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callbacks

sleap_io.rendering.callbacks

Callback context classes for custom rendering.

This module provides context objects that are passed to user-defined callbacks during rendering, giving access to the Skia canvas and rendering metadata.

Classes:

Name Description
InstanceContext

Context passed to per-instance callbacks.
RenderContext

Context passed to pre/post render callbacks.

Attributes:

Name Type Description
TYPE_CHECKING

Returns True when the argument is true, False otherwise.
__cached__

str(object='') -> str
__doc__

str(object='') -> str
__file__

str(object='') -> str
__name__

str(object='') -> str
__package__

str(object='') -> str

TYPE_CHECKING = False module-attribute

Returns True when the argument is true, False otherwise. The builtins True and False are the only two instances of the class bool. The class bool is a subclass of the class int, and cannot be subclassed.

__cached__ = '/home/runner/work/sleap-io/sleap-io/sleap_io/rendering/__pycache__/callbacks.cpython-313.pyc' module-attribute

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

__doc__ = 'Callback context classes for custom rendering.\n\nThis module provides context objects that are passed to user-defined callbacks\nduring rendering, giving access to the Skia canvas and rendering metadata.\n' module-attribute

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

__file__ = '/home/runner/work/sleap-io/sleap-io/sleap_io/rendering/callbacks.py' module-attribute

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

__name__ = 'sleap_io.rendering.callbacks' module-attribute

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

__package__ = 'sleap_io.rendering' module-attribute

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

InstanceContext

Context passed to per-instance callbacks.

This context provides access to the Skia canvas and instance-level metadata for drawing custom overlays after each instance is rendered.

Attributes:

Name Type Description
canvas

Skia canvas for drawing.
instance_idx

Index of this instance within the frame.
points

(n_nodes, 2) array of keypoint coordinates.
track_id

Track ID if assigned, else None.
track_name

Track name string if available.
confidence

Instance confidence score if available.
skeleton_edges

Edge connectivity as list of (src, dst) tuples.
node_names

List of node name strings.
scale

Current scale factor for rendering.
offset

Current offset (x, y) for cropped/zoomed views.

Methods:

Name Description
__eq__

Method generated by attrs for class InstanceContext.
__init__

Method generated by attrs for class InstanceContext.
__repr__

Method generated by attrs for class InstanceContext.
get_bbox

Get bounding box of valid points.
get_centroid

Get centroid of valid points.
world_to_canvas

Transform world coordinates to canvas coordinates.
Source code in sleap_io/rendering/callbacks.py 
@define
class InstanceContext:
    """Context passed to per-instance callbacks.

    This context provides access to the Skia canvas and instance-level metadata
    for drawing custom overlays after each instance is rendered.

    Attributes:
        canvas: Skia canvas for drawing.
        instance_idx: Index of this instance within the frame.
        points: (n_nodes, 2) array of keypoint coordinates.
        track_id: Track ID if assigned, else None.
        track_name: Track name string if available.
        confidence: Instance confidence score if available.
        skeleton_edges: Edge connectivity as list of (src, dst) tuples.
        node_names: List of node name strings.
        scale: Current scale factor for rendering.
        offset: Current offset (x, y) for cropped/zoomed views.
    """

    canvas: "skia.Canvas"
    instance_idx: int
    points: np.ndarray
    skeleton_edges: list[tuple[int, int]]
    node_names: list[str]
    track_id: int | None = None
    track_name: str | None = None
    confidence: float | None = None
    scale: float = 1.0
    offset: tuple[float, float] = (0.0, 0.0)

    def world_to_canvas(self, x: float, y: float) -> tuple[float, float]:
        """Transform world coordinates to canvas coordinates.

        Args:
            x: X coordinate in world/frame space.
            y: Y coordinate in world/frame space.

        Returns:
            (x, y) coordinates in canvas space.
        """
        return (
            (x - self.offset[0]) * self.scale,
            (y - self.offset[1]) * self.scale,
        )

    def get_centroid(self) -> tuple[float, float] | None:
        """Get centroid of valid points.

        Returns:
            (x, y) mean of valid (non-NaN) points, or None if all invalid.
        """
        valid_mask = np.isfinite(self.points).all(axis=1)
        valid_points = self.points[valid_mask]
        if len(valid_points) == 0:
            return None
        mean_pt = valid_points.mean(axis=0)
        return (float(mean_pt[0]), float(mean_pt[1]))

    def get_bbox(self) -> tuple[float, float, float, float] | None:
        """Get bounding box of valid points.

        Returns:
            (x1, y1, x2, y2) bounding box, or None if no valid points.
        """
        valid_mask = np.isfinite(self.points).all(axis=1)
        valid_points = self.points[valid_mask]
        if len(valid_points) == 0:
            return None
        return (
            float(valid_points[:, 0].min()),
            float(valid_points[:, 1].min()),
            float(valid_points[:, 0].max()),
            float(valid_points[:, 1].max()),
        )

__annotations__ = {'canvas': "'skia.Canvas'", 'instance_idx': 'int', 'points': 'np.ndarray', 'skeleton_edges': 'list[tuple[int, int]]', 'node_names': 'list[str]', 'track_id': 'int | None', 'track_name': 'str | None', 'confidence': 'float | None', 'scale': 'float', 'offset': 'tuple[float, float]'} class-attribute

dict() -> new empty dictionary dict(mapping) -> new dictionary initialized from a mapping object's (key, value) pairs dict(iterable) -> new dictionary initialized as if via: d = {} for k, v in iterable: d[k] = v dict(**kwargs) -> new dictionary initialized with the name=value pairs in the keyword argument list. For example: dict(one=1, two=2)

__attrs_own_setattr__ = False class-attribute

Returns True when the argument is true, False otherwise. The builtins True and False are the only two instances of the class bool. The class bool is a subclass of the class int, and cannot be subclassed.

__attrs_props__ = ClassProps(is_exception=False, is_slotted=True, has_weakref_slot=True, is_frozen=False, kw_only=<KeywordOnly.NO: 'no'>, collected_fields_by_mro=True, added_init=True, added_repr=True, added_eq=True, added_ordering=False, hashability=<Hashability.UNHASHABLE: 'unhashable'>, added_match_args=True, added_str=False, added_pickling=True, on_setattr_hook=<function pipe.<locals>.wrapped_pipe at 0x7f08471ce840>, field_transformer=None) class-attribute

Effective class properties as derived from parameters to attr.s() or define() decorators.

This is the same data structure that attrs uses internally to decide how to construct the final class.

Warning:

This feature is currently **experimental** and is not covered by our
strict backwards-compatibility guarantees.

Attributes:

Name Type Description
is_exception bool

Whether the class is treated as an exception class.
is_slotted bool

Whether the class is slotted <slotted classes>.
has_weakref_slot bool

Whether the class has a slot for weak references.
is_frozen bool

Whether the class is frozen.
kw_only KeywordOnly

Whether / how the class enforces keyword-only arguments on the __init__ method.
collected_fields_by_mro bool

Whether the class fields were collected by method resolution order. That is, correctly but unlike dataclasses.
added_init bool

Whether the class has an attrs-generated __init__ method.
added_repr bool

Whether the class has an attrs-generated __repr__ method.
added_eq bool

Whether the class has attrs-generated equality methods.
added_ordering bool

Whether the class has attrs-generated ordering methods.
hashability Hashability

How hashable <hashing> the class is.
added_match_args bool

Whether the class supports positional match <match> over its fields.
added_str bool

Whether the class has an attrs-generated __str__ method.
added_pickling bool

Whether the class has attrs-generated __getstate__ and __setstate__ methods for pickle.
on_setattr_hook Callable[[Any, Attribute[Any], Any], Any] | None

The class's __setattr__ hook.
field_transformer Callable[[Attribute[Any]], Attribute[Any]] | None

The class's field transformers <transform-fields>.

.. versionadded:: 25.4.0

__doc__ = 'Context passed to per-instance callbacks.\n\nThis context provides access to the Skia canvas and instance-level metadata\nfor drawing custom overlays after each instance is rendered.\n\nAttributes:\n canvas: Skia canvas for drawing.\n instance_idx: Index of this instance within the frame.\n points: (n_nodes, 2) array of keypoint coordinates.\n track_id: Track ID if assigned, else None.\n track_name: Track name string if available.\n confidence: Instance confidence score if available.\n skeleton_edges: Edge connectivity as list of (src, dst) tuples.\n node_names: List of node name strings.\n scale: Current scale factor for rendering.\n offset: Current offset (x, y) for cropped/zoomed views.\n' class-attribute

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

__firstlineno__ = 61 class-attribute

int([x]) -> integer int(x, base=10) -> integer

Convert a number or string to an integer, or return 0 if no arguments are given. If x is a number, return x.int(). For floating-point numbers, this truncates towards zero.

If x is not a number or if base is given, then x must be a string, bytes, or bytearray instance representing an integer literal in the given base. The literal can be preceded by '+' or '-' and be surrounded by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to interpret the base from the string as an integer iteral.

int('0b100', base=0) 4

__match_args__ = ('canvas', 'instance_idx', 'points', 'skeleton_edges', 'node_names', 'track_id', 'track_name', 'confidence', 'scale', 'offset') class-attribute

Built-in immutable sequence.

If no argument is given, the constructor returns an empty tuple. If iterable is specified the tuple is initialized from iterable's items.

If the argument is a tuple, the return value is the same object.

__module__ = 'sleap_io.rendering.callbacks' class-attribute

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

__slots__ = ('canvas', 'instance_idx', 'points', 'skeleton_edges', 'node_names', 'track_id', 'track_name', 'confidence', 'scale', 'offset', '__weakref__') class-attribute

Built-in immutable sequence.

If no argument is given, the constructor returns an empty tuple. If iterable is specified the tuple is initialized from iterable's items.

If the argument is a tuple, the return value is the same object.

__static_attributes__ = () class-attribute

Built-in immutable sequence.

If no argument is given, the constructor returns an empty tuple. If iterable is specified the tuple is initialized from iterable's items.

If the argument is a tuple, the return value is the same object.

__weakref__ property

list of weak references to the object

__eq__(other)

Method generated by attrs for class InstanceContext.

Source code in sleap_io/rendering/callbacks.py 
@define
class RenderContext:
    """Context passed to pre/post render callbacks.

    This context provides access to the Skia canvas and frame-level metadata
    for drawing custom overlays before or after pose rendering.

    Attributes:
        canvas: Skia canvas for drawing.
        frame_idx: Current frame index.
        frame_size: (width, height) tuple of original frame dimensions.
        instances: List of instances in this frame.
        skeleton_edges: Edge connectivity as list of (src, dst) tuples.

__init__(canvas, instance_idx, points, skeleton_edges, node_names, track_id=None, track_name=None, confidence=None, scale=1.0, offset=(0.0, 0.0))

Method generated by attrs for class InstanceContext.

Source code in sleap_io/rendering/callbacks.py 
    node_names: List of node name strings.
    scale: Current scale factor for rendering.
    offset: Current offset (x, y) for cropped/zoomed views.
"""

canvas: "skia.Canvas"
frame_idx: int
frame_size: tuple[int, int]
instances: list
skeleton_edges: list[tuple[int, int]]
node_names: list[str]

__repr__()

Method generated by attrs for class InstanceContext.

Source code in sleap_io/rendering/callbacks.py 
"""Callback context classes for custom rendering.

This module provides context objects that are passed to user-defined callbacks
during rendering, giving access to the Skia canvas and rendering metadata.
"""

from __future__ import annotations

from typing import TYPE_CHECKING

import numpy as np
from attrs import define

if TYPE_CHECKING:
    import skia

get_bbox()

Get bounding box of valid points.

Returns:

Type Description
tuple[float, float, float, float] | None

(x1, y1, x2, y2) bounding box, or None if no valid points.
Source code in sleap_io/rendering/callbacks.py 
def get_bbox(self) -> tuple[float, float, float, float] | None:
    """Get bounding box of valid points.

    Returns:
        (x1, y1, x2, y2) bounding box, or None if no valid points.
    """
    valid_mask = np.isfinite(self.points).all(axis=1)
    valid_points = self.points[valid_mask]
    if len(valid_points) == 0:
        return None
    return (
        float(valid_points[:, 0].min()),
        float(valid_points[:, 1].min()),
        float(valid_points[:, 0].max()),
        float(valid_points[:, 1].max()),
    )

get_centroid()

Get centroid of valid points.

Returns:

Type Description
tuple[float, float] | None

(x, y) mean of valid (non-NaN) points, or None if all invalid.
Source code in sleap_io/rendering/callbacks.py 
def get_centroid(self) -> tuple[float, float] | None:
    """Get centroid of valid points.

    Returns:
        (x, y) mean of valid (non-NaN) points, or None if all invalid.
    """
    valid_mask = np.isfinite(self.points).all(axis=1)
    valid_points = self.points[valid_mask]
    if len(valid_points) == 0:
        return None
    mean_pt = valid_points.mean(axis=0)
    return (float(mean_pt[0]), float(mean_pt[1]))

world_to_canvas(x, y)

Transform world coordinates to canvas coordinates.

Parameters:

Name Type Description Default
x float

X coordinate in world/frame space.

 required
y float

Y coordinate in world/frame space.

 required

Returns:

Type Description
tuple[float, float]

(x, y) coordinates in canvas space.
Source code in sleap_io/rendering/callbacks.py 
def world_to_canvas(self, x: float, y: float) -> tuple[float, float]:
    """Transform world coordinates to canvas coordinates.

    Args:
        x: X coordinate in world/frame space.
        y: Y coordinate in world/frame space.

    Returns:
        (x, y) coordinates in canvas space.
    """
    return (
        (x - self.offset[0]) * self.scale,
        (y - self.offset[1]) * self.scale,
    )

RenderContext

Context passed to pre/post render callbacks.

This context provides access to the Skia canvas and frame-level metadata for drawing custom overlays before or after pose rendering.

Attributes:

Name Type Description
canvas

Skia canvas for drawing.
frame_idx

Current frame index.
frame_size

(width, height) tuple of original frame dimensions.
instances

List of instances in this frame.
skeleton_edges

Edge connectivity as list of (src, dst) tuples.
node_names

List of node name strings.
scale

Current scale factor for rendering.
offset

Current offset (x, y) for cropped/zoomed views.

Methods:

Name Description
__eq__

Method generated by attrs for class RenderContext.
__init__

Method generated by attrs for class RenderContext.
__repr__

Method generated by attrs for class RenderContext.
world_to_canvas

Transform world coordinates to canvas coordinates.
Source code in sleap_io/rendering/callbacks.py 
@define
class RenderContext:
    """Context passed to pre/post render callbacks.

    This context provides access to the Skia canvas and frame-level metadata
    for drawing custom overlays before or after pose rendering.

    Attributes:
        canvas: Skia canvas for drawing.
        frame_idx: Current frame index.
        frame_size: (width, height) tuple of original frame dimensions.
        instances: List of instances in this frame.
        skeleton_edges: Edge connectivity as list of (src, dst) tuples.
        node_names: List of node name strings.
        scale: Current scale factor for rendering.
        offset: Current offset (x, y) for cropped/zoomed views.
    """

    canvas: "skia.Canvas"
    frame_idx: int
    frame_size: tuple[int, int]
    instances: list
    skeleton_edges: list[tuple[int, int]]
    node_names: list[str]
    scale: float = 1.0
    offset: tuple[float, float] = (0.0, 0.0)

    def world_to_canvas(self, x: float, y: float) -> tuple[float, float]:
        """Transform world coordinates to canvas coordinates.

        Args:
            x: X coordinate in world/frame space.
            y: Y coordinate in world/frame space.

        Returns:
            (x, y) coordinates in canvas space.
        """
        return (
            (x - self.offset[0]) * self.scale,
            (y - self.offset[1]) * self.scale,
        )

__annotations__ = {'canvas': "'skia.Canvas'", 'frame_idx': 'int', 'frame_size': 'tuple[int, int]', 'instances': 'list', 'skeleton_edges': 'list[tuple[int, int]]', 'node_names': 'list[str]', 'scale': 'float', 'offset': 'tuple[float, float]'} class-attribute

dict() -> new empty dictionary dict(mapping) -> new dictionary initialized from a mapping object's (key, value) pairs dict(iterable) -> new dictionary initialized as if via: d = {} for k, v in iterable: d[k] = v dict(**kwargs) -> new dictionary initialized with the name=value pairs in the keyword argument list. For example: dict(one=1, two=2)

__attrs_own_setattr__ = False class-attribute

Returns True when the argument is true, False otherwise. The builtins True and False are the only two instances of the class bool. The class bool is a subclass of the class int, and cannot be subclassed.

__attrs_props__ = ClassProps(is_exception=False, is_slotted=True, has_weakref_slot=True, is_frozen=False, kw_only=<KeywordOnly.NO: 'no'>, collected_fields_by_mro=True, added_init=True, added_repr=True, added_eq=True, added_ordering=False, hashability=<Hashability.UNHASHABLE: 'unhashable'>, added_match_args=True, added_str=False, added_pickling=True, on_setattr_hook=<function pipe.<locals>.wrapped_pipe at 0x7f08471ce840>, field_transformer=None) class-attribute

Effective class properties as derived from parameters to attr.s() or define() decorators.

This is the same data structure that attrs uses internally to decide how to construct the final class.

Warning:

This feature is currently **experimental** and is not covered by our
strict backwards-compatibility guarantees.

Attributes:

Name Type Description
is_exception bool

Whether the class is treated as an exception class.
is_slotted bool

Whether the class is slotted <slotted classes>.
has_weakref_slot bool

Whether the class has a slot for weak references.
is_frozen bool

Whether the class is frozen.
kw_only KeywordOnly

Whether / how the class enforces keyword-only arguments on the __init__ method.
collected_fields_by_mro bool

Whether the class fields were collected by method resolution order. That is, correctly but unlike dataclasses.
added_init bool

Whether the class has an attrs-generated __init__ method.
added_repr bool

Whether the class has an attrs-generated __repr__ method.
added_eq bool

Whether the class has attrs-generated equality methods.
added_ordering bool

Whether the class has attrs-generated ordering methods.
hashability Hashability

How hashable <hashing> the class is.
added_match_args bool

Whether the class supports positional match <match> over its fields.
added_str bool

Whether the class has an attrs-generated __str__ method.
added_pickling bool

Whether the class has attrs-generated __getstate__ and __setstate__ methods for pickle.
on_setattr_hook Callable[[Any, Attribute[Any], Any], Any] | None

The class's __setattr__ hook.
field_transformer Callable[[Attribute[Any]], Attribute[Any]] | None

The class's field transformers <transform-fields>.

.. versionadded:: 25.4.0

__doc__ = 'Context passed to pre/post render callbacks.\n\nThis context provides access to the Skia canvas and frame-level metadata\nfor drawing custom overlays before or after pose rendering.\n\nAttributes:\n canvas: Skia canvas for drawing.\n frame_idx: Current frame index.\n frame_size: (width, height) tuple of original frame dimensions.\n instances: List of instances in this frame.\n skeleton_edges: Edge connectivity as list of (src, dst) tuples.\n node_names: List of node name strings.\n scale: Current scale factor for rendering.\n offset: Current offset (x, y) for cropped/zoomed views.\n' class-attribute

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

__firstlineno__ = 18 class-attribute

int([x]) -> integer int(x, base=10) -> integer

Convert a number or string to an integer, or return 0 if no arguments are given. If x is a number, return x.int(). For floating-point numbers, this truncates towards zero.

If x is not a number or if base is given, then x must be a string, bytes, or bytearray instance representing an integer literal in the given base. The literal can be preceded by '+' or '-' and be surrounded by whitespace. The base defaults to 10. Valid bases are 0 and 2-36. Base 0 means to interpret the base from the string as an integer iteral.

int('0b100', base=0) 4

__match_args__ = ('canvas', 'frame_idx', 'frame_size', 'instances', 'skeleton_edges', 'node_names', 'scale', 'offset') class-attribute

Built-in immutable sequence.

If no argument is given, the constructor returns an empty tuple. If iterable is specified the tuple is initialized from iterable's items.

If the argument is a tuple, the return value is the same object.

__module__ = 'sleap_io.rendering.callbacks' class-attribute

str(object='') -> str str(bytes_or_buffer[, encoding[, errors]]) -> str

Create a new string object from the given object. If encoding or errors is specified, then the object must expose a data buffer that will be decoded using the given encoding and error handler. Otherwise, returns the result of object.str() (if defined) or repr(object). encoding defaults to 'utf-8'. errors defaults to 'strict'.

__slots__ = ('canvas', 'frame_idx', 'frame_size', 'instances', 'skeleton_edges', 'node_names', 'scale', 'offset', '__weakref__') class-attribute

Built-in immutable sequence.

If no argument is given, the constructor returns an empty tuple. If iterable is specified the tuple is initialized from iterable's items.

If the argument is a tuple, the return value is the same object.

__static_attributes__ = () class-attribute

Built-in immutable sequence.

If no argument is given, the constructor returns an empty tuple. If iterable is specified the tuple is initialized from iterable's items.

If the argument is a tuple, the return value is the same object.

__weakref__ property

list of weak references to the object

__eq__(other)

Method generated by attrs for class RenderContext.

Source code in sleap_io/rendering/callbacks.py 
@define
class RenderContext:
    """Context passed to pre/post render callbacks.

    This context provides access to the Skia canvas and frame-level metadata
    for drawing custom overlays before or after pose rendering.

    Attributes:
        canvas: Skia canvas for drawing.
        frame_idx: Current frame index.
        frame_size: (width, height) tuple of original frame dimensions.

__init__(canvas, frame_idx, frame_size, instances, skeleton_edges, node_names, scale=1.0, offset=(0.0, 0.0))

Method generated by attrs for class RenderContext.

Source code in sleap_io/rendering/callbacks.py 
    instances: List of instances in this frame.
    skeleton_edges: Edge connectivity as list of (src, dst) tuples.
    node_names: List of node name strings.
    scale: Current scale factor for rendering.
    offset: Current offset (x, y) for cropped/zoomed views.
"""

canvas: "skia.Canvas"
frame_idx: int

__repr__()

Method generated by attrs for class RenderContext.

Source code in sleap_io/rendering/callbacks.py 
"""Callback context classes for custom rendering.

This module provides context objects that are passed to user-defined callbacks
during rendering, giving access to the Skia canvas and rendering metadata.
"""

from __future__ import annotations

from typing import TYPE_CHECKING

import numpy as np
from attrs import define

if TYPE_CHECKING:
    import skia

world_to_canvas(x, y)

Transform world coordinates to canvas coordinates.

Parameters:

Name Type Description Default
x float

X coordinate in world/frame space.

 required
y float

Y coordinate in world/frame space.

 required

Returns:

Type Description
tuple[float, float]

(x, y) coordinates in canvas space.
Source code in sleap_io/rendering/callbacks.py 
def world_to_canvas(self, x: float, y: float) -> tuple[float, float]:
    """Transform world coordinates to canvas coordinates.

    Args:
        x: X coordinate in world/frame space.
        y: Y coordinate in world/frame space.

    Returns:
        (x, y) coordinates in canvas space.
    """
    return (
        (x - self.offset[0]) * self.scale,
        (y - self.offset[1]) * self.scale,
    )