pyx/path.py

   1 # -*- encoding: utf-8 -*-
   2 #
   3 #
   4 # Copyright (C) 2002-2006 Jörg Lehmann <joergl@users.sourceforge.net>
   5 # Copyright (C) 2003-2005 Michael Schindler <m-schindler@users.sourceforge.net>
   6 # Copyright (C) 2002-2011 André Wobst <wobsta@users.sourceforge.net>
   7 #
   8 # This file is part of PyX (http://pyx.sourceforge.net/).
   9 #
  10 # PyX is free software; you can redistribute it and/or modify
  11 # it under the terms of the GNU General Public License as published by
  12 # the Free Software Foundation; either version 2 of the License, or
  13 # (at your option) any later version.
  14 #
  15 # PyX is distributed in the hope that it will be useful,
  16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 # GNU General Public License for more details.
  19 #
  20 # You should have received a copy of the GNU General Public License
  21 # along with PyX; if not, write to the Free Software
  22 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  23
  24 import math
  25 from math import cos, sin, tan, acos, pi, radians, degrees
  26 from . import trafo, unit
  27 from .normpath import NormpathException, normpath, normsubpath, normline_pt, normcurve_pt
  28 from . import bbox as bboxmodule
  29
  30 # set is available as an external interface to the normpath.set method
  31 from .normpath import set
  32 # normpath's invalid is available as an external interface
  33 from .normpath import invalid
  34
  35
  36 class _marker: pass
  37
  38 ################################################################################
  39
  40 # specific exception for path-related problems
  41 class PathException(Exception): pass
  42
  43 ################################################################################
  44 # Bezier helper functions
  45 ################################################################################
  46
  47 def _bezierpolyrange(x0, x1, x2, x3):
  48     tc = [0, 1]
  49
  50     a = x3 - 3*x2 + 3*x1 - x0
  51     b = 2*x0 - 4*x1 + 2*x2
  52     c = x1 - x0
  53
  54     s = b*b - 4*a*c
  55     if s >= 0:
  56         if b >= 0:
  57             q = -0.5*(b+math.sqrt(s))
  58         else:
  59             q = -0.5*(b-math.sqrt(s))
  60
  61         try:
  62             t = q*1.0/a
  63         except ZeroDivisionError:
  64             pass
  65         else:
  66             if 0 < t < 1:
  67                 tc.append(t)
  68
  69         try:
  70             t = c*1.0/q
  71         except ZeroDivisionError:
  72             pass
  73         else:
  74             if 0 < t < 1:
  75                 tc.append(t)
  76
  77     p = [(((a*t + 1.5*b)*t + 3*c)*t + x0) for t in tc]
  78
  79     return min(*p), max(*p)
  80
  81
  82 def _arctobcurve(x_pt, y_pt, r_pt, phi1, phi2):
  83     """generate the best bezier curve corresponding to an arc segment"""
  84
  85     dphi = phi2-phi1
  86
  87     if dphi==0: return None
  88
  89     # the two endpoints should be clear
  90     x0_pt, y0_pt = x_pt+r_pt*cos(phi1), y_pt+r_pt*sin(phi1)
  91     x3_pt, y3_pt = x_pt+r_pt*cos(phi2), y_pt+r_pt*sin(phi2)
  92
  93     # optimal relative distance along tangent for second and third
  94     # control point
  95     l = r_pt*4*(1-cos(dphi/2))/(3*sin(dphi/2))
  96
  97     x1_pt, y1_pt = x0_pt-l*sin(phi1), y0_pt+l*cos(phi1)
  98     x2_pt, y2_pt = x3_pt+l*sin(phi2), y3_pt-l*cos(phi2)
  99
 100     return normcurve_pt(x0_pt, y0_pt, x1_pt, y1_pt, x2_pt, y2_pt, x3_pt, y3_pt)
 101
 102
 103 def _arctobezierpath(x_pt, y_pt, r_pt, phi1, phi2, dphimax=45):
 104     apath = []
 105
 106     phi1 = radians(phi1)
 107     phi2 = radians(phi2)
 108     dphimax = radians(dphimax)
 109
 110     if phi2<phi1:
 111         # guarantee that phi2>phi1 ...
 112         phi2 = phi2 + (math.floor((phi1-phi2)/(2*pi))+1)*2*pi
 113     elif phi2>phi1+2*pi:
 114         # ... or remove unnecessary multiples of 2*pi
 115         phi2 = phi2 - (math.floor((phi2-phi1)/(2*pi))-1)*2*pi
 116
 117     if r_pt == 0 or phi1-phi2 == 0: return []
 118
 119     subdivisions = abs(int((1.0*(phi1-phi2))/dphimax))+1
 120
 121     dphi = (1.0*(phi2-phi1))/subdivisions
 122
 123     for i in range(subdivisions):
 124         apath.append(_arctobcurve(x_pt, y_pt, r_pt, phi1+i*dphi, phi1+(i+1)*dphi))
 125
 126     return apath
 127
 128 def _arcpoint(x_pt, y_pt, r_pt, angle):
 129     """return starting point of arc segment"""
 130     return x_pt+r_pt*cos(radians(angle)), y_pt+r_pt*sin(radians(angle))
 131
 132 def _arcbboxdata(x_pt, y_pt, r_pt, angle1, angle2):
 133     phi1 = radians(angle1)
 134     phi2 = radians(angle2)
 135
 136     # starting end end point of arc segment
 137     sarcx_pt, sarcy_pt = _arcpoint(x_pt, y_pt, r_pt, angle1)
 138     earcx_pt, earcy_pt = _arcpoint(x_pt, y_pt, r_pt, angle2)
 139
 140     # Now, we have to determine the corners of the bbox for the
 141     # arc segment, i.e. global maxima/mimima of cos(phi) and sin(phi)
 142     # in the interval [phi1, phi2]. These can either be located
 143     # on the borders of this interval or in the interior.
 144
 145     if phi2 < phi1:
 146         # guarantee that phi2>phi1
 147         phi2 = phi2 + (math.floor((phi1-phi2)/(2*pi))+1)*2*pi
 148
 149     # next minimum of cos(phi) looking from phi1 in counterclockwise
 150     # direction: 2*pi*floor((phi1-pi)/(2*pi)) + 3*pi
 151
 152     if phi2 < (2*math.floor((phi1-pi)/(2*pi))+3)*pi:
 153         minarcx_pt = min(sarcx_pt, earcx_pt)
 154     else:
 155         minarcx_pt = x_pt-r_pt
 156
 157     # next minimum of sin(phi) looking from phi1 in counterclockwise
 158     # direction: 2*pi*floor((phi1-3*pi/2)/(2*pi)) + 7/2*pi
 159
 160     if phi2 < (2*math.floor((phi1-3.0*pi/2)/(2*pi))+7.0/2)*pi:
 161         minarcy_pt = min(sarcy_pt, earcy_pt)
 162     else:
 163         minarcy_pt = y_pt-r_pt
 164
 165     # next maximum of cos(phi) looking from phi1 in counterclockwise
 166     # direction: 2*pi*floor((phi1)/(2*pi))+2*pi
 167
 168     if phi2 < (2*math.floor((phi1)/(2*pi))+2)*pi:
 169         maxarcx_pt = max(sarcx_pt, earcx_pt)
 170     else:
 171         maxarcx_pt = x_pt+r_pt
 172
 173     # next maximum of sin(phi) looking from phi1 in counterclockwise
 174     # direction: 2*pi*floor((phi1-pi/2)/(2*pi)) + 1/2*pi
 175
 176     if phi2 < (2*math.floor((phi1-pi/2)/(2*pi))+5.0/2)*pi:
 177         maxarcy_pt = max(sarcy_pt, earcy_pt)
 178     else:
 179         maxarcy_pt = y_pt+r_pt
 180
 181     return minarcx_pt, minarcy_pt, maxarcx_pt, maxarcy_pt
 182
 183
 184 ################################################################################
 185 # path context and pathitem base class
 186 ################################################################################
 187
 188 class context:
 189
 190     """context for pathitem"""
 191
 192     def __init__(self, x_pt, y_pt, subfirstx_pt, subfirsty_pt):
 193         """initializes a context for path items
 194
 195         x_pt, y_pt are the currentpoint. subfirstx_pt, subfirsty_pt
 196         are the starting point of the current subpath. There are no
 197         invalid contexts, i.e. all variables need to be set to integer
 198         or float numbers.
 199         """
 200         self.x_pt = x_pt
 201         self.y_pt = y_pt
 202         self.subfirstx_pt = subfirstx_pt
 203         self.subfirsty_pt = subfirsty_pt
 204
 205
 206 class pathitem:
 207
 208     """element of a PS style path"""
 209
 210     def __str__(self):
 211         raise NotImplementedError()
 212
 213     def createcontext(self):
 214         """creates a context from the current pathitem
 215
 216         Returns a context instance. Is called, when no context has yet
 217         been defined, i.e. for the very first pathitem. Most of the
 218         pathitems do not provide this method. Note, that you should pass
 219         the context created by createcontext to updatebbox and updatenormpath
 220         of successive pathitems only; use the context-free createbbox and
 221         createnormpath for the first pathitem instead.
 222         """
 223         raise PathException("path must start with moveto or the like (%r)" % self)
 224
 225     def createbbox(self):
 226         """creates a bbox from the current pathitem
 227
 228         Returns a bbox instance. Is called, when a bbox has to be
 229         created instead of updating it, i.e. for the very first
 230         pathitem. Most pathitems do not provide this method.
 231         updatebbox must not be called for the created instance and the
 232         same pathitem.
 233         """
 234         raise PathException("path must start with moveto or the like (%r)" % self)
 235
 236     def createnormpath(self, epsilon=_marker):
 237         """create a normpath from the current pathitem
 238
 239         Return a normpath instance. Is called, when a normpath has to
 240         be created instead of updating it, i.e. for the very first
 241         pathitem. Most pathitems do not provide this method.
 242         updatenormpath must not be called for the created instance and
 243         the same pathitem.
 244         """
 245         raise PathException("path must start with moveto or the like (%r)" % self)
 246
 247     def updatebbox(self, bbox, context):
 248         """updates the bbox to contain the pathitem for the given
 249         context
 250
 251         Is called for all subsequent pathitems in a path to complete
 252         the bbox information. Both, the bbox and context are updated
 253         inplace. Does not return anything.
 254         """
 255         raise NotImplementedError()
 256
 257     def updatenormpath(self, normpath, context):
 258         """update the normpath to contain the pathitem for the given
 259         context
 260
 261         Is called for all subsequent pathitems in a path to complete
 262         the normpath. Both the normpath and the context are updated
 263         inplace. Most pathitem implementations will use
 264         normpath.normsubpath[-1].append to add normsubpathitem(s).
 265         Does not return anything.
 266         """
 267         raise NotImplementedError()
 268
 269     def outputPS(self, file, writer):
 270         """write PS representation of pathitem to file"""
 271
 272
 273
 274 ################################################################################
 275 # various pathitems
 276 ################################################################################
 277 # Each one comes in two variants:
 278 #  - one with suffix _pt. This one requires the coordinates
 279 #    to be already in pts (mainly used for internal purposes)
 280 #  - another which accepts arbitrary units
 281
 282
 283 class closepath(pathitem):
 284
 285     """Connect subpath back to its starting point"""
 286
 287     __slots__ = ()
 288
 289     def __str__(self):
 290         return "closepath()"
 291
 292     def updatebbox(self, bbox, context):
 293         context.x_pt = context.subfirstx_pt
 294         context.y_pt = context.subfirsty_pt
 295
 296     def updatenormpath(self, normpath, context):
 297         normpath.normsubpaths[-1].close()
 298         context.x_pt = context.subfirstx_pt
 299         context.y_pt = context.subfirsty_pt
 300
 301     def outputPS(self, file, writer):
 302         file.write("closepath\n")
 303
 304
 305 class pdfmoveto_pt(normline_pt):
 306
 307     def outputPDF(self, file, writer):
 308         pass
 309
 310
 311 class moveto_pt(pathitem):
 312
 313     """Start a new subpath and set current point to (x_pt, y_pt) (coordinates in pts)"""
 314
 315     __slots__ = "x_pt", "y_pt"
 316
 317     def __init__(self, x_pt, y_pt):
 318         self.x_pt = x_pt
 319         self.y_pt = y_pt
 320
 321     def __str__(self):
 322         return "moveto_pt(%g, %g)" % (self.x_pt, self.y_pt)
 323
 324     def createcontext(self):
 325         return context(self.x_pt, self.y_pt, self.x_pt, self.y_pt)
 326
 327     def createbbox(self):
 328         return bboxmodule.bbox_pt(self.x_pt, self.y_pt, self.x_pt, self.y_pt)
 329
 330     def createnormpath(self, epsilon=_marker):
 331         if epsilon is _marker:
 332             return normpath([normsubpath([normline_pt(self.x_pt, self.y_pt, self.x_pt, self.y_pt)])])
 333         elif epsilon is None:
 334             return normpath([normsubpath([pdfmoveto_pt(self.x_pt, self.y_pt, self.x_pt, self.y_pt)],
 335                                          epsilon=epsilon)])
 336         else:
 337             return normpath([normsubpath([normline_pt(self.x_pt, self.y_pt, self.x_pt, self.y_pt)],
 338                                          epsilon=epsilon)])
 339
 340     def updatebbox(self, bbox, context):
 341         bbox.includepoint_pt(self.x_pt, self.y_pt)
 342         context.x_pt = context.subfirstx_pt = self.x_pt
 343         context.y_pt = context.subfirsty_pt = self.y_pt
 344
 345     def updatenormpath(self, normpath, context):
 346         if normpath.normsubpaths[-1].epsilon is not None:
 347             normpath.append(normsubpath([normline_pt(self.x_pt, self.y_pt, self.x_pt, self.y_pt)],
 348                                         epsilon=normpath.normsubpaths[-1].epsilon))
 349         else:
 350             normpath.append(normsubpath(epsilon=normpath.normsubpaths[-1].epsilon))
 351         context.x_pt = context.subfirstx_pt = self.x_pt
 352         context.y_pt = context.subfirsty_pt = self.y_pt
 353
 354     def outputPS(self, file, writer):
 355         file.write("%g %g moveto\n" % (self.x_pt, self.y_pt) )
 356
 357
 358 class lineto_pt(pathitem):
 359
 360     """Append straight line to (x_pt, y_pt) (coordinates in pts)"""
 361
 362     __slots__ = "x_pt", "y_pt"
 363
 364     def __init__(self, x_pt, y_pt):
 365         self.x_pt = x_pt
 366         self.y_pt = y_pt
 367
 368     def __str__(self):
 369         return "lineto_pt(%g, %g)" % (self.x_pt, self.y_pt)
 370
 371     def updatebbox(self, bbox, context):
 372         bbox.includepoint_pt(self.x_pt, self.y_pt)
 373         context.x_pt = self.x_pt
 374         context.y_pt = self.y_pt
 375
 376     def updatenormpath(self, normpath, context):
 377         normpath.normsubpaths[-1].append(normline_pt(context.x_pt, context.y_pt,
 378                                                      self.x_pt, self.y_pt))
 379         context.x_pt = self.x_pt
 380         context.y_pt = self.y_pt
 381
 382     def outputPS(self, file, writer):
 383         file.write("%g %g lineto\n" % (self.x_pt, self.y_pt) )
 384
 385
 386 class curveto_pt(pathitem):
 387
 388     """Append curveto (coordinates in pts)"""
 389
 390     __slots__ = "x1_pt", "y1_pt", "x2_pt", "y2_pt", "x3_pt", "y3_pt"
 391
 392     def __init__(self, x1_pt, y1_pt, x2_pt, y2_pt, x3_pt, y3_pt):
 393         self.x1_pt = x1_pt
 394         self.y1_pt = y1_pt
 395         self.x2_pt = x2_pt
 396         self.y2_pt = y2_pt
 397         self.x3_pt = x3_pt
 398         self.y3_pt = y3_pt
 399
 400     def __str__(self):
 401         return "curveto_pt(%g, %g, %g, %g, %g, %g)" % (self.x1_pt, self.y1_pt,
 402                                                        self.x2_pt, self.y2_pt,
 403                                                        self.x3_pt, self.y3_pt)
 404
 405     def updatebbox(self, bbox, context):
 406         xmin_pt, xmax_pt = _bezierpolyrange(context.x_pt, self.x1_pt, self.x2_pt, self.x3_pt)
 407         ymin_pt, ymax_pt = _bezierpolyrange(context.y_pt, self.y1_pt, self.y2_pt, self.y3_pt)
 408         bbox.includepoint_pt(xmin_pt, ymin_pt)
 409         bbox.includepoint_pt(xmax_pt, ymax_pt)
 410         context.x_pt = self.x3_pt
 411         context.y_pt = self.y3_pt
 412
 413     def updatenormpath(self, normpath, context):
 414         normpath.normsubpaths[-1].append(normcurve_pt(context.x_pt, context.y_pt,
 415                                                       self.x1_pt, self.y1_pt,
 416                                                       self.x2_pt, self.y2_pt,
 417                                                       self.x3_pt, self.y3_pt))
 418         context.x_pt = self.x3_pt
 419         context.y_pt = self.y3_pt
 420
 421     def outputPS(self, file, writer):
 422         file.write("%g %g %g %g %g %g curveto\n" % (self.x1_pt, self.y1_pt,
 423                                                     self.x2_pt, self.y2_pt,
 424                                                     self.x3_pt, self.y3_pt))
 425
 426
 427 class rmoveto_pt(pathitem):
 428
 429     """Perform relative moveto (coordinates in pts)"""
 430
 431     __slots__ = "dx_pt", "dy_pt"
 432
 433     def __init__(self, dx_pt, dy_pt):
 434          self.dx_pt = dx_pt
 435          self.dy_pt = dy_pt
 436
 437     def __str__(self):
 438         return "rmoveto_pt(%g, %g)" % (self.dx_pt, self.dy_pt)
 439
 440     def updatebbox(self, bbox, context):
 441         bbox.includepoint_pt(context.x_pt + self.dx_pt, context.y_pt + self.dy_pt)
 442         context.x_pt += self.dx_pt
 443         context.y_pt += self.dy_pt
 444         context.subfirstx_pt = context.x_pt
 445         context.subfirsty_pt = context.y_pt
 446
 447     def updatenormpath(self, normpath, context):
 448         context.x_pt += self.dx_pt
 449         context.y_pt += self.dy_pt
 450         context.subfirstx_pt = context.x_pt
 451         context.subfirsty_pt = context.y_pt
 452         if normpath.normsubpaths[-1].epsilon is not None:
 453             normpath.append(normsubpath([normline_pt(context.x_pt, context.y_pt,
 454                                                      context.x_pt, context.y_pt)],
 455                                         epsilon=normpath.normsubpaths[-1].epsilon))
 456         else:
 457             normpath.append(normsubpath(epsilon=normpath.normsubpaths[-1].epsilon))
 458
 459     def outputPS(self, file, writer):
 460         file.write("%g %g rmoveto\n" % (self.dx_pt, self.dy_pt) )
 461
 462
 463 class rlineto_pt(pathitem):
 464
 465     """Perform relative lineto (coordinates in pts)"""
 466
 467     __slots__ = "dx_pt", "dy_pt"
 468
 469     def __init__(self, dx_pt, dy_pt):
 470         self.dx_pt = dx_pt
 471         self.dy_pt = dy_pt
 472
 473     def __str__(self):
 474         return "rlineto_pt(%g %g)" % (self.dx_pt, self.dy_pt)
 475
 476     def updatebbox(self, bbox, context):
 477         bbox.includepoint_pt(context.x_pt + self.dx_pt, context.y_pt + self.dy_pt)
 478         context.x_pt += self.dx_pt
 479         context.y_pt += self.dy_pt
 480
 481     def updatenormpath(self, normpath, context):
 482         normpath.normsubpaths[-1].append(normline_pt(context.x_pt, context.y_pt,
 483                                                      context.x_pt + self.dx_pt, context.y_pt + self.dy_pt))
 484         context.x_pt += self.dx_pt
 485         context.y_pt += self.dy_pt
 486
 487     def outputPS(self, file, writer):
 488         file.write("%g %g rlineto\n" % (self.dx_pt, self.dy_pt) )
 489
 490
 491 class rcurveto_pt(pathitem):
 492
 493     """Append rcurveto (coordinates in pts)"""
 494
 495     __slots__ = "dx1_pt", "dy1_pt", "dx2_pt", "dy2_pt", "dx3_pt", "dy3_pt"
 496
 497     def __init__(self, dx1_pt, dy1_pt, dx2_pt, dy2_pt, dx3_pt, dy3_pt):
 498         self.dx1_pt = dx1_pt
 499         self.dy1_pt = dy1_pt
 500         self.dx2_pt = dx2_pt
 501         self.dy2_pt = dy2_pt
 502         self.dx3_pt = dx3_pt
 503         self.dy3_pt = dy3_pt
 504
 505     def __str__(self):
 506         return "rcurveto_pt(%g, %g, %g, %g, %g, %g)" % (self.dx1_pt, self.dy1_pt,
 507                                                         self.dx2_pt, self.dy2_pt,
 508                                                         self.dx3_pt, self.dy3_pt)
 509
 510     def updatebbox(self, bbox, context):
 511         xmin_pt, xmax_pt = _bezierpolyrange(context.x_pt,
 512                                             context.x_pt+self.dx1_pt,
 513                                             context.x_pt+self.dx2_pt,
 514                                             context.x_pt+self.dx3_pt)
 515         ymin_pt, ymax_pt = _bezierpolyrange(context.y_pt,
 516                                             context.y_pt+self.dy1_pt,
 517                                             context.y_pt+self.dy2_pt,
 518                                             context.y_pt+self.dy3_pt)
 519         bbox.includepoint_pt(xmin_pt, ymin_pt)
 520         bbox.includepoint_pt(xmax_pt, ymax_pt)
 521         context.x_pt += self.dx3_pt
 522         context.y_pt += self.dy3_pt
 523
 524     def updatenormpath(self, normpath, context):
 525         normpath.normsubpaths[-1].append(normcurve_pt(context.x_pt, context.y_pt,
 526                                                       context.x_pt + self.dx1_pt, context.y_pt + self.dy1_pt,
 527                                                       context.x_pt + self.dx2_pt, context.y_pt + self.dy2_pt,
 528                                                       context.x_pt + self.dx3_pt, context.y_pt + self.dy3_pt))
 529         context.x_pt += self.dx3_pt
 530         context.y_pt += self.dy3_pt
 531
 532     def outputPS(self, file, writer):
 533         file.write("%g %g %g %g %g %g rcurveto\n" % (self.dx1_pt, self.dy1_pt,
 534                                                      self.dx2_pt, self.dy2_pt,
 535                                                      self.dx3_pt, self.dy3_pt))
 536
 537
 538 class arc_pt(pathitem):
 539
 540     """Append counterclockwise arc (coordinates in pts)"""
 541
 542     __slots__ = "x_pt", "y_pt", "r_pt", "angle1", "angle2"
 543
 544     def __init__(self, x_pt, y_pt, r_pt, angle1, angle2):
 545         self.x_pt = x_pt
 546         self.y_pt = y_pt
 547         self.r_pt = r_pt
 548         self.angle1 = angle1
 549         self.angle2 = angle2
 550
 551     def __str__(self):
 552         return "arc_pt(%g, %g, %g, %g, %g)" % (self.x_pt, self.y_pt, self.r_pt,
 553                                                self.angle1, self.angle2)
 554
 555     def createcontext(self):
 556         x_pt, y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 557         return context(x_pt, y_pt, x_pt, y_pt)
 558
 559     def createbbox(self):
 560         return bboxmodule.bbox_pt(*_arcbboxdata(self.x_pt, self.y_pt, self.r_pt,
 561                                                 self.angle1, self.angle2))
 562
 563     def createnormpath(self, epsilon=_marker):
 564         if epsilon is _marker:
 565             return normpath([normsubpath(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle1, self.angle2))])
 566         else:
 567             return normpath([normsubpath(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle1, self.angle2),
 568                                          epsilon=epsilon)])
 569
 570     def updatebbox(self, bbox, context):
 571         minarcx_pt, minarcy_pt, maxarcx_pt, maxarcy_pt = _arcbboxdata(self.x_pt, self.y_pt, self.r_pt,
 572                                                                       self.angle1, self.angle2)
 573         bbox.includepoint_pt(minarcx_pt, minarcy_pt)
 574         bbox.includepoint_pt(maxarcx_pt, maxarcy_pt)
 575         context.x_pt, context.y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 576
 577     def updatenormpath(self, normpath, context):
 578         if normpath.normsubpaths[-1].closed:
 579             normpath.append(normsubpath([normline_pt(context.x_pt, context.y_pt,
 580                                                          *_arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle1))],
 581                                         epsilon=normpath.normsubpaths[-1].epsilon))
 582         else:
 583             normpath.normsubpaths[-1].append(normline_pt(context.x_pt, context.y_pt,
 584                                                          *_arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle1)))
 585         normpath.normsubpaths[-1].extend(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle1, self.angle2))
 586         context.x_pt, context.y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 587
 588     def outputPS(self, file, writer):
 589         file.write("%g %g %g %g %g arc\n" % (self.x_pt, self.y_pt,
 590                                              self.r_pt,
 591                                              self.angle1,
 592                                              self.angle2))
 593
 594
 595 class arcn_pt(pathitem):
 596
 597     """Append clockwise arc (coordinates in pts)"""
 598
 599     __slots__ = "x_pt", "y_pt", "r_pt", "angle1", "angle2"
 600
 601     def __init__(self, x_pt, y_pt, r_pt, angle1, angle2):
 602         self.x_pt = x_pt
 603         self.y_pt = y_pt
 604         self.r_pt = r_pt
 605         self.angle1 = angle1
 606         self.angle2 = angle2
 607
 608     def __str__(self):
 609         return "arcn_pt(%g, %g, %g, %g, %g)" % (self.x_pt, self.y_pt, self.r_pt,
 610                                                 self.angle1, self.angle2)
 611
 612     def createcontext(self):
 613         x_pt, y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 614         return context(x_pt, y_pt, x_pt, y_pt)
 615
 616     def createbbox(self):
 617         return bboxmodule.bbox_pt(*_arcbboxdata(self.x_pt, self.y_pt, self.r_pt,
 618                                                 self.angle2, self.angle1))
 619
 620     def createnormpath(self, epsilon=_marker):
 621         if epsilon is _marker:
 622             return normpath([normsubpath(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle2, self.angle1))]).reversed()
 623         else:
 624             return normpath([normsubpath(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle2, self.angle1),
 625                                          epsilon=epsilon)]).reversed()
 626
 627     def updatebbox(self, bbox, context):
 628         minarcx_pt, minarcy_pt, maxarcx_pt, maxarcy_pt = _arcbboxdata(self.x_pt, self.y_pt, self.r_pt,
 629                                                                       self.angle2, self.angle1)
 630         bbox.includepoint_pt(minarcx_pt, minarcy_pt)
 631         bbox.includepoint_pt(maxarcx_pt, maxarcy_pt)
 632         context.x_pt, context.y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 633
 634     def updatenormpath(self, normpath, context):
 635         if normpath.normsubpaths[-1].closed:
 636             normpath.append(normsubpath([normline_pt(context.x_pt, context.y_pt,
 637                                                          *_arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle1))],
 638                                         epsilon=normpath.normsubpaths[-1].epsilon))
 639         else:
 640             normpath.normsubpaths[-1].append(normline_pt(context.x_pt, context.y_pt,
 641                                                          *_arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle1)))
 642         bpathitems = _arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle2, self.angle1)
 643         bpathitems.reverse()
 644         for bpathitem in bpathitems:
 645             normpath.normsubpaths[-1].append(bpathitem.reversed())
 646         context.x_pt, context.y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 647
 648     def outputPS(self, file, writer):
 649         file.write("%g %g %g %g %g arcn\n" % (self.x_pt, self.y_pt,
 650                                               self.r_pt,
 651                                               self.angle1,
 652                                               self.angle2))
 653
 654
 655 class arct_pt(pathitem):
 656
 657     """Append tangent arc (coordinates in pts)"""
 658
 659     __slots__ = "x1_pt", "y1_pt", "x2_pt", "y2_pt", "r_pt"
 660
 661     def __init__(self, x1_pt, y1_pt, x2_pt, y2_pt, r_pt):
 662         self.x1_pt = x1_pt
 663         self.y1_pt = y1_pt
 664         self.x2_pt = x2_pt
 665         self.y2_pt = y2_pt
 666         self.r_pt = r_pt
 667
 668     def __str__(self):
 669         return "arct_pt(%g, %g, %g, %g, %g)" % (self.x1_pt, self.y1_pt,
 670                                                 self.x2_pt, self.y2_pt,
 671                                                 self.r_pt)
 672
 673     def _pathitems(self, x_pt, y_pt):
 674         """return pathitems corresponding to arct for given currentpoint x_pt, y_pt.
 675
 676         The return is a list containing line_pt, arc_pt, a arcn_pt instances.
 677
 678         This is a helper routine for updatebbox and updatenormpath,
 679         which will delegate the work to the constructed pathitem.
 680         """
 681
 682         # direction of tangent 1
 683         dx1_pt, dy1_pt = self.x1_pt-x_pt, self.y1_pt-y_pt
 684         l1_pt = math.hypot(dx1_pt, dy1_pt)
 685         dx1, dy1 = dx1_pt/l1_pt, dy1_pt/l1_pt
 686
 687         # direction of tangent 2
 688         dx2_pt, dy2_pt = self.x2_pt-self.x1_pt, self.y2_pt-self.y1_pt
 689         l2_pt = math.hypot(dx2_pt, dy2_pt)
 690         dx2, dy2 = dx2_pt/l2_pt, dy2_pt/l2_pt
 691
 692         # intersection angle between two tangents in the range (-pi, pi).
 693         # We take the orientation from the sign of the vector product.
 694         # Negative (positive) angles alpha corresponds to a turn to the right (left)
 695         # as seen from currentpoint.
 696         if dx1*dy2-dy1*dx2 > 0:
 697             alpha = acos(dx1*dx2+dy1*dy2)
 698         else:
 699             alpha = -acos(dx1*dx2+dy1*dy2)
 700
 701         try:
 702             # two tangent points
 703             xt1_pt = self.x1_pt - dx1*self.r_pt*tan(abs(alpha)/2)
 704             yt1_pt = self.y1_pt - dy1*self.r_pt*tan(abs(alpha)/2)
 705             xt2_pt = self.x1_pt + dx2*self.r_pt*tan(abs(alpha)/2)
 706             yt2_pt = self.y1_pt + dy2*self.r_pt*tan(abs(alpha)/2)
 707
 708             # direction point 1 -> center of arc
 709             dmx_pt = 0.5*(xt1_pt+xt2_pt) - self.x1_pt
 710             dmy_pt = 0.5*(yt1_pt+yt2_pt) - self.y1_pt
 711             lm_pt = math.hypot(dmx_pt, dmy_pt)
 712             dmx, dmy = dmx_pt/lm_pt, dmy_pt/lm_pt
 713
 714             # center of arc
 715             mx_pt = self.x1_pt + dmx*self.r_pt/cos(alpha/2)
 716             my_pt = self.y1_pt + dmy*self.r_pt/cos(alpha/2)
 717
 718             # angle around which arc is centered
 719             phi = degrees(math.atan2(-dmy, -dmx))
 720
 721             # half angular width of arc
 722             deltaphi = degrees(alpha)/2
 723
 724             line = lineto_pt(*_arcpoint(mx_pt, my_pt, self.r_pt, phi-deltaphi))
 725             if alpha > 0:
 726                 return [line, arc_pt(mx_pt, my_pt, self.r_pt, phi-deltaphi, phi+deltaphi)]
 727             else:
 728                 return [line, arcn_pt(mx_pt, my_pt, self.r_pt, phi-deltaphi, phi+deltaphi)]
 729
 730         except ZeroDivisionError:
 731             # in the degenerate case, we just return a line as specified by the PS
 732             # language reference
 733             return [lineto_pt(self.x1_pt, self.y1_pt)]
 734
 735     def updatebbox(self, bbox, context):
 736         for pathitem in self._pathitems(context.x_pt, context.y_pt):
 737             pathitem.updatebbox(bbox, context)
 738
 739     def updatenormpath(self, normpath, context):
 740         for pathitem in self._pathitems(context.x_pt, context.y_pt):
 741             pathitem.updatenormpath(normpath, context)
 742
 743     def outputPS(self, file, writer):
 744         file.write("%g %g %g %g %g arct\n" % (self.x1_pt, self.y1_pt,
 745                                               self.x2_pt, self.y2_pt,
 746                                               self.r_pt))
 747
 748 #
 749 # now the pathitems that convert from user coordinates to pts
 750 #
 751
 752 class moveto(moveto_pt):
 753
 754     """Set current point to (x, y)"""
 755
 756     __slots__ = "x_pt", "y_pt"
 757
 758     def __init__(self, x, y):
 759         moveto_pt.__init__(self, unit.topt(x), unit.topt(y))
 760
 761
 762 class lineto(lineto_pt):
 763
 764     """Append straight line to (x, y)"""
 765
 766     __slots__ = "x_pt", "y_pt"
 767
 768     def __init__(self, x, y):
 769         lineto_pt.__init__(self, unit.topt(x), unit.topt(y))
 770
 771
 772 class curveto(curveto_pt):
 773
 774     """Append curveto"""
 775
 776     __slots__ = "x1_pt", "y1_pt", "x2_pt", "y2_pt", "x3_pt", "y3_pt"
 777
 778     def __init__(self, x1, y1, x2, y2, x3, y3):
 779         curveto_pt.__init__(self,
 780                             unit.topt(x1), unit.topt(y1),
 781                             unit.topt(x2), unit.topt(y2),
 782                             unit.topt(x3), unit.topt(y3))
 783
 784 class rmoveto(rmoveto_pt):
 785
 786     """Perform relative moveto"""
 787
 788     __slots__ = "dx_pt", "dy_pt"
 789
 790     def __init__(self, dx, dy):
 791         rmoveto_pt.__init__(self, unit.topt(dx), unit.topt(dy))
 792
 793
 794 class rlineto(rlineto_pt):
 795
 796     """Perform relative lineto"""
 797
 798     __slots__ = "dx_pt", "dy_pt"
 799
 800     def __init__(self, dx, dy):
 801         rlineto_pt.__init__(self, unit.topt(dx), unit.topt(dy))
 802
 803
 804 class rcurveto(rcurveto_pt):
 805
 806     """Append rcurveto"""
 807
 808     __slots__ = "dx1_pt", "dy1_pt", "dx2_pt", "dy2_pt", "dx3_pt", "dy3_pt"
 809
 810     def __init__(self, dx1, dy1, dx2, dy2, dx3, dy3):
 811         rcurveto_pt.__init__(self,
 812                              unit.topt(dx1), unit.topt(dy1),
 813                              unit.topt(dx2), unit.topt(dy2),
 814                              unit.topt(dx3), unit.topt(dy3))
 815
 816
 817 class arcn(arcn_pt):
 818
 819     """Append clockwise arc"""
 820
 821     __slots__ = "x_pt", "y_pt", "r_pt", "angle1", "angle2"
 822
 823     def __init__(self, x, y, r, angle1, angle2):
 824         arcn_pt.__init__(self, unit.topt(x), unit.topt(y), unit.topt(r), angle1, angle2)
 825
 826
 827 class arc(arc_pt):
 828
 829     """Append counterclockwise arc"""
 830
 831     __slots__ = "x_pt", "y_pt", "r_pt", "angle1", "angle2"
 832
 833     def __init__(self, x, y, r, angle1, angle2):
 834         arc_pt.__init__(self, unit.topt(x), unit.topt(y), unit.topt(r), angle1, angle2)
 835
 836
 837 class arct(arct_pt):
 838
 839     """Append tangent arc"""
 840
 841     __slots__ = "x1_pt", "y1_pt", "x2_pt", "y2_pt", "r_pt"
 842
 843     def __init__(self, x1, y1, x2, y2, r):
 844         arct_pt.__init__(self, unit.topt(x1), unit.topt(y1),
 845                          unit.topt(x2), unit.topt(y2), unit.topt(r))
 846
 847 #
 848 # "combined" pathitems provided for performance reasons
 849 #
 850
 851 class multilineto_pt(pathitem):
 852
 853     """Perform multiple linetos (coordinates in pts)"""
 854
 855     __slots__ = "points_pt"
 856
 857     def __init__(self, points_pt):
 858         self.points_pt = points_pt
 859
 860     def __str__(self):
 861         result = []
 862         for point_pt in self.points_pt:
 863             result.append("(%g, %g)" % point_pt )
 864         return "multilineto_pt([%s])" % (", ".join(result))
 865
 866     def updatebbox(self, bbox, context):
 867         for point_pt in self.points_pt:
 868             bbox.includepoint_pt(*point_pt)
 869         if self.points_pt:
 870             context.x_pt, context.y_pt = self.points_pt[-1]
 871
 872     def updatenormpath(self, normpath, context):
 873         x0_pt, y0_pt = context.x_pt, context.y_pt
 874         for point_pt in self.points_pt:
 875             normpath.normsubpaths[-1].append(normline_pt(x0_pt, y0_pt, *point_pt))
 876             x0_pt, y0_pt = point_pt
 877         context.x_pt, context.y_pt = x0_pt, y0_pt
 878
 879     def outputPS(self, file, writer):
 880         for point_pt in self.points_pt:
 881             file.write("%g %g lineto\n" % point_pt )
 882
 883
 884 class multicurveto_pt(pathitem):
 885
 886     """Perform multiple curvetos (coordinates in pts)"""
 887
 888     __slots__ = "points_pt"
 889
 890     def __init__(self, points_pt):
 891         self.points_pt = points_pt
 892
 893     def __str__(self):
 894         result = []
 895         for point_pt in self.points_pt:
 896             result.append("(%g, %g, %g, %g, %g, %g)" % point_pt )
 897         return "multicurveto_pt([%s])" % (", ".join(result))
 898
 899     def updatebbox(self, bbox, context):
 900         for point_pt in self.points_pt:
 901             xmin_pt, xmax_pt = _bezierpolyrange(context.x_pt, point_pt[0], point_pt[2], point_pt[4])
 902             ymin_pt, ymax_pt = _bezierpolyrange(context.y_pt, point_pt[1], point_pt[3], point_pt[5])
 903             bbox.includepoint_pt(xmin_pt, ymin_pt)
 904             bbox.includepoint_pt(xmax_pt, ymax_pt)
 905             context.x_pt, context.y_pt = point_pt[4:]
 906
 907     def updatenormpath(self, normpath, context):
 908         x0_pt, y0_pt = context.x_pt, context.y_pt
 909         for point_pt in self.points_pt:
 910             normpath.normsubpaths[-1].append(normcurve_pt(x0_pt, y0_pt, *point_pt))
 911             x0_pt, y0_pt = point_pt[4:]
 912         context.x_pt, context.y_pt = x0_pt, y0_pt
 913
 914     def outputPS(self, file, writer):
 915         for point_pt in self.points_pt:
 916             file.write("%g %g %g %g %g %g curveto\n" % point_pt)
 917
 918
 919 ################################################################################
 920 # path: PS style path
 921 ################################################################################
 922
 923 class path:
 924
 925     """PS style path"""
 926
 927     __slots__ = "pathitems", "_normpath"
 928
 929     def __init__(self, *pathitems):
 930         """construct a path from pathitems *args"""
 931
 932         for apathitem in pathitems:
 933             assert isinstance(apathitem, pathitem), "only pathitem instances allowed"
 934
 935         self.pathitems = list(pathitems)
 936         # normpath cache (when no epsilon is set)
 937         self._normpath = None
 938
 939     def __add__(self, other):
 940         """create new path out of self and other"""
 941         return path(*(self.pathitems + other.path().pathitems))
 942
 943     def __iadd__(self, other):
 944         """add other inplace
 945
 946         If other is a normpath instance, it is converted to a path before
 947         being added.
 948         """
 949         self.pathitems += other.path().pathitems
 950         self._normpath = None
 951         return self
 952
 953     def __getitem__(self, i):
 954         """return path item i"""
 955         return self.pathitems[i]
 956
 957     def __len__(self):
 958         """return the number of path items"""
 959         return len(self.pathitems)
 960
 961     def __str__(self):
 962         l = ", ".join(map(str, self.pathitems))
 963         return "path(%s)" % l
 964
 965     def append(self, apathitem):
 966         """append a path item"""
 967         assert isinstance(apathitem, pathitem), "only pathitem instance allowed"
 968         self.pathitems.append(apathitem)
 969         self._normpath = None
 970
 971     def arclen_pt(self):
 972         """return arc length in pts"""
 973         return self.normpath().arclen_pt()
 974
 975     def arclen(self):
 976         """return arc length"""
 977         return self.normpath().arclen()
 978
 979     def arclentoparam_pt(self, lengths_pt):
 980         """return the param(s) matching the given length(s)_pt in pts"""
 981         return self.normpath().arclentoparam_pt(lengths_pt)
 982
 983     def arclentoparam(self, lengths):
 984         """return the param(s) matching the given length(s)"""
 985         return self.normpath().arclentoparam(lengths)
 986
 987     def at_pt(self, params):
 988         """return coordinates of path in pts at param(s) or arc length(s) in pts"""
 989         return self.normpath().at_pt(params)
 990
 991     def at(self, params):
 992         """return coordinates of path at param(s) or arc length(s)"""
 993         return self.normpath().at(params)
 994
 995     def atbegin_pt(self):
 996         """return coordinates of the beginning of first subpath in path in pts"""
 997         return self.normpath().atbegin_pt()
 998
 999     def atbegin(self):
1000         """return coordinates of the beginning of first subpath in path"""
1001         return self.normpath().atbegin()
1002
1003     def atend_pt(self):
1004         """return coordinates of the end of last subpath in path in pts"""
1005         return self.normpath().atend_pt()
1006
1007     def atend(self):
1008         """return coordinates of the end of last subpath in path"""
1009         return self.normpath().atend()
1010
1011     def bbox(self):
1012         """return bbox of path"""
1013         if self.pathitems:
1014             bbox = self.pathitems[0].createbbox()
1015             context = self.pathitems[0].createcontext()
1016             for pathitem in self.pathitems[1:]:
1017                 pathitem.updatebbox(bbox, context)
1018             return bbox
1019         else:
1020             return bboxmodule.empty()
1021
1022     def begin(self):
1023         """return param corresponding of the beginning of the path"""
1024         return self.normpath().begin()
1025
1026     def curveradius_pt(self, params):
1027         """return the curvature radius in pts at param(s) or arc length(s) in pts
1028
1029         The curvature radius is the inverse of the curvature. When the
1030         curvature is 0, None is returned. Note that this radius can be negative
1031         or positive, depending on the sign of the curvature."""
1032         return self.normpath().curveradius_pt(params)
1033
1034     def curveradius(self, params):
1035         """return the curvature radius at param(s) or arc length(s)
1036
1037         The curvature radius is the inverse of the curvature. When the
1038         curvature is 0, None is returned. Note that this radius can be negative
1039         or positive, depending on the sign of the curvature."""
1040         return self.normpath().curveradius(params)
1041
1042     def end(self):
1043         """return param corresponding of the end of the path"""
1044         return self.normpath().end()
1045
1046     def extend(self, pathitems):
1047         """extend path by pathitems"""
1048         for apathitem in pathitems:
1049             assert isinstance(apathitem, pathitem), "only pathitem instance allowed"
1050         self.pathitems.extend(pathitems)
1051         self._normpath = None
1052
1053     def intersect(self, other):
1054         """intersect self with other path
1055
1056         Returns a tuple of lists consisting of the parameter values
1057         of the intersection points of the corresponding normpath.
1058         """
1059         return self.normpath().intersect(other)
1060
1061     def join(self, other):
1062         """join other path/normpath inplace
1063
1064         If other is a normpath instance, it is converted to a path before
1065         being joined.
1066         """
1067         self.pathitems = self.joined(other).path().pathitems
1068         self._normpath = None
1069         return self
1070
1071     def joined(self, other):
1072         """return path consisting of self and other joined together"""
1073         return self.normpath().joined(other).path()
1074
1075     # << operator also designates joining
1076     __lshift__ = joined
1077
1078     def normpath(self, epsilon=_marker):
1079         """convert the path into a normpath"""
1080         # use cached value if existent and epsilon is _marker
1081         if self._normpath is not None and epsilon is _marker:
1082             return self._normpath
1083         if self.pathitems:
1084             if epsilon is _marker:
1085                 normpath = self.pathitems[0].createnormpath()
1086             else:
1087                 normpath = self.pathitems[0].createnormpath(epsilon)
1088             context = self.pathitems[0].createcontext()
1089             for pathitem in self.pathitems[1:]:
1090                 pathitem.updatenormpath(normpath, context)
1091         else:
1092             if epsilon is _marker:
1093                 normpath = normpath([])
1094             else:
1095                 normpath = normpath(epsilon=epsilon)
1096         if epsilon is _marker:
1097             self._normpath = normpath
1098         return normpath
1099
1100     def paramtoarclen_pt(self, params):
1101         """return arc lenght(s) in pts matching the given param(s)"""
1102         return self.normpath().paramtoarclen_pt(params)
1103
1104     def paramtoarclen(self, params):
1105         """return arc lenght(s) matching the given param(s)"""
1106         return self.normpath().paramtoarclen(params)
1107
1108     def path(self):
1109         """return corresponding path, i.e., self"""
1110         return self
1111
1112     def reversed(self):
1113         """return reversed normpath"""
1114         # TODO: couldn't we try to return a path instead of converting it
1115         #       to a normpath (but this might not be worth the trouble)
1116         return self.normpath().reversed()
1117
1118     def rotation_pt(self, params):
1119         """return rotation at param(s) or arc length(s) in pts"""
1120         return self.normpath().rotation(params)
1121
1122     def rotation(self, params):
1123         """return rotation at param(s) or arc length(s)"""
1124         return self.normpath().rotation(params)
1125
1126     def split_pt(self, params):
1127         """split normpath at param(s) or arc length(s) in pts and return list of normpaths"""
1128         return self.normpath().split(params)
1129
1130     def split(self, params):
1131         """split normpath at param(s) or arc length(s) and return list of normpaths"""
1132         return self.normpath().split(params)
1133
1134     def tangent_pt(self, params, length):
1135         """return tangent vector of path at param(s) or arc length(s) in pts
1136
1137         If length in pts is not None, the tangent vector will be scaled to
1138         the desired length.
1139         """
1140         return self.normpath().tangent_pt(params, length)
1141
1142     def tangent(self, params, length=1):
1143         """return tangent vector of path at param(s) or arc length(s)
1144
1145         If length is not None, the tangent vector will be scaled to
1146         the desired length.
1147         """
1148         return self.normpath().tangent(params, length)
1149
1150     def trafo_pt(self, params):
1151         """return transformation at param(s) or arc length(s) in pts"""
1152         return self.normpath().trafo(params)
1153
1154     def trafo(self, params):
1155         """return transformation at param(s) or arc length(s)"""
1156         return self.normpath().trafo(params)
1157
1158     def transformed(self, trafo):
1159         """return transformed path"""
1160         return self.normpath().transformed(trafo)
1161
1162     def outputPS(self, file, writer):
1163         """write PS code to file"""
1164         for pitem in self.pathitems:
1165             pitem.outputPS(file, writer)
1166
1167     def outputPDF(self, file, writer):
1168         """write PDF code to file"""
1169         # PDF only supports normsubpathitems; we need to use a normpath
1170         # with epsilon equals None to prevent failure for paths shorter
1171         # than epsilon
1172         self.normpath(epsilon=None).outputPDF(file, writer)
1173
1174
1175 #
1176 # some special kinds of path, again in two variants
1177 #
1178
1179 class line_pt(path):
1180
1181     """straight line from (x1_pt, y1_pt) to (x2_pt, y2_pt) in pts"""
1182
1183     def __init__(self, x1_pt, y1_pt, x2_pt, y2_pt):
1184         path.__init__(self, moveto_pt(x1_pt, y1_pt), lineto_pt(x2_pt, y2_pt))
1185
1186
1187 class curve_pt(path):
1188
1189     """bezier curve with control points (x0_pt, y1_pt),..., (x3_pt, y3_pt) in pts"""
1190
1191     def __init__(self, x0_pt, y0_pt, x1_pt, y1_pt, x2_pt, y2_pt, x3_pt, y3_pt):
1192         path.__init__(self,
1193                       moveto_pt(x0_pt, y0_pt),
1194                       curveto_pt(x1_pt, y1_pt, x2_pt, y2_pt, x3_pt, y3_pt))
1195
1196
1197 class rect_pt(path):
1198
1199     """rectangle at position (x_pt, y_pt) with width_pt and height_pt in pts"""
1200
1201     def __init__(self, x_pt, y_pt, width_pt, height_pt):
1202         path.__init__(self, moveto_pt(x_pt, y_pt),
1203                             lineto_pt(x_pt+width_pt, y_pt),
1204                             lineto_pt(x_pt+width_pt, y_pt+height_pt),
1205                             lineto_pt(x_pt, y_pt+height_pt),
1206                             closepath())
1207
1208
1209 class circle_pt(path):
1210
1211     """circle with center (x_pt, y_pt) and radius_pt in pts"""
1212
1213     def __init__(self, x_pt, y_pt, radius_pt, arcepsilon=0.1):
1214         path.__init__(self, moveto_pt(x_pt+radius_pt, y_pt),
1215                             arc_pt(x_pt, y_pt, radius_pt, arcepsilon, 360-arcepsilon),
1216                             closepath())
1217
1218
1219 class ellipse_pt(path):
1220
1221     """ellipse with center (x_pt, y_pt) in pts,
1222     the two axes (a_pt, b_pt) in pts,
1223     and the angle angle of the first axis"""
1224
1225     def __init__(self, x_pt, y_pt, a_pt, b_pt, angle, **kwargs):
1226         t = trafo.scale(a_pt, b_pt, epsilon=None).rotated(angle).translated_pt(x_pt, y_pt)
1227         p = circle_pt(0, 0, 1, **kwargs).normpath(epsilon=None).transformed(t).path()
1228         path.__init__(self, *p.pathitems)
1229
1230
1231 class line(line_pt):
1232
1233     """straight line from (x1, y1) to (x2, y2)"""
1234
1235     def __init__(self, x1, y1, x2, y2):
1236         line_pt.__init__(self, unit.topt(x1), unit.topt(y1),
1237                                unit.topt(x2), unit.topt(y2))
1238
1239
1240 class curve(curve_pt):
1241
1242     """bezier curve with control points (x0, y1),..., (x3, y3)"""
1243
1244     def __init__(self, x0, y0, x1, y1, x2, y2, x3, y3):
1245         curve_pt.__init__(self, unit.topt(x0), unit.topt(y0),
1246                                 unit.topt(x1), unit.topt(y1),
1247                                 unit.topt(x2), unit.topt(y2),
1248                                 unit.topt(x3), unit.topt(y3))
1249
1250
1251 class rect(rect_pt):
1252
1253     """rectangle at position (x,y) with width and height"""
1254
1255     def __init__(self, x, y, width, height):
1256         rect_pt.__init__(self, unit.topt(x), unit.topt(y),
1257                                unit.topt(width), unit.topt(height))
1258
1259
1260 class circle(circle_pt):
1261
1262     """circle with center (x,y) and radius"""
1263
1264     def __init__(self, x, y, radius, **kwargs):
1265         circle_pt.__init__(self, unit.topt(x), unit.topt(y), unit.topt(radius), **kwargs)
1266
1267
1268 class ellipse(ellipse_pt):
1269
1270     """ellipse with center (x, y), the two axes (a, b),
1271     and the angle angle of the first axis"""
1272
1273     def __init__(self, x, y, a, b, angle, **kwargs):
1274         ellipse_pt.__init__(self, unit.topt(x), unit.topt(y), unit.topt(a), unit.topt(b), angle, **kwargs)