pyx/path.py

   1 # -*- coding: ISO-8859-1 -*-
   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) 2002-2006 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 from __future__ import nested_scopes
  25
  26 import math
  27 from math import cos, sin, tan, acos, pi
  28 try:
  29     from math import radians, degrees
  30 except ImportError:
  31     # fallback implementation for Python 2.1
  32     def radians(x): return x*pi/180
  33     def degrees(x): return x*180/pi
  34
  35 import trafo, unit
  36 from normpath import NormpathException, normpath, normsubpath, normline_pt, normcurve_pt
  37 import bbox as bboxmodule
  38
  39 # set is available as an external interface to the normpath.set method
  40 from normpath import set
  41 # normpath's invalid is available as an external interface
  42 from normpath import invalid
  43
  44 try:
  45     sum([])
  46 except NameError:
  47     # fallback implementation for Python 2.2 and below
  48     def sum(list):
  49         return reduce(lambda x, y: x+y, list, 0)
  50
  51 try:
  52     enumerate([])
  53 except NameError:
  54     # fallback implementation for Python 2.2 and below
  55     def enumerate(list):
  56         return zip(xrange(len(list)), list)
  57
  58 # use new style classes when possible
  59 __metaclass__ = type
  60
  61 class _marker: pass
  62
  63 ################################################################################
  64
  65 # specific exception for path-related problems
  66 class PathException(Exception): pass
  67
  68 ################################################################################
  69 # Bezier helper functions
  70 ################################################################################
  71
  72 def _bezierpolyrange(x0, x1, x2, x3):
  73     tc = [0, 1]
  74
  75     a = x3 - 3*x2 + 3*x1 - x0
  76     b = 2*x0 - 4*x1 + 2*x2
  77     c = x1 - x0
  78
  79     s = b*b - 4*a*c
  80     if s >= 0:
  81         if b >= 0:
  82             q = -0.5*(b+math.sqrt(s))
  83         else:
  84             q = -0.5*(b-math.sqrt(s))
  85
  86         try:
  87             t = q*1.0/a
  88         except ZeroDivisionError:
  89             pass
  90         else:
  91             if 0 < t < 1:
  92                 tc.append(t)
  93
  94         try:
  95             t = c*1.0/q
  96         except ZeroDivisionError:
  97             pass
  98         else:
  99             if 0 < t < 1:
 100                 tc.append(t)
 101
 102     p = [(((a*t + 1.5*b)*t + 3*c)*t + x0) for t in tc]
 103
 104     return min(*p), max(*p)
 105
 106
 107 def _arctobcurve(x_pt, y_pt, r_pt, phi1, phi2):
 108     """generate the best bezier curve corresponding to an arc segment"""
 109
 110     dphi = phi2-phi1
 111
 112     if dphi==0: return None
 113
 114     # the two endpoints should be clear
 115     x0_pt, y0_pt = x_pt+r_pt*cos(phi1), y_pt+r_pt*sin(phi1)
 116     x3_pt, y3_pt = x_pt+r_pt*cos(phi2), y_pt+r_pt*sin(phi2)
 117
 118     # optimal relative distance along tangent for second and third
 119     # control point
 120     l = r_pt*4*(1-cos(dphi/2))/(3*sin(dphi/2))
 121
 122     x1_pt, y1_pt = x0_pt-l*sin(phi1), y0_pt+l*cos(phi1)
 123     x2_pt, y2_pt = x3_pt+l*sin(phi2), y3_pt-l*cos(phi2)
 124
 125     return normcurve_pt(x0_pt, y0_pt, x1_pt, y1_pt, x2_pt, y2_pt, x3_pt, y3_pt)
 126
 127
 128 def _arctobezierpath(x_pt, y_pt, r_pt, phi1, phi2, dphimax=45):
 129     apath = []
 130
 131     phi1 = radians(phi1)
 132     phi2 = radians(phi2)
 133     dphimax = radians(dphimax)
 134
 135     if phi2<phi1:
 136         # guarantee that phi2>phi1 ...
 137         phi2 = phi2 + (math.floor((phi1-phi2)/(2*pi))+1)*2*pi
 138     elif phi2>phi1+2*pi:
 139         # ... or remove unnecessary multiples of 2*pi
 140         phi2 = phi2 - (math.floor((phi2-phi1)/(2*pi))-1)*2*pi
 141
 142     if r_pt == 0 or phi1-phi2 == 0: return []
 143
 144     subdivisions = abs(int((1.0*(phi1-phi2))/dphimax))+1
 145
 146     dphi = (1.0*(phi2-phi1))/subdivisions
 147
 148     for i in range(subdivisions):
 149         apath.append(_arctobcurve(x_pt, y_pt, r_pt, phi1+i*dphi, phi1+(i+1)*dphi))
 150
 151     return apath
 152
 153 def _arcpoint(x_pt, y_pt, r_pt, angle):
 154     """return starting point of arc segment"""
 155     return x_pt+r_pt*cos(radians(angle)), y_pt+r_pt*sin(radians(angle))
 156
 157 def _arcbboxdata(x_pt, y_pt, r_pt, angle1, angle2):
 158     phi1 = radians(angle1)
 159     phi2 = radians(angle2)
 160
 161     # starting end end point of arc segment
 162     sarcx_pt, sarcy_pt = _arcpoint(x_pt, y_pt, r_pt, angle1)
 163     earcx_pt, earcy_pt = _arcpoint(x_pt, y_pt, r_pt, angle2)
 164
 165     # Now, we have to determine the corners of the bbox for the
 166     # arc segment, i.e. global maxima/mimima of cos(phi) and sin(phi)
 167     # in the interval [phi1, phi2]. These can either be located
 168     # on the borders of this interval or in the interior.
 169
 170     if phi2 < phi1:
 171         # guarantee that phi2>phi1
 172         phi2 = phi2 + (math.floor((phi1-phi2)/(2*pi))+1)*2*pi
 173
 174     # next minimum of cos(phi) looking from phi1 in counterclockwise
 175     # direction: 2*pi*floor((phi1-pi)/(2*pi)) + 3*pi
 176
 177     if phi2 < (2*math.floor((phi1-pi)/(2*pi))+3)*pi:
 178         minarcx_pt = min(sarcx_pt, earcx_pt)
 179     else:
 180         minarcx_pt = x_pt-r_pt
 181
 182     # next minimum of sin(phi) looking from phi1 in counterclockwise
 183     # direction: 2*pi*floor((phi1-3*pi/2)/(2*pi)) + 7/2*pi
 184
 185     if phi2 < (2*math.floor((phi1-3.0*pi/2)/(2*pi))+7.0/2)*pi:
 186         minarcy_pt = min(sarcy_pt, earcy_pt)
 187     else:
 188         minarcy_pt = y_pt-r_pt
 189
 190     # next maximum of cos(phi) looking from phi1 in counterclockwise
 191     # direction: 2*pi*floor((phi1)/(2*pi))+2*pi
 192
 193     if phi2 < (2*math.floor((phi1)/(2*pi))+2)*pi:
 194         maxarcx_pt = max(sarcx_pt, earcx_pt)
 195     else:
 196         maxarcx_pt = x_pt+r_pt
 197
 198     # next maximum of sin(phi) looking from phi1 in counterclockwise
 199     # direction: 2*pi*floor((phi1-pi/2)/(2*pi)) + 1/2*pi
 200
 201     if phi2 < (2*math.floor((phi1-pi/2)/(2*pi))+5.0/2)*pi:
 202         maxarcy_pt = max(sarcy_pt, earcy_pt)
 203     else:
 204         maxarcy_pt = y_pt+r_pt
 205
 206     return minarcx_pt, minarcy_pt, maxarcx_pt, maxarcy_pt
 207
 208
 209 ################################################################################
 210 # path context and pathitem base class
 211 ################################################################################
 212
 213 class context:
 214
 215     """context for pathitem"""
 216
 217     def __init__(self, x_pt, y_pt, subfirstx_pt, subfirsty_pt):
 218         """initializes a context for path items
 219
 220         x_pt, y_pt are the currentpoint. subfirstx_pt, subfirsty_pt
 221         are the starting point of the current subpath. There are no
 222         invalid contexts, i.e. all variables need to be set to integer
 223         or float numbers.
 224         """
 225         self.x_pt = x_pt
 226         self.y_pt = y_pt
 227         self.subfirstx_pt = subfirstx_pt
 228         self.subfirsty_pt = subfirsty_pt
 229
 230
 231 class pathitem:
 232
 233     """element of a PS style path"""
 234
 235     def __str__(self):
 236         raise NotImplementedError()
 237
 238     def createcontext(self):
 239         """creates a context from the current pathitem
 240
 241         Returns a context instance. Is called, when no context has yet
 242         been defined, i.e. for the very first pathitem. Most of the
 243         pathitems do not provide this method. Note, that you should pass
 244         the context created by createcontext to updatebbox and updatenormpath
 245         of successive pathitems only; use the context-free createbbox and
 246         createnormpath for the first pathitem instead.
 247         """
 248         raise PathException("path must start with moveto or the like (%r)" % self)
 249
 250     def createbbox(self):
 251         """creates a bbox from the current pathitem
 252
 253         Returns a bbox instance. Is called, when a bbox has to be
 254         created instead of updating it, i.e. for the very first
 255         pathitem. Most pathitems do not provide this method.
 256         updatebbox must not be called for the created instance and the
 257         same pathitem.
 258         """
 259         raise PathException("path must start with moveto or the like (%r)" % self)
 260
 261     def createnormpath(self, epsilon=_marker):
 262         """create a normpath from the current pathitem
 263
 264         Return a normpath instance. Is called, when a normpath has to
 265         be created instead of updating it, i.e. for the very first
 266         pathitem. Most pathitems do not provide this method.
 267         updatenormpath must not be called for the created instance and
 268         the same pathitem.
 269         """
 270         raise PathException("path must start with moveto or the like (%r)" % self)
 271
 272     def updatebbox(self, bbox, context):
 273         """updates the bbox to contain the pathitem for the given
 274         context
 275
 276         Is called for all subsequent pathitems in a path to complete
 277         the bbox information. Both, the bbox and context are updated
 278         inplace. Does not return anything.
 279         """
 280         raise NotImplementedError()
 281
 282     def updatenormpath(self, normpath, context):
 283         """update the normpath to contain the pathitem for the given
 284         context
 285
 286         Is called for all subsequent pathitems in a path to complete
 287         the normpath. Both the normpath and the context are updated
 288         inplace. Most pathitem implementations will use
 289         normpath.normsubpath[-1].append to add normsubpathitem(s).
 290         Does not return anything.
 291         """
 292         raise NotImplementedError()
 293
 294     def outputPS(self, file, writer):
 295         """write PS representation of pathitem to file"""
 296
 297
 298
 299 ################################################################################
 300 # various pathitems
 301 ################################################################################
 302 # Each one comes in two variants:
 303 #  - one with suffix _pt. This one requires the coordinates
 304 #    to be already in pts (mainly used for internal purposes)
 305 #  - another which accepts arbitrary units
 306
 307
 308 class closepath(pathitem):
 309
 310     """Connect subpath back to its starting point"""
 311
 312     __slots__ = ()
 313
 314     def __str__(self):
 315         return "closepath()"
 316
 317     def updatebbox(self, bbox, context):
 318         context.x_pt = context.subfirstx_pt
 319         context.y_pt = context.subfirsty_pt
 320
 321     def updatenormpath(self, normpath, context):
 322         normpath.normsubpaths[-1].close()
 323         context.x_pt = context.subfirstx_pt
 324         context.y_pt = context.subfirsty_pt
 325
 326     def outputPS(self, file, writer):
 327         file.write("closepath\n")
 328
 329
 330 class moveto_pt(pathitem):
 331
 332     """Start a new subpath and set current point to (x_pt, y_pt) (coordinates in pts)"""
 333
 334     __slots__ = "x_pt", "y_pt"
 335
 336     def __init__(self, x_pt, y_pt):
 337         self.x_pt = x_pt
 338         self.y_pt = y_pt
 339
 340     def __str__(self):
 341         return "moveto_pt(%g, %g)" % (self.x_pt, self.y_pt)
 342
 343     def createcontext(self):
 344         return context(self.x_pt, self.y_pt, self.x_pt, self.y_pt)
 345
 346     def createbbox(self):
 347         return bboxmodule.bbox_pt(self.x_pt, self.y_pt, self.x_pt, self.y_pt)
 348
 349     def createnormpath(self, epsilon=_marker):
 350         if epsilon is _marker:
 351             return normpath([normsubpath([normline_pt(self.x_pt, self.y_pt, self.x_pt, self.y_pt)])])
 352         else:
 353             return normpath([normsubpath([normline_pt(self.x_pt, self.y_pt, self.x_pt, self.y_pt)],
 354                                          epsilon=epsilon)])
 355
 356     def updatebbox(self, bbox, context):
 357         bbox.includepoint_pt(self.x_pt, self.y_pt)
 358         context.x_pt = context.subfirstx_pt = self.x_pt
 359         context.y_pt = context.subfirsty_pt = self.y_pt
 360
 361     def updatenormpath(self, normpath, context):
 362         if normpath.normsubpaths[-1].epsilon is not None:
 363             normpath.append(normsubpath([normline_pt(self.x_pt, self.y_pt, self.x_pt, self.y_pt)],
 364                                         epsilon=normpath.normsubpaths[-1].epsilon))
 365         else:
 366             normpath.append(normsubpath(epsilon=normpath.normsubpaths[-1].epsilon))
 367         context.x_pt = context.subfirstx_pt = self.x_pt
 368         context.y_pt = context.subfirsty_pt = self.y_pt
 369
 370     def outputPS(self, file, writer):
 371         file.write("%g %g moveto\n" % (self.x_pt, self.y_pt) )
 372
 373
 374 class lineto_pt(pathitem):
 375
 376     """Append straight line to (x_pt, y_pt) (coordinates in pts)"""
 377
 378     __slots__ = "x_pt", "y_pt"
 379
 380     def __init__(self, x_pt, y_pt):
 381         self.x_pt = x_pt
 382         self.y_pt = y_pt
 383
 384     def __str__(self):
 385         return "lineto_pt(%g, %g)" % (self.x_pt, self.y_pt)
 386
 387     def updatebbox(self, bbox, context):
 388         bbox.includepoint_pt(self.x_pt, self.y_pt)
 389         context.x_pt = self.x_pt
 390         context.y_pt = self.y_pt
 391
 392     def updatenormpath(self, normpath, context):
 393         normpath.normsubpaths[-1].append(normline_pt(context.x_pt, context.y_pt,
 394                                                      self.x_pt, self.y_pt))
 395         context.x_pt = self.x_pt
 396         context.y_pt = self.y_pt
 397
 398     def outputPS(self, file, writer):
 399         file.write("%g %g lineto\n" % (self.x_pt, self.y_pt) )
 400
 401
 402 class curveto_pt(pathitem):
 403
 404     """Append curveto (coordinates in pts)"""
 405
 406     __slots__ = "x1_pt", "y1_pt", "x2_pt", "y2_pt", "x3_pt", "y3_pt"
 407
 408     def __init__(self, x1_pt, y1_pt, x2_pt, y2_pt, x3_pt, y3_pt):
 409         self.x1_pt = x1_pt
 410         self.y1_pt = y1_pt
 411         self.x2_pt = x2_pt
 412         self.y2_pt = y2_pt
 413         self.x3_pt = x3_pt
 414         self.y3_pt = y3_pt
 415
 416     def __str__(self):
 417         return "curveto_pt(%g, %g, %g, %g, %g, %g)" % (self.x1_pt, self.y1_pt,
 418                                                        self.x2_pt, self.y2_pt,
 419                                                        self.x3_pt, self.y3_pt)
 420
 421     def updatebbox(self, bbox, context):
 422         xmin_pt, xmax_pt = _bezierpolyrange(context.x_pt, self.x1_pt, self.x2_pt, self.x3_pt)
 423         ymin_pt, ymax_pt = _bezierpolyrange(context.y_pt, self.y1_pt, self.y2_pt, self.y3_pt)
 424         bbox.includepoint_pt(xmin_pt, ymin_pt)
 425         bbox.includepoint_pt(xmax_pt, ymax_pt)
 426         context.x_pt = self.x3_pt
 427         context.y_pt = self.y3_pt
 428
 429     def updatenormpath(self, normpath, context):
 430         normpath.normsubpaths[-1].append(normcurve_pt(context.x_pt, context.y_pt,
 431                                                       self.x1_pt, self.y1_pt,
 432                                                       self.x2_pt, self.y2_pt,
 433                                                       self.x3_pt, self.y3_pt))
 434         context.x_pt = self.x3_pt
 435         context.y_pt = self.y3_pt
 436
 437     def outputPS(self, file, writer):
 438         file.write("%g %g %g %g %g %g curveto\n" % (self.x1_pt, self.y1_pt,
 439                                                     self.x2_pt, self.y2_pt,
 440                                                     self.x3_pt, self.y3_pt))
 441
 442
 443 class rmoveto_pt(pathitem):
 444
 445     """Perform relative moveto (coordinates in pts)"""
 446
 447     __slots__ = "dx_pt", "dy_pt"
 448
 449     def __init__(self, dx_pt, dy_pt):
 450          self.dx_pt = dx_pt
 451          self.dy_pt = dy_pt
 452
 453     def __str__(self):
 454         return "rmoveto_pt(%g, %g)" % (self.dx_pt, self.dy_pt)
 455
 456     def updatebbox(self, bbox, context):
 457         bbox.includepoint_pt(context.x_pt + self.dx_pt, context.y_pt + self.dy_pt)
 458         context.x_pt += self.dx_pt
 459         context.y_pt += self.dy_pt
 460         context.subfirstx_pt = context.x_pt
 461         context.subfirsty_pt = context.y_pt
 462
 463     def updatenormpath(self, normpath, context):
 464         context.x_pt += self.dx_pt
 465         context.y_pt += self.dy_pt
 466         context.subfirstx_pt = context.x_pt
 467         context.subfirsty_pt = context.y_pt
 468         if normpath.normsubpaths[-1].epsilon is not None:
 469             normpath.append(normsubpath([normline_pt(context.x_pt, context.y_pt,
 470                                                      context.x_pt, context.y_pt)],
 471                                         epsilon=normpath.normsubpaths[-1].epsilon))
 472         else:
 473             normpath.append(normsubpath(epsilon=normpath.normsubpaths[-1].epsilon))
 474
 475     def outputPS(self, file, writer):
 476         file.write("%g %g rmoveto\n" % (self.dx_pt, self.dy_pt) )
 477
 478
 479 class rlineto_pt(pathitem):
 480
 481     """Perform relative lineto (coordinates in pts)"""
 482
 483     __slots__ = "dx_pt", "dy_pt"
 484
 485     def __init__(self, dx_pt, dy_pt):
 486         self.dx_pt = dx_pt
 487         self.dy_pt = dy_pt
 488
 489     def __str__(self):
 490         return "rlineto_pt(%g %g)" % (self.dx_pt, self.dy_pt)
 491
 492     def updatebbox(self, bbox, context):
 493         bbox.includepoint_pt(context.x_pt + self.dx_pt, context.y_pt + self.dy_pt)
 494         context.x_pt += self.dx_pt
 495         context.y_pt += self.dy_pt
 496
 497     def updatenormpath(self, normpath, context):
 498         normpath.normsubpaths[-1].append(normline_pt(context.x_pt, context.y_pt,
 499                                                      context.x_pt + self.dx_pt, context.y_pt + self.dy_pt))
 500         context.x_pt += self.dx_pt
 501         context.y_pt += self.dy_pt
 502
 503     def outputPS(self, file, writer):
 504         file.write("%g %g rlineto\n" % (self.dx_pt, self.dy_pt) )
 505
 506
 507 class rcurveto_pt(pathitem):
 508
 509     """Append rcurveto (coordinates in pts)"""
 510
 511     __slots__ = "dx1_pt", "dy1_pt", "dx2_pt", "dy2_pt", "dx3_pt", "dy3_pt"
 512
 513     def __init__(self, dx1_pt, dy1_pt, dx2_pt, dy2_pt, dx3_pt, dy3_pt):
 514         self.dx1_pt = dx1_pt
 515         self.dy1_pt = dy1_pt
 516         self.dx2_pt = dx2_pt
 517         self.dy2_pt = dy2_pt
 518         self.dx3_pt = dx3_pt
 519         self.dy3_pt = dy3_pt
 520
 521     def __str__(self):
 522         return "rcurveto_pt(%g, %g, %g, %g, %g, %g)" % (self.dx1_pt, self.dy1_pt,
 523                                                         self.dx2_pt, self.dy2_pt,
 524                                                         self.dx3_pt, self.dy3_pt)
 525
 526     def updatebbox(self, bbox, context):
 527         xmin_pt, xmax_pt = _bezierpolyrange(context.x_pt,
 528                                             context.x_pt+self.dx1_pt,
 529                                             context.x_pt+self.dx2_pt,
 530                                             context.x_pt+self.dx3_pt)
 531         ymin_pt, ymax_pt = _bezierpolyrange(context.y_pt,
 532                                             context.y_pt+self.dy1_pt,
 533                                             context.y_pt+self.dy2_pt,
 534                                             context.y_pt+self.dy3_pt)
 535         bbox.includepoint_pt(xmin_pt, ymin_pt)
 536         bbox.includepoint_pt(xmax_pt, ymax_pt)
 537         context.x_pt += self.dx3_pt
 538         context.y_pt += self.dy3_pt
 539
 540     def updatenormpath(self, normpath, context):
 541         normpath.normsubpaths[-1].append(normcurve_pt(context.x_pt, context.y_pt,
 542                                                       context.x_pt + self.dx1_pt, context.y_pt + self.dy1_pt,
 543                                                       context.x_pt + self.dx2_pt, context.y_pt + self.dy2_pt,
 544                                                       context.x_pt + self.dx3_pt, context.y_pt + self.dy3_pt))
 545         context.x_pt += self.dx3_pt
 546         context.y_pt += self.dy3_pt
 547
 548     def outputPS(self, file, writer):
 549         file.write("%g %g %g %g %g %g rcurveto\n" % (self.dx1_pt, self.dy1_pt,
 550                                                      self.dx2_pt, self.dy2_pt,
 551                                                      self.dx3_pt, self.dy3_pt))
 552
 553
 554 class arc_pt(pathitem):
 555
 556     """Append counterclockwise arc (coordinates in pts)"""
 557
 558     __slots__ = "x_pt", "y_pt", "r_pt", "angle1", "angle2"
 559
 560     def __init__(self, x_pt, y_pt, r_pt, angle1, angle2):
 561         self.x_pt = x_pt
 562         self.y_pt = y_pt
 563         self.r_pt = r_pt
 564         self.angle1 = angle1
 565         self.angle2 = angle2
 566
 567     def __str__(self):
 568         return "arc_pt(%g, %g, %g, %g, %g)" % (self.x_pt, self.y_pt, self.r_pt,
 569                                                self.angle1, self.angle2)
 570
 571     def createcontext(self):
 572         x_pt, y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 573         return context(x_pt, y_pt, x_pt, y_pt)
 574
 575     def createbbox(self):
 576         return bboxmodule.bbox_pt(*_arcbboxdata(self.x_pt, self.y_pt, self.r_pt,
 577                                                 self.angle1, self.angle2))
 578
 579     def createnormpath(self, epsilon=_marker):
 580         if epsilon is _marker:
 581             return normpath([normsubpath(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle1, self.angle2))])
 582         else:
 583             return normpath([normsubpath(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle1, self.angle2),
 584                                          epsilon=epsilon)])
 585
 586     def updatebbox(self, bbox, context):
 587         minarcx_pt, minarcy_pt, maxarcx_pt, maxarcy_pt = _arcbboxdata(self.x_pt, self.y_pt, self.r_pt,
 588                                                                       self.angle1, self.angle2)
 589         bbox.includepoint_pt(minarcx_pt, minarcy_pt)
 590         bbox.includepoint_pt(maxarcx_pt, maxarcy_pt)
 591         context.x_pt, context.y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 592
 593     def updatenormpath(self, normpath, context):
 594         if normpath.normsubpaths[-1].closed:
 595             normpath.append(normsubpath([normline_pt(context.x_pt, context.y_pt,
 596                                                          *_arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle1))],
 597                                         epsilon=normpath.normsubpaths[-1].epsilon))
 598         else:
 599             normpath.normsubpaths[-1].append(normline_pt(context.x_pt, context.y_pt,
 600                                                          *_arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle1)))
 601         normpath.normsubpaths[-1].extend(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle1, self.angle2))
 602         context.x_pt, context.y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 603
 604     def outputPS(self, file, writer):
 605         file.write("%g %g %g %g %g arc\n" % (self.x_pt, self.y_pt,
 606                                              self.r_pt,
 607                                              self.angle1,
 608                                              self.angle2))
 609
 610
 611 class arcn_pt(pathitem):
 612
 613     """Append clockwise arc (coordinates in pts)"""
 614
 615     __slots__ = "x_pt", "y_pt", "r_pt", "angle1", "angle2"
 616
 617     def __init__(self, x_pt, y_pt, r_pt, angle1, angle2):
 618         self.x_pt = x_pt
 619         self.y_pt = y_pt
 620         self.r_pt = r_pt
 621         self.angle1 = angle1
 622         self.angle2 = angle2
 623
 624     def __str__(self):
 625         return "arcn_pt(%g, %g, %g, %g, %g)" % (self.x_pt, self.y_pt, self.r_pt,
 626                                                 self.angle1, self.angle2)
 627
 628     def createcontext(self):
 629         x_pt, y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 630         return context(x_pt, y_pt, x_pt, y_pt)
 631
 632     def createbbox(self):
 633         return bboxmodule.bbox_pt(*_arcbboxdata(self.x_pt, self.y_pt, self.r_pt,
 634                                                 self.angle2, self.angle1))
 635
 636     def createnormpath(self, epsilon=_marker):
 637         if epsilon is _marker:
 638             return normpath([normsubpath(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle2, self.angle1))]).reversed()
 639         else:
 640             return normpath([normsubpath(_arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle2, self.angle1),
 641                                          epsilon=epsilon)]).reversed()
 642
 643     def updatebbox(self, bbox, context):
 644         minarcx_pt, minarcy_pt, maxarcx_pt, maxarcy_pt = _arcbboxdata(self.x_pt, self.y_pt, self.r_pt,
 645                                                                       self.angle2, self.angle1)
 646         bbox.includepoint_pt(minarcx_pt, minarcy_pt)
 647         bbox.includepoint_pt(maxarcx_pt, maxarcy_pt)
 648         context.x_pt, context.y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 649
 650     def updatenormpath(self, normpath, context):
 651         if normpath.normsubpaths[-1].closed:
 652             normpath.append(normsubpath([normline_pt(context.x_pt, context.y_pt,
 653                                                          *_arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle1))],
 654                                         epsilon=normpath.normsubpaths[-1].epsilon))
 655         else:
 656             normpath.normsubpaths[-1].append(normline_pt(context.x_pt, context.y_pt,
 657                                                          *_arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle1)))
 658         bpathitems = _arctobezierpath(self.x_pt, self.y_pt, self.r_pt, self.angle2, self.angle1)
 659         bpathitems.reverse()
 660         for bpathitem in bpathitems:
 661             normpath.normsubpaths[-1].append(bpathitem.reversed())
 662         context.x_pt, context.y_pt = _arcpoint(self.x_pt, self.y_pt, self.r_pt, self.angle2)
 663
 664     def outputPS(self, file, writer):
 665         file.write("%g %g %g %g %g arcn\n" % (self.x_pt, self.y_pt,
 666                                               self.r_pt,
 667                                               self.angle1,
 668                                               self.angle2))
 669
 670
 671 class arct_pt(pathitem):
 672
 673     """Append tangent arc (coordinates in pts)"""
 674
 675     __slots__ = "x1_pt", "y1_pt", "x2_pt", "y2_pt", "r_pt"
 676
 677     def __init__(self, x1_pt, y1_pt, x2_pt, y2_pt, r_pt):
 678         self.x1_pt = x1_pt
 679         self.y1_pt = y1_pt
 680         self.x2_pt = x2_pt
 681         self.y2_pt = y2_pt
 682         self.r_pt = r_pt
 683
 684     def __str__(self):
 685         return "arct_pt(%g, %g, %g, %g, %g)" % (self.x1_pt, self.y1_pt,
 686                                                 self.x2_pt, self.y2_pt,
 687                                                 self.r_pt)
 688
 689     def _pathitems(self, x_pt, y_pt):
 690         """return pathitems corresponding to arct for given currentpoint x_pt, y_pt.
 691
 692         The return is a list containing line_pt, arc_pt, a arcn_pt instances.
 693
 694         This is a helper routine for updatebbox and updatenormpath,
 695         which will delegate the work to the constructed pathitem.
 696         """
 697
 698         # direction of tangent 1
 699         dx1_pt, dy1_pt = self.x1_pt-x_pt, self.y1_pt-y_pt
 700         l1_pt = math.hypot(dx1_pt, dy1_pt)
 701         dx1, dy1 = dx1_pt/l1_pt, dy1_pt/l1_pt
 702
 703         # direction of tangent 2
 704         dx2_pt, dy2_pt = self.x2_pt-self.x1_pt, self.y2_pt-self.y1_pt
 705         l2_pt = math.hypot(dx2_pt, dy2_pt)
 706         dx2, dy2 = dx2_pt/l2_pt, dy2_pt/l2_pt
 707
 708         # intersection angle between two tangents in the range (-pi, pi).
 709         # We take the orientation from the sign of the vector product.
 710         # Negative (positive) angles alpha corresponds to a turn to the right (left)
 711         # as seen from currentpoint.
 712         if dx1*dy2-dy1*dx2 > 0:
 713             alpha = acos(dx1*dx2+dy1*dy2)
 714         else:
 715             alpha = -acos(dx1*dx2+dy1*dy2)
 716
 717         try:
 718             # two tangent points
 719             xt1_pt = self.x1_pt - dx1*self.r_pt*tan(abs(alpha)/2)
 720             yt1_pt = self.y1_pt - dy1*self.r_pt*tan(abs(alpha)/2)
 721             xt2_pt = self.x1_pt + dx2*self.r_pt*tan(abs(alpha)/2)
 722             yt2_pt = self.y1_pt + dy2*self.r_pt*tan(abs(alpha)/2)
 723
 724             # direction point 1 -> center of arc
 725             dmx_pt = 0.5*(xt1_pt+xt2_pt) - self.x1_pt
 726             dmy_pt = 0.5*(yt1_pt+yt2_pt) - self.y1_pt
 727             lm_pt = math.hypot(dmx_pt, dmy_pt)
 728             dmx, dmy = dmx_pt/lm_pt, dmy_pt/lm_pt
 729
 730             # center of arc
 731             mx_pt = self.x1_pt + dmx*self.r_pt/cos(alpha/2)
 732             my_pt = self.y1_pt + dmy*self.r_pt/cos(alpha/2)
 733
 734             # angle around which arc is centered
 735             phi = degrees(math.atan2(-dmy, -dmx))
 736
 737             # half angular width of arc
 738             deltaphi = degrees(alpha)/2
 739
 740             line = lineto_pt(*_arcpoint(mx_pt, my_pt, self.r_pt, phi-deltaphi))
 741             if alpha > 0:
 742                 return [line, arc_pt(mx_pt, my_pt, self.r_pt, phi-deltaphi, phi+deltaphi)]
 743             else:
 744                 return [line, arcn_pt(mx_pt, my_pt, self.r_pt, phi-deltaphi, phi+deltaphi)]
 745
 746         except ZeroDivisionError:
 747             # in the degenerate case, we just return a line as specified by the PS
 748             # language reference
 749             return [lineto_pt(self.x1_pt, self.y1_pt)]
 750
 751     def updatebbox(self, bbox, context):
 752         for pathitem in self._pathitems(context.x_pt, context.y_pt):
 753             pathitem.updatebbox(bbox, context)
 754
 755     def updatenormpath(self, normpath, context):
 756         for pathitem in self._pathitems(context.x_pt, context.y_pt):
 757             pathitem.updatenormpath(normpath, context)
 758
 759     def outputPS(self, file, writer):
 760         file.write("%g %g %g %g %g arct\n" % (self.x1_pt, self.y1_pt,
 761                                               self.x2_pt, self.y2_pt,
 762                                               self.r_pt))
 763
 764 #
 765 # now the pathitems that convert from user coordinates to pts
 766 #
 767
 768 class moveto(moveto_pt):
 769
 770     """Set current point to (x, y)"""
 771
 772     __slots__ = "x_pt", "y_pt"
 773
 774     def __init__(self, x, y):
 775         moveto_pt.__init__(self, unit.topt(x), unit.topt(y))
 776
 777
 778 class lineto(lineto_pt):
 779
 780     """Append straight line to (x, y)"""
 781
 782     __slots__ = "x_pt", "y_pt"
 783
 784     def __init__(self, x, y):
 785         lineto_pt.__init__(self, unit.topt(x), unit.topt(y))
 786
 787
 788 class curveto(curveto_pt):
 789
 790     """Append curveto"""
 791
 792     __slots__ = "x1_pt", "y1_pt", "x2_pt", "y2_pt", "x3_pt", "y3_pt"
 793
 794     def __init__(self, x1, y1, x2, y2, x3, y3):
 795         curveto_pt.__init__(self,
 796                             unit.topt(x1), unit.topt(y1),
 797                             unit.topt(x2), unit.topt(y2),
 798                             unit.topt(x3), unit.topt(y3))
 799
 800 class rmoveto(rmoveto_pt):
 801
 802     """Perform relative moveto"""
 803
 804     __slots__ = "dx_pt", "dy_pt"
 805
 806     def __init__(self, dx, dy):
 807         rmoveto_pt.__init__(self, unit.topt(dx), unit.topt(dy))
 808
 809
 810 class rlineto(rlineto_pt):
 811
 812     """Perform relative lineto"""
 813
 814     __slots__ = "dx_pt", "dy_pt"
 815
 816     def __init__(self, dx, dy):
 817         rlineto_pt.__init__(self, unit.topt(dx), unit.topt(dy))
 818
 819
 820 class rcurveto(rcurveto_pt):
 821
 822     """Append rcurveto"""
 823
 824     __slots__ = "dx1_pt", "dy1_pt", "dx2_pt", "dy2_pt", "dx3_pt", "dy3_pt"
 825
 826     def __init__(self, dx1, dy1, dx2, dy2, dx3, dy3):
 827         rcurveto_pt.__init__(self,
 828                              unit.topt(dx1), unit.topt(dy1),
 829                              unit.topt(dx2), unit.topt(dy2),
 830                              unit.topt(dx3), unit.topt(dy3))
 831
 832
 833 class arcn(arcn_pt):
 834
 835     """Append clockwise arc"""
 836
 837     __slots__ = "x_pt", "y_pt", "r_pt", "angle1", "angle2"
 838
 839     def __init__(self, x, y, r, angle1, angle2):
 840         arcn_pt.__init__(self, unit.topt(x), unit.topt(y), unit.topt(r), angle1, angle2)
 841
 842
 843 class arc(arc_pt):
 844
 845     """Append counterclockwise arc"""
 846
 847     __slots__ = "x_pt", "y_pt", "r_pt", "angle1", "angle2"
 848
 849     def __init__(self, x, y, r, angle1, angle2):
 850         arc_pt.__init__(self, unit.topt(x), unit.topt(y), unit.topt(r), angle1, angle2)
 851
 852
 853 class arct(arct_pt):
 854
 855     """Append tangent arc"""
 856
 857     __slots__ = "x1_pt", "y1_pt", "x2_pt", "y2_pt", "r_pt"
 858
 859     def __init__(self, x1, y1, x2, y2, r):
 860         arct_pt.__init__(self, unit.topt(x1), unit.topt(y1),
 861                          unit.topt(x2), unit.topt(y2), unit.topt(r))
 862
 863 #
 864 # "combined" pathitems provided for performance reasons
 865 #
 866
 867 class multilineto_pt(pathitem):
 868
 869     """Perform multiple linetos (coordinates in pts)"""
 870
 871     __slots__ = "points_pt"
 872
 873     def __init__(self, points_pt):
 874         self.points_pt = points_pt
 875
 876     def __str__(self):
 877         result = []
 878         for point_pt in self.points_pt:
 879             result.append("(%g, %g)" % point_pt )
 880         return "multilineto_pt([%s])" % (", ".join(result))
 881
 882     def updatebbox(self, bbox, context):
 883         for point_pt in self.points_pt:
 884             bbox.includepoint_pt(*point_pt)
 885         if self.points_pt:
 886             context.x_pt, context.y_pt = self.points_pt[-1]
 887
 888     def updatenormpath(self, normpath, context):
 889         x0_pt, y0_pt = context.x_pt, context.y_pt
 890         for point_pt in self.points_pt:
 891             normpath.normsubpaths[-1].append(normline_pt(x0_pt, y0_pt, *point_pt))
 892             x0_pt, y0_pt = point_pt
 893         context.x_pt, context.y_pt = x0_pt, y0_pt
 894
 895     def outputPS(self, file, writer):
 896         for point_pt in self.points_pt:
 897             file.write("%g %g lineto\n" % point_pt )
 898
 899
 900 class multicurveto_pt(pathitem):
 901
 902     """Perform multiple curvetos (coordinates in pts)"""
 903
 904     __slots__ = "points_pt"
 905
 906     def __init__(self, points_pt):
 907         self.points_pt = points_pt
 908
 909     def __str__(self):
 910         result = []
 911         for point_pt in self.points_pt:
 912             result.append("(%g, %g, %g, %g, %g, %g)" % point_pt )
 913         return "multicurveto_pt([%s])" % (", ".join(result))
 914
 915     def updatebbox(self, bbox, context):
 916         for point_pt in self.points_pt:
 917             bbox.includepoint_pt(*point_pt[0: 2])
 918             bbox.includepoint_pt(*point_pt[2: 4])
 919             bbox.includepoint_pt(*point_pt[4: 6])
 920         if self.points_pt:
 921             context.x_pt, context.y_pt = self.points_pt[-1][4:]
 922
 923     def updatenormpath(self, normpath, context):
 924         x0_pt, y0_pt = context.x_pt, context.y_pt
 925         for point_pt in self.points_pt:
 926             normpath.normsubpaths[-1].append(normcurve_pt(x0_pt, y0_pt, *point_pt))
 927             x0_pt, y0_pt = point_pt[4:]
 928         context.x_pt, context.y_pt = x0_pt, y0_pt
 929
 930     def outputPS(self, file, writer):
 931         for point_pt in self.points_pt:
 932             file.write("%g %g %g %g %g %g curveto\n" % point_pt)
 933
 934
 935 ################################################################################
 936 # path: PS style path
 937 ################################################################################
 938
 939 class path:
 940
 941     """PS style path"""
 942
 943     __slots__ = "pathitems", "_normpath"
 944
 945     def __init__(self, *pathitems):
 946         """construct a path from pathitems *args"""
 947
 948         for apathitem in pathitems:
 949             assert isinstance(apathitem, pathitem), "only pathitem instances allowed"
 950
 951         self.pathitems = list(pathitems)
 952         # normpath cache (when no epsilon is set)
 953         self._normpath = None
 954
 955     def __add__(self, other):
 956         """create new path out of self and other"""
 957         return path(*(self.pathitems + other.path().pathitems))
 958
 959     def __iadd__(self, other):
 960         """add other inplace
 961
 962         If other is a normpath instance, it is converted to a path before
 963         being added.
 964         """
 965         self.pathitems += other.path().pathitems
 966         self._normpath = None
 967         return self
 968
 969     def __getitem__(self, i):
 970         """return path item i"""
 971         return self.pathitems[i]
 972
 973     def __len__(self):
 974         """return the number of path items"""
 975         return len(self.pathitems)
 976
 977     def __str__(self):
 978         l = ", ".join(map(str, self.pathitems))
 979         return "path(%s)" % l
 980
 981     def append(self, apathitem):
 982         """append a path item"""
 983         assert isinstance(apathitem, pathitem), "only pathitem instance allowed"
 984         self.pathitems.append(apathitem)
 985         self._normpath = None
 986
 987     def arclen_pt(self):
 988         """return arc length in pts"""
 989         return self.normpath().arclen_pt()
 990
 991     def arclen(self):
 992         """return arc length"""
 993         return self.normpath().arclen()
 994
 995     def arclentoparam_pt(self, lengths_pt):
 996         """return the param(s) matching the given length(s)_pt in pts"""
 997         return self.normpath().arclentoparam_pt(lengths_pt)
 998
 999     def arclentoparam(self, lengths):
1000         """return the param(s) matching the given length(s)"""
1001         return self.normpath().arclentoparam(lengths)
1002
1003     def at_pt(self, params):
1004         """return coordinates of path in pts at param(s) or arc length(s) in pts"""
1005         return self.normpath().at_pt(params)
1006
1007     def at(self, params):
1008         """return coordinates of path at param(s) or arc length(s)"""
1009         return self.normpath().at(params)
1010
1011     def atbegin_pt(self):
1012         """return coordinates of the beginning of first subpath in path in pts"""
1013         return self.normpath().atbegin_pt()
1014
1015     def atbegin(self):
1016         """return coordinates of the beginning of first subpath in path"""
1017         return self.normpath().atbegin()
1018
1019     def atend_pt(self):
1020         """return coordinates of the end of last subpath in path in pts"""
1021         return self.normpath().atend_pt()
1022
1023     def atend(self):
1024         """return coordinates of the end of last subpath in path"""
1025         return self.normpath().atend()
1026
1027     def bbox(self):
1028         """return bbox of path"""
1029         if self.pathitems:
1030             bbox = self.pathitems[0].createbbox()
1031             context = self.pathitems[0].createcontext()
1032             for pathitem in self.pathitems[1:]:
1033                 pathitem.updatebbox(bbox, context)
1034             return bbox
1035         else:
1036             return bboxmodule.empty()
1037
1038     def begin(self):
1039         """return param corresponding of the beginning of the path"""
1040         return self.normpath().begin()
1041
1042     def curveradius_pt(self, params):
1043         """return the curvature radius in pts at param(s) or arc length(s) in pts
1044
1045         The curvature radius is the inverse of the curvature. When the
1046         curvature is 0, None is returned. Note that this radius can be negative
1047         or positive, depending on the sign of the curvature."""
1048         return self.normpath().curveradius_pt(params)
1049
1050     def curveradius(self, params):
1051         """return the curvature radius at param(s) or arc length(s)
1052
1053         The curvature radius is the inverse of the curvature. When the
1054         curvature is 0, None is returned. Note that this radius can be negative
1055         or positive, depending on the sign of the curvature."""
1056         return self.normpath().curveradius(params)
1057
1058     def end(self):
1059         """return param corresponding of the end of the path"""
1060         return self.normpath().end()
1061
1062     def extend(self, pathitems):
1063         """extend path by pathitems"""
1064         for apathitem in pathitems:
1065             assert isinstance(apathitem, pathitem), "only pathitem instance allowed"
1066         self.pathitems.extend(pathitems)
1067         self._normpath = None
1068
1069     def intersect(self, other):
1070         """intersect self with other path
1071
1072         Returns a tuple of lists consisting of the parameter values
1073         of the intersection points of the corresponding normpath.
1074         """
1075         return self.normpath().intersect(other)
1076
1077     def join(self, other):
1078         """join other path/normpath inplace
1079
1080         If other is a normpath instance, it is converted to a path before
1081         being joined.
1082         """
1083         self.pathitems = self.joined(other).path().pathitems
1084         self._normpath = None
1085         return self
1086
1087     def joined(self, other):
1088         """return path consisting of self and other joined together"""
1089         return self.normpath().joined(other).path()
1090
1091     # << operator also designates joining
1092     __lshift__ = joined
1093
1094     def normpath(self, epsilon=_marker):
1095         """convert the path into a normpath"""
1096         # use cached value if existent and epsilon is _marker
1097         if self._normpath is not None and epsilon is _marker:
1098             return self._normpath
1099         if self.pathitems:
1100             if epsilon is _marker:
1101                 normpath = self.pathitems[0].createnormpath()
1102             else:
1103                 normpath = self.pathitems[0].createnormpath(epsilon)
1104             context = self.pathitems[0].createcontext()
1105             for pathitem in self.pathitems[1:]:
1106                 pathitem.updatenormpath(normpath, context)
1107         else:
1108             if epsilon is _marker:
1109                 normpath = normpath([])
1110             else:
1111                 normpath = normpath(epsilon=epsilon)
1112         if epsilon is _marker:
1113             self._normpath = normpath
1114         return normpath
1115
1116     def paramtoarclen_pt(self, params):
1117         """return arc lenght(s) in pts matching the given param(s)"""
1118         return self.normpath().paramtoarclen_pt(params)
1119
1120     def paramtoarclen(self, params):
1121         """return arc lenght(s) matching the given param(s)"""
1122         return self.normpath().paramtoarclen(params)
1123
1124     def path(self):
1125         """return corresponding path, i.e., self"""
1126         return self
1127
1128     def reversed(self):
1129         """return reversed normpath"""
1130         # TODO: couldn't we try to return a path instead of converting it
1131         #       to a normpath (but this might not be worth the trouble)
1132         return self.normpath().reversed()
1133
1134     def rotation_pt(self, params):
1135         """return rotation at param(s) or arc length(s) in pts"""
1136         return self.normpath().rotation(params)
1137
1138     def rotation(self, params):
1139         """return rotation at param(s) or arc length(s)"""
1140         return self.normpath().rotation(params)
1141
1142     def split_pt(self, params):
1143         """split normpath at param(s) or arc length(s) in pts and return list of normpaths"""
1144         return self.normpath().split(params)
1145
1146     def split(self, params):
1147         """split normpath at param(s) or arc length(s) and return list of normpaths"""
1148         return self.normpath().split(params)
1149
1150     def tangent_pt(self, params, length):
1151         """return tangent vector of path at param(s) or arc length(s) in pts
1152
1153         If length in pts is not None, the tangent vector will be scaled to
1154         the desired length.
1155         """
1156         return self.normpath().tangent_pt(params, length)
1157
1158     def tangent(self, params, length=1):
1159         """return tangent vector of path at param(s) or arc length(s)
1160
1161         If length is not None, the tangent vector will be scaled to
1162         the desired length.
1163         """
1164         return self.normpath().tangent(params, length)
1165
1166     def trafo_pt(self, params):
1167         """return transformation at param(s) or arc length(s) in pts"""
1168         return self.normpath().trafo(params)
1169
1170     def trafo(self, params):
1171         """return transformation at param(s) or arc length(s)"""
1172         return self.normpath().trafo(params)
1173
1174     def transformed(self, trafo):
1175         """return transformed path"""
1176         return self.normpath().transformed(trafo)
1177
1178     def outputPS(self, file, writer):
1179         """write PS code to file"""
1180         for pitem in self.pathitems:
1181             pitem.outputPS(file, writer)
1182
1183     def outputPDF(self, file, writer):
1184         """write PDF code to file"""
1185         # PDF only supports normsubpathitems; we need to use a normpath
1186         # with epsilon equals None to prevent failure for paths shorter
1187         # than epsilon
1188         self.normpath(epsilon=None).outputPDF(file, writer)
1189
1190
1191 #
1192 # some special kinds of path, again in two variants
1193 #
1194
1195 class line_pt(path):
1196
1197     """straight line from (x1_pt, y1_pt) to (x2_pt, y2_pt) in pts"""
1198
1199     def __init__(self, x1_pt, y1_pt, x2_pt, y2_pt):
1200         path.__init__(self, moveto_pt(x1_pt, y1_pt), lineto_pt(x2_pt, y2_pt))
1201
1202
1203 class curve_pt(path):
1204
1205     """bezier curve with control points (x0_pt, y1_pt),..., (x3_pt, y3_pt) in pts"""
1206
1207     def __init__(self, x0_pt, y0_pt, x1_pt, y1_pt, x2_pt, y2_pt, x3_pt, y3_pt):
1208         path.__init__(self,
1209                       moveto_pt(x0_pt, y0_pt),
1210                       curveto_pt(x1_pt, y1_pt, x2_pt, y2_pt, x3_pt, y3_pt))
1211
1212
1213 class rect_pt(path):
1214
1215     """rectangle at position (x_pt, y_pt) with width_pt and height_pt in pts"""
1216
1217     def __init__(self, x_pt, y_pt, width_pt, height_pt):
1218         path.__init__(self, moveto_pt(x_pt, y_pt),
1219                             lineto_pt(x_pt+width_pt, y_pt),
1220                             lineto_pt(x_pt+width_pt, y_pt+height_pt),
1221                             lineto_pt(x_pt, y_pt+height_pt),
1222                             closepath())
1223
1224
1225 class circle_pt(path):
1226
1227     """circle with center (x_pt, y_pt) and radius_pt in pts"""
1228
1229     def __init__(self, x_pt, y_pt, radius_pt, arcepsilon=0.1):
1230         path.__init__(self, moveto_pt(x_pt+radius_pt, y_pt),
1231                             arc_pt(x_pt, y_pt, radius_pt, arcepsilon, 360-arcepsilon),
1232                             closepath())
1233
1234
1235 class ellipse_pt(path):
1236
1237     """ellipse with center (x_pt, y_pt) in pts,
1238     the two axes (a_pt, b_pt) in pts,
1239     and the angle angle of the first axis"""
1240
1241     def __init__(self, x_pt, y_pt, a_pt, b_pt, angle, **kwargs):
1242         t = trafo.scale(a_pt, b_pt, epsilon=None).rotated(angle).translated_pt(x_pt, y_pt)
1243         p = circle_pt(0, 0, 1, **kwargs).normpath(epsilon=None).transformed(t).path()
1244         path.__init__(self, *p.pathitems)
1245
1246
1247 class line(line_pt):
1248
1249     """straight line from (x1, y1) to (x2, y2)"""
1250
1251     def __init__(self, x1, y1, x2, y2):
1252         line_pt.__init__(self, unit.topt(x1), unit.topt(y1),
1253                                unit.topt(x2), unit.topt(y2))
1254
1255
1256 class curve(curve_pt):
1257
1258     """bezier curve with control points (x0, y1),..., (x3, y3)"""
1259
1260     def __init__(self, x0, y0, x1, y1, x2, y2, x3, y3):
1261         curve_pt.__init__(self, unit.topt(x0), unit.topt(y0),
1262                                 unit.topt(x1), unit.topt(y1),
1263                                 unit.topt(x2), unit.topt(y2),
1264                                 unit.topt(x3), unit.topt(y3))
1265
1266
1267 class rect(rect_pt):
1268
1269     """rectangle at position (x,y) with width and height"""
1270
1271     def __init__(self, x, y, width, height):
1272         rect_pt.__init__(self, unit.topt(x), unit.topt(y),
1273                                unit.topt(width), unit.topt(height))
1274
1275
1276 class circle(circle_pt):
1277
1278     """circle with center (x,y) and radius"""
1279
1280     def __init__(self, x, y, radius, **kwargs):
1281         circle_pt.__init__(self, unit.topt(x), unit.topt(y), unit.topt(radius), **kwargs)
1282
1283
1284 class ellipse(ellipse_pt):
1285
1286     """ellipse with center (x, y), the two axes (a, b),
1287     and the angle angle of the first axis"""
1288
1289     def __init__(self, x, y, a, b, angle, **kwargs):
1290         ellipse_pt.__init__(self, unit.topt(x), unit.topt(y), unit.topt(a), unit.topt(b), angle, **kwargs)