class CustomTissueMask(TissueMask):
    def __init__(self, scale_factor=32):
        self.scale_factor = scale_factor

    def _mask(self, slide):
        img = slide.scaled_image(self.scale_factor)
        filters = FiltersComposition(Slide).tissue_mask_filters
        mask = filters(img)
        return mask
grid_tiles_extractor = GridTiler(
    tile_size=(512, 512),
    level=0,
    check_tissue=False, # default
    pixel_overlap=64, # default
    prefix="grid/", # save tiles in the "grid" subdirectory of slide's processed_path
    suffix=".png" # default
    )
thumb = grid_tiles_extractor.locate_tiles(
    slide=slide,
    extraction_mask=CustomTissueMask(),
    scale_factor=32,
    alpha=200,
    outline="#046C4C",
)
thumb.save("./tmp/1900991B_grid_thumb.png")