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         """intersects 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         if sp:
  48             self.normsubpaths = self.split(sp[-1:])[1].normsubpaths
  49
  50         # cut off the end of self
  51         sp = self.intersect(box2.path())[0]
  52         if sp:
  53             self.normsubpaths = self.split(sp[:1])[0].normsubpaths
  54
  55     def shortenpath(self, dists):
  56         """shortens a path by the given distances"""
  57
  58         # XXX later, this should be done by extended boxes instead of intersecting with circles
  59         # cut off the start of self
  60         center = self.begin_pt()
  61         cutpath = path.circle_pt(center[0], center[1], dists[0])
  62         try:
  63             cutpath = cutpath.normpath()
  64         except path.PathException:
  65             pass
  66         else:
  67             sp = self.intersect(cutpath)[0]
  68             self.normsubpaths = self.split(sp[-1:])[1].normsubpaths
  69
  70         # cut off the end of self
  71         center = self.end_pt()
  72         cutpath = path.circle_pt(center[0], center[1], dists[1])
  73         try:
  74             cutpath = cutpath.normpath()
  75         except path.PathException:
  76             pass
  77         else:
  78             sp = self.intersect(cutpath)[0]
  79             self.normsubpaths = self.split(sp[:1])[0].normsubpaths
  80
  81
  82 ################
  83 ## classes
  84 ################
  85
  86
  87 class line_pt(connector_pt):
  88
  89     def __init__(self, box1, box2, boxdists=[0,0]):
  90
  91         self.box1 = box1
  92         self.box2 = box2
  93
  94         connector_pt.__init__(self,
  95             [path.normsubpath([path.normline(*(self.box1.center+self.box2.center))], 0)])
  96
  97         self.omitends(box1, box2)
  98         self.shortenpath(boxdists)
  99
 100
 101 class arc_pt(connector_pt):
 102
 103     def __init__(self, box1, box2, relangle=45,
 104                  absbulge=None, relbulge=None, boxdists=[0,0]):
 105
 106         # the deviation of arc from the straight line can be specified:
 107         # 1. By an angle between a straight line and the arc
 108         #    This angle is measured at the centers of the box.
 109         # 2. By the largest normal distance between line and arc: absbulge
 110         #    or, equivalently, by the bulge relative to the length of the
 111         #    straight line from center to center.
 112         # Only one can be used.
 113
 114         self.box1 = box1
 115         self.box2 = box2
 116
 117         rel = (self.box2.center[0] - self.box1.center[0],
 118                self.box2.center[1] - self.box1.center[1])
 119         distance = hypot(*rel)
 120
 121         # usage of bulge overrides the relangle parameter
 122         if relbulge is not None or absbulge is not None:
 123             relangle = None
 124             bulge = 0
 125             try: bulge += absbulge
 126             except: pass
 127             try: bulge += relbulge*distance
 128             except: pass
 129
 130             try: radius = abs(0.5 * (bulge + 0.25 * distance**2 / bulge))
 131             except: radius = 10 * distance # default value for too straight arcs
 132             radius = min(radius, 10 * distance)
 133             center = 2.0*(radius-abs(bulge))/distance
 134             center *= 2*(bulge>0.0)-1
 135         # otherwise use relangle
 136         else:
 137             bulge=None
 138             try: radius = 0.5 * distance / abs(cos(0.5*math.pi - radians(relangle)))
 139             except: radius = 10 * distance
 140             try: center = tan(0.5*math.pi - radians(relangle))
 141             except: center = 0
 142
 143         # up to here center is only the distance from the middle of the
 144         # straight connection
 145         center = (0.5 * (self.box1.center[0] + self.box2.center[0] - rel[1]*center),
 146                   0.5 * (self.box1.center[1] + self.box2.center[1] + rel[0]*center))
 147         angle1 = atan2(self.box1.center[1] - center[1], self.box1.center[0] - center[0])
 148         angle2 = atan2(self.box2.center[1] - center[1], self.box2.center[0] - center[0])
 149
 150         # draw the arc in positive direction by default
 151         # negative direction if relangle<0 or bulge<0
 152         if (relangle is not None and relangle < 0) or (bulge is not None and bulge < 0):
 153             connectorpath = path.path(path.moveto_pt(*self.box1.center),
 154                                       path.arcn_pt(center[0], center[1], radius, degrees(angle1), degrees(angle2)))
 155             connector_pt.__init__(self, connectorpath.normpath().normsubpaths)
 156         else:
 157             connectorpath = path.path(path.moveto_pt(*self.box1.center),
 158                                       path.arc_pt(center[0], center[1], radius, degrees(angle1), degrees(angle2)))
 159             connector_pt.__init__(self, connectorpath.normpath().normsubpaths)
 160
 161         self.omitends(box1, box2)
 162         self.shortenpath(boxdists)
 163
 164
 165 class curve_pt(connector_pt):
 166
 167     def __init__(self, box1, box2,
 168                  relangle1=45, relangle2=45,
 169                  absangle1=None, absangle2=None,
 170                  absbulge=0, relbulge=0.39, boxdists=[0,0]):
 171
 172         # The deviation of the curve from a straight line can be specified:
 173         # A. By an angle at each center
 174         #    These angles are either absolute angles with origin at the positive x-axis
 175         #    or the relative angle with origin at the straight connection line
 176         # B. By the (expected) largest normal distance between line and arc: absbulge
 177         #    and/or by the (expected) bulge relative to the length of the
 178         #    straight line from center to center.
 179         # Here, we need both informations.
 180         #
 181         # a curve with relbulge=0.39 and relangle1,2=45 leads
 182         # approximately to the arc with angle=45
 183
 184         self.box1 = box1
 185         self.box2 = box2
 186
 187         rel = (self.box2.center[0] - self.box1.center[0],
 188                self.box2.center[1] - self.box1.center[1])
 189         distance = hypot(*rel)
 190         # absolute angle of the straight connection
 191         dangle = atan2(rel[1], rel[0])
 192
 193         # calculate the armlength and absolute angles for the control points:
 194         # absolute and relative bulges are added
 195         bulge = abs(distance*relbulge + absbulge)
 196
 197         if absangle1 is not None:
 198             angle1 = radians(absangle1)
 199         else:
 200             angle1 = dangle - radians(relangle1)
 201         if absangle2 is not None:
 202             angle2 = radians(absangle2)
 203         else:
 204             angle2 = dangle + radians(relangle2)
 205
 206         # get the control points
 207         control1 = (cos(angle1), sin(angle1))
 208         control2 = (cos(angle2), sin(angle2))
 209         control1 = (self.box1.center[0] + control1[0] * bulge, self.box1.center[1] + control1[1] * bulge)
 210         control2 = (self.box2.center[0] - control2[0] * bulge, self.box2.center[1] - control2[1] * bulge)
 211
 212         connector_pt.__init__(self,
 213                [path.normsubpath([path.normcurve(*(self.box1.center +
 214                                                    control1 +
 215                                                    control2 + self.box2.center))], 0)])
 216
 217         self.omitends(box1, box2)
 218         self.shortenpath(boxdists)
 219
 220
 221 class twolines_pt(connector_pt):
 222
 223     def __init__(self, box1, box2,
 224                  absangle1=None, absangle2=None,
 225                  relangle1=None, relangle2=None, relangleM=None,
 226                  length1=None, length2=None,
 227                  bezierradius=None, beziersoftness=1,
 228                  arcradius=None,
 229                  boxdists=[0,0]):
 230
 231         # The connection with two lines can be done in the following ways:
 232         # 1. an angle at each box-center
 233         # 2. two armlengths (if they are long enough)
 234         # 3. angle and armlength at the same box
 235         # 4. angle and armlength at different boxes
 236         # 5. one armlength and the angle between the arms
 237         #
 238         # Angles at the box-centers can be relative or absolute
 239         # The angle in the middle is always relative
 240         # lengths are always absolute
 241
 242         self.box1 = box1
 243         self.box2 = box2
 244
 245         begin = self.box1.center
 246         end = self.box2.center
 247         rel = (self.box2.center[0] - self.box1.center[0],
 248                self.box2.center[1] - self.box1.center[1])
 249         distance = hypot(*rel)
 250         dangle = atan2(rel[1], rel[0])
 251
 252         # find out what arguments are given:
 253         if relangle1 is not None: relangle1 = radians(relangle1)
 254         if relangle2 is not None: relangle2 = radians(relangle2)
 255         if relangleM is not None: relangleM = radians(relangleM)
 256         # absangle has priority over relangle:
 257         if absangle1 is not None: relangle1 = dangle - radians(absangle1)
 258         if absangle2 is not None: relangle2 = math.pi - dangle + radians(absangle2)
 259
 260         # check integrity of arguments
 261         no_angles, no_lengths=0,0
 262         for anangle in (relangle1, relangle2, relangleM):
 263             if anangle is not None: no_angles += 1
 264         for alength in (length1, length2):
 265             if alength is not None: no_lengths += 1
 266
 267         if no_angles + no_lengths != 2:
 268             raise NotImplementedError, "Please specify exactly two angles or lengths"
 269
 270         # calculate necessary angles and armlengths
 271         # always length1 and relangle1
 272
 273         # the case with two given angles
 274         # use the "sine-theorem" for calculating length1
 275         if no_angles == 2:
 276             if relangle1 is None: relangle1 = math.pi - relangle2 - relangleM
 277             elif relangle2 is None: relangle2 = math.pi - relangle1 - relangleM
 278             elif relangleM is None: relangleM = math.pi - relangle1 - relangle2
 279             length1 = distance * abs(sin(relangle2)/sin(relangleM))
 280             middle = self._middle_a(begin, dangle, length1, relangle1)
 281         # the case with two given lengths
 282         # uses the "cosine-theorem" for calculating length1
 283         elif no_lengths == 2:
 284             relangle1 = acos((distance**2 + length1**2 - length2**2) / (2.0*distance*length1))
 285             middle = self._middle_a(begin, dangle, length1, relangle1)
 286         # the case with one length and one angle
 287         else:
 288             if relangle1 is not None:
 289                 if length1 is not None:
 290                     middle = self._middle_a(begin, dangle, length1, relangle1)
 291                 elif length2 is not None:
 292                     length1 = self._missinglength(length2, distance, relangle1)
 293                     middle = self._middle_a(begin, dangle, length1, relangle1)
 294             elif relangle2 is not None:
 295                 if length1 is not None:
 296                     length2 = self._missinglength(length1, distance, relangle2)
 297                     middle = self._middle_b(end, dangle, length2, relangle2)
 298                 elif length2 is not None:
 299                     middle = self._middle_b(end, dangle, length2, relangle2)
 300             elif relangleM is not None:
 301                 if length1 is not None:
 302                     length2 = self._missinglength(distance, length1, relangleM)
 303                     relangle1 = acos((distance**2 + length1**2 - length2**2) / (2.0*distance*length1))
 304                     middle = self._middle_a(begin, dangle, length1, relangle1)
 305                 elif length2 is not None:
 306                     length1 = self._missinglength(distance, length2, relangleM)
 307                     relangle1 = acos((distance**2 + length1**2 - length2**2) / (2.0*distance*length1))
 308                     middle = self._middle_a(begin, dangle, length1, relangle1)
 309             else:
 310                 raise NotImplementedError, "I found a strange combination of arguments"
 311
 312         connectorpath = path.path(path.moveto_pt(*self.box1.center),
 313                                   path.lineto_pt(*middle),
 314                                   path.lineto_pt(*self.box2.center))
 315         connector_pt.__init__(self, connectorpath.normpath().normsubpaths)
 316
 317         self.omitends(box1, box2)
 318         self.shortenpath(boxdists)
 319
 320     def _middle_a(self, begin, dangle, length1, angle1):
 321         a = dangle - angle1
 322         dir = cos(a), sin(a)
 323         return begin[0] + length1*dir[0], begin[1] + length1*dir[1]
 324
 325     def _middle_b(self, end, dangle, length2, angle2):
 326         # a = -math.pi + dangle + angle2
 327         return self._middle_a(end, -math.pi+dangle, length2, -angle2)
 328
 329     def _missinglength(self, lenA, lenB, angleA):
 330         # calculate lenC, where side A and angleA are opposite
 331         tmp1 = lenB * cos(angleA)
 332         tmp2 = sqrt(tmp1**2 - lenB**2 + lenA**2)
 333         if tmp1 > tmp2: return tmp1 - tmp2
 334         return tmp1 + tmp2
 335
 336
 337
 338 class line(line_pt):
 339
 340     """a line is the straight connector between the centers of two boxes"""
 341
 342     def __init__(self, box1, box2, boxdists=[0,0]):
 343
 344         boxdists_pt = (unit.topt(helper.getitemno(boxdists, 0)),
 345                        unit.topt(helper.getitemno(boxdists, 1)))
 346
 347         line_pt.__init__(self, box1, box2, boxdists=boxdists_pt)
 348
 349
 350 class curve(curve_pt):
 351
 352     """a curve is the curved connector between the centers of two boxes.
 353     The constructor needs both angle and bulge"""
 354
 355
 356     def __init__(self, box1, box2,
 357                  relangle1=45, relangle2=45,
 358                  absangle1=None, absangle2=None,
 359                  absbulge=0, relbulge=0.39,
 360                  boxdists=[0,0]):
 361
 362         boxdists_pt = (unit.topt(helper.getitemno(boxdists, 0)),
 363                        unit.topt(helper.getitemno(boxdists, 1)))
 364
 365         curve_pt.__init__(self, box1, box2,
 366                           relangle1=relangle1, relangle2=relangle2,
 367                           absangle1=absangle1, absangle2=absangle2,
 368                           absbulge=unit.topt(absbulge), relbulge=relbulge,
 369                           boxdists=boxdists_pt)
 370
 371 class arc(arc_pt):
 372
 373     """an arc is a round connector between the centers of two boxes.
 374     The constructor gets
 375          either an angle in (-pi,pi)
 376          or a bulge parameter in (-distance, distance)
 377            (relbulge and absbulge are added)"""
 378
 379     def __init__(self, box1, box2, relangle=45,
 380                  absbulge=None, relbulge=None, boxdists=[0,0]):
 381
 382         boxdists_pt = (unit.topt(helper.getitemno(boxdists, 0)),
 383                        unit.topt(helper.getitemno(boxdists, 1)))
 384
 385         if absbulge is not None:
 386             absbulge = unit.topt(absbulge)
 387         arc_pt.__init__(self, box1, box2,
 388                         relangle=relangle,
 389                         absbulge=absbulge, relbulge=relbulge,
 390                         boxdists=boxdists_pt)
 391
 392
 393 class twolines(twolines_pt):
 394
 395     """a twolines is a connector consisting of two straight lines.
 396     The construcor takes a combination of angles and lengths:
 397       either two angles (relative or absolute)
 398       or two lenghts
 399       or one length and one angle"""
 400
 401     def __init__(self, box1, box2,
 402                  absangle1=None, absangle2=None,
 403                  relangle1=None, relangle2=None, relangleM=None,
 404                  length1=None, length2=None,
 405                  bezierradius=None, beziersoftness=1,
 406                  arcradius=None,
 407                  boxdists=[0,0]):
 408
 409         boxdists_pt = (unit.topt(helper.getitemno(boxdists, 0)),
 410                        unit.topt(helper.getitemno(boxdists, 1)))
 411
 412         if length1 is not None:
 413             length1 = unit.topt(length1)
 414         if length2 is not None:
 415             length2 = unit.topt(length2)
 416         if bezierradius is not None:
 417             bezierradius = unit.topt(bezierradius)
 418         if arcradius is not None:
 419             arcradius = unit.topt(arcradius)
 420         twolines_pt.__init__(self, box1, box2,
 421                              absangle1=absangle1, absangle2=absangle2,
 422                              relangle1=relangle1, relangle2=relangle2,
 423                              relangleM=relangleM,
 424                              length1=length1, length2=length2,
 425                              bezierradius=bezierradius, beziersoftness=1,
 426                              arcradius=arcradius,
 427                              boxdists=boxdists_pt)
 428
 429
 430