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# path

## `matplotlib.path`

A module for dealing with the polylines used throughout matplotlib.

The primary class for polyline handling in matplotlib is `Path`. Almost all vector drawing makes use of Paths somewhere in the drawing pipeline.

Whilst a `Path` instance itself cannot be drawn, there exists `Artist` subclasses which can be used for convenient Path visualisation - the two most frequently used of these are `PathPatch` and `PathCollection`.

class `matplotlib.path.``Path`(vertices, codes=None, _interpolation_steps=1, closed=False, readonly=False)

  Bases: `object`

  `Path` represents a series of possibly disconnected, possibly closed, line and curve segments.

  The underlying storage is made up of two parallel numpy arrays:
    - vertices: an Nx2 float array of vertices
    - codes: an N-length uint8 array of vertex types

  These two arrays always have the same length in the first dimension. For example, to represent a cubic curve, you must provide three vertices as well as three codes `CURVE3`.

  The code types are:

  > - `STOP` : 1 vertex (ignored)

  >     A marker for the end of the entire path (currently not required and ignored)

  > - `MOVETO` : 1 vertex

  >     Pick up the pen and move to the given vertex.

  > - `LINETO` : 1 vertex

  >     Draw a line from the current position to the given vertex.

  > - `CURVE3` : 1 control point, 1 endpoint

  >     Draw a quadratic Bezier curve from the current position, with the given control point, to the given end point.

  > - `CURVE4` : 2 control points, 1 endpoint

  >     Draw a cubic Bezier curve from the current position, with the given control points, to the given end point.

  > - `CLOSEPOLY` : 1 vertex (ignored)

  >     Draw a line segment to the start point of the current polyline.

  Users of Path objects should not access the vertices and codes arrays directly. Instead, they should use `iter_segments()` or `cleaned()` to get the vertex/code pairs. This is important, since many `Path` objects, as an optimization, do not store a codes at all, but have a default one provided for them by `iter_segments()`.

  Note

  The vertices and codes arrays should be treated as immutable – there are a number of optimizations and assumptions made up front in the constructor that will not change when the data changes.

  Create a new path with the given vertices and codes.

  Parameters: | vertices : array_like The `(n, 2)` float array, masked array or sequence of pairs representing the vertices of the path. If vertices contains masked values, they will be converted to NaNs which are then handled correctly by the Agg PathIterator and other consumers of path data, such as `iter_segments()`. codes : {None, array_like}, optional n-length array integers representing the codes of the path. If not None, codes must be the same length as vertices. If None, vertices will be treated as a series of line segments. _interpolation_steps : int, optional Used as a hint to certain projections, such as Polar, that this path should be linearly interpolated immediately before drawing. This attribute is primarily an implementation detail and is not intended for public use. closed : bool, optional If codes is None and closed is True, vertices will be treated as line segments of a closed polygon. readonly : bool, optional Makes the path behave in an immutable way and sets the vertices and codes as read-only arrays.

  `CLOSEPOLY` = 79
  `CURVE3` = 3
  `CURVE4` = 4
  `LINETO` = 2
  `MOVETO` = 1
  `NUM_VERTICES_FOR_CODE` = {0: 1, 1: 1, 2: 1, 3: 2, 4: 3, 79: 1}

    A dictionary mapping Path codes to the number of vertices that the code expects.

  `STOP` = 0
  classmethod `arc`(theta1, theta2, n=None, is_wedge=False)

    Return an arc on the unit circle from angle theta1 to angle theta2 (in degrees).

    If n is provided, it is the number of spline segments to make. If n is not provided, the number of spline segments is determined based on the delta between theta1 and theta2.

    > Masionobe, L. 2003. Drawing an elliptical arc using polylines, quadratic or cubic Bezier curves.

  classmethod `circle`(center=(0.0, 0.0), radius=1.0, readonly=False)

    Return a Path representing a circle of a given radius and center.

    Parameters: | center : pair of floats The center of the circle. Default `(0, 0)`. radius : float The radius of the circle. Default is 1. readonly : bool Whether the created path should have the “readonly” argument set when creating the Path instance.

    Notes

    The circle is approximated using cubic Bezier curves. This uses 8 splines around the circle using the approach presented here:

    > Lancaster, Don. Approximating a Circle or an Ellipse Using Four Bezier Cubic Splines.

  `cleaned`(transform=None, remove_nans=False, clip=None, quantize=False, simplify=False, curves=False, stroke_width=1.0, snap=False, sketch=None)

    Cleans up the path according to the parameters returning a new Path instance.

    See also

    See `iter_segments()` for details of the keyword arguments.

    Returns: | Path instance with cleaned up vertices and codes.

  `clip_to_bbox`(bbox, inside=True)

    Clip the path to the given bounding box.

    The path must be made up of one or more closed polygons. This algorithm will not behave correctly for unclosed paths.

    If inside is `True`, clip to the inside of the box, otherwise to the outside of the box.

  `code_type`

    alias of `uint8`

  `codes`

    The list of codes in the `Path` as a 1-D numpy array. Each code is one of `STOP`, `MOVETO`, `LINETO`, `CURVE3`, `CURVE4` or `CLOSEPOLY`. For codes that correspond to more than one vertex (`CURVE3` and `CURVE4`), that code will be repeated so that the length of `self.vertices` and `self.codes` is always the same.

  `contains_path`(path, transform=None)

    Returns whether this (closed) path completely contains the given path.

    If transform is not `None`, the path will be transformed before performing the test.

  `contains_point`(point, transform=None, radius=0.0)

    Returns whether the (closed) path contains the given point.

    If transform is not `None`, the path will be transformed before performing the test.

    radius allows the path to be made slightly larger or smaller.

  `contains_points`(points, transform=None, radius=0.0)

    Returns a bool array which is `True` if the (closed) path contains the corresponding point.

    If transform is not `None`, the path will be transformed before performing the test.

    radius allows the path to be made slightly larger or smaller.

  `copy`()

    Returns a shallow copy of the `Path`, which will share the vertices and codes with the source `Path`.

  `deepcopy`(memo=None)

    Returns a deepcopy of the `Path`. The `Path` will not be readonly, even if the source `Path` is.

  `get_extents`(transform=None)

    Returns the extents (xmin, ymin, xmax, ymax) of the path.

    Unlike computing the extents on the vertices alone, this algorithm will take into account the curves and deal with control points appropriately.

  `has_nonfinite`

    `True` if the vertices array has nonfinite values.

  classmethod `hatch`(hatchpattern, density=6)

    Given a hatch specifier, hatchpattern, generates a Path that can be used in a repeated hatching pattern. density is the number of lines per unit square.

  `interpolated`(steps)

    Returns a new path resampled to length N x steps. Does not currently handle interpolating curves.

  `intersects_bbox`(bbox, filled=True)

    Returns True if this path intersects a given `Bbox`.

    filled, when True, treats the path as if it was filled. That is, if the path completely encloses the bounding box, `intersects_bbox()` will return True.

    The bounding box is always considered filled.

  `intersects_path`(other, filled=True)

    Returns True if this path intersects another given path.

    filled, when True, treats the paths as if they were filled. That is, if one path completely encloses the other, `intersects_path()` will return True.

  `iter_segments`(transform=None, remove_nans=True, clip=None, snap=False, stroke_width=1.0, simplify=None, curves=True, sketch=None)

    Iterates over all of the curve segments in the path. Each iteration returns a 2-tuple (vertices, code), where vertices is a sequence of 1 - 3 coordinate pairs, and code is one of the `Path` codes.

    Additionally, this method can provide a number of standard cleanups and conversions to the path.

    Parameters: | transform : None or `Transform` instance If not None, the given affine transformation will be applied to the path. remove_nans : {False, True}, optional If True, will remove all NaNs from the path and insert MOVETO commands to skip over them. clip : None or sequence, optional If not None, must be a four-tuple (x1, y1, x2, y2) defining a rectangle in which to clip the path. snap : None or bool, optional If None, auto-snap to pixels, to reduce fuzziness of rectilinear lines. If True, force snapping, and if False, don’t snap. stroke_width : float, optional The width of the stroke being drawn. Needed as a hint for the snapping algorithm. simplify : None or bool, optional If True, perform simplification, to remove vertices that do not affect the appearance of the path. If False, perform no simplification. If None, use the should_simplify member variable. curves : {True, False}, optional If True, curve segments will be returned as curve segments. If False, all curves will be converted to line segments. sketch : None or sequence, optional If not None, must be a 3-tuple of the form (scale, length, randomness), representing the sketch parameters.

  classmethod `make_compound_path`(*args)

    Make a compound path from a list of Path objects.

  classmethod `make_compound_path_from_polys`(XY)

    Make a compound path object to draw a number of polygons with equal numbers of sides XY is a (numpolys x numsides x 2) numpy array of vertices. Return object is a `Path`

    (Source code, png, pdf)

  `readonly`

    `True` if the `Path` is read-only.

  `should_simplify`

    `True` if the vertices array should be simplified.

  `simplify_threshold`

    The fraction of a pixel difference below which vertices will be simplified out.

  `to_polygons`(transform=None, width=0, height=0, closed_only=True)

    Convert this path to a list of polygons or polylines. Each polygon/polyline is an Nx2 array of vertices. In other words, each polygon has no `MOVETO` instructions or curves. This is useful for displaying in backends that do not support compound paths or Bezier curves, such as GDK.

    If width and height are both non-zero then the lines will be simplified so that vertices outside of (0, 0), (width, height) will be clipped.

    If closed_only is `True` (default), only closed polygons, with the last point being the same as the first point, will be returned. Any unclosed polylines in the path will be explicitly closed. If closed_only is `False`, any unclosed polygons in the path will be returned as unclosed polygons, and the closed polygons will be returned explicitly closed by setting the last point to the same as the first point.

  `transformed`(transform)

    Return a transformed copy of the path.

    See also

    `matplotlib.transforms.TransformedPath`
      A specialized path class that will cache the transformed result and automatically update when the transform changes.
  classmethod `unit_circle`()

    Return the readonly `Path` of the unit circle.

    For most cases, `Path.circle()` will be what you want.

  classmethod `unit_circle_righthalf`()

    Return a `Path` of the right half of a unit circle. The circle is approximated using cubic Bezier curves. This uses 4 splines around the circle using the approach presented here:

    > Lancaster, Don. Approximating a Circle or an Ellipse Using Four Bezier Cubic Splines.

  classmethod `unit_rectangle`()

    Return a `Path` instance of the unit rectangle from (0, 0) to (1, 1).

  classmethod `unit_regular_asterisk`(numVertices)

    Return a `Path` for a unit regular asterisk with the given numVertices and radius of 1.0, centered at (0, 0).

  classmethod `unit_regular_polygon`(numVertices)

    Return a `Path` instance for a unit regular polygon with the given numVertices and radius of 1.0, centered at (0, 0).

  classmethod `unit_regular_star`(numVertices, innerCircle=0.5)

    Return a `Path` for a unit regular star with the given numVertices and radius of 1.0, centered at (0, 0).

  `vertices`

    The list of vertices in the `Path` as an Nx2 numpy array.

  classmethod `wedge`(theta1, theta2, n=None)

    Return a wedge of the unit circle from angle theta1 to angle theta2 (in degrees).

    If n is provided, it is the number of spline segments to make. If n is not provided, the number of spline segments is determined based on the delta between theta1 and theta2.

`matplotlib.path.``get_path_collection_extents`(master_transform, paths, transforms, offsets, offset_transform)

  Given a sequence of `Path` objects, `Transform` objects and offsets, as found in a `PathCollection`, returns the bounding box that encapsulates all of them.

  master_transform is a global transformation to apply to all paths

  paths is a sequence of `Path` instances.

  transforms is a sequence of `Affine2D` instances.

  offsets is a sequence of (x, y) offsets (or an Nx2 array)

  offset_transform is a `Affine2D` to apply to the offsets before applying the offset to the path.

  The way that paths, transforms and offsets are combined follows the same method as for collections. Each is iterated over independently, so if you have 3 paths, 2 transforms and 1 offset, their combinations are as follows:

  > (A, A, A), (B, B, A), (C, A, A)

`matplotlib.path.``get_paths_extents`(paths, transforms=[])

  Given a sequence of `Path` objects and optional `Transform` objects, returns the bounding box that encapsulates all of them.

  paths is a sequence of `Path` instances.

  transforms is an optional sequence of `Affine2D` instances to apply to each path.