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PyDoc: corrections to formatting and resolve warnings

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Use RST formatting for doc-strings used in Python API docs
as well as minor corrections, also add links for foreach_get/set.
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Campbell Barton
2024-08-19 10:48:06 +10:00
parent 7c68ac258f
commit fe6ab4f344
2 changed files with 70 additions and 55 deletions
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119
doc/python_api/examples/bpy.types.Attribute.py
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@@ -1,101 +1,114 @@
"""
Attributes are used to store data that corresponds to geometry elements. Geometry elements are items in one of the geometry domains like points, curves, or faces.
Attributes are used to store data that corresponds to geometry elements.
Geometry elements are items in one of the geometry domains like points, curves, or faces.
An attribute has a ``name``, a ``type``, and is stored on a ``domain``.
``name``
The name of this attribute. Names have to be unique within the same geometry.
If the name starts with a ``.``, the attribute is hidden from the UI.
``type``
The type of data that this attribute stores, e.g. a float, integer, color, etc.
See `Attribute Type Items <bpy_types_enum_items/attribute_type_items.html>`__.
``domain``
The geometry domain that the attribute is stored on.
See `Attribute Domain Items <bpy_types_enum_items/attribute_domain_items.html>`__.
An attribute has a `name`, a `type`, and is stored on a `domain`.
- `name`: The name of this attribute. Names have to be unique within the same geometry. If the name starts with a \".\", the attribute is hidden from the UI.
- `type`: The type of data that this attribute stores, e.g. a float, integer, color, etc. See `Attribute Type Items <bpy_types_enum_items/attribute_type_items.html>`_.
- `domain`: The geomerty domain that the attribute is stored on. See `Attribute Domain Items <bpy_types_enum_items/attribute_domain_items.html>`_.
Using Attributes
++++++++++++++++
Attributes can be stored on geometries like :class:`Mesh`, :class:`Curves`, :class:`PointCloud`, etc.
These geometries have attribute groups (usually called ``attributes``). Using the groups, attributes can then be accessed by their name:
These geometries have attribute groups (usually called ``attributes``).
Using the groups, attributes can then be accessed by their name:
.. code-block:: python
radii = curves.attributes["radius"]
radii = curves.attributes["radius"]
Creating and storing custom attributes is done using the ``attributes.new`` function:
.. code-block:: python
# Add a new attribute named `my_attribute_name` of type `float` on the point domain of the geometry.
my_attribute = curves.attributes.new("my_attribute_name", 'FLOAT', 'POINT')
# Add a new attribute named `my_attribute_name` of type `float` on the point domain of the geometry.
my_attribute = curves.attributes.new("my_attribute_name", 'FLOAT', 'POINT')
Removing attributes can be done like so:
.. code-block:: python
attribute = drawing.attributes["some_attribute"]
drawing.attributes.remove(attribute)
attribute = drawing.attributes["some_attribute"]
drawing.attributes.remove(attribute)
.. note::
Some attributes are required and cannot be removed, like ``"position"``.
Some attributes are required and cannot be removed, like ``"position"``.
Attribute values are read by accessing their ``attribute.data`` collection property.
However, in cases where multiple values should be read at once, it is better to use the ``foreach_get`` function and read the values into a ``numpy`` buffer.
However, in cases where multiple values should be read at once,
it is better to use the :class:`bpy_prop_collection.foreach_get` function and read the values into a ``numpy`` buffer.
.. code-block:: python
import numpy as np
import numpy as np
# Get the radius attribute.
radii = curves.attributes["radius"]
# Print the radius of the first point.
print(radii.data[0].value)
# Output: 0.005
# Get the radius attribute.
radii = curves.attributes["radius"]
# Print the radius of the first point.
print(radii.data[0].value)
# Output: 0.005
# Get the total number of points.
num_points = attributes.domain_size('POINT')
# Create an empty buffer to read all the radii into.
radii_data = np.zeros(num_points, dtype=np.float32)
# Read all the radii of the curves into `radii_data` at once.
radii.data.foreach_get('value', radii_data)
# Print all the radii.
print(radii_data)
# Output: [0.1, 0.2, 0.3, 0.4, ... ]
# Get the total number of points.
num_points = attributes.domain_size('POINT')
# Create an empty buffer to read all the radii into.
radii_data = np.zeros(num_points, dtype=np.float32)
# Read all the radii of the curves into `radii_data` at once.
radii.data.foreach_get('value', radii_data)
# Print all the radii.
print(radii_data)
# Output: [0.1, 0.2, 0.3, 0.4, ... ]
.. note::
Some attribute types use different named properties to access their value.
Instead of ``value``, vectors use ``vector``, and colors use ``color``.
Some attribute types use different named properties to access their value.
Instead of ``value``, vectors use ``vector``, and colors use ``color``.
Writing to different attribute types is very similar. You can simply assign to a value directly.
Again, when writing to multiple values, it is recommended to use the ``foreach_set`` function to write the values from a ``numpy`` buffer.
Again, when writing to multiple values, it is recommended to use the :class:`bpy_prop_collection.foreach_set` function
to write the values from a ``numpy`` buffer.
.. code-block:: python
import numpy as np
import numpy as np
radii = curves.attributes["radius"]
# Write a radius with a value of 0.5 to the first point.
radii.data[0].value = 0.5
print(radii.data[0].value)
# Output: 0.5
radii = curves.attributes["radius"]
# Write a radius with a value of 0.5 to the first point.
radii.data[0].value = 0.5
print(radii.data[0].value)
# Output: 0.5
num_points = attributes.domain_size('POINT')
# Generate random radii with values between 0.001 and 0.05 using numpy.
new_radii = np.random.uniform(0.001, 0.05, num_points)
# Write the new radii to the radius attribute.
radii.data.foreach_set('value', new_radii)
num_points = attributes.domain_size('POINT')
# Generate random radii with values between 0.001 and 0.05 using numpy.
new_radii = np.random.uniform(0.001, 0.05, num_points)
# Write the new radii to the radius attribute.
radii.data.foreach_set('value', new_radii)
The ``foreach_get``/``foreach_set`` methods require a flat array. This is sometimes not desirable, e.g. when reading/writing positions, which are 3D vectors.
The :class:`bpy_prop_collection.foreach_get` / :class:`bpy_prop_collection.foreach_set` methods require a flat array.
This is sometimes not desirable, e.g. when reading/writing positions, which are 3D vectors.
In these cases, it's possible to use ``np.ravel`` to pass the data as a flat array:
.. code-block:: python
num_points = attributes.domain_size('POINT')
positions = curves.attributes['position']
# Here, we're using a numpy array with shape (num_points, 3) so that each
# element is a 3d vector.
positions_data = np.zeros((num_points, 3), dtype=np.float32)
# The `np.ravel` function will pass the `positions_data` as a flat array
# without changing the original shape.
positions.data.foreach_get('vector', np.ravel(positions_data))
print(positions_data)
# Output: [[0.1, 0.2, 0.3], [0.4, 0.5, 0.6], ...]
num_points = attributes.domain_size('POINT')
positions = curves.attributes['position']
# Here, we're using a numpy array with shape (num_points, 3) so that each
# element is a 3d vector.
positions_data = np.zeros((num_points, 3), dtype=np.float32)
# The `np.ravel` function will pass the `positions_data` as a flat array
# without changing the original shape.
positions.data.foreach_get('vector', np.ravel(positions_data))
print(positions_data)
# Output: [[0.1, 0.2, 0.3], [0.4, 0.5, 0.6], ...]
"""

6
scripts/modules/bpy_types.py
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@@ -1405,8 +1405,10 @@ class GreasePencilDrawing(StructRNA):
"""
Return a collection of all the Grease Pencil strokes in this drawing.
.. note:: This API should *not* be used for performance critical operations.
Use the :class:`GreasePencilDrawing.attributes` API instead.
.. note::
This API should *not* be used for performance critical operations.
Use the :class:`GreasePencilDrawing.attributes` API instead.
"""
from grease_pencil_python import GreasePencilStrokeSlice
num_strokes = self.attributes.domain_size('CURVE')