matplotlib.github.com/_modules/matplotlib/path.html at master · TanShiKai/matplotlib.github.com

History

1135 lines (946 loc) · 132 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

586

587

588

589

590

591

592

593

594

595

596

597

598

599

600

601

602

603

604

605

606

607

608

609

610

611

612

613

614

615

616

617

618

619

620

621

622

623

624

625

626

627

628

629

630

631

632

633

634

635

636

637

638

639

640

641

642

643

644

645

646

647

648

649

650

651

652

653

654

655

656

657

658

659

660

661

662

663

664

665

666

667

668

669

670

671

672

673

674

675

676

677

678

679

680

681

682

683

684

685

686

687

688

689

690

691

692

693

694

695

696

697

698

699

700

701

702

703

704

705

706

707

708

709

710

711

712

713

714

715

716

717

718

719

720

721

722

723

724

725

726

727

728

729

730

731

732

733

734

735

736

737

738

739

740

741

742

743

744

745

746

747

748

749

750

751

752

753

754

755

756

757

758

759

760

761

762

763

764

765

766

767

768

769

770

771

772

773

774

775

776

777

778

779

780

781

782

783

784

785

786

787

788

789

790

791

792

793

794

795

796

797

798

799

800

801

802

803

804

805

806

807

808

809

810

811

812

813

814

815

816

817

818

819

820

821

822

823

824

825

826

827

828

829

830

831

832

833

834

835

836

837

838

839

840

841

842

843

844

845

846

847

848

849

850

851

852

853

854

855

856

857

858

859

860

861

862

863

864

865

866

867

868

869

870

871

872

873

874

875

876

877

878

879

880

881

882

883

884

885

886

887

888

889

890

891

892

893

894

895

896

897

898

899

900

901

902

903

904

905

906

907

908

909

910

911

912

913

914

915

916

917

918

919

920

921

922

923

924

925

926

927

928

929

930

931

932

933

934

935

936

937

938

939

940

941

942

943

944

945

946

947

948

949

950

951

952

953

954

955

956

957

958

959

960

961

962

963

964

965

966

967

968

969

970

971

972

973

974

975

976

977

978

979

980

981

982

983

984

985

986

987

988

989

990

991

992

993

994

995

996

997

998

999

1000

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"

"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<head>

<title>matplotlib.path — Matplotlib 3.1.1 documentation</title>

type="text/css" />

type="text/css" />

title="Search within Matplotlib 3.1.1 documentation"

href="../../_static/opensearch.xml"/>

</head>

<body>

<div style="float: left; position: absolute; width: 496px; bottom: 0; padding-bottom: 24px">Version 3.1.1</div>

<div id="forkongithub"><a href="https://github.com/matplotlib/matplotlib">Fork me on GitHub</a></div>

</div>

<ul>

<li><a href="../../users/installing.html">Installation</a></li>

<li><a href="../../contents.html">Documentation</a></li>

<li><a href="../../gallery/index.html">Examples</a></li>

<li><a href="../../tutorials/index.html">Tutorials</a></li>

<li><a href="../../devel/index.html">Contributing</a></li>

</ul>

</nav>

<h3>Navigation</h3>

<ul>

<a href="../../genindex.html" title="General Index"

accesskey="I">index</a></li>

<a href="../../py-modindex.html" title="Python Module Index"

>modules</a> |</li>

<li><a href="../../contents.html">contents</a> »</li>

<li><a href="../index.html" >Module code</a> »</li>

<li><a href="../matplotlib.html" accesskey="U">matplotlib</a> »</li>

</ul>

</div>

<h3>Quick search</h3>

</form>

</div>

<h3>Related Topics</h3>

<ul>

<li><a href="../../contents.html">Documentation overview</a><ul>

<li><a href="../index.html">Module code</a><ul>

<li><a href="../matplotlib.html">matplotlib</a><ul>

</ul></li>

</ul>

</div>

<h1>Source code for matplotlib.path</h1><div class="highlight"><pre>

r"""

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 `Path`\s somewhere in the drawing pipeline.

Whilst a `Path` instance itself cannot be drawn, some `.Artist` subclasses,

such as `.PathPatch` and `.PathCollection`, can be used for convenient `Path`

visualisation.

"""

from functools import lru_cache

from weakref import WeakValueDictionary

import numpy as np

from . import _path, cbook, rcParams

from .cbook import _to_unmasked_float_array, simple_linear_interpolation

<div class="viewcode-block" id="Path"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path">[docs]</a>class Path(object):

"""

:class:`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 :meth:`iter_segments`

or :meth:`cleaned` to get the vertex/code pairs. This is important,

since many :class:`Path` objects, as an optimization, do not store a

*codes* at all, but have a default one provided for them by

:meth:`iter_segments`.

Some behavior of Path objects can be controlled by rcParams. See

the rcParams whose keys contain 'path.'.

.. 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.

"""

code_type = np.uint8

# Path codes

STOP = code_type(0) # 1 vertex

MOVETO = code_type(1) # 1 vertex

LINETO = code_type(2) # 1 vertex

CURVE3 = code_type(3) # 2 vertices

CURVE4 = code_type(4) # 3 vertices

CLOSEPOLY = code_type(79) # 1 vertex

#: A dictionary mapping Path codes to the number of vertices that the

#: code expects.

NUM_VERTICES_FOR_CODE = {STOP: 1,

MOVETO: 1,

LINETO: 1,

CURVE3: 2,

CURVE4: 3,

CLOSEPOLY: 1}

def __init__(self, vertices, codes=None, _interpolation_steps=1,

closed=False, readonly=False):

"""

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

:meth:`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.

"""

vertices = _to_unmasked_float_array(vertices)

if vertices.ndim != 2 or vertices.shape[1] != 2:

raise ValueError(

"'vertices' must be a 2D list or array with shape Nx2")

if codes is not None:

codes = np.asarray(codes, self.code_type)

if codes.ndim != 1 or len(codes) != len(vertices):

raise ValueError("'codes' must be a 1D list or array with the "

"same length of 'vertices'")

if len(codes) and codes[0] != self.MOVETO:

raise ValueError("The first element of 'code' must be equal "

"to 'MOVETO' ({})".format(self.MOVETO))

elif closed and len(vertices):

codes = np.empty(len(vertices), dtype=self.code_type)

codes[0] = self.MOVETO

codes[1:-1] = self.LINETO

codes[-1] = self.CLOSEPOLY

self._vertices = vertices

self._codes = codes

self._interpolation_steps = _interpolation_steps

self._update_values()

if readonly:

self._vertices.flags.writeable = False

if self._codes is not None:

self._codes.flags.writeable = False

self._readonly = True

else:

self._readonly = False

@classmethod

def _fast_from_codes_and_verts(cls, verts, codes, internals_from=None):

"""

Creates a Path instance without the expense of calling the constructor.

Parameters

----------

verts : numpy array

codes : numpy array

internals_from : Path or None

If not None, another `Path` from which the attributes

``should_simplify``, ``simplify_threshold``, and

``interpolation_steps`` will be copied. Note that ``readonly`` is

never copied, and always set to ``False`` by this constructor.

"""

pth = cls.__new__(cls)

pth._vertices = _to_unmasked_float_array(verts)

pth._codes = codes

pth._readonly = False

if internals_from is not None:

pth._should_simplify = internals_from._should_simplify

pth._simplify_threshold = internals_from._simplify_threshold

pth._interpolation_steps = internals_from._interpolation_steps

else:

pth._should_simplify = True

pth._simplify_threshold = rcParams['path.simplify_threshold']

pth._interpolation_steps = 1

return pth

def _update_values(self):

self._simplify_threshold = rcParams['path.simplify_threshold']

self._should_simplify = (

self._simplify_threshold > 0 and

rcParams['path.simplify'] and

len(self._vertices) >= 128 and

(self._codes is None or np.all(self._codes <= Path.LINETO))

)

@property

def vertices(self):

"""

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

"""

return self._vertices

@vertices.setter

def vertices(self, vertices):

if self._readonly:

raise AttributeError("Can't set vertices on a readonly Path")

self._vertices = vertices

self._update_values()

@property

def codes(self):

"""

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.

"""

return self._codes

@codes.setter

def codes(self, codes):

if self._readonly:

raise AttributeError("Can't set codes on a readonly Path")

self._codes = codes

self._update_values()

@property

def simplify_threshold(self):

"""

The fraction of a pixel difference below which vertices will

be simplified out.

"""

return self._simplify_threshold

@simplify_threshold.setter

def simplify_threshold(self, threshold):

self._simplify_threshold = threshold

@cbook.deprecated(

"3.1", alternative="not np.isfinite(self.vertices).all()")

@property

def has_nonfinite(self):

"""

`True` if the vertices array has nonfinite values.

"""

return not np.isfinite(self._vertices).all()

@property

def should_simplify(self):

"""

`True` if the vertices array should be simplified.

"""

return self._should_simplify

@should_simplify.setter

def should_simplify(self, should_simplify):

self._should_simplify = should_simplify

@property

def readonly(self):

"""

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

"""

return self._readonly

def __copy__(self):

"""

Returns a shallow copy of the `Path`, which will share the

vertices and codes with the source `Path`.

"""

import copy

return copy.copy(self)

copy = __copy__

def __deepcopy__(self, memo=None):

"""

Returns a deepcopy of the `Path`. The `Path` will not be

readonly, even if the source `Path` is.

"""

try:

codes = self.codes.copy()

except AttributeError:

codes = None

return self.__class__(

self.vertices.copy(), codes,

_interpolation_steps=self._interpolation_steps)

deepcopy = __deepcopy__

<div class="viewcode-block" id="Path.make_compound_path_from_polys"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.make_compound_path_from_polys">[docs]</a> @classmethod

def make_compound_path_from_polys(cls, 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

:class:`Path`

.. plot:: gallery/misc/histogram_path.py

"""

# for each poly: 1 for the MOVETO, (numsides-1) for the LINETO, 1 for

# the CLOSEPOLY; the vert for the closepoly is ignored but we still

# need it to keep the codes aligned with the vertices

numpolys, numsides, two = XY.shape

if two != 2:

raise ValueError("The third dimension of 'XY' must be 2")

stride = numsides + 1

nverts = numpolys * stride

verts = np.zeros((nverts, 2))

codes = np.full(nverts, cls.LINETO, dtype=cls.code_type)

codes[0::stride] = cls.MOVETO

codes[numsides::stride] = cls.CLOSEPOLY

for i in range(numsides):

verts[i::stride] = XY[:, i]

return cls(verts, codes)</div>

<div class="viewcode-block" id="Path.make_compound_path"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.make_compound_path">[docs]</a> @classmethod

def make_compound_path(cls, *args):

"""Make a compound path from a list of Path objects."""

# Handle an empty list in args (i.e. no args).

if not args:

return Path(np.empty([0, 2], dtype=np.float32))

lengths = [len(x) for x in args]

total_length = sum(lengths)

vertices = np.vstack([x.vertices for x in args])

vertices.reshape((total_length, 2))

codes = np.empty(total_length, dtype=cls.code_type)

i = 0

for path in args:

if path.codes is None:

codes[i] = cls.MOVETO

codes[i + 1:i + len(path.vertices)] = cls.LINETO

else:

codes[i:i + len(path.codes)] = path.codes

i += len(path.vertices)

return cls(vertices, codes)</div>

def __repr__(self):

return "Path(%r, %r)" % (self.vertices, self.codes)

def __len__(self):

return len(self.vertices)

<div class="viewcode-block" id="Path.iter_segments"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.iter_segments">[docs]</a> def iter_segments(self, 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 a `Path` code.

Additionally, this method can provide a number of standard cleanups and

conversions to the path.

Parameters

----------

transform : None or :class:`~matplotlib.transforms.Transform`

If not None, the given affine transformation will be applied to the

path.

remove_nans : bool, optional

Whether to remove all NaNs from the path and skip over them using

MOVETO commands.

clip : None or (float, float, float, float), 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 True, snap all nodes to pixels; if False, don't snap them.

If None, perform snapping if the path contains only segments

parallel to the x or y axes, and no more than 1024 of them.

stroke_width : float, optional

The width of the stroke being drawn (used for path snapping).

simplify : None or bool, optional

Whether to simplify the path by removing vertices

that do not affect its appearance. If None, use the

:attr:`should_simplify` attribute. See also :rc:`path.simplify`

and :rc:`path.simplify_threshold`.

curves : bool, 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.

"""

if not len(self):

return

cleaned = self.cleaned(transform=transform,

remove_nans=remove_nans, clip=clip,

snap=snap, stroke_width=stroke_width,

simplify=simplify, curves=curves,

sketch=sketch)

# Cache these object lookups for performance in the loop.

NUM_VERTICES_FOR_CODE = self.NUM_VERTICES_FOR_CODE

STOP = self.STOP

vertices = iter(cleaned.vertices)

codes = iter(cleaned.codes)

for curr_vertices, code in zip(vertices, codes):

if code == STOP:

break

extra_vertices = NUM_VERTICES_FOR_CODE[code] - 1

if extra_vertices:

for i in range(extra_vertices):

next(codes)

curr_vertices = np.append(curr_vertices, next(vertices))

yield curr_vertices, code</div>

<div class="viewcode-block" id="Path.cleaned"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.cleaned">[docs]</a> def cleaned(self, transform=None, remove_nans=False, clip=None,

quantize=False, simplify=False, curves=False,

stroke_width=1.0, snap=False, sketch=None):

"""

Return a new Path with vertices and codes cleaned according to the

parameters.

See Also

--------

Path.iter_segments : for details of the keyword arguments.

"""

vertices, codes = _path.cleanup_path(

self, transform, remove_nans, clip, snap, stroke_width, simplify,

curves, sketch)

pth = Path._fast_from_codes_and_verts(vertices, codes, self)

if not simplify:

pth._should_simplify = False

return pth</div>

<div class="viewcode-block" id="Path.transformed"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.transformed">[docs]</a> def transformed(self, 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.

"""

return Path(transform.transform(self.vertices), self.codes,

self._interpolation_steps)</div>

<div class="viewcode-block" id="Path.contains_point"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.contains_point">[docs]</a> def contains_point(self, 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.

"""

if transform is not None:

transform = transform.frozen()

# `point_in_path` does not handle nonlinear transforms, so we

# transform the path ourselves. If `transform` is affine, letting

# `point_in_path` handle the transform avoids allocating an extra

# buffer.

if transform and not transform.is_affine:

self = transform.transform_path(self)

transform = None

return _path.point_in_path(point[0], point[1], radius, self, transform)</div>

<div class="viewcode-block" id="Path.contains_points"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.contains_points">[docs]</a> def contains_points(self, 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.

"""

if transform is not None:

transform = transform.frozen()

result = _path.points_in_path(points, radius, self, transform)

return result.astype('bool')</div>

<div class="viewcode-block" id="Path.contains_path"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.contains_path">[docs]</a> def contains_path(self, 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.

"""

if transform is not None:

transform = transform.frozen()

return _path.path_in_path(self, None, path, transform)</div>

<div class="viewcode-block" id="Path.get_extents"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.get_extents">[docs]</a> def get_extents(self, 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.

"""

from .transforms import Bbox

path = self

if transform is not None:

transform = transform.frozen()

if not transform.is_affine:

path = self.transformed(transform)

transform = None

return Bbox(_path.get_path_extents(path, transform))</div>

<div class="viewcode-block" id="Path.intersects_path"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.intersects_path">[docs]</a> def intersects_path(self, 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,

:meth:`intersects_path` will return True.

"""

return _path.path_intersects_path(self, other, filled)</div>

<div class="viewcode-block" id="Path.intersects_bbox"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.intersects_bbox">[docs]</a> def intersects_bbox(self, bbox, filled=True):

"""

Returns *True* if this path intersects a given

:class:`~matplotlib.transforms.Bbox`.

*filled*, when True, treats the path as if it was filled.

That is, if the path completely encloses the bounding box,

:meth:`intersects_bbox` will return True.

The bounding box is always considered filled.

"""

return _path.path_intersects_rectangle(self,

bbox.x0, bbox.y0, bbox.x1, bbox.y1, filled)</div>

<div class="viewcode-block" id="Path.interpolated"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.interpolated">[docs]</a> def interpolated(self, steps):

"""

Returns a new path resampled to length N x steps. Does not

currently handle interpolating curves.

"""

if steps == 1:

return self

vertices = simple_linear_interpolation(self.vertices, steps)

codes = self.codes

if codes is not None:

new_codes = np.full((len(codes) - 1) * steps + 1, Path.LINETO,

dtype=self.code_type)

new_codes[0::steps] = codes

else:

new_codes = None

return Path(vertices, new_codes)</div>

<div class="viewcode-block" id="Path.to_polygons"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.to_polygons">[docs]</a> def to_polygons(self, 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.

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.

"""

if len(self.vertices) == 0:

return []

if transform is not None:

transform = transform.frozen()

if self.codes is None and (width == 0 or height == 0):

vertices = self.vertices

if closed_only:

if len(vertices) < 3:

return []

elif np.any(vertices[0] != vertices[-1]):

vertices = [*vertices, vertices[0]]

if transform is None:

return [vertices]

else:

return [transform.transform(vertices)]

# Deal with the case where there are curves and/or multiple

# subpaths (using extension code)

return _path.convert_path_to_polygons(

self, transform, width, height, closed_only)</div>

_unit_rectangle = None

<div class="viewcode-block" id="Path.unit_rectangle"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.unit_rectangle">[docs]</a> @classmethod

def unit_rectangle(cls):

"""

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

"""

if cls._unit_rectangle is None:

cls._unit_rectangle = \

cls([[0.0, 0.0], [1.0, 0.0], [1.0, 1.0], [0.0, 1.0],

[0.0, 0.0]],

[cls.MOVETO, cls.LINETO, cls.LINETO, cls.LINETO,

cls.CLOSEPOLY],

readonly=True)

return cls._unit_rectangle</div>

_unit_regular_polygons = WeakValueDictionary()

<div class="viewcode-block" id="Path.unit_regular_polygon"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.unit_regular_polygon">[docs]</a> @classmethod

def unit_regular_polygon(cls, numVertices):

"""

Return a :class:`Path` instance for a unit regular polygon with the

given *numVertices* and radius of 1.0, centered at (0, 0).

"""

if numVertices <= 16:

path = cls._unit_regular_polygons.get(numVertices)

else:

path = None

if path is None:

theta = ((2 * np.pi / numVertices) * np.arange(numVertices + 1)

# This initial rotation is to make sure the polygon always

# "points-up".

+ np.pi / 2)

verts = np.column_stack((np.cos(theta), np.sin(theta)))

codes[0] = cls.MOVETO

codes[1:-1] = cls.LINETO

codes[-1] = cls.CLOSEPOLY

path = cls(verts, codes, readonly=True)

if numVertices <= 16:

cls._unit_regular_polygons[numVertices] = path

return path</div>

_unit_regular_stars = WeakValueDictionary()

<div class="viewcode-block" id="Path.unit_regular_star"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.unit_regular_star">[docs]</a> @classmethod

def unit_regular_star(cls, numVertices, innerCircle=0.5):

"""

Return a :class:`Path` for a unit regular star with the given

numVertices and radius of 1.0, centered at (0, 0).

"""

if numVertices <= 16:

path = cls._unit_regular_stars.get((numVertices, innerCircle))

else:

path = None

if path is None:

ns2 = numVertices * 2

theta = (2*np.pi/ns2 * np.arange(ns2 + 1))

# This initial rotation is to make sure the polygon always

# "points-up"

theta += np.pi / 2.0

r = np.ones(ns2 + 1)

r[1::2] = innerCircle

verts = np.vstack((r*np.cos(theta), r*np.sin(theta))).transpose()

codes = np.empty((ns2 + 1,))

codes[1:-1] = cls.LINETO

codes[-1] = cls.CLOSEPOLY

if numVertices <= 16:

cls._unit_regular_stars[(numVertices, innerCircle)] = path

return path</div>

<div class="viewcode-block" id="Path.unit_regular_asterisk"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.unit_regular_asterisk">[docs]</a> @classmethod

def unit_regular_asterisk(cls, numVertices):

"""

Return a :class:`Path` for a unit regular asterisk with the given

numVertices and radius of 1.0, centered at (0, 0).

"""

return cls.unit_regular_star(numVertices, 0.0)</div>

_unit_circle = None

<div class="viewcode-block" id="Path.unit_circle"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.unit_circle">[docs]</a> @classmethod

def unit_circle(cls):

"""

Return the readonly :class:`Path` of the unit circle.

For most cases, :func:`Path.circle` will be what you want.

"""

if cls._unit_circle is None:

cls._unit_circle = cls.circle(center=(0, 0), radius=1,

readonly=True)

return cls._unit_circle</div>

<div class="viewcode-block" id="Path.circle"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.circle">[docs]</a> @classmethod

def circle(cls, center=(0., 0.), radius=1., 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 8 cubic Bezier curves, as described in

Lancaster, Don. `Approximating a Circle or an Ellipse Using Four

Bezier Cubic Splines <http://www.tinaja.com/glib/ellipse4.pdf>`_.

"""

MAGIC = 0.2652031

SQRTHALF = np.sqrt(0.5)

MAGIC45 = SQRTHALF * MAGIC

vertices = np.array([[0.0, -1.0],

[MAGIC, -1.0],

[SQRTHALF-MAGIC45, -SQRTHALF-MAGIC45],

[SQRTHALF, -SQRTHALF],

[SQRTHALF+MAGIC45, -SQRTHALF+MAGIC45],

[1.0, -MAGIC],

[1.0, 0.0],

[1.0, MAGIC],

[SQRTHALF+MAGIC45, SQRTHALF-MAGIC45],

[SQRTHALF, SQRTHALF],

[SQRTHALF-MAGIC45, SQRTHALF+MAGIC45],

[MAGIC, 1.0],

[0.0, 1.0],

[-MAGIC, 1.0],

[-SQRTHALF+MAGIC45, SQRTHALF+MAGIC45],

[-SQRTHALF, SQRTHALF],

[-SQRTHALF-MAGIC45, SQRTHALF-MAGIC45],

[-1.0, MAGIC],

[-1.0, 0.0],

[-1.0, -MAGIC],

[-SQRTHALF-MAGIC45, -SQRTHALF+MAGIC45],

[-SQRTHALF, -SQRTHALF],

[-SQRTHALF+MAGIC45, -SQRTHALF-MAGIC45],

[-MAGIC, -1.0],

[0.0, -1.0],

[0.0, -1.0]],

dtype=float)

codes = [cls.CURVE4] * 26

codes[-1] = cls.CLOSEPOLY

return Path(vertices * radius + center, codes, readonly=readonly)</div>

_unit_circle_righthalf = None

<div class="viewcode-block" id="Path.unit_circle_righthalf"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.unit_circle_righthalf">[docs]</a> @classmethod

def unit_circle_righthalf(cls):

"""

Return a `Path` of the right half of a unit circle.

See `Path.circle` for the reference on the approximation used.

"""

if cls._unit_circle_righthalf is None:

MAGIC = 0.2652031

MAGIC45 = SQRTHALF * MAGIC

vertices = np.array(

[[0.0, -1.0],

[MAGIC, -1.0],

[SQRTHALF, -SQRTHALF],

[1.0, -MAGIC],

[1.0, 0.0],

[1.0, MAGIC],

[SQRTHALF, SQRTHALF],

[MAGIC, 1.0],

[0.0, 1.0],

[0.0, -1.0]],

float)

codes = np.full(14, cls.CURVE4, dtype=cls.code_type)

codes[-1] = cls.CLOSEPOLY

cls._unit_circle_righthalf = cls(vertices, codes, readonly=True)

return cls._unit_circle_righthalf</div>

<div class="viewcode-block" id="Path.arc"><a class="viewcode-back" href="../../api/path_api.html#matplotlib.path.Path.arc">[docs]</a> @classmethod

def arc(cls, theta1, theta2, n=None, is_wedge=False):

"""

Return the unit circle arc from angles *theta1* to *theta2* (in

degrees).

*theta2* is unwrapped to produce the shortest arc within 360 degrees.

That is, if *theta2* > *theta1* + 360, the arc will be from *theta1* to

*theta2* - 360 and not a full circle plus some extra overlap.

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

<http://www.spaceroots.org/documents/ellipse/index.html>`_.

"""

halfpi = np.pi * 0.5

eta1 = theta1

eta2 = theta2 - 360 * np.floor((theta2 - theta1) / 360)

# Ensure 2pi range is not flattened to 0 due to floating-point errors,

# but don't try to expand existing 0 range.

if theta2 != theta1 and eta2 <= eta1:

eta2 += 360

eta1, eta2 = np.deg2rad([eta1, eta2])

# number of curve segments to make

if n is None:

n = int(2 ** np.ceil((eta2 - eta1) / halfpi))

if n < 1:

raise ValueError("n must be >= 1 or None")

deta = (eta2 - eta1) / n

t = np.tan(0.5 * deta)

alpha = np.sin(deta) * (np.sqrt(4.0 + 3.0 * t * t) - 1) / 3.0

steps = np.linspace(eta1, eta2, n + 1, True)

cos_eta = np.cos(steps)

sin_eta = np.sin(steps)

xA = cos_eta[:-1]

yA = sin_eta[:-1]

xA_dot = -yA

yA_dot = xA

xB = cos_eta[1:]

yB = sin_eta[1:]

xB_dot = -yB

yB_dot = xB

if is_wedge:

length = n * 3 + 4

vertices = np.zeros((length, 2), float)

codes = np.full(length, cls.CURVE4, dtype=cls.code_type)

vertices[1] = [xA[0], yA[0]]

codes[0:2] = [cls.MOVETO, cls.LINETO]

codes[-2:] = [cls.LINETO, cls.CLOSEPOLY]

vertex_offset = 2

end = length - 2

else:

length = n * 3 + 1

vertices = np.empty((length, 2), float)

codes = np.full(length, cls.CURVE4, dtype=cls.code_type)

vertices[0] = [xA[0], yA[0]]

vertex_offset = 1

end = length

vertices[vertex_offset:end:3, 0] = xA + alpha * xA_dot

vertices[vertex_offset:end:3, 1] = yA + alpha * yA_dot

vertices[vertex_offset+1:end:3, 0] = xB - alpha * xB_dot

View remainder of file in raw view

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

FilesExpand file tree

path.html

Latest commit

History

path.html

File metadata and controls