e9140b2da9
This is a generalization of the existing concept of tri-layer support
that's already well known. Essentially, a conditional-layer
configuration activates a particular layer (the then-layer) when one or
more other layers (the if-layers) are activated.
This is commonly used on ortho keyboards to activate a third "adjust"
layer while the primary two layers ("lower" and "raise") are active.
91 lines
3.7 KiB
C
91 lines
3.7 KiB
C
/*
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* Copyright (c) 2021 The ZMK Contributors
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*
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* SPDX-License-Identifier: MIT
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*/
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#define DT_DRV_COMPAT zmk_conditional_layers
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#include <stdint.h>
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#include <devicetree.h>
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#include <logging/log.h>
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#include <zmk/event_manager.h>
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#include <zmk/keymap.h>
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#include <zmk/events/layer_state_changed.h>
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LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
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#if DT_HAS_COMPAT_STATUS_OKAY(DT_DRV_COMPAT)
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// Conditional layer configuration that activates the specified then-layer when all if-layers are
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// active. With two if-layers, this is referred to as "tri-layer", and is commonly used to activate
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// a third "adjust" layer if and only if the "lower" and "raise" layers are both active.
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struct conditional_layer_cfg {
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// A bitmask of each layer that must be pressed for this conditional layer config to activate.
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zmk_keymap_layers_state_t if_layers_state_mask;
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// The layer number that should be active while all layers in the if-layers mask are active.
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int8_t then_layer;
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};
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#define IF_LAYER_BIT(i, n) BIT(DT_PROP_BY_IDX(n, if_layers, i)) |
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// Evaluates to conditional_layer_cfg struct initializer.
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#define CONDITIONAL_LAYER_DECL(n) \
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{ \
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/* TODO: Replace UTIL_LISTIFY with DT_FOREACH_PROP_ELEM after Zepyhr 2.6.0 upgrade. */ \
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.if_layers_state_mask = UTIL_LISTIFY(DT_PROP_LEN(n, if_layers), IF_LAYER_BIT, n) 0, \
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.then_layer = DT_PROP(n, then_layer), \
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},
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// All conditional layer configurations in the keymap.
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static const struct conditional_layer_cfg CONDITIONAL_LAYER_CFGS[] = {
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DT_INST_FOREACH_CHILD(0, CONDITIONAL_LAYER_DECL)};
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static const int32_t NUM_CONDITIONAL_LAYER_CFGS =
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sizeof(CONDITIONAL_LAYER_CFGS) / sizeof(*CONDITIONAL_LAYER_CFGS);
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static void conditional_layer_activate(int8_t layer) {
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// This may trigger another event that could, in turn, activate additional then-layers. However,
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// the process will eventually terminate (at worst, when every layer is active).
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if (!zmk_keymap_layer_active(layer)) {
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LOG_DBG("layer %d", layer);
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zmk_keymap_layer_activate(layer);
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}
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}
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static void conditional_layer_deactivate(int8_t layer) {
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// This may deactivate a then-layer that's already active via another mechanism (e.g., a
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// momentary layer behavior). However, the same problem arises when multiple keys with the same
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// &mo binding are held and then one is released, so it's probably not an issue in practice.
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if (zmk_keymap_layer_active(layer)) {
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LOG_DBG("layer %d", layer);
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zmk_keymap_layer_deactivate(layer);
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}
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}
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// On layer state changes, examines each conditional layer config to determine if then-layer in the
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// config should activate based on the currently active set of if-layers.
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static int layer_state_changed_listener(const zmk_event_t *ev) {
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for (int i = 0; i < NUM_CONDITIONAL_LAYER_CFGS; i++) {
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const struct conditional_layer_cfg *cfg = CONDITIONAL_LAYER_CFGS + i;
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zmk_keymap_layers_state_t mask = cfg->if_layers_state_mask;
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// Activate then-layer if and only if all if-layers are already active. Note that we
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// reevaluate the current layer state for each config since activation of one layer can also
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// trigger activation of another.
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if ((zmk_keymap_layer_state() & mask) == mask) {
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conditional_layer_activate(cfg->then_layer);
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} else {
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conditional_layer_deactivate(cfg->then_layer);
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}
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}
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return 0;
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}
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ZMK_LISTENER(conditional_layer, layer_state_changed_listener);
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ZMK_SUBSCRIPTION(conditional_layer, zmk_layer_state_changed);
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#endif
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