pythonnative/src/pythonnative/style.py at v0.43.1 · pythonnative/pythonnative · GitHub

Repository navigation

History

841 lines (694 loc) · 25.7 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

"""StyleSheet, typed `Style`, style resolution, and theming.

PythonNative ships a single, fully-typed [`Style`][pythonnative.Style]

TypedDict that enumerates every supported style property and constrains

enum-shaped values via [`typing.Literal`][typing.Literal]. The TypedDict

gives editors and type-checkers (mypy, pyright) full autocomplete and

validation: a typo such as ``flex_direction="collumn"`` is now a static

error, not a silent runtime no-op.

Style values remain plain dicts at runtime so they are trivial to

compose, diff, and store. Properties unrecognized by a platform handler

are still ignored, so third-party handlers may extend the palette

without modifying core types.

The runtime helpers ([`resolve_style`][pythonnative.style.resolve_style],

[`StyleSheet`][pythonnative.StyleSheet]) accept either a ``Style``

TypedDict, a regular ``Dict[str, Any]`` (for forward-compat or

unrestricted use), or a list of either kind of dict, and always

return a fresh, flat dict.

Example:

```python

import pythonnative as pn

styles = pn.StyleSheet.create(

title=pn.style(font_size=24, bold=True, color="#333"),

container=pn.style(padding=16, spacing=12),

)

pn.Column(

pn.Text("Hello", style=styles["title"]),

style=styles["container"],

)

```

"""

import dataclasses

import difflib

from dataclasses import dataclass

from typing import Any, Dict, List, Literal, Optional, Tuple, TypedDict, Union, get_args

from . import diagnostics

from .hooks import Context, create_context, use_color_scheme, use_context

# ======================================================================

# Atomic value types

# ======================================================================

Color = str

"""Color value: ``"#RRGGBB"``, ``"#AARRGGBB"``, or any string a platform

handler recognizes (e.g., ``"red"``). Stored verbatim and parsed by the

handler at apply-time, so palettes from third-party libraries pass through

unchanged."""

Dimension = Union[int, float, str]

"""A length value. Numbers are points/dp; strings ending in ``"%"`` are

parent-relative percentages."""

class EdgeInsets(TypedDict, total=False):

"""Per-edge spacing values used for ``padding`` and ``margin``.

Mirrors React Native's ``EdgeInsets`` shape with PythonNative's

convenience aliases. Any subset of keys may be supplied.

"""

top: Dimension

right: Dimension

bottom: Dimension

left: Dimension

horizontal: Dimension

vertical: Dimension

all: Dimension

EdgeValue = Union[Dimension, EdgeInsets]

"""Padding/margin value: a uniform number, a ``"%"`` string, or an

[`EdgeInsets`][pythonnative.EdgeInsets] dict."""

class AccessibilityState(TypedDict, total=False):

"""Current widget state exposed to assistive technology.

Passed via the ``accessibility_state=`` prop on interactive

components. All keys are optional; omitted keys are treated as

unset (not ``False``).

Attributes:

disabled: The widget is visible but not interactive.

selected: The widget is currently selected (e.g. the active

tab).

checked: Toggle/checkbox state. ``"mixed"`` represents a

tri-state checkbox.

busy: The widget is loading or otherwise temporarily busy.

expanded: A disclosure/accordion is currently expanded.

"""

disabled: bool

selected: bool

checked: Union[bool, Literal["mixed"]]

busy: bool

expanded: bool

class ShadowOffset(TypedDict):

"""Shadow displacement in points."""

width: float

height: float

ShadowOffsetValue = Union[ShadowOffset, Tuple[float, float], List[float]]

"""``shadow_offset`` / ``text_shadow_offset`` value: an

[`ShadowOffset`][pythonnative.ShadowOffset] dict or an ``(x, y)`` pair."""

# ----------------------------------------------------------------------

# Transforms

# ----------------------------------------------------------------------

class TransformRotate(TypedDict):

"""Rotation transform in degrees (numeric) or with explicit unit suffix."""

rotate: Union[float, str]

class TransformScale(TypedDict):

"""Uniform scale transform."""

scale: float

class TransformScaleX(TypedDict):

"""Horizontal-only scale transform."""

scale_x: float

class TransformScaleY(TypedDict):

"""Vertical-only scale transform."""

scale_y: float

class TransformTranslate(TypedDict, total=False):

"""Translation transform along one or both axes."""

translate_x: float

translate_y: float

TransformEntry = Union[

TransformRotate,

TransformScale,

TransformScaleX,

TransformScaleY,

TransformTranslate,

Dict[str, Any],

]

"""A single transform operation."""

TransformSpec = Union[TransformEntry, List[TransformEntry]]

"""``transform`` style value: a single operation or an ordered list."""

# ----------------------------------------------------------------------

# Enum-shaped style values

# ----------------------------------------------------------------------

FlexDirection = Literal["row", "column", "row_reverse", "column_reverse"]

FlexWrap = Literal["nowrap", "wrap", "wrap_reverse"]

AlignContent = Literal[

"flex_start",

"center",

"flex_end",

"stretch",

"space_between",

"space_around",

"space_evenly",

]

LayoutDirection = Literal["ltr", "rtl"]

JustifyContent = Literal[

"flex_start",

"center",

"flex_end",

"space_between",

"space_around",

"space_evenly",

"start",

"leading",

"top",

"end",

"trailing",

"bottom",

]

AlignItems = Literal[

"stretch",

"flex_start",

"center",

"flex_end",

"baseline",

"auto",

"start",

"leading",

"top",

"end",

"trailing",

"bottom",

"fill",

]

AlignSelf = AlignItems

Position = Literal["relative", "absolute"]

Display = Literal["flex", "none"]

"""``display`` style value. ``"none"`` removes the node and its subtree

from layout entirely (no size, gap, or margin contribution; every frame

in the subtree is ``(0, 0, 0, 0)``)."""

Overflow = Literal["visible", "hidden", "scroll"]

TextAlign = Literal["left", "center", "right", "justify", "start", "end"]

TextDecoration = Literal["none", "underline", "line_through"]

TextTransform = Literal["none", "uppercase", "lowercase", "capitalize"]

"""``text_transform`` style value. Applied in Python before the string

reaches the native label, so measurement and rendering agree."""

MarginValue = Union[Dimension, Literal["auto"]]

"""A margin length: points, a ``"%"`` string, or ``"auto"`` to absorb free space."""

FontWeight = Literal[

"normal",

"bold",

"100",

"200",

"300",

"400",

"500",

"600",

"700",

"800",

"900",

]

ScaleType = Literal["cover", "contain", "stretch", "center"]

KeyboardType = Literal[

"default",

"email_address",

"number_pad",

"decimal_pad",

"phone_pad",

"url",

]

AutoCapitalize = Literal["none", "sentences", "words", "characters"]

ReturnKeyType = Literal["default", "done", "go", "next", "send", "search"]

PointerEvents = Literal["auto", "none", "box_none", "box_only"]

"""Touch-handling mode for a view and its subtree:

- ``"auto"``: the view and its children receive touches (default).

- ``"none"``: neither the view nor its children receive touches;

touches pass through to whatever is underneath.

- ``"box_none"``: the view itself ignores touches but its children

still receive them (decorative overlays with interactive content).

- ``"box_only"``: the view receives touches but its children do not.

"""

# ======================================================================

# Style TypedDict

# ======================================================================

class Style(TypedDict, total=False):

"""Statically-typed style dictionary.

Lists every style property recognized by the built-in components

plus their layout engine, with enum-shaped values constrained via

[`Literal`][typing.Literal]. ``Style`` is a `total=False` TypedDict

so any subset of keys is valid at construction time.

Custom native components may accept additional, unlisted keys;

they are ignored by the built-in handlers but flow through the

reconciler unmodified, so third-party handlers can read them.

Example:

```python

import pythonnative as pn

title: pn.Style = {

"font_size": 24,

"color": "#0A84FF",

"text_align": "center",

}

pn.Text("Hello", style=title)

```

"""

# --- Layout: sizing ---

width: Dimension

height: Dimension

min_width: Dimension

max_width: Dimension

min_height: Dimension

max_height: Dimension

aspect_ratio: float

# --- Layout: flex ---

flex: float

flex_grow: float

flex_shrink: float

flex_basis: Dimension

flex_direction: FlexDirection

flex_wrap: FlexWrap

justify_content: JustifyContent

align_items: AlignItems

align_self: AlignSelf

align_content: AlignContent

direction: LayoutDirection

display: Display

# --- Layout: position ---

position: Position

top: Dimension

right: Dimension

bottom: Dimension

left: Dimension

start: Dimension

end: Dimension

# --- Layout: spacing ---

padding: EdgeValue

padding_top: Dimension

padding_bottom: Dimension

padding_left: Dimension

padding_right: Dimension

padding_start: Dimension

padding_end: Dimension

padding_horizontal: Dimension

padding_vertical: Dimension

margin: Union[MarginValue, EdgeInsets]

margin_top: MarginValue

margin_bottom: MarginValue

margin_left: MarginValue

margin_right: MarginValue

margin_start: MarginValue

margin_end: MarginValue

margin_horizontal: MarginValue

margin_vertical: MarginValue

spacing: float

gap: float

row_gap: float

column_gap: float

# --- Visual: clipping & overflow ---

overflow: Overflow

# --- Visual: colors ---

background_color: Color

color: Color

border_color: Color

placeholder_color: Color

tint_color: Color

# --- Visual: borders ---

border_width: float

border_radius: float

border_top_left_radius: float

border_top_right_radius: float

border_bottom_left_radius: float

border_bottom_right_radius: float

border_top_width: float

border_right_width: float

border_bottom_width: float

border_left_width: float

border_top_color: Color

border_right_color: Color

border_bottom_color: Color

border_left_color: Color

# --- Visual: typography ---

font_size: float

font_family: str

font_weight: FontWeight

bold: bool

italic: bool

text_align: TextAlign

text_decoration: TextDecoration

text_transform: TextTransform

line_height: float

letter_spacing: float

max_lines: int

text_shadow_color: Color

text_shadow_offset: ShadowOffsetValue

text_shadow_radius: float

# --- Visual: shadows / effects ---

shadow_color: Color

shadow_offset: ShadowOffsetValue

shadow_opacity: float

shadow_radius: float

elevation: float

opacity: float

transform: TransformSpec

# --- Interaction & stacking ---

z_index: int

pointer_events: PointerEvents

StyleProp = Union[Style, Dict[str, Any], List[Optional[Union[Style, Dict[str, Any]]]], None]

"""Public type for the ``style`` parameter on every component factory.

Accepts a [`Style`][pythonnative.Style] TypedDict (recommended), a

plain ``Dict[str, Any]`` (forward-compat / unrestricted), a list of

either with ``None`` entries skipped, or ``None``."""

# ======================================================================

# Runtime helpers

# ======================================================================

def style(**properties: Any) -> Style:

"""Construct a [`Style`][pythonnative.Style] from keyword arguments.

Equivalent to ``Style(...)`` but works with any Python version

(``TypedDict.__init__`` is fragile prior to 3.11) and reads more

naturally inside expressions:

```python

pn.View(child, style=pn.style(padding=16, background_color="#fff"))

```

Unknown keys are accepted at runtime to keep the door open for

third-party styling extensions; static type checkers will still

reject them when this helper's return type is annotated as

``Style``.

Args:

**properties: Style key/value pairs.

Returns:

A fresh ``Style`` dict containing the supplied entries.

"""

return properties # type: ignore[return-value]

def resolve_style(value: StyleProp) -> Dict[str, Any]:

"""Flatten a `style` prop into a single dict.

Accepts ``None``, a single dict (``Style`` or untyped), or a list of

dicts (later entries override earlier ones, mirroring React Native's

array-style pattern). Used by every built-in element factory in

`pythonnative.components`.

Args:

value: The raw value of the component's `style` argument.

Returns:

A flat dict suitable for the native handler. Always a fresh

dict, never the input.

"""

if value is None:

return {}

if isinstance(value, dict):

return dict(value)

result: Dict[str, Any] = {}

for entry in value:

if entry:

result.update(entry)

return result

_KNOWN_STYLE_KEYS = frozenset(Style.__annotations__)

"""Every key declared on the [`Style`][pythonnative.Style] TypedDict."""

_STYLE_VALUE_CHOICES: Dict[str, frozenset] = {

"display": frozenset(get_args(Display)),

"position": frozenset(get_args(Position)),

"direction": frozenset(get_args(LayoutDirection)),

"text_decoration": frozenset(get_args(TextDecoration)),

"text_transform": frozenset(get_args(TextTransform)),

"pointer_events": frozenset(get_args(PointerEvents)),

}

"""Keys whose string values are checked against their ``Literal`` choices

in dev mode. Only keys whose handlers accept exactly the declared

literals are listed, so friendly aliases (``align_items: "leading"``,

``font_weight: "semibold"``) never trigger false positives."""

def _is_number(value: Any) -> bool:

return isinstance(value, (int, float)) and not isinstance(value, bool)

def _text_shadow_offset_ok(value: Any) -> bool:

if isinstance(value, dict):

return all(_is_number(value.get(k, 0)) for k in ("width", "height"))

if isinstance(value, (tuple, list)) and len(value) == 2:

return all(_is_number(v) for v in value)

return False

def _bad_value_message(key: str, value: Any) -> Optional[str]:

"""Return a description of why ``value`` is invalid for ``key``, or ``None``."""

choices = _STYLE_VALUE_CHOICES.get(key)

if choices is not None:

if not isinstance(value, str) or value not in choices:

allowed = ", ".join(repr(c) for c in sorted(choices))

return f"Invalid value {value!r} for style key {key!r}; expected one of {allowed}."

return None

if key == "text_shadow_offset" and not _text_shadow_offset_ok(value):

return (

f"Invalid value {value!r} for style key 'text_shadow_offset'; "

"expected {'width': x, 'height': y} or an (x, y) pair."

)

if key == "text_shadow_radius" and (not _is_number(value) or value < 0):

return f"Invalid value {value!r} for style key 'text_shadow_radius'; expected a non-negative number."

return None

def validate_style_keys(style_dict: Dict[str, Any], owner: str = "") -> None:

"""Warn (once per key) about style keys no built-in handler reads.

Dev-mode only; production skips the scan entirely. Typos get a

"did you mean" suggestion via fuzzy matching against the declared

[`Style`][pythonnative.Style] keys. Unknown keys still flow through

to handlers untouched, so custom components that read extra keys

keep working (at the cost of one dev warning).

A small set of enum-shaped keys (``display``, ``position``,

``direction``, ``text_decoration``, ``text_transform``,

``pointer_events``) and the ``text_shadow_*`` keys also have their

values checked; a bad value warns once per key/value pair and is

otherwise passed through (the engine and handlers ignore values

they don't recognize).

Args:

style_dict: The flattened style dict about to be merged into an

element's props.

owner: Element type name for the warning message (e.g.

``"Text"``).

"""

if not diagnostics.is_dev() or not style_dict:

return

for key, value in style_dict.items():

if key in _KNOWN_STYLE_KEYS:

if value is None:

continue

problem = _bad_value_message(key, value)

if problem is not None:

diagnostics.warn_once(

problem + (f" (on {owner})" if owner else ""),

key=f"style-value:{owner}:{key}:{value!r}",

)

continue

matches = difflib.get_close_matches(str(key), _KNOWN_STYLE_KEYS, n=1)

hint = f" Did you mean {matches[0]!r}?" if matches else ""

diagnostics.warn_once(

f"Unknown style key {key!r}"

+ (f" on {owner}" if owner else "")

+ f".{hint} Built-in components ignore keys they don't recognize.",

key=f"style:{owner}:{key}",

)

# ======================================================================

# StyleSheet

# ======================================================================

class StyleSheet:

"""Utility for creating, composing, and flattening style dictionaries.

All methods are stateless and return fresh dicts, so the values can

be reused safely across components.

"""

@staticmethod

def create(**named_styles: Style) -> Dict[str, Style]:

"""Create a set of named styles from keyword arguments.

Args:

**named_styles: Each keyword argument is a style name

mapping to a [`Style`][pythonnative.Style] dict.

Returns:

A dict mapping each name to a copy of the supplied style,

so the caller can mutate the result without affecting the

originals.

Example:

```python

from pythonnative import StyleSheet, style

styles = StyleSheet.create(

heading=style(font_size=28, bold=True),

body=style(font_size=16),

)

```

"""

return {name: dict(props) for name, props in named_styles.items()} # type: ignore[misc]

@staticmethod

def compose(*styles: StyleProp) -> Style:

"""Merge multiple style dicts.

Args:

*styles: Style dicts to merge. Later dicts override keys

from earlier ones. Falsy entries (``None``) are skipped.

List entries are flattened in turn.

Returns:

A new ``Style`` dict containing the merged result.

"""

merged: Dict[str, Any] = {}

for entry in styles:

if entry is None:

continue

if isinstance(entry, dict):

merged.update(entry)

continue

for nested in entry:

if nested:

merged.update(nested)

return merged # type: ignore[return-value]

@staticmethod

def flatten(styles: StyleProp) -> Style:

"""Flatten a style value or list of styles into a single dict.

Equivalent to

[`resolve_style`][pythonnative.style.resolve_style] but exposed

on `StyleSheet` for parity with React Native's API and typed

as returning a ``Style``.

Args:

styles: A single dict, a list of dicts, or `None`.

Returns:

A flat ``Style`` dict combining the inputs.

"""

return resolve_style(styles) # type: ignore[return-value]

@staticmethod

def absolute_fill() -> Style:

"""Return a style that absolutely fills the parent.

Convenience preset matching React Native's

``StyleSheet.absoluteFill``: ``position: "absolute"`` with

every inset pinned to ``0``.

"""

return {"position": "absolute", "top": 0, "right": 0, "bottom": 0, "left": 0}

# ======================================================================

# Theming

# ======================================================================

@dataclass(frozen=True)

class Theme:

"""Design tokens read through [`use_theme`][pythonnative.use_theme].

A ``Theme`` is an immutable, fully typed record, so

``theme.text_color`` autocompletes and a typo is a static error

rather than a runtime ``KeyError``. Derive a custom theme from a

built-in one with [`replace`][pythonnative.style.Theme.replace]:

```python

brand = pn.DEFAULT_LIGHT_THEME.replace(primary_color="#FF2D55")

```

Attributes:

primary_color: Main accent color.

secondary_color: Secondary accent color.

background_color: Screen background.

surface_color: Raised surfaces such as cards and sheets.

text_color: Primary text.

text_secondary_color: De-emphasized text.

error_color: Destructive and error states.

success_color: Success states.

warning_color: Warning states.

font_size: Body text size, in points.

font_size_small: Caption size, in points.

font_size_large: Subtitle size, in points.

font_size_title: Title size, in points.

spacing: Base spacing unit, in points.

spacing_large: Large spacing unit, in points.

border_radius: Default corner radius, in points.

"""

primary_color: Color

secondary_color: Color

background_color: Color

surface_color: Color

text_color: Color

text_secondary_color: Color

error_color: Color

success_color: Color

warning_color: Color

font_size: float = 16

font_size_small: float = 13

font_size_large: float = 20

font_size_title: float = 28

spacing: float = 8

spacing_large: float = 16

border_radius: float = 8

def replace(self, **changes: Any) -> "Theme":

"""Return a copy of this theme with the given fields replaced.

Raises:

TypeError: If ``changes`` names a field that doesn't exist.

"""

return dataclasses.replace(self, **changes)

DEFAULT_LIGHT_THEME = Theme(

primary_color="#007AFF",

secondary_color="#5856D6",

background_color="#FFFFFF",

surface_color="#F2F2F7",

text_color="#000000",

text_secondary_color="#8E8E93",

error_color="#FF3B30",

success_color="#34C759",

warning_color="#FF9500",

)

"""Built-in light theme selected by [`use_theme`][pythonnative.use_theme]."""

DEFAULT_DARK_THEME = Theme(

primary_color="#0A84FF",

secondary_color="#5E5CE6",

background_color="#000000",

surface_color="#1C1C1E",

text_color="#FFFFFF",

text_secondary_color="#8E8E93",

error_color="#FF453A",

success_color="#30D158",

warning_color="#FF9F0A",

)

"""Built-in dark theme selected by [`use_theme`][pythonnative.use_theme]."""

_FOLLOW_SYSTEM_THEME = object()

"""Sentinel default for `ThemeContext`: resolve from the color scheme."""

ThemeContext: Context = create_context(_FOLLOW_SYSTEM_THEME)

"""Theme context that follows the system color scheme by default.

Without a provider, [`use_theme`][pythonnative.use_theme] resolves to

[`DEFAULT_LIGHT_THEME`][pythonnative.style.DEFAULT_LIGHT_THEME] or

[`DEFAULT_DARK_THEME`][pythonnative.style.DEFAULT_DARK_THEME] based on

the current appearance. Wrap a subtree in

[`ThemeContext.Provider(my_theme, ...)`][pythonnative.hooks.Context.Provider] to

pin an explicit theme for that subtree, then read it inside

descendants via [`use_theme`][pythonnative.use_theme] (or

[`use_context(ThemeContext)`][pythonnative.use_context]).

"""

def default_theme(scheme: str) -> Theme:

"""Return the built-in [`Theme`][pythonnative.Theme] for ``scheme`` (``"light"`` / ``"dark"``)."""

return DEFAULT_DARK_THEME if scheme == "dark" else DEFAULT_LIGHT_THEME

def use_theme() -> Theme:

"""Return the active [`Theme`][pythonnative.Theme], following the system appearance by default.

If an ancestor mounted a ``ThemeContext.Provider(...)``, that

theme is returned as-is. Otherwise the built-in light or dark

theme is selected from the effective color scheme (via

[`use_color_scheme`][pythonnative.use_color_scheme], so the

component re-renders when the system appearance flips).

Returns:

The active theme.

Raises:

RuntimeError: If called outside a `@component` function.

Example:

```python

import pythonnative as pn

@pn.component

def Card():

theme = pn.use_theme()

return pn.View(

pn.Text("Hello", style=pn.style(color=theme.text_color)),

style=pn.style(background_color=theme.surface_color),

)

```

"""

scheme = use_color_scheme()

theme = use_context(ThemeContext)

if theme is _FOLLOW_SYSTEM_THEME:

return default_theme(scheme)

if not isinstance(theme, Theme):

raise TypeError(f"ThemeContext.Provider expects a pn.Theme, got {type(theme).__name__}: {theme!r}")

return theme

__all__ = [

"AlignItems",

"AlignSelf",

"AutoCapitalize",

"Color",

"DEFAULT_DARK_THEME",

"DEFAULT_LIGHT_THEME",

"Dimension",

"Display",

"EdgeInsets",

"EdgeValue",

"FlexDirection",

"FontWeight",

"JustifyContent",

"KeyboardType",

"MarginValue",

"Overflow",

"PointerEvents",

"Position",

"ReturnKeyType",

"ScaleType",

"ShadowOffset",

"ShadowOffsetValue",

"Style",

"StyleProp",

"StyleSheet",

"TextAlign",

"TextDecoration",

"TextTransform",

"Theme",

"ThemeContext",

"TransformEntry",

"TransformRotate",

"TransformScale",

"TransformScaleX",

"TransformScaleY",

"TransformSpec",

"TransformTranslate",

"default_theme",

"resolve_style",

"style",

"use_theme",

"validate_style_keys",

]

pythonnative/src/pythonnative/style.py at v0.43.1 · pythonnative/pythonnative · GitHub

Repository navigation

Expand file tree

Breadcrumbs

style.py

Latest commit

History

Breadcrumbs

style.py

File metadata and controls