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