` configuration is not met. As such, we recommend avoiding using regular +layer behaviors for `then-layer` targets. +::: diff --git a/docs/sidebars.js b/docs/sidebars.js index 2a406589..04389695 100644 --- a/docs/sidebars.js +++ b/docs/sidebars.js @@ -11,6 +11,7 @@ module.exports = { Features: [ "features/keymaps", "features/combos", + "features/conditional-layers", "features/debouncing", "features/displays", "features/encoders",