qmk_firmware/quantum/led_matrix/animations/cycle_out_in_anim.h

#ifndef DISABLE_LED_MATRIX_CYCLE_OUT_IN
LED_MATRIX_EFFECT(CYCLE_OUT_IN)
#    ifdef LED_MATRIX_CUSTOM_EFFECT_IMPLS

static uint8_t CYCLE_OUT_IN_math(uint8_t val, int16_t dx, int16_t dy, uint8_t dist, uint8_t time) { return scale8(3 * dist / 2 + time, val); }

bool CYCLE_OUT_IN(effect_params_t* params) { return effect_runner_dx_dy_dist(params, &CYCLE_OUT_IN_math); }

#    endif  // LED_MATRIX_CUSTOM_EFFECT_IMPLS
#endif      // DISABLE_LED_MATRIX_CYCLE_OUT_IN