feat(underglow): Convert HSB changes to absolute.

* Public type for HSB led color.
* New API for calculating "next" HSB based on current
  state.
* Update behavior to convert the increment/decrement
  commands to absolute command as well.

app/include/dt-bindings/zmk/rgb.h

@@ -32,5 +32,6 @@
 #define RGB_SPD RGB_SPD_CMD 0
 #define RGB_EFF RGB_EFF_CMD 0
 #define RGB_EFR RGB_EFR_CMD 0
-#define RGB_COLOR_HSB(h, s, v) RGB_COLOR_HSB_CMD(((h) << 16) + ((s) << 8) + (v))
+#define RGB_COLOR_HSB_VAL(h, s, v) (((h) << 16) + ((s) << 8) + (v))
+#define RGB_COLOR_HSB(h, s, v) RGB_COLOR_HSB_CMD##(RGB_COLOR_HSB_VAL(h, s, v))
 #define RGB_COLOR_HSV RGB_COLOR_HSB

app/include/zmk/rgb_underglow.h

@@ -6,13 +6,22 @@
 
 #pragma once
 
+struct zmk_led_hsb {
+    uint16_t h;
+    uint8_t s;
+    uint8_t b;
+};
+
 int zmk_rgb_underglow_toggle();
 int zmk_rgb_underglow_get_state(bool *state);
 int zmk_rgb_underglow_on();
 int zmk_rgb_underglow_off();
 int zmk_rgb_underglow_cycle_effect(int direction);
+struct zmk_led_hsb zmk_rgb_underglow_calc_hue(int direction);
+struct zmk_led_hsb zmk_rgb_underglow_calc_sat(int direction);
+struct zmk_led_hsb zmk_rgb_underglow_calc_brt(int direction);
 int zmk_rgb_underglow_change_hue(int direction);
 int zmk_rgb_underglow_change_sat(int direction);
 int zmk_rgb_underglow_change_brt(int direction);
 int zmk_rgb_underglow_change_spd(int direction);
-int zmk_rgb_underglow_set_hsb(uint16_t hue, uint8_t saturation, uint8_t brightness);
+int zmk_rgb_underglow_set_hsb(struct zmk_led_hsb color);

app/src/behaviors/behavior_rgb_underglow.c

@@ -33,12 +33,57 @@ on_keymap_binding_convert_central_state_dependent_params(struct zmk_behavior_bin
         }
 
         binding->param1 = state ? RGB_OFF_CMD : RGB_ON_CMD;
-        LOG_DBG("RGB relative toggle convert to absolute %s", state ? "OFF" : "ON");
-        return 0;
+        break;
+    }
+    case RGB_BRI_CMD: {
+        struct zmk_led_hsb color = zmk_rgb_underglow_calc_brt(1);
+
+        binding->param1 = RGB_COLOR_HSB_CMD;
+        binding->param2 = RGB_COLOR_HSB_VAL(color.h, color.s, color.b);
+        break;
+    }
+    case RGB_BRD_CMD: {
+        struct zmk_led_hsb color = zmk_rgb_underglow_calc_brt(-1);
+
+        binding->param1 = RGB_COLOR_HSB_CMD;
+        binding->param2 = RGB_COLOR_HSB_VAL(color.h, color.s, color.b);
+        break;
+    }
+    case RGB_HUI_CMD: {
+        struct zmk_led_hsb color = zmk_rgb_underglow_calc_hue(1);
+
+        binding->param1 = RGB_COLOR_HSB_CMD;
+        binding->param2 = RGB_COLOR_HSB_VAL(color.h, color.s, color.b);
+        break;
+    }
+    case RGB_HUD_CMD: {
+        struct zmk_led_hsb color = zmk_rgb_underglow_calc_hue(-1);
+
+        binding->param1 = RGB_COLOR_HSB_CMD;
+        binding->param2 = RGB_COLOR_HSB_VAL(color.h, color.s, color.b);
+        break;
+    }
+    case RGB_SAI_CMD: {
+        struct zmk_led_hsb color = zmk_rgb_underglow_calc_sat(1);
+
+        binding->param1 = RGB_COLOR_HSB_CMD;
+        binding->param2 = RGB_COLOR_HSB_VAL(color.h, color.s, color.b);
+        break;
+    }
+    case RGB_SAD_CMD: {
+        struct zmk_led_hsb color = zmk_rgb_underglow_calc_sat(-1);
+
+        binding->param1 = RGB_COLOR_HSB_CMD;
+        binding->param2 = RGB_COLOR_HSB_VAL(color.h, color.s, color.b);
+        break;
     }
     default:
         return 0;
     }
+
+    LOG_DBG("RGB relative convert to absolute (%d/%d)", binding->param1, binding->param2);
+
+    return 0;
 };
 
 static int on_keymap_binding_pressed(struct zmk_behavior_binding *binding,
@@ -71,8 +116,9 @@ static int on_keymap_binding_pressed(struct zmk_behavior_binding *binding,
     case RGB_EFR_CMD:
         return zmk_rgb_underglow_cycle_effect(-1);
     case RGB_COLOR_HSB_CMD:
-        return zmk_rgb_underglow_set_hsb((binding->param2 >> 16) & 0xFFFF,
-                                         (binding->param2 >> 8) & 0xFF, binding->param2 & 0xFF);
+        return zmk_rgb_underglow_set_hsb((struct zmk_led_hsb){.h = (binding->param2 >> 16) & 0xFFFF,
+                                                              .s = (binding->param2 >> 8) & 0xFF,
+                                                              .b = binding->param2 & 0xFF});
     }
 
     return -ENOTSUP;

app/src/rgb_underglow.c

@@ -17,11 +17,17 @@
 #include <drivers/led_strip.h>
 #include <drivers/ext_power.h>
 
+#include <zmk/rgb_underglow.h>
+
 LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
 #define STRIP_LABEL DT_LABEL(DT_CHOSEN(zmk_underglow))
 #define STRIP_NUM_PIXELS DT_PROP(DT_CHOSEN(zmk_underglow), chain_length)
 
+#define HUE_MAX 360
+#define SAT_MAX 100
+#define BRT_MAX 100
+
 enum rgb_underglow_effect {
     UNDERGLOW_EFFECT_SOLID,
     UNDERGLOW_EFFECT_BREATHE,
@@ -30,16 +36,8 @@ enum rgb_underglow_effect {
     UNDERGLOW_EFFECT_NUMBER // Used to track number of underglow effects
 };
 
-struct led_hsb {
-    uint16_t h;
-    uint8_t s;
-    uint8_t b;
-};
-
 struct rgb_underglow_state {
-    uint16_t hue;
-    uint8_t saturation;
-    uint8_t brightness;
+    struct zmk_led_hsb color;
     uint8_t animation_speed;
     uint8_t current_effect;
     uint16_t animation_step;
@@ -56,13 +54,13 @@ static struct rgb_underglow_state state;
 static const struct device *ext_power;
 #endif
 
-static struct led_rgb hsb_to_rgb(struct led_hsb hsb) {
+static struct led_rgb hsb_to_rgb(struct zmk_led_hsb hsb) {
     double r, g, b;
 
     uint8_t i = hsb.h / 60;
-    double v = hsb.b / 100.0;
-    double s = hsb.s / 100.0;
-    double f = hsb.h / 360.0 * 6 - i;
+    double v = hsb.b / ((float)BRT_MAX);
+    double s = hsb.s / ((float)SAT_MAX);
+    double f = hsb.h / ((float)HUE_MAX) * 6 - i;
     double p = v * (1 - s);
     double q = v * (1 - f * s);
     double t = v * (1 - (1 - f) * s);
@@ -107,23 +105,14 @@ static struct led_rgb hsb_to_rgb(struct led_hsb hsb) {
 
 static void zmk_rgb_underglow_effect_solid() {
     for (int i = 0; i < STRIP_NUM_PIXELS; i++) {
-        int hue = state.hue;
-        int sat = state.saturation;
-        int brt = state.brightness;
-
-        struct led_hsb hsb = {hue, sat, brt};
-
-        pixels[i] = hsb_to_rgb(hsb);
+        pixels[i] = hsb_to_rgb(state.color);
     }
 }
 
 static void zmk_rgb_underglow_effect_breathe() {
     for (int i = 0; i < STRIP_NUM_PIXELS; i++) {
-        int hue = state.hue;
-        int sat = state.saturation;
-        int brt = abs(state.animation_step - 1200) / 12;
-
-        struct led_hsb hsb = {hue, sat, brt};
+        struct zmk_led_hsb hsb = state.color;
+        hsb.b = abs(state.animation_step - 1200) / 12;
 
         pixels[i] = hsb_to_rgb(hsb);
     }
@@ -137,32 +126,26 @@ static void zmk_rgb_underglow_effect_breathe() {
 
 static void zmk_rgb_underglow_effect_spectrum() {
     for (int i = 0; i < STRIP_NUM_PIXELS; i++) {
-        int hue = state.animation_step;
-        int sat = state.saturation;
-        int brt = state.brightness;
-
-        struct led_hsb hsb = {hue, sat, brt};
+        struct zmk_led_hsb hsb = state.color;
+        hsb.h = state.animation_step;
 
         pixels[i] = hsb_to_rgb(hsb);
     }
 
     state.animation_step += state.animation_speed;
-    state.animation_step = state.animation_step % 360;
+    state.animation_step = state.animation_step % HUE_MAX;
 }
 
 static void zmk_rgb_underglow_effect_swirl() {
     for (int i = 0; i < STRIP_NUM_PIXELS; i++) {
-        int hue = (360 / STRIP_NUM_PIXELS * i + state.animation_step) % 360;
-        int sat = state.saturation;
-        int brt = state.brightness;
-
-        struct led_hsb hsb = {hue, sat, brt};
+        struct zmk_led_hsb hsb = state.color;
+        hsb.h = (HUE_MAX / STRIP_NUM_PIXELS * i + state.animation_step) % HUE_MAX;
 
         pixels[i] = hsb_to_rgb(hsb);
     }
 
     state.animation_step += state.animation_speed * 2;
-    state.animation_step = state.animation_step % 360;
+    state.animation_step = state.animation_step % HUE_MAX;
 }
 
 static void zmk_rgb_underglow_tick(struct k_work *work) {
@@ -243,9 +226,11 @@ static int zmk_rgb_underglow_init(const struct device *_arg) {
 #endif
 
     state = (struct rgb_underglow_state){
-        hue : CONFIG_ZMK_RGB_UNDERGLOW_HUE_START,
-        saturation : CONFIG_ZMK_RGB_UNDERGLOW_SAT_START,
-        brightness : CONFIG_ZMK_RGB_UNDERGLOW_BRT_START,
+        color : {
+            h : CONFIG_ZMK_RGB_UNDERGLOW_HUE_START,
+            s : CONFIG_ZMK_RGB_UNDERGLOW_SAT_START,
+            b : CONFIG_ZMK_RGB_UNDERGLOW_BRT_START,
+        },
         animation_speed : CONFIG_ZMK_RGB_UNDERGLOW_SPD_START,
         current_effect : CONFIG_ZMK_RGB_UNDERGLOW_EFF_START,
         animation_step : 0,
@@ -337,16 +322,8 @@ int zmk_rgb_underglow_cycle_effect(int direction) {
     if (!led_strip)
         return -ENODEV;
 
-    if (state.current_effect == 0 && direction < 0) {
-        state.current_effect = UNDERGLOW_EFFECT_NUMBER - 1;
-        return 0;
-    }
-
-    state.current_effect += direction;
-
-    if (state.current_effect >= UNDERGLOW_EFFECT_NUMBER) {
-        state.current_effect = 0;
-    }
+    state.current_effect += UNDERGLOW_EFFECT_NUMBER + direction;
+    state.current_effect %= UNDERGLOW_EFFECT_NUMBER;
 
     state.animation_step = 0;
 
@@ -357,30 +334,58 @@ int zmk_rgb_underglow_toggle() {
     return state.on ? zmk_rgb_underglow_off() : zmk_rgb_underglow_on();
 }
 
-int zmk_rgb_underglow_set_hsb(uint16_t hue, uint8_t saturation, uint8_t brightness) {
-    if (hue > 360 || saturation > 100 || brightness > 100) {
+int zmk_rgb_underglow_set_hsb(struct zmk_led_hsb color) {
+    if (color.h > HUE_MAX || color.s > SAT_MAX || color.b > BRT_MAX) {
         return -ENOTSUP;
     }
 
-    state.hue = hue;
-    state.saturation = saturation;
-    state.brightness = brightness;
+    state.color = color;
 
     return 0;
 }
 
+struct zmk_led_hsb zmk_rgb_underglow_calc_hue(int direction) {
+    struct zmk_led_hsb color = state.color;
+
+    color.h += HUE_MAX + (direction * CONFIG_ZMK_RGB_UNDERGLOW_HUE_STEP);
+    color.h %= HUE_MAX;
+
+    return color;
+}
+
+struct zmk_led_hsb zmk_rgb_underglow_calc_sat(int direction) {
+    struct zmk_led_hsb color = state.color;
+
+    int s = color.s + (direction * CONFIG_ZMK_RGB_UNDERGLOW_SAT_STEP);
+    if (s < 0) {
+        s = 0;
+    } else if (s > SAT_MAX) {
+        s = SAT_MAX;
+    }
+    color.s = s;
+
+    return color;
+}
+
+struct zmk_led_hsb zmk_rgb_underglow_calc_brt(int direction) {
+    struct zmk_led_hsb color = state.color;
+
+    int b = color.b + (direction * CONFIG_ZMK_RGB_UNDERGLOW_BRT_STEP);
+    if (b < 0) {
+        b = 0;
+    } else if (b > BRT_MAX) {
+        b = BRT_MAX;
+    }
+    color.b = b;
+
+    return color;
+}
+
 int zmk_rgb_underglow_change_hue(int direction) {
     if (!led_strip)
         return -ENODEV;
 
-    if (state.hue == 0 && direction < 0) {
-        state.hue = 360 - CONFIG_ZMK_RGB_UNDERGLOW_HUE_STEP;
-        return 0;
-    }
-
-    state.hue += direction * CONFIG_ZMK_RGB_UNDERGLOW_HUE_STEP;
-
-    state.hue = state.hue % 360;
+    state.color = zmk_rgb_underglow_calc_hue(direction);
 
     return zmk_rgb_underglow_save_state();
 }
@@ -389,15 +394,7 @@ int zmk_rgb_underglow_change_sat(int direction) {
     if (!led_strip)
         return -ENODEV;
 
-    if (state.saturation == 0 && direction < 0) {
-        return 0;
-    }
-
-    state.saturation += direction * CONFIG_ZMK_RGB_UNDERGLOW_SAT_STEP;
-
-    if (state.saturation > 100) {
-        state.saturation = 100;
-    }
+    state.color = zmk_rgb_underglow_calc_sat(direction);
 
     return zmk_rgb_underglow_save_state();
 }
@@ -406,15 +403,7 @@ int zmk_rgb_underglow_change_brt(int direction) {
     if (!led_strip)
         return -ENODEV;
 
-    if (state.brightness == 0 && direction < 0) {
-        return 0;
-    }
-
-    state.brightness += direction * CONFIG_ZMK_RGB_UNDERGLOW_BRT_STEP;
-
-    if (state.brightness > 100) {
-        state.brightness = 100;
-    }
+    state.color = zmk_rgb_underglow_calc_brt(direction);
 
     return zmk_rgb_underglow_save_state();
 }