Function lv_draw_layer_create 

pub unsafe extern "C" fn lv_draw_layer_create(
    parent_layer: *mut lv_layer_t,
    color_format: lv_color_format_t,
    area: *const lv_area_t,
) -> *mut lv_layer_t

Create (allocate) a new layer on a parent layer @param parent_layer the parent layer to which the layer will be merged when it’s rendered @param color_format the color format of the layer @param area the areas of the layer (absolute coordinates) @return the new target_layer or NULL on error