qmk_firmware/quantum/rgb_matrix/animations/runners/effect_runner_i.h

#pragma once

typedef HSV (*i_f)(HSV hsv, uint8_t i, uint8_t time);

bool effect_runner_i(effect_params_t* params, i_f effect_func) {
    RGB_MATRIX_USE_LIMITS(led_min, led_max);

    uint8_t time = scale16by8(g_rgb_timer, qadd8(rgb_matrix_config.speed / 4, 1));
    for (uint8_t i = led_min; i < led_max; i++) {
        RGB_MATRIX_TEST_LED_FLAGS();
        RGB rgb = rgb_matrix_hsv_to_rgb(effect_func(rgb_matrix_config.hsv, i, time));
        rgb_matrix_set_color(i, rgb.r, rgb.g, rgb.b);
    }
    return rgb_matrix_check_finished_leds(led_max);
}