Type layer_category as Literal everywhere (#454)

* introduce literal

* fix import and properties

* remove LayerCategories

* fix imports

* Update webknossos/Changelog.md

Co-authored-by: Jonathan Striebel <[email protected]>

* rename layer categories

* Update test_dataset.py

Co-authored-by: Jonathan Striebel <[email protected]>

Author: rschwanhold

webknossos/Changelog.md

@@ -62,6 +62,7 @@ For upgrade instructions, please check the respective *Breaking Changes* section
 [Commits](https://github.com/scalableminds/webknossos-cuber/compare/v0.8.16...v0.8.18)
 
 ### Breaking Changes
+- The class `LayerCategories` was removed. `COLOR_TYPE` and `SEGMENTATION_TYPE` were renamed to `COLOR_CATEGORY` and `SEGMENTATION_CATEGORY` and can now be imported directly. The type of many parameters were changed from `str` to the literal `LayerCategoryType`. [#454](https://github.com/scalableminds/webknossos-libs/pull/454)
 ### Added
 - The Dataset class now has a new method: add_shallow_copy. [#437](https://github.com/scalableminds/webknossos-libs/pull/437)
 ### Changed

webknossos/tests/test_buffered_slice_utils.py

@@ -6,7 +6,7 @@
 import numpy as np
 import wkw
 
-from webknossos.dataset import Dataset, LayerCategories
+from webknossos.dataset import COLOR_CATEGORY, Dataset
 from webknossos.geometry import Mag, Vec3Int
 
 TESTOUTPUT_DIR = Path("testoutput")
@@ -28,9 +28,9 @@ def test_buffered_slice_writer() -> None:
 
     delete_dir(dataset_dir)
     ds = Dataset.create(dataset_dir, scale=(1, 1, 1))
-    mag_view = ds.add_layer(
-        "color", LayerCategories.COLOR_TYPE, dtype_per_channel=dtype
-    ).add_mag(mag)
+    mag_view = ds.add_layer("color", COLOR_CATEGORY, dtype_per_channel=dtype).add_mag(
+        mag
+    )
 
     with mag_view.get_buffered_slice_writer(origin) as writer:
         for i in range(13):
@@ -89,9 +89,7 @@ def test_buffered_slice_writer_along_different_axis(tmp_path: Path) -> None:
 
     for dim in [0, 1, 2]:
         ds = Dataset.create(tmp_path / f"buffered_slice_writer_{dim}", scale=(1, 1, 1))
-        mag_view = ds.add_layer(
-            "color", LayerCategories.COLOR_TYPE, num_channels=3
-        ).add_mag(1)
+        mag_view = ds.add_layer("color", COLOR_CATEGORY, num_channels=3).add_mag(1)
 
         with mag_view.get_buffered_slice_writer(
             offset, buffer_size=5, dimension=dim
@@ -116,9 +114,7 @@ def test_buffered_slice_reader_along_different_axis(tmp_path: Path) -> None:
 
     for dim in [0, 1, 2]:
         ds = Dataset.create(tmp_path / f"buffered_slice_reader_{dim}", scale=(1, 1, 1))
-        mag_view = ds.add_layer(
-            "color", LayerCategories.COLOR_TYPE, num_channels=3
-        ).add_mag(1)
+        mag_view = ds.add_layer("color", COLOR_CATEGORY, num_channels=3).add_mag(1)
         mag_view.write(test_cube, offset=offset)
 
         with mag_view.get_buffered_slice_reader(