Retrieve the flash power level.
camera_error_t camera_get_flash_level(camera_handle_t handle, uint32_t *percent)
The handle returned by a call to the camera_open() function.
A pointer to the returned percentage value.
Use this function to get the available flash power level, as a percentage of the maximum. A non-zero level indicates that there is sufficient power available to fire the flash (see camera_config_flash()).