Only rescale points for older napari versions (#33)

napari v0.5 includes a fix to handle expected combinations of point size
and layer scale. Previously, we worked around that issue by rescaling
the point sizes ourselves. After this PR, we only do that for older
versions of napari. The check is cached to avoid spamming the logs.

Alternatively, we could require `napari>=0.5` in `setup.cfg`. I decided
to support both versions for now, since v0.5 is quite new and comes with
a few of its own new bugs.

This was tested manually by installing v0.4.19 and v0.5.2 of napari and
visually inspecting the resulting point sizes.

src/napari_cryoet_data_portal/_open_widget.py

@@ -1,7 +1,9 @@
 from dataclasses import dataclass
+from functools import lru_cache
 from typing import TYPE_CHECKING, Generator, Optional, Tuple
 
 import numpy as np
+from cryoet_data_portal import Annotation, Client, Tomogram
 from npe2.types import FullLayerData
 from qtpy.QtCore import Qt
 from qtpy.QtWidgets import (
@@ -14,7 +16,6 @@
     QVBoxLayout,
     QWidget,
 )
-from cryoet_data_portal import Annotation, Client, Tomogram
 
 from napari_cryoet_data_portal._logging import logger
 from napari_cryoet_data_portal._progress_widget import ProgressWidget
@@ -139,8 +140,11 @@ def _loadTomogram(
         # A single client is not thread safe, so we need a new instance for each query.
         client = Client(self._uri)
         annotations = Annotation.find(
-            client, 
-            [Annotation.tomogram_voxel_spacing_id == tomogram.tomogram_voxel_spacing_id],
+            client,
+            [
+                Annotation.tomogram_voxel_spacing_id
+                == tomogram.tomogram_voxel_spacing_id
+            ],
         )
 
         for annotation in annotations:
@@ -164,7 +168,9 @@ def _onLayerLoaded(self, layer_data: FullLayerData) -> None:
             raise AssertionError(f"Unexpected {layer_type=}")
 
 
-def _handle_image_at_resolution(layer_data: FullLayerData, resolution: Resolution) -> FullLayerData:
+def _handle_image_at_resolution(
+    layer_data: FullLayerData, resolution: Resolution
+) -> FullLayerData:
     data, attrs, layer_type = layer_data
     # Skip indexing for multi-resolution to avoid adding any
     # unnecessary nodes to the dask compute graph.
@@ -191,11 +197,42 @@ def _handle_image_at_resolution(layer_data: FullLayerData, resolution: Resolutio
     return data, attrs, layer_type
 
 
-def _handle_points_at_scale(layer_data: FullLayerData, image_scale: Tuple[float, float, float]) -> FullLayerData:
+def _handle_points_at_scale(
+    layer_data: FullLayerData, image_scale: Tuple[float, float, float]
+) -> FullLayerData:
     data, attrs, layer_type = layer_data
     # Inherit scale from full resolution image, so that points are visually
     # aligned with the image.
     attrs["scale"] = image_scale
-    # Scaling points also changes the size, so adjust accordingly.
-    attrs["size"] /= np.mean(image_scale)
-    return data, attrs, layer_type
+    # Scaling points also changes the size in some version of napari, so adjust accordingly.
+    if _is_napari_version_less_than("0.5"):
+        attrs["size"] /= np.mean(image_scale)
+    return data, attrs, layer_type
+
+
+@lru_cache(maxsize=None)
+def _is_napari_version_less_than(version: str) -> bool:
+    try:
+        import napari
+    except ImportError:
+        logger.warn("Failed to import napari")
+        return False
+    try:
+        from packaging.version import InvalidVersion, Version
+    except ImportError:
+        logger.warn("Failed to import packaging")
+        return False
+    try:
+        actual_version = Version(napari.__version__)
+    except InvalidVersion:
+        logger.warn(
+            "Failed to parse actual napari version from %s ",
+            napari.__version__,
+        )
+        return False
+    try:
+        target_version = Version(version)
+    except InvalidVersion:
+        logger.warn("Failed to parse target napari version from %s", version)
+        return False
+    return actual_version < target_version