pyx/connector.py

   1 #!/usr/bin/env python
   2 # -*- coding: ISO-8859-1 -*-
   3 #
   4 #
   5 # Copyright (C) 2003-2004 Michael Schindler <m-schindler@users.sourceforge.net>
   6 #
   7 # This file is part of PyX (http://pyx.sourceforge.net/).
   8 #
   9 # PyX is free software; you can redistribute it and/or modify
  10 # it under the terms of the GNU General Public License as published by
  11 # the Free Software Foundation; either version 2 of the License, or
  12 # (at your option) any later version.
  13 #
  14 # PyX is distributed in the hope that it will be useful,
  15 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 # GNU General Public License for more details.
  18 #
  19 # You should have received a copy of the GNU General Public License
  20 # along with PyX; if not, write to the Free Software
  21 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22
  23
  24 import math
  25 from math import pi, sin, cos, atan2, tan, hypot, acos, sqrt
  26 import path, trafo, unit, helper
  27 try:
  28     from math import radians, degrees
  29 except ImportError:
  30     # fallback implementation for Python 2.1 and below
  31     def radians(x): return x*pi/180
  32     def degrees(x): return x*180/pi
  33
  34
  35 #########################
  36 ##   helpers
  37 #########################
  38
  39 def _topt(length, default_type=None):
  40     if length is None: return None
  41     if default_type is not None:
  42         return unit.topt(unit.length(length, default_type=default_type))
  43     else:
  44         return unit.topt(unit.length(length))
  45
  46 class connector_pt(path.normpath):
  47
  48     def omitends(self, box1, box2):
  49         """intersect a path with the boxes' paths"""
  50
  51         # cut off the start of self
  52         # XXX how can decoration of this box1.path() be handled?
  53         sp = self.intersect(box1.path())[0]
  54         sp.sort()
  55         if sp:
  56             self.subpaths = self.split(sp[-1:])[1].subpaths
  57
  58         # cut off the end of self
  59         sp = self.intersect(box2.path())[0]
  60         sp.sort()
  61         if sp:
  62             self.subpaths = self.split(sp[:1])[0].subpaths
  63
  64     def shortenpath(self, dists):
  65         """shorten a path by the given distances"""
  66
  67         # cut off the start of self
  68         # XXX should path.lentopar used here?
  69         center = (unit.topt(self.begin()[0]), unit.topt(self.begin()[1]))
  70         sp = self.intersect(path.circle_pt(center[0], center[1], dists[0]))[0]
  71         sp.sort()
  72         if sp:
  73             self.subpaths = self.split(sp[-1:])[1].subpaths
  74
  75         # cut off the end of self
  76         center = (unit.topt(self.end()[0]), unit.topt(self.end()[1]))
  77         sp = self.intersect(path.circle_pt(center[0], center[1], dists[1]))[0]
  78         sp.sort()
  79         if sp:
  80             self.subpaths = self.split(sp[:1])[0].subpaths
  81
  82
  83 ################
  84 ## classes
  85 ################
  86
  87
  88 class line_pt(connector_pt):
  89
  90     def __init__(self, box1, box2, boxdists=[0,0]):
  91
  92         self.box1 = box1
  93         self.box2 = box2
  94
  95         connector_pt.__init__(self,
  96             [path.normsubpath([path.normline(*(self.box1.center+self.box2.center))], 0)])
  97
  98         self.omitends(box1, box2)
  99         self.shortenpath(boxdists)
 100
 101
 102 class arc_pt(connector_pt):
 103
 104     def __init__(self, box1, box2, relangle=45,
 105                  absbulge=None, relbulge=None, boxdists=[0,0]):
 106
 107         # the deviation of arc from the straight line can be specified:
 108         # 1. By an angle between a straight line and the arc
 109         #    This angle is measured at the centers of the box.
 110         # 2. By the largest normal distance between line and arc: absbulge
 111         #    or, equivalently, by the bulge relative to the length of the
 112         #    straight line from center to center.
 113         # Only one can be used.
 114
 115         self.box1 = box1
 116         self.box2 = box2
 117
 118         rel = (self.box2.center[0] - self.box1.center[0],
 119                self.box2.center[1] - self.box1.center[1])
 120         distance = hypot(*rel)
 121
 122         # usage of bulge overrides the relangle parameter
 123         if relbulge is not None or absbulge is not None:
 124             relangle = None
 125             bulge = 0
 126             try: bulge += absbulge
 127             except: pass
 128             try: bulge += relbulge*distance
 129             except: pass
 130
 131             try: radius = abs(0.5 * (bulge + 0.25 * distance**2 / bulge))
 132             except: radius = 10 * distance # default value for too straight arcs
 133             radius = min(radius, 10 * distance)
 134             center = 2.0*(radius-abs(bulge))/distance
 135             center *= 2*(bulge>0.0)-1
 136         # otherwise use relangle
 137         else:
 138             bulge=None
 139             try: radius = 0.5 * distance / abs(cos(0.5*math.pi - radians(relangle)))
 140             except: radius = 10 * distance
 141             try: center = tan(0.5*math.pi - radians(relangle))
 142             except: center = 0
 143
 144         # up to here center is only the distance from the middle of the
 145         # straight connection
 146         center = (0.5 * (self.box1.center[0] + self.box2.center[0] - rel[1]*center),
 147                   0.5 * (self.box1.center[1] + self.box2.center[1] + rel[0]*center))
 148         angle1 = atan2(self.box1.center[1] - center[1], self.box1.center[0] - center[0])
 149         angle2 = atan2(self.box2.center[1] - center[1], self.box2.center[0] - center[0])
 150
 151         # draw the arc in positive direction by default
 152         # negative direction if relangle<0 or bulge<0
 153         if (relangle is not None and relangle < 0) or (bulge is not None and bulge < 0):
 154             connector_pt.__init__(self,
 155                 path.path(path.moveto_pt(*self.box1.center),
 156                           path.arcn_pt(center[0], center[1], radius, degrees(angle1), degrees(angle2))))
 157         else:
 158             connector_pt.__init__(self,
 159                 path.path(path.moveto_pt(*self.box1.center),
 160                           path.arc_pt(center[0], center[1], radius, degrees(angle1), degrees(angle2))))
 161
 162         self.omitends(box1, box2)
 163         self.shortenpath(boxdists)
 164
 165
 166 class curve_pt(connector_pt):
 167
 168     def __init__(self, box1, box2,
 169                  relangle1=45, relangle2=45,
 170                  absangle1=None, absangle2=None,
 171                  absbulge=0, relbulge=0.39, boxdists=[0,0]):
 172
 173         # The deviation of the curve from a straight line can be specified:
 174         # A. By an angle at each center
 175         #    These angles are either absolute angles with origin at the positive x-axis
 176         #    or the relative angle with origin at the straight connection line
 177         # B. By the (expected) largest normal distance between line and arc: absbulge
 178         #    and/or by the (expected) bulge relative to the length of the
 179         #    straight line from center to center.
 180         # Here, we need both informations.
 181         #
 182         # a curve with relbulge=0.39 and relangle1,2=45 leads
 183         # approximately to the arc with angle=45
 184
 185         self.box1 = box1
 186         self.box2 = box2
 187
 188         rel = (self.box2.center[0] - self.box1.center[0],
 189                self.box2.center[1] - self.box1.center[1])
 190         distance = hypot(*rel)
 191         # absolute angle of the straight connection
 192         dangle = atan2(rel[1], rel[0])
 193
 194         # calculate the armlength and absolute angles for the control points:
 195         # absolute and relative bulges are added
 196         bulge = abs(distance*relbulge + absbulge)
 197
 198         if absangle1 is not None:
 199             angle1 = radians(absangle1)
 200         else:
 201             angle1 = dangle - radians(relangle1)
 202         if absangle2 is not None:
 203             angle2 = radians(absangle2)
 204         else:
 205             angle2 = dangle + radians(relangle2)
 206
 207         # get the control points
 208         control1 = (cos(angle1), sin(angle1))
 209         control2 = (cos(angle2), sin(angle2))
 210         control1 = (self.box1.center[0] + control1[0] * bulge, self.box1.center[1] + control1[1] * bulge)
 211         control2 = (self.box2.center[0] - control2[0] * bulge, self.box2.center[1] - control2[1] * bulge)
 212
 213         connector_pt.__init__(self,
 214                [path.normsubpath([path.normcurve(*(self.box1.center +
 215                                                    control1 +
 216                                                    control2 + self.box2.center))], 0)])
 217
 218         self.omitends(box1, box2)
 219         self.shortenpath(boxdists)
 220
 221
 222 class twolines_pt(connector_pt):
 223
 224     def __init__(self, box1, box2,
 225                  absangle1=None, absangle2=None,
 226                  relangle1=None, relangle2=None, relangleM=None,
 227                  length1=None, length2=None,
 228                  bezierradius=None, beziersoftness=1,
 229                  arcradius=None,
 230                  boxdists=[0,0]):
 231
 232         # The connection with two lines can be done in the following ways:
 233         # 1. an angle at each box-center
 234         # 2. two armlengths (if they are long enough)
 235         # 3. angle and armlength at the same box
 236         # 4. angle and armlength at different boxes
 237         # 5. one armlength and the angle between the arms
 238         #
 239         # Angles at the box-centers can be relative or absolute
 240         # The angle in the middle is always relative
 241         # lengths are always absolute
 242
 243         self.box1 = box1
 244         self.box2 = box2
 245
 246         begin = self.box1.center
 247         end = self.box2.center
 248         rel = (self.box2.center[0] - self.box1.center[0],
 249                self.box2.center[1] - self.box1.center[1])
 250         distance = hypot(*rel)
 251         dangle = atan2(rel[1], rel[0])
 252
 253         # find out what arguments are given:
 254         if relangle1 is not None: relangle1 = radians(relangle1)
 255         if relangle2 is not None: relangle2 = radians(relangle2)
 256         if relangleM is not None: relangleM = radians(relangleM)
 257         # absangle has priority over relangle:
 258         if absangle1 is not None: relangle1 = dangle - radians(absangle1)
 259         if absangle2 is not None: relangle2 = math.pi - dangle + radians(absangle2)
 260
 261         # check integrity of arguments
 262         no_angles, no_lengths=0,0
 263         for anangle in (relangle1, relangle2, relangleM):
 264             if anangle is not None: no_angles += 1
 265         for alength in (length1, length2):
 266             if alength is not None: no_lengths += 1
 267
 268         if no_angles + no_lengths != 2:
 269             raise NotImplementedError, "Please specify exactly two angles or lengths"
 270
 271         # calculate necessary angles and armlengths
 272         # always length1 and relangle1
 273
 274         # the case with two given angles
 275         # use the "sine-theorem" for calculating length1
 276         if no_angles == 2:
 277             if relangle1 is None: relangle1 = math.pi - relangle2 - relangleM
 278             elif relangle2 is None: relangle2 = math.pi - relangle1 - relangleM
 279             elif relangleM is None: relangleM = math.pi - relangle1 - relangle2
 280             length1 = distance * abs(sin(relangle2)/sin(relangleM))
 281             middle = self._middle_a(begin, dangle, length1, relangle1)
 282         # the case with two given lengths
 283         # uses the "cosine-theorem" for calculating length1
 284         elif no_lengths == 2:
 285             relangle1 = acos((distance**2 + length1**2 - length2**2) / (2.0*distance*length1))
 286             middle = self._middle_a(begin, dangle, length1, relangle1)
 287         # the case with one length and one angle
 288         else:
 289             if relangle1 is not None:
 290                 if length1 is not None:
 291                     middle = self._middle_a(begin, dangle, length1, relangle1)
 292                 elif length2 is not None:
 293                     length1 = self._missinglength(length2, distance, relangle1)
 294                     middle = self._middle_a(begin, dangle, length1, relangle1)
 295             elif relangle2 is not None:
 296                 if length1 is not None:
 297                     length2 = self._missinglength(length1, distance, relangle2)
 298                     middle = self._middle_b(end, dangle, length2, relangle2)
 299                 elif length2 is not None:
 300                     middle = self._middle_b(end, dangle, length2, relangle2)
 301             elif relangleM is not None:
 302                 if length1 is not None:
 303                     length2 = self._missinglength(distance, length1, relangleM)
 304                     relangle1 = acos((distance**2 + length1**2 - length2**2) / (2.0*distance*length1))
 305                     middle = self._middle_a(begin, dangle, length1, relangle1)
 306                 elif length2 is not None:
 307                     length1 = self._missinglength(distance, length2, relangleM)
 308                     relangle1 = acos((distance**2 + length1**2 - length2**2) / (2.0*distance*length1))
 309                     middle = self._middle_a(begin, dangle, length1, relangle1)
 310             else:
 311                 raise NotImplementedError, "I found a strange combination of arguments"
 312
 313         connector_pt.__init__(self,
 314             path.path(path.moveto_pt(*self.box1.center),
 315                       path.lineto_pt(*middle),
 316                       path.lineto_pt(*self.box2.center)))
 317
 318         self.omitends(box1, box2)
 319         self.shortenpath(boxdists)
 320
 321     def _middle_a(self, begin, dangle, length1, angle1):
 322         a = dangle - angle1
 323         dir = cos(a), sin(a)
 324         return begin[0] + length1*dir[0], begin[1] + length1*dir[1]
 325
 326     def _middle_b(self, end, dangle, length2, angle2):
 327         # a = -math.pi + dangle + angle2
 328         return self._middle_a(end, -math.pi+dangle, length2, -angle2)
 329
 330     def _missinglength(self, lenA, lenB, angleA):
 331         # calculate lenC, where side A and angleA are opposite
 332         tmp1 = lenB * cos(angleA)
 333         tmp2 = sqrt(tmp1**2 - lenB**2 + lenA**2)
 334         if tmp1 > tmp2: return tmp1 - tmp2
 335         return tmp1 + tmp2
 336
 337
 338
 339 class line(line_pt):
 340
 341     """a line is the straight connector between the centers of two boxes"""
 342
 343     def __init__(self, box1, box2, boxdists=[0,0]):
 344
 345         boxdists_pt = (_topt(helper.getitemno(boxdists, 0), default_type="v"),
 346                        _topt(helper.getitemno(boxdists, 1), default_type="v"))
 347
 348         line_pt.__init__(self, box1, box2, boxdists=boxdists_pt)
 349
 350
 351 class curve(curve_pt):
 352
 353     """a curve is the curved connector between the centers of two boxes.
 354     The constructor needs both angle and bulge"""
 355
 356
 357     def __init__(self, box1, box2,
 358                  relangle1=45, relangle2=45,
 359                  absangle1=None, absangle2=None,
 360                  absbulge=0, relbulge=0.39,
 361                  boxdists=[0,0]):
 362
 363         boxdists_pt = (_topt(helper.getitemno(boxdists, 0), default_type="v"),
 364                        _topt(helper.getitemno(boxdists, 1), default_type="v"))
 365
 366         curve_pt.__init__(self, box1, box2,
 367                         relangle1=relangle1, relangle2=relangle2,
 368                         absangle1=absangle1, absangle2=absangle2,
 369                         absbulge=_topt(absbulge), relbulge=relbulge,
 370                         boxdists=boxdists_pt)
 371
 372 class arc(arc_pt):
 373
 374     """an arc is a round connector between the centers of two boxes.
 375     The constructor gets
 376          either an angle in (-pi,pi)
 377          or a bulge parameter in (-distance, distance)
 378            (relbulge and absbulge are added)"""
 379
 380     def __init__(self, box1, box2, relangle=45,
 381                  absbulge=None, relbulge=None, boxdists=[0,0]):
 382
 383         boxdists_pt = (_topt(helper.getitemno(boxdists, 0), default_type="v"),
 384                        _topt(helper.getitemno(boxdists, 1), default_type="v"))
 385
 386         arc_pt.__init__(self, box1, box2,
 387                       relangle=relangle,
 388                       absbulge=_topt(absbulge), relbulge=relbulge,
 389                       boxdists=boxdists_pt)
 390
 391
 392 class twolines(twolines_pt):
 393
 394     """a twolines is a connector consisting of two straight lines.
 395     The construcor takes a combination of angles and lengths:
 396       either two angles (relative or absolute)
 397       or two lenghts
 398       or one length and one angle"""
 399
 400     def __init__(self, box1, box2,
 401                  absangle1=None, absangle2=None,
 402                  relangle1=None, relangle2=None, relangleM=None,
 403                  length1=None, length2=None,
 404                  bezierradius=None, beziersoftness=1,
 405                  arcradius=None,
 406                  boxdists=[0,0]):
 407
 408         boxdists_pt = (_topt(helper.getitemno(boxdists, 0), default_type="v"),
 409                        _topt(helper.getitemno(boxdists, 1), default_type="v"))
 410
 411         twolines_pt.__init__(self, box1, box2,
 412                        absangle1=absangle1, absangle2=absangle2,
 413                        relangle1=relangle1, relangle2=relangle2,
 414                        relangleM=relangleM,
 415                        length1=_topt(length1), length2=_topt(length2),
 416                        bezierradius=_topt(bezierradius), beziersoftness=1,
 417                        arcradius=_topt(arcradius),
 418                        boxdists=boxdists_pt)
 419
 420
 421