Coverage for gws-app/gws/lib/svg/draw.py: 82%

1"""Build SVG fragments from shapes and drawing soups."""

3from typing import Optional, cast

5import base64

6import math

7import shapely

8import shapely.geometry

9import shapely.ops

11import gws

12import gws.lib.extent

13import gws.lib.font

14import gws.lib.shape

15import gws.lib.uom

16import gws.lib.xmlx as xmlx

18from . import element

20DEFAULT_FONT_SIZE = 10

21DEFAULT_MARKER_SIZE = 10

22DEFAULT_POINT_SIZE = 10

24MAX_SOUP_POINTS = 5000

25MAX_SOUP_TAGS = 5000

28def shape_to_fragment(shape: gws.Shape, view: gws.MapView, label: str = None, style: gws.Style = None) -> list[gws.XmlElement]:

29 """Convert a shape to an SVG fragment.

31 The shape is transformed to pixel coordinates using the view. Without a style, only the geometry is drawn.

32 With a style, the fragment can contain a marker definition, the geometry, an icon and a label,

33 depending on the style values and the view scale.

35 Args:

36 shape: Shape to draw.

37 view: Map view, which defines the pixel transformation, scale and dpi.

38 label: Label text, can contain newlines.

39 style: Style to apply.

41 Returns:

42 A list of SVG elements, empty if the shape is missing or empty.

44 Raises:

45 ``gws.Error``: If the geometry type is not supported.

46 """

48 if not shape:

49 return []

51 geom = cast(gws.lib.shape.Shape, shape).geom

52 if geom.is_empty:

53 return []

55 trans = _map_view_transformer(view)

56 geom = shapely.ops.transform(trans, geom)

58 if not style:

59 return [_geometry(geom)]

61 sv = style.values

62 with_geometry = sv.with_geometry == 'all'

63 with_label = label and _is_label_visible(view, sv)

64 gt = _geom_type(geom)

66 text = None

68 if with_label:

69 extra_y_offset = 0

70 if sv.label_offset_y is None:

71 if gt == _TYPE_POINT:

72 extra_y_offset = (sv.label_font_size or DEFAULT_FONT_SIZE) * 2

73 if gt == _TYPE_LINESTRING:

74 extra_y_offset = 6

75 text = _label(geom, label, sv, extra_y_offset)

77 marker = None

78 marker_id = None

80 if with_geometry and sv.marker:

81 marker_id = '_M' + gws.u.random_string(8)

82 marker = _marker(marker_id, sv)

84 atts: dict = {}

86 icon = None

88 if with_geometry and sv.icon is not None:

89 res = _parse_icon(sv.icon, view.dpi)

90 if res:

91 icon_el, w, h = res

92 x, y, w, h = _icon_size_and_position(geom, sv, w, h)

93 atts = {

94 'x': f'{int(x)}',

95 'y': f'{int(y)}',

96 'width': f'{int(w)}',

97 'height': f'{int(h)}',

98 }

99 icon = xmlx.tag(

100 icon_el.name,

101 gws.u.merge(icon_el.attrib, atts),

102 *icon_el.children()

103 )

104

105 body = None

106

107 if with_geometry:

108 _add_paint_atts(atts, sv)

109 if marker:

110 atts['marker-start'] = atts['marker-mid'] = atts['marker-end'] = f'url(#{marker_id})'

111 if gt in {_TYPE_POINT, _TYPE_MULTIPOINT}:

112 atts['r'] = (sv.point_size or DEFAULT_POINT_SIZE) // 2

113 if gt in {_TYPE_LINESTRING, _TYPE_MULTILINESTRING}:

114 atts['fill'] = 'none'

115 body = _geometry(geom, atts)

116

117 return gws.u.compact([marker, body, icon, text])

118

119

120def soup_to_fragment(view: gws.MapView, points: list[gws.Point], tags: list) -> list[gws.XmlElement]:

121 """Convert an SVG "soup" to an SVG fragment.

122

123 A soup represents client-side SVG drawings (e.g. dimensions) in a resolution-independent way.

124 It has two components:

125

126 - a list of points, in the map coordinate system,

127 - a list of tuples ``(tag-name, {atts}, child1, child2, ...)``, where children are tuples of the same form or strings.

128

129 First, points are converted to pixels using the view's transform. Then, the attributes of each tag are evaluated.

130 If an attribute value is a list, it is a function call: the first element is a function name,

131 the rest are arguments. The functions are:

132

133 - ``['x', n]``: returns the x pixel coordinate of ``points[n]``,

134 - ``['y', n]``: returns the y pixel coordinate of ``points[n]``,

135 - ``['r', p1, p2, r]``: computes the slope between ``points[p1]`` and ``points[p2]`` and returns

136 ``rotate(slope, x, y)`` with the coordinates of ``points[r]``.

137

138 The result is normalized, so unsafe tags and attributes are removed.

139

140 Args:

141 view: Map view, which defines the pixel transformation.

142 points: Points in map coordinates.

143 tags: Tag tuples.

144

145 Returns:

146 A list of SVG elements.

147

148 Raises:

149 ``gws.Error``: If the soup is too large or invalid, or uses an unknown function.

150 """

151

152 if len(points) > MAX_SOUP_POINTS:

153 raise gws.Error(f'too many soup points: {len(points)}')

154 if len(tags) > MAX_SOUP_TAGS:

155 raise gws.Error(f'too many soup tags: {len(tags)}')

156

157 trans = _map_view_transformer(view)

158

159 try:

160 px = [trans(*p) for p in points]

161 except Exception as exc:

162 raise gws.Error('invalid soup') from exc

163

164 def eval_func(v):

165 if v[0] == 'x':

166 return round(px[v[1]][0])

167 if v[0] == 'y':

168 return round(px[v[1]][1])

169 if v[0] == 'r':

170 a = _slope(px[v[1]], px[v[2]])

171 adeg = math.degrees(a)

172 x, y = px[v[3]]

173 return f'rotate({adeg:.0f}, {x:.0f}, {y:.0f})'

174 raise gws.Error(f'unknown soup function: {v[0]!r}')

175

176 def eval_funcs(tag):

177 res = []

178 for arg in tag:

179 if isinstance(arg, dict):

180 d = {}

181 for k, v in arg.items():

182 d[k] = eval_func(v) if isinstance(v, (list, tuple)) else v

183 res.append(d)

184 elif isinstance(arg, (list, tuple)):

185 res.append(eval_funcs(arg))

186 else:

187 res.append(arg)

188 return res

189

190 def soup_tag(ls):

191 args = [soup_tag(a) if isinstance(a, (list, tuple)) else a for a in ls[1:]]

192 return xmlx.tag(ls[0], *args)

193

194 els = []

195

196 try:

197 for tag in tags:

198 els.append(soup_tag(eval_funcs(tag)))

199 except Exception as exc:

200 raise gws.Error('invalid soup') from exc

201

202 return element.normalize_fragment(els)

203

204

205# ----------------------------------------------------------------------------------------------------------------------

206# transform

207

208def _map_view_transformer(view: gws.MapView):

209 """Create a transformer from map coordinates to pixel coordinates of a view.

210

211 Pixel coordinates are integers, relative to the top left corner of the view

212 at the view's scale and DPI. For a rotated view, points are rotated around the view center.

213

214 Args:

215 view: Map view.

216

217 Returns:

218 A function ``f(x, y) -> (px, py)``.

219 """

220

221 # @TODO cache the transformer

222

223 def translate(x, y):

224 x = x - ext[0]

225 y = ext[3] - y

226 return x * m2px, y * m2px

227

228 def translate_int(x, y):

229 x, y = translate(x, y)

230 return int(x), int(y)

231

232 def rotate(x, y):

233 return (

234 cosa * (x - ox) - sina * (y - oy) + ox,

235 sina * (x - ox) + cosa * (y - oy) + oy)

236

237 def translate_rotate_int(x, y):

238 x, y = translate(x, y)

239 x, y = rotate(x, y)

240 return int(x), int(y)

241

242 m2px = 1000.0 * gws.lib.uom.mm_to_px(1 / view.scale, view.dpi)

243

244 ext = view.bounds.extent

245

246 if not view.rotation:

247 return translate_int

248

249 ox, oy = translate(*gws.lib.extent.center(ext))

250 cosa = math.cos(math.radians(view.rotation))

251 sina = math.sin(math.radians(view.rotation))

252

253 return translate_rotate_int

254

255

256# ----------------------------------------------------------------------------------------------------------------------

257# geometry

258

259def _geometry(geom: shapely.geometry.base.BaseGeometry, atts: dict = None) -> gws.XmlElement:

260 def _xy(xy):

261 x, y = xy

262 return f'{x} {y}'

263

264 def _lpath(coords):

265 ps = []

266 cs = iter(coords)

267 for c in cs:

268 ps.append(f'M {_xy(c)}')

269 break

270 for c in cs:

271 ps.append(f'L {_xy(c)}')

272 return ' '.join(ps)

273

274 gt = _geom_type(geom)

275

276 if gt == _TYPE_POINT:

277 g = cast(shapely.geometry.Point, geom)

278 return xmlx.tag('circle', {'cx': int(g.x), 'cy': int(g.y)}, atts)

279

280 if gt == _TYPE_LINESTRING:

281 g = cast(shapely.geometry.LineString, geom)

282 d = _lpath(g.coords)

283 return xmlx.tag('path', {'d': d}, atts)

284

285 if gt == _TYPE_POLYGON:

286 g = cast(shapely.geometry.Polygon, geom)

287 d = ' '.join(_lpath(interior.coords) + ' z' for interior in g.interiors)

288 d = _lpath(g.exterior.coords) + ' z ' + d

289 return xmlx.tag('path', {'fill-rule': 'evenodd', 'd': d.strip()}, atts)

290

291 if gt >= _TYPE_MULTIPOINT:

292 g = cast(shapely.geometry.base.BaseMultipartGeometry, geom)

293 return xmlx.tag('g', *[_geometry(p, atts) for p in g.geoms])

294

295

296def _enum_points(geom):

297 gt = _geom_type(geom)

298

299 if gt in {_TYPE_POINT, _TYPE_LINESTRING, _TYPE_LINEARRING}:

300 return geom.coords

301 if gt == _TYPE_POLYGON:

302 return geom.exterior.coords

303 if gt >= _TYPE_MULTIPOINT:

304 return [p for g in geom.geoms for p in _enum_points(g)]

305

306

307# https://shapely.readthedocs.io/en/stable/reference/shapely.get_type_id.html

308

309_TYPE_POINT = 0

310_TYPE_LINESTRING = 1

311_TYPE_LINEARRING = 2

312_TYPE_POLYGON = 3

313_TYPE_MULTIPOINT = 4

314_TYPE_MULTILINESTRING = 5

315_TYPE_MULTIPOLYGON = 6

316_TYPE_GEOMETRYCOLLECTION = 7

317

318

319def _geom_type(geom):

320 p = shapely.get_type_id(geom)

321 if _TYPE_POINT <= p <= _TYPE_MULTIPOLYGON:

322 return p

323 raise gws.Error(f'unsupported geometry type {geom.type!r}')

324

325

326# ----------------------------------------------------------------------------------------------------------------------

327# marker

328

329# @TODO only type=circle is implemented

330

331def _marker(uid, sv: gws.StyleValues) -> gws.XmlElement:

332 size = sv.marker_size or DEFAULT_MARKER_SIZE

333 size2 = size // 2

334

335 content = None

336 atts: dict = {}

337

338 _add_paint_atts(atts, sv, 'marker_')

339

340 if sv.marker == 'circle':

341 atts.update({

342 'cx': size2,

343 'cy': size2,

344 'r': size2,

345 })

346 content = xmlx.tag('circle', atts)

347

348 if content:

349 return xmlx.tag('marker', {

350 'id': uid,

351 'viewBox': f'0 0 {size} {size}',

352 'refX': size2,

353 'refY': size2,

354 'markerUnits': 'userSpaceOnUse',

355 'markerWidth': size,

356 'markerHeight': size,

357 }, content)

358

359

360# ----------------------------------------------------------------------------------------------------------------------

361# labels

362

363# @TODO label positioning needs more work

364

365def _is_label_visible(view: gws.MapView, sv: gws.StyleValues) -> bool:

366 if sv.with_label != 'all':

367 return False

368 if view.scale < int(sv.get('label_min_scale', 0)):

369 return False

370 if view.scale > int(sv.get('label_max_scale', 1e10)):

371 return False

372 return True

373

374

375def _label(geom, label: str, sv: gws.StyleValues, extra_y_offset=0) -> gws.XmlElement:

376 xy = _label_position(geom, sv, extra_y_offset)

377 return _label_text(xy[0], xy[1], label, sv)

378

379

380def _label_position(geom, sv: gws.StyleValues, extra_y_offset=0) -> gws.Point:

381 if sv.label_placement == 'start':

382 x, y = _enum_points(geom)[0]

383 elif sv.label_placement == 'end':

384 x, y = _enum_points(geom)[-1]

385 else:

386 c = geom.centroid

387 x, y = c.x, c.y

388 return (

389 round(x) + (sv.label_offset_x or 0),

390 round(y) + extra_y_offset + (sv.label_font_size >> 1) + (sv.label_offset_y or 0)

391 )

392

393

394def _label_text(cx, cy, label, sv: gws.StyleValues) -> gws.XmlElement:

395 font_name = _font_name(sv)

396 font_size = sv.label_font_size or DEFAULT_FONT_SIZE

397 font = gws.lib.font.from_name(font_name, font_size)

398

399 anchor = 'start'

400

401 if sv.label_align == 'right':

402 anchor = 'end'

403 elif sv.label_align == 'center':

404 anchor = 'middle'

405

406 atts = {'text-anchor': anchor}

407

408 _add_font_atts(atts, sv, 'label_')

409 _add_paint_atts(atts, sv, 'label_')

410

411 lines = label.split('\n')

412 _, em_height = _font_size(font, 'MMM')

413 metrics = [_font_size(font, s) for s in lines]

414

415 line_height = sv.label_line_height or 1

416 padding = sv.label_padding or [0, 0, 0, 0]

417

418 ly = cy - padding[2]

419 lx = cx

420

421 if anchor == 'start':

422 lx += padding[3]

423 elif anchor == 'end':

424 lx -= padding[1]

425 else:

426 lx += padding[3] // 2

427

428 height = em_height * len(lines) + line_height * (len(lines) - 1) + padding[0] + padding[2]

429

430 pad_bottom = metrics[-1][1] - em_height

431 if pad_bottom > 0:

432 height += pad_bottom

433 ly -= pad_bottom

434

435 spans = []

436 for s in reversed(lines):

437 spans.append(xmlx.tag('tspan', {'x': lx, 'y': ly}, s))

438 ly -= (em_height + line_height)

439

440 tags = []

441

442 tags.append(xmlx.tag('text', atts, *reversed(spans)))

443

444 # @TODO a hack to emulate 'paint-order' which wkhtmltopdf doesn't seem to support

445 # place a copy without the stroke above the text

446 if atts.get('stroke'):

447 no_stroke_atts = {k: v for k, v in atts.items() if not k.startswith('stroke')}

448 tags.append(xmlx.tag('text', no_stroke_atts, *reversed(spans)))

449

450 # @TODO label backgrounds don't really work

451 if sv.label_background:

452 width = max(xy[0] for xy in metrics) + padding[1] + padding[3]

453

454 if anchor == 'start':

455 bx = cx

456 elif anchor == 'end':

457 bx = cx - width

458 else:

459 bx = cx - width // 2

460

461 ratts = {

462 'x': bx,

463 'y': cy - height,

464 'width': width,

465 'height': height,

466 'fill': sv.label_background,

467 }

468

469 tags.insert(0, xmlx.tag('rect', ratts))

470

471 # a hack to move labels forward: emit a (non-supported) z-index attribute

472 # and sort elements by it later on (see `fragment_to_element`)

473

474 return xmlx.tag('g', {'z-index': 100}, *tags)

475

476

477# ----------------------------------------------------------------------------------------------------------------------

478# icons

479

480# @TODO options for icon positioning

481

482

483def _parse_icon(svg: gws.XmlElement, dpi) -> Optional[tuple[gws.XmlElement, float, float]]:

484 # see lib.style.icon

485

486 if not isinstance(svg, gws.XmlElement):

487 return

488

489 w = svg.get('width')

490 h = svg.get('height')

491

492 if not w or not h:

493 gws.log.error(f'xml_icon: width and height required')

494 return

495

496 try:

497 w, wu = gws.lib.uom.parse(w, gws.Uom.px)

498 h, hu = gws.lib.uom.parse(h, gws.Uom.px)

499 except ValueError:

500 gws.log.error(f'xml_icon: invalid units: {w!r} {h!r}')

501 return

502

503 if wu == gws.Uom.mm:

504 w = gws.lib.uom.mm_to_px(w, dpi)

505 if hu == gws.Uom.mm:

506 h = gws.lib.uom.mm_to_px(h, dpi)

507

508 return svg, w, h

509

510

511def _icon_size_and_position(geom, sv, width, height) -> tuple[int, int, int, int]:

512 c = geom.centroid

513 return (

514 int(c.x - width / 2),

515 int(c.y - height / 2),

516 int(width),

517 int(height))

518

519

520# ----------------------------------------------------------------------------------------------------------------------

521# fonts

522

523# @TODO: allow for more fonts and customize the mapping

524

525

526_DEFAULT_FONT = 'DejaVuSans'

527

528

529def _add_font_atts(atts, sv, prefix=''):

530 font_name = _font_name(sv, prefix)

531 font_size = sv.get(prefix + 'font_size') or DEFAULT_FONT_SIZE

532

533 atts.update(gws.u.compact({

534 'font-family': font_name.split('-')[0],

535 'font-size': f'{font_size}px',

536 'font-weight': sv.get(prefix + 'font_weight'),

537 'font-style': sv.get(prefix + 'font_style'),

538 }))

539

540

541def _font_name(sv, prefix=''):

542 w = sv.get(prefix + 'font_weight')

543 if w == 'bold':

544 return _DEFAULT_FONT + '-Bold'

545 return _DEFAULT_FONT

546

547

548def _font_size(font, text):

549 bb = font.getbbox(text)

550 return bb[2] - bb[0], bb[3] - bb[1]

551

552

553# ----------------------------------------------------------------------------------------------------------------------

554# paint

555

556def _add_paint_atts(atts, sv, prefix=''):

557 atts['fill'] = sv.get(prefix + 'fill') or 'none'

558

559 v = sv.get(prefix + 'stroke')

560 if not v:

561 return

562

563 atts['stroke'] = v

564

565 v = sv.get(prefix + 'stroke_width')

566 atts['stroke-width'] = f'{v or 1}px'

567

568 v = sv.get(prefix + 'stroke_dasharray')

569 if v:

570 atts['stroke-dasharray'] = ' '.join(str(x) for x in v)

571

572 for k in 'dashoffset', 'linecap', 'linejoin', 'miterlimit':

573 v = sv.get(prefix + 'stroke_' + k)

574 if v:

575 atts['stroke-' + k] = v

576

577

578# ----------------------------------------------------------------------------------------------------------------------

579# misc

580

581def _slope(a: gws.Point, b: gws.Point) -> float:

582 # slope between two points

583 dx = b[0] - a[0]

584 dy = b[1] - a[1]

585

586 if dx == 0:

587 dx = 0.01

588

589 return math.atan(dy / dx)