PERF: delay rarely used imports from visualization.api submodule

yt/tests/test_external_frontends.py

@@ -1,3 +1,4 @@
+import importlib.metadata
 import sys
 
 import pytest
@@ -39,7 +40,7 @@ def mock_entry_points(group=None):
         else:
             return {"yt.frontends": [MockEntryPoint]}
 
-    monkeypatch.setattr(yt.loaders, "entry_points", mock_entry_points)
+    monkeypatch.setattr(importlib.metadata, "entry_points", mock_entry_points)
     assert "ExtDataset" not in output_type_registry
 
     yield

yt/visualization/fixed_resolution.py

@@ -10,10 +10,6 @@
 from yt.frontends.ytdata.utilities import save_as_dataset
 from yt.funcs import get_output_filename, iter_fields, mylog
 from yt.loaders import load_uniform_grid
-from yt.utilities.lib.api import (  # type: ignore
-    CICDeposit_2,
-    add_points_to_greyscale_image,
-)
 from yt.utilities.lib.pixelization_routines import (
     pixelize_cylinder,
     rotate_particle_coord,
@@ -702,6 +698,8 @@ def __getitem__(self, item):
         if item in self.data:
             return self.data[item]
 
+        from yt.utilities.lib.api import CICDeposit_2, add_points_to_greyscale_image
+
         deposition = self.data_source.deposition
         density = self.data_source.density
 

yt/visualization/plot_modifications.py

@@ -14,12 +14,10 @@
 from yt._maintenance.deprecation import issue_deprecation_warning
 from yt._typing import AnyFieldKey, FieldKey
 from yt.data_objects.data_containers import YTDataContainer
-from yt.data_objects.level_sets.clump_handling import Clump
 from yt.data_objects.selection_objects.cut_region import YTCutRegion
 from yt.frontends.ytdata.data_structures import YTClumpContainer
 from yt.funcs import is_sequence, mylog, validate_width_tuple
 from yt.geometry.api import Geometry
-from yt.geometry.unstructured_mesh_handler import UnstructuredIndex
 from yt.units import dimensions
 from yt.units.yt_array import YTArray, YTQuantity, uhstack  # type: ignore
 from yt.utilities.exceptions import (
@@ -29,8 +27,6 @@
     YTUnsupportedPlotCallback,
 )
 from yt.utilities.lib.geometry_utils import triangle_plane_intersect
-from yt.utilities.lib.line_integral_convolution import line_integral_convolution_2d
-from yt.utilities.lib.mesh_triangulation import triangulate_indices
 from yt.utilities.lib.pixelization_routines import (
     pixelize_cartesian,
     pixelize_off_axis_cartesian,
@@ -1628,6 +1624,8 @@ def __init__(self, clumps, *, plot_args=None, **kwargs):
         self.plot_args = plot_args
 
     def __call__(self, plot):
+        from yt.data_objects.level_sets.clump_handling import Clump
+
         bounds = self._physical_bounds(plot)
         extent = self._plot_bounds(plot)
 
@@ -2391,6 +2389,9 @@ def promote_2d_to_3d(self, coords, indices, plot):
         return new_coords, new_connects
 
     def __call__(self, plot):
+        from yt.geometry.unstructured_mesh_handler import UnstructuredIndex
+        from yt.utilities.lib.mesh_triangulation import triangulate_indices
+
         index = plot.ds.index
         if not issubclass(type(index), UnstructuredIndex):
             raise RuntimeError(
@@ -3199,6 +3200,10 @@ def __init__(
     def __call__(self, plot):
         from matplotlib import cm
 
+        from yt.utilities.lib.line_integral_convolution import (
+            line_integral_convolution_2d,
+        )
+
         bounds = self._physical_bounds(plot)
         extent = self._plot_bounds(plot)