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, 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 class connector_pt(path.normpath):
  40
  41     def omitends(self, box1, box2):
  42         """intersect a path with the boxes' paths"""
  43
  44         # cut off the start of self
  45         # XXX how can decoration of this box1.path() be handled?
  46         sp = self.intersect(box1.path())[0]
  47         sp.sort()
  48         if sp:
  49             self.subpaths = self.split(sp[-1:])[1].subpaths
  50
  51         # cut off the end of self
  52         sp = self.intersect(box2.path())[0]
  53         sp.sort()
  54         if sp:
  55             self.subpaths = self.split(sp[:1])[0].subpaths
  56
  57     def shortenpath(self, dists):
  58         """shorten a path by the given distances"""
  59
  60         # cut off the start of self
  61         # XXX should path.lentopar used here?
  62         center = (unit.topt(self.begin()[0]), unit.topt(self.begin()[1]))
  63         sp = self.intersect(path.circle_pt(center[0], center[1], dists[0]))[0]
  64         sp.sort()
  65         if sp:
  66             self.subpaths = self.split(sp[-1:])[1].subpaths
  67
  68         # cut off the end of self
  69         center = (unit.topt(self.end()[0]), unit.topt(self.end()[1]))
  70         sp = self.intersect(path.circle_pt(center[0], center[1], dists[1]))[0]
  71         sp.sort()
  72         if sp:
  73             self.subpaths = self.split(sp[:1])[0].subpaths
  74
  75
  76 ################
  77 ## classes
  78 ################
  79
  80
  81 class line_pt(connector_pt):
  82
  83     def __init__(self, box1, box2, boxdists=[0,0]):
  84
  85         self.box1 = box1
  86         self.box2 = box2
  87
  88         connector_pt.__init__(self,
  89             [path.normsubpath([path.normline(*(self.box1.center+self.box2.center))], 0)])
  90
  91         self.omitends(box1, box2)
  92         self.shortenpath(boxdists)
  93
  94
  95 class arc_pt(connector_pt):
  96
  97     def __init__(self, box1, box2, relangle=45,
  98                  absbulge=None, relbulge=None, boxdists=[0,0]):
  99
 100         # the deviation of arc from the straight line can be specified:
 101         # 1. By an angle between a straight line and the arc
 102         #    This angle is measured at the centers of the box.
 103         # 2. By the largest normal distance between line and arc: absbulge
 104         #    or, equivalently, by the bulge relative to the length of the
 105         #    straight line from center to center.
 106         # Only one can be used.
 107
 108         self.box1 = box1
 109         self.box2 = box2
 110
 111         rel = (self.box2.center[0] - self.box1.center[0],
 112                self.box2.center[1] - self.box1.center[1])
 113         distance = hypot(*rel)
 114
 115         # usage of bulge overrides the relangle parameter
 116         if relbulge is not None or absbulge is not None:
 117             relangle = None
 118             bulge = 0
 119             try: bulge += absbulge
 120             except: pass
 121             try: bulge += relbulge*distance
 122             except: pass
 123
 124             try: radius = abs(0.5 * (bulge + 0.25 * distance**2 / bulge))
 125             except: radius = 10 * distance # default value for too straight arcs
 126             radius = min(radius, 10 * distance)
 127             center = 2.0*(radius-abs(bulge))/distance
 128             center *= 2*(bulge>0.0)-1
 129         # otherwise use relangle
 130         else:
 131             bulge=None
 132             try: radius = 0.5 * distance / abs(cos(0.5*math.pi - radians(relangle)))
 133             except: radius = 10 * distance
 134             try: center = tan(0.5*math.pi - radians(relangle))
 135             except: center = 0
 136
 137         # up to here center is only the distance from the middle of the
 138         # straight connection
 139         center = (0.5 * (self.box1.center[0] + self.box2.center[0] - rel[1]*center),
 140                   0.5 * (self.box1.center[1] + self.box2.center[1] + rel[0]*center))
 141         angle1 = atan2(self.box1.center[1] - center[1], self.box1.center[0] - center[0])
 142         angle2 = atan2(self.box2.center[1] - center[1], self.box2.center[0] - center[0])
 143
 144         # draw the arc in positive direction by default
 145         # negative direction if relangle<0 or bulge<0
 146         if (relangle is not None and relangle < 0) or (bulge is not None and bulge < 0):
 147             connector_pt.__init__(self,
 148                 path.path(path.moveto_pt(*self.box1.center),
 149                           path.arcn_pt(center[0], center[1], radius, degrees(angle1), degrees(angle2))))
 150         else:
 151             connector_pt.__init__(self,
 152                 path.path(path.moveto_pt(*self.box1.center),
 153                           path.arc_pt(center[0], center[1], radius, degrees(angle1), degrees(angle2))))
 154
 155         self.omitends(box1, box2)
 156         self.shortenpath(boxdists)
 157
 158
 159 class curve_pt(connector_pt):
 160
 161     def __init__(self, box1, box2,
 162                  relangle1=45, relangle2=45,
 163                  absangle1=None, absangle2=None,
 164                  absbulge=0, relbulge=0.39, boxdists=[0,0]):
 165
 166         # The deviation of the curve from a straight line can be specified:
 167         # A. By an angle at each center
 168         #    These angles are either absolute angles with origin at the positive x-axis
 169         #    or the relative angle with origin at the straight connection line
 170         # B. By the (expected) largest normal distance between line and arc: absbulge
 171         #    and/or by the (expected) bulge relative to the length of the
 172         #    straight line from center to center.
 173         # Here, we need both informations.
 174         #
 175         # a curve with relbulge=0.39 and relangle1,2=45 leads
 176         # approximately to the arc with angle=45
 177
 178         self.box1 = box1
 179         self.box2 = box2
 180
 181         rel = (self.box2.center[0] - self.box1.center[0],
 182                self.box2.center[1] - self.box1.center[1])
 183         distance = hypot(*rel)
 184         # absolute angle of the straight connection
 185         dangle = atan2(rel[1], rel[0])
 186
 187         # calculate the armlength and absolute angles for the control points:
 188         # absolute and relative bulges are added
 189         bulge = abs(distance*relbulge + absbulge)
 190
 191         if absangle1 is not None:
 192             angle1 = radians(absangle1)
 193         else:
 194             angle1 = dangle - radians(relangle1)
 195         if absangle2 is not None:
 196             angle2 = radians(absangle2)
 197         else:
 198             angle2 = dangle + radians(relangle2)
 199
 200         # get the control points
 201         control1 = (cos(angle1), sin(angle1))
 202         control2 = (cos(angle2), sin(angle2))
 203         control1 = (self.box1.center[0] + control1[0] * bulge, self.box1.center[1] + control1[1] * bulge)
 204         control2 = (self.box2.center[0] - control2[0] * bulge, self.box2.center[1] - control2[1] * bulge)
 205
 206         connector_pt.__init__(self,
 207                [path.normsubpath([path.normcurve(*(self.box1.center +
 208                                                    control1 +
 209                                                    control2 + self.box2.center))], 0)])
 210
 211         self.omitends(box1, box2)
 212         self.shortenpath(boxdists)
 213
 214
 215 class twolines_pt(connector_pt):
 216
 217     def __init__(self, box1, box2,
 218                  absangle1=None, absangle2=None,
 219                  relangle1=None, relangle2=None, relangleM=None,
 220                  length1=None, length2=None,
 221                  bezierradius=None, beziersoftness=1,
 222                  arcradius=None,
 223                  boxdists=[0,0]):
 224
 225         # The connection with two lines can be done in the following ways:
 226         # 1. an angle at each box-center
 227         # 2. two armlengths (if they are long enough)
 228         # 3. angle and armlength at the same box
 229         # 4. angle and armlength at different boxes
 230         # 5. one armlength and the angle between the arms
 231         #
 232         # Angles at the box-centers can be relative or absolute
 233         # The angle in the middle is always relative
 234         # lengths are always absolute
 235
 236         self.box1 = box1
 237         self.box2 = box2
 238
 239         begin = self.box1.center
 240         end = self.box2.center
 241         rel = (self.box2.center[0] - self.box1.center[0],
 242                self.box2.center[1] - self.box1.center[1])
 243         distance = hypot(*rel)
 244         dangle = atan2(rel[1], rel[0])
 245
 246         # find out what arguments are given:
 247         if relangle1 is not None: relangle1 = radians(relangle1)
 248         if relangle2 is not None: relangle2 = radians(relangle2)
 249         if relangleM is not None: relangleM = radians(relangleM)
 250         # absangle has priority over relangle:
 251         if absangle1 is not None: relangle1 = dangle - radians(absangle1)
 252         if absangle2 is not None: relangle2 = math.pi - dangle + radians(absangle2)
 253
 254         # check integrity of arguments
 255         no_angles, no_lengths=0,0
 256         for anangle in (relangle1, relangle2, relangleM):
 257             if anangle is not None: no_angles += 1
 258         for alength in (length1, length2):
 259             if alength is not None: no_lengths += 1
 260
 261         if no_angles + no_lengths != 2:
 262             raise NotImplementedError, "Please specify exactly two angles or lengths"
 263
 264         # calculate necessary angles and armlengths
 265         # always length1 and relangle1
 266
 267         # the case with two given angles
 268         # use the "sine-theorem" for calculating length1
 269         if no_angles == 2:
 270             if relangle1 is None: relangle1 = math.pi - relangle2 - relangleM
 271             elif relangle2 is None: relangle2 = math.pi - relangle1 - relangleM
 272             elif relangleM is None: relangleM = math.pi - relangle1 - relangle2
 273             length1 = distance * abs(sin(relangle2)/sin(relangleM))
 274             middle = self._middle_a(begin, dangle, length1, relangle1)
 275         # the case with two given lengths
 276         # uses the "cosine-theorem" for calculating length1
 277         elif no_lengths == 2:
 278             relangle1 = acos((distance**2 + length1**2 - length2**2) / (2.0*distance*length1))
 279             middle = self._middle_a(begin, dangle, length1, relangle1)
 280         # the case with one length and one angle
 281         else:
 282             if relangle1 is not None:
 283                 if length1 is not None:
 284                     middle = self._middle_a(begin, dangle, length1, relangle1)
 285                 elif length2 is not None:
 286                     length1 = self._missinglength(length2, distance, relangle1)
 287                     middle = self._middle_a(begin, dangle, length1, relangle1)
 288             elif relangle2 is not None:
 289                 if length1 is not None:
 290                     length2 = self._missinglength(length1, distance, relangle2)
 291                     middle = self._middle_b(end, dangle, length2, relangle2)
 292                 elif length2 is not None:
 293                     middle = self._middle_b(end, dangle, length2, relangle2)
 294             elif relangleM is not None:
 295                 if length1 is not None:
 296                     length2 = self._missinglength(distance, length1, relangleM)
 297                     relangle1 = acos((distance**2 + length1**2 - length2**2) / (2.0*distance*length1))
 298                     middle = self._middle_a(begin, dangle, length1, relangle1)
 299                 elif length2 is not None:
 300                     length1 = self._missinglength(distance, length2, relangleM)
 301                     relangle1 = acos((distance**2 + length1**2 - length2**2) / (2.0*distance*length1))
 302                     middle = self._middle_a(begin, dangle, length1, relangle1)
 303             else:
 304                 raise NotImplementedError, "I found a strange combination of arguments"
 305
 306         connector_pt.__init__(self,
 307             path.path(path.moveto_pt(*self.box1.center),
 308                       path.lineto_pt(*middle),
 309                       path.lineto_pt(*self.box2.center)))
 310
 311         self.omitends(box1, box2)
 312         self.shortenpath(boxdists)
 313
 314     def _middle_a(self, begin, dangle, length1, angle1):
 315         a = dangle - angle1
 316         dir = cos(a), sin(a)
 317         return begin[0] + length1*dir[0], begin[1] + length1*dir[1]
 318
 319     def _middle_b(self, end, dangle, length2, angle2):
 320         # a = -math.pi + dangle + angle2
 321         return self._middle_a(end, -math.pi+dangle, length2, -angle2)
 322
 323     def _missinglength(self, lenA, lenB, angleA):
 324         # calculate lenC, where side A and angleA are opposite
 325         tmp1 = lenB * cos(angleA)
 326         tmp2 = sqrt(tmp1**2 - lenB**2 + lenA**2)
 327         if tmp1 > tmp2: return tmp1 - tmp2
 328         return tmp1 + tmp2
 329
 330
 331
 332 class line(line_pt):
 333
 334     """a line is the straight connector between the centers of two boxes"""
 335
 336     def __init__(self, box1, box2, boxdists=[0,0]):
 337
 338         boxdists_pt = (unit.topt(helper.getitemno(boxdists, 0)),
 339                        unit.topt(helper.getitemno(boxdists, 1)))
 340
 341         line_pt.__init__(self, box1, box2, boxdists=boxdists_pt)
 342
 343
 344 class curve(curve_pt):
 345
 346     """a curve is the curved connector between the centers of two boxes.
 347     The constructor needs both angle and bulge"""
 348
 349
 350     def __init__(self, box1, box2,
 351                  relangle1=45, relangle2=45,
 352                  absangle1=None, absangle2=None,
 353                  absbulge=0, relbulge=0.39,
 354                  boxdists=[0,0]):
 355
 356         boxdists_pt = (unit.topt(helper.getitemno(boxdists, 0)),
 357                        unit.topt(helper.getitemno(boxdists, 1)))
 358
 359         curve_pt.__init__(self, box1, box2,
 360                         relangle1=relangle1, relangle2=relangle2,
 361                         absangle1=absangle1, absangle2=absangle2,
 362                         absbulge=unit.topt(absbulge), relbulge=relbulge,
 363                         boxdists=boxdists_pt)
 364
 365 class arc(arc_pt):
 366
 367     """an arc is a round connector between the centers of two boxes.
 368     The constructor gets
 369          either an angle in (-pi,pi)
 370          or a bulge parameter in (-distance, distance)
 371            (relbulge and absbulge are added)"""
 372
 373     def __init__(self, box1, box2, relangle=45,
 374                  absbulge=None, relbulge=None, boxdists=[0,0]):
 375
 376         boxdists_pt = (unit.topt(helper.getitemno(boxdists, 0)),
 377                        unit.topt(helper.getitemno(boxdists, 1)))
 378
 379         if absbulge is not None:
 380             absbulge = unit.topt(absbulge)
 381         arc_pt.__init__(self, box1, box2,
 382                       relangle=relangle,
 383                       absbulge=absbulge, relbulge=relbulge,
 384                       boxdists=boxdists_pt)
 385
 386
 387 class twolines(twolines_pt):
 388
 389     """a twolines is a connector consisting of two straight lines.
 390     The construcor takes a combination of angles and lengths:
 391       either two angles (relative or absolute)
 392       or two lenghts
 393       or one length and one angle"""
 394
 395     def __init__(self, box1, box2,
 396                  absangle1=None, absangle2=None,
 397                  relangle1=None, relangle2=None, relangleM=None,
 398                  length1=None, length2=None,
 399                  bezierradius=None, beziersoftness=1,
 400                  arcradius=None,
 401                  boxdists=[0,0]):
 402
 403         boxdists_pt = (unit.topt(helper.getitemno(boxdists, 0)),
 404                        unit.topt(helper.getitemno(boxdists, 1)))
 405
 406         if length1 is not None:
 407             length1 = unit.topt(length1)
 408         if length2 is not None:
 409             length2 = unit.topt(length2)
 410         if bezierradius is not None:
 411             bezierradius = unit.topt(bezierradius)
 412         if arcradius is not None:
 413             arcradius = unit.topt(arcradius)
 414         twolines_pt.__init__(self, box1, box2,
 415                        absangle1=absangle1, absangle2=absangle2,
 416                        relangle1=relangle1, relangle2=relangle2,
 417                        relangleM=relangleM,
 418                        length1=length1, length2=length2,
 419                        bezierradius=bezierradius, beziersoftness=1,
 420                        arcradius=arcradius,
 421                        boxdists=boxdists_pt)
 422
 423
 424