# Coverage for pygeodesy/clipy.py : 94%

## 242 statements 227 run 15 missing 16 excluded

Hot-keys on this page

r m x p toggle line displays

j k next/prev highlighted chunk

0 (zero) top of page

1 (one) first highlighted chunk

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 | # -*- coding: utf-8 -*- u'''Functions to I{clip} a path or polygon of C{LatLon} points against a rectangular box or clip region. @newfield example: Example, Examples ''' from pygeodesy.basics import len2 from pygeodesy.errors import _AssertionError, PointsError, _ValueError from pygeodesy.fmath import fsum_ from pygeodesy.formy import points2 from pygeodesy.interns import EPS, _dot_, _end_, _lat_, _lon_, _name_, \ NN, _not_convex_, _start_, _too_few_, _0_0 from pygeodesy.lazily import _ALL_DOCS, _ALL_LAZY from pygeodesy.named import _Named, _NamedTuple, _Pass from pygeodesy.points import areaOf, _imdex2, boundsOf, isconvex_, \ LatLon_ as LL_ from pygeodesy.units import Bool, Number_ __all__ = _ALL_LAZY.clipy __version__ = '20.09.15' class ClipError(_ValueError): '''Clip box or clip region issue. ''' def __init__(self, *name_n_corners, **txt): '''New L{ClipError}. @arg name_n_corners: Either just a name (C{str}) or name, number, corners (C{str}, C{int}, C{tuple}). @kwarg txt: Optional explanation of the error (C{str}). ''' if len(name_n_corners) == 3: t, n, v = name_n_corners n = 'box' if n == 2 else 'region' n = '%s clip %s' % (t, n) name_n_corners = n, v _ValueError.__init__(self, *name_n_corners, **txt) def _eq(p1, p2): '''(INTERNAL) Check for near-equal points. ''' return not _neq(p1, p2) def _neq(p1, p2): '''(INTERNAL) Check for not near-equal points. ''' return abs(p1.lat - p2.lat) > EPS or \ abs(p1.lon - p2.lon) > EPS def _points2(points, closed, inull): '''(INTERNAL) Get the points to clip. ''' if closed and inull: n, pts = len2(points) # only remove the final, closing point if n > 1 and _eq(pts[n-1], pts[0]): n -= 1 pts = pts[:n] if n < 3: raise PointsError(points=n, txt=_too_few_) else: n, pts = points2(points, closed=closed) return n, list(pts) class _CS(_Named): '''(INTERNAL) Cohen-Sutherland line clipping. ''' # single-bit clip codes _IN = 0 # inside clip box _XMAX = 1 # right of upperright.lon _XMIN = 2 # left of lowerleft.lon _YMAX = 4 # above upperright.lat _YMIN = 8 # below lowerleft.lat _dx = _0_0 # pts edge delta lon _dy = _0_0 # pts edge delta lat _x1 = _0_0 # pts corner _y1 = _0_0 # pts corner _xmax = _0_0 # clip box upperright.lon _xmin = _0_0 # clip box lowerleft.lon _ymax = _0_0 # clip box upperright.lat _ymin = _0_0 # clip box lowerleft.lat def __init__(self, lowerleft, upperright, name=__name__): try: self._ymin, self._ymax = lowerleft.lat, upperright.lat self._xmin, self._xmax = lowerleft.lon, upperright.lon if self._xmin > self._xmax or self._ymin > self._ymax: raise ValueError except (AttributeError, TypeError, ValueError) as x: raise ClipError(name, 2, (lowerleft, upperright), txt=str(x)) self.name = name # def clip4(self, p, c): # clip point p for code c # if c & _CS._YMIN: # return self.lon4(p, self._ymin) # elif c & _CS._YMAX: # return self.lon4(p, self._ymax) # elif c & _CS._XMIN: # return self.lat4(p, self._xmin) # elif c & _CS._XMAX: # return self.lat4(p, self._xmax) # # should never get here # raise _AssertionError(_dot_(self._name, self.clip4.__name__)) def code4(self, p): # compute code for point p if p.lat < self._ymin: c, m, b = _CS._YMIN, self.lon4, self._ymin elif p.lat > self._ymax: c, m, b = _CS._YMAX, self.lon4, self._ymax else: c, m, b = _CS._IN, self.nop4, None if p.lon < self._xmin: c |= _CS._XMIN m, b = self.lat4, self._xmin elif p.lon > self._xmax: c |= _CS._XMAX m, b = self.lat4, self._xmax return c, m, b, p def edge(self, p1, p2): # set edge p1 to p2 self._y1, self._dy = p1.lat, float(p2.lat - p1.lat) self._x1, self._dx = p1.lon, float(p2.lon - p1.lon) return abs(self._dx) > EPS or abs(self._dy) > EPS def lat4(self, x, p): # new lat and code at lon x y = self._y1 + self._dy * float(x - self._x1) / self._dx if y < self._ymin: # still outside return _CS._YMIN, self.lon4, self._ymin, p elif y > self._ymax: # still outside return _CS._YMAX, self.lon4, self._ymax, p else: # inside return _CS._IN, self.nop4, None, p.classof(y, x) def lon4(self, y, p): # new lon and code at lat y x = self._x1 + self._dx * float(y - self._y1) / self._dy if x < self._xmin: # still outside return _CS._XMIN, self.lat4, self._xmin, p elif x > self._xmax: # still outside return _CS._XMAX, self.lat4, self._xmax, p else: # inside return _CS._IN, self.nop4, None, p.classof(y, x) def nop4(self, b, p): # PYCHOK no cover if p: # should never get here raise _AssertionError(_dot_(self.name, self.nop4.__name__)) return _CS._IN, self.nop4, b, p class ClipCS3Tuple(_NamedTuple): '''3-Tuple C{(start, end, index)} for each edge of a I{clipped} path with the C{start} and C{end} points (C{LatLon}) of the portion of the edge inside or on the clip box and the C{index} (C{int}) of the edge in the original path. ''' _Names_ = (_start_, _end_, 'index') _Units_ = (_Pass, _Pass, Number_) def clipCS3(points, lowerleft, upperright, closed=False, inull=False): '''Clip a path against a rectangular clip box using the U{Cohen-Sutherland <https://WikiPedia.org/wiki/Cohen-Sutherland_algorithm>} algorithm. @arg points: The points (C{LatLon}[]). @arg lowerleft: Bottom-left corner of the clip box (C{LatLon}). @arg upperright: Top-right corner of the clip box (C{LatLon}). @kwarg closed: Optionally, close the path (C{bool}). @kwarg inull: Optionally, retain null edges if inside (C{bool}). @return: Yield a L{ClipCS3Tuple}C{(start, end, index)} for each edge of the clipped path. @raise ClipError: The B{C{lowerleft}} and B{C{upperright}} corners specify an invalid clip box. @raise PointsError: Insufficient number of B{C{points}}. ''' cs = _CS(lowerleft, upperright, name=clipCS3.__name__) n, pts = _points2(points, closed, inull) i, m = _imdex2(closed, n) cmbp = cs.code4(pts[i]) for i in range(m, n): c1, m1, b1, p1 = cmbp c2, m2, b2, p2 = cmbp = cs.code4(pts[i]) if c1 & c2: # edge outside continue if not cs.edge(p1, p2): if inull: # null edge if not c1: yield ClipCS3Tuple(p1, p1, i) elif not c2: yield ClipCS3Tuple(p2, p2, i) continue for _ in range(5): if c1: # clip p1 c1, m1, b1, p1 = m1(b1, p1) elif c2: # clip p2 c2, m2, b2, p2 = m2(b2, p2) else: # inside if inull or _neq(p1, p2): yield ClipCS3Tuple(p1, p2, i) break if c1 & c2: # edge outside break else: # PYCHOK no cover raise _AssertionError(_dot_(cs.name, 'for_else')) class _List(list): '''(INTERNAL) List of clipped points. ''' _inull = False def __init__(self, inull): self._inull = inull list.__init__(self) def append(self, p): if (not self) or self._inull or _neq(p, self[-1]): list.append(self, p) class _LLi_(LL_): '''(INTERNAL) LatLon_ for _SH intersections. ''' __slots__ = _lat_, _lon_, 'classof', 'edge', _name_ def __init__(self, lat, lon, classof, edge): self.lat = lat self.lon = lon self.classof = classof self.edge = edge # clip edge self.name = NN class _SH(_Named): '''(INTERNAL) Sutherland-Hodgman polyon clipping. ''' _cs = () # clip corners _cw = 0 # counter-/clockwise _dx = _0_0 # clip edge[e] delta lon _dy = _0_0 # clip edge[e] delta lat _nc = 0 # len(._cs) _x1 = _0_0 # clip edge[e] lon origin _xy = _0_0 # see .clipedges _y1 = _0_0 # clip edge[e] lat origin def __init__(self, corners, name=__name__): n, cs = 0, corners try: # check the clip box/region n, cs = len2(cs) if n == 2: # make a box b, l, t, r = boundsOf(cs, wrap=False) cs = LL_(b, l), LL_(t, l), LL_(t, r), LL_(b, r) n, cs = points2(cs, closed=True) self._cs = cs = cs[:n] self._nc = n self._cw = isconvex_(cs, adjust=False, wrap=False) if not self._cw: raise ValueError(_not_convex_) if areaOf(cs, adjust=True, radius=1, wrap=True) < EPS: raise ValueError('near-zero area') except (PointsError, TypeError, ValueError) as x: raise ClipError(name, n, cs, txt=str(x)) self.name = name def clip2(self, points, closed, inull): # MCCABE 17, clip points np, pts = _points2(points, closed, inull) pcs = _List(inull) # clipped points ne = 0 # number of non-null clip edges no = ni = True # all out- and inside? for e in self.clipedges(): ne += 1 # non-null clip edge # clip points, closed always d2, p2 = self.dot2(pts[np - 1]) for i in range(np): d1, p1 = d2, p2 d2, p2 = self.dot2(pts[i]) if d1 < 0: # p1 inside, ... # pcs.append(p1) if d2 < 0: # ... p2 inside p = p2 else: # ... p2 outside p = self.intersect(p1, p2, e) if d2 > 0: no = False pcs.append(p) elif d2 < 0: # p1 out-, p2 inside p = self.intersect(p1, p2, e) pcs.append(p) pcs.append(p2) if d1 > 0: no = ni = False elif d1 > 0: # both out ni = False if pcs: # replace points pts[:] = pcs pcs[:] = [] np = len(pts) if ne < 3: raise ClipError(self.name, ne, self._cs, txt=_too_few_) # ni is True iff all points are on or on the # right side (i.e. inside) of all clip edges, # no is True iff all points are on or at one # side (left or right) of each clip edge: if # none are inside (ni is False) and if all # are on the same side (no is True), then all # must be outside if no and not ni: np, pts = 0, [] elif np > 1: p = pts[0] if closed: # close clipped pts if _neq(pts[np - 1], p): pts.append(p) np += 1 elif not inull: # open clipped pts while np > 0 and _eq(pts[np - 1], p): pts.pop() np -= 1 # assert len(pts) == np return np, pts def clipedges(self): # yield clip edge index # and set self._x1, ._y1, ._dx, ._dy and # ._xy for each non-null clip edge c2 = self._cs[self._nc - 1] for e in range(self._nc): c1, c2 = c2, self._cs[e] self._y1, self._dy = c1.lat, float(c2.lat - c1.lat) self._x1, self._dx = c1.lon, float(c2.lon - c1.lon) if abs(self._dx) > EPS or abs(self._dy) > EPS: self._xy = self._y1 * self._dx - self._x1 * self._dy yield e + 1 def clipped2(self, p): # return (clipped point [i], edge) if isinstance(p, _LLi_): # intersection point return p.classof(p.lat, p.lon), p.edge else: # original point return p, 0 def dot2(self, p): # dot product of point p to the current # clip corner c1 and clip edge c1 to c2, indicating whether # points[i] is located to the right, to the left or on top # of the (extended) clip edge from c1 to c2 d = self._dx * float(p.lat - self._y1) - \ self._dy * float(p.lon - self._x1) # clockwise corners, +1 means points[i] is to the right # of, -1 means on the left of, 0 means on edge c1 to c2 d = (-self._cw) if d < 0 else (self._cw if d > 0 else 0) return d, p def intersect(self, p1, p2, edge): # compute intersection # of polygon edge p1 to p2 and the current clip edge, # where p1 and p2 are known to NOT be located on the # same side or on top of the current clip edge # <https://StackOverflow.com/questions/563198/ # how-do-you-detect-where-two-line-segments-intersect> fy = float(p2.lat - p1.lat) fx = float(p2.lon - p1.lon) fp = fy * self._dx - fx * self._dy if abs(fp) < EPS: # PYCHOK no cover raise _AssertionError(_dot_(self.name, self.intersect.__name__)) r = fsum_(self._xy, -p1.lat * self._dx, p1.lon * self._dy) / fp y = p1.lat + r * fy x = p1.lon + r * fx return _LLi_(y, x, p1.classof, edge) class ClipSH3Tuple(_NamedTuple): '''3-Tuple C{(start, end, original)} for each edge of a I{clipped} polygon, the C{start} and C{end} points (C{LatLon}) of the portion of the edge inside or on the clip region and C{original} indicates whether the edge is part of the original polygon or part of the clip region (C{bool}). ''' _Names_ = (_start_, _end_, 'original') _Units_ = (_Pass, _Pass, Bool) def clipSH(points, corners, closed=False, inull=False): '''Clip a polygon against a clip region or box using the U{Sutherland-Hodgman <https://WikiPedia.org/wiki/Sutherland_Hodgman_algorithm>} algorithm. @arg points: The polygon points (C{LatLon}[]). @arg corners: Three or more points defining a convex clip region (C{LatLon}[]) or two points to specify a rectangular clip box. @kwarg closed: Close the clipped points (C{bool}). @kwarg inull: Optionally, include null edges (C{bool}). @return: Yield the clipped points (C{LatLon}[]). @raise ClipError: The B{C{corners}} specify a polar, zero-area, non-convex or otherwise invalid clip box or region. @raise PointsError: Insufficient number of B{C{points}}. ''' sh = _SH(corners, name=clipSH.__name__) n, pts = sh.clip2(points, closed, inull) for i in range(n): yield sh.clipped2(pts[i])[0] def clipSH3(points, corners, closed=False, inull=False): '''Clip a polygon against a clip region or box using the U{Sutherland-Hodgman <https://WikiPedia.org/wiki/Sutherland_Hodgman_algorithm>} algorithm. @arg points: The polygon points (C{LatLon}[]). @arg corners: Three or more points defining a convex clip region (C{LatLon}[]) or two points to specify a rectangular clip box. @kwarg closed: Close the clipped points (C{bool}). @kwarg inull: Optionally, include null edges (C{bool}). @return: Yield a L{ClipSH3Tuple}C{(start, end, original)} for each edge of the clipped polygon. @raise ClipError: The B{C{corners}} specify a polar, zero-area, non-convex or otherwise invalid clip box or region. @raise PointsError: Insufficient number of B{C{points}}. ''' sh = _SH(corners, name=clipSH3.__name__) n, pts = sh.clip2(points, closed, inull) if n > 0: p2, e2 = sh.clipped2(pts[0]) for i in range(1, n): p1, e1 = p2, e2 p2, e2 = sh.clipped2(pts[i]) yield ClipSH3Tuple(p1, p2, not bool(e1 and e2 and e1 == e2)) __all__ += _ALL_DOCS(ClipCS3Tuple, ClipSH3Tuple) # **) MIT License # # Copyright (C) 2018-2020 -- mrJean1 at Gmail -- All Rights Reserved. # # Permission is hereby granted, free of charge, to any person obtaining a # copy of this software and associated documentation files (the "Software"), # to deal in the Software without restriction, including without limitation # the rights to use, copy, modify, merge, publish, distribute, sublicense, # and/or sell copies of the Software, and to permit persons to whom the # Software is furnished to do so, subject to the following conditions: # # The above copyright notice and this permission notice shall be included # in all copies or substantial portions of the Software. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS # OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL # THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR # OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, # ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR # OTHER DEALINGS IN THE SOFTWARE.