pyx/deco.py

   1 #!/usr/bin/env python
   2 # -*- coding: ISO-8859-1 -*-
   3 #
   4 #
   5 # Copyright (C) 2002-2005 Jörg Lehmann <joergl@users.sourceforge.net>
   6 # Copyright (C) 2003-2004 Michael Schindler <m-schindler@users.sourceforge.net>
   7 # Copyright (C) 2002-2005 André Wobst <wobsta@users.sourceforge.net>
   8 #
   9 # This file is part of PyX (http://pyx.sourceforge.net/).
  10 #
  11 # PyX is free software; you can redistribute it and/or modify
  12 # it under the terms of the GNU General Public License as published by
  13 # the Free Software Foundation; either version 2 of the License, or
  14 # (at your option) any later version.
  15 #
  16 # PyX is distributed in the hope that it will be useful,
  17 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 # GNU General Public License for more details.
  20 #
  21 # You should have received a copy of the GNU General Public License
  22 # along with PyX; if not, write to the Free Software
  23 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  24
  25 # TODO:
  26 # - should we improve on the arc length -> arg parametrization routine or
  27 #   should we at least factor it out?
  28
  29 import sys, math
  30 import attr, canvas, color, helper, path, style, trafo, unit
  31
  32 try:
  33     from math import radians
  34 except ImportError:
  35     # fallback implementation for Python 2.1 and below
  36     def radians(x): return x*math.pi/180
  37
  38 #
  39 # Decorated path
  40 #
  41
  42 class decoratedpath(canvas.canvasitem):
  43     """Decorated path
  44
  45     The main purpose of this class is during the drawing
  46     (stroking/filling) of a path. It collects attributes for the
  47     stroke and/or fill operations.
  48     """
  49
  50     def __init__(self, path, strokepath=None, fillpath=None,
  51                  styles=None, strokestyles=None, fillstyles=None,
  52                  ornaments=None):
  53
  54         self.path = path
  55
  56         # global style for stroking and filling and subdps
  57         self.styles = styles
  58
  59         # styles which apply only for stroking and filling
  60         self.strokestyles = strokestyles
  61         self.fillstyles = fillstyles
  62
  63         # the decoratedpath can contain additional elements of the
  64         # path (ornaments), e.g., arrowheads.
  65         if ornaments is None:
  66             self.ornaments = canvas.canvas()
  67         else:
  68             self.ornaments = ornaments
  69
  70         self.nostrokeranges = None
  71
  72     def ensurenormpath(self):
  73         """convert self.path into a normpath"""
  74         assert self.nostrokeranges is None or isinstance(self.path, path.normpath), "you don't understand what you are doing"
  75         self.path = self.path.normpath()
  76
  77     def excluderange(self, begin, end):
  78         assert isinstance(self.path, path.normpath), "you don't understand what this is about"
  79         if self.nostrokeranges is None:
  80             self.nostrokeranges = [(begin, end)]
  81         else:
  82             ibegin = 0
  83             while ibegin < len(self.nostrokeranges) and self.nostrokeranges[ibegin][1] < begin:
  84                 ibegin += 1
  85
  86             if ibegin == len(self.nostrokeranges):
  87                 self.nostrokeranges.append((begin, end))
  88                 return
  89
  90             iend = len(self.nostrokeranges) - 1
  91             while 0 <= iend and end < self.nostrokeranges[iend][0]:
  92                 iend -= 1
  93
  94             if iend == -1:
  95                 self.nostrokeranges.insert(0, (begin, end))
  96                 return
  97
  98             if self.nostrokeranges[ibegin][0] < begin:
  99                 begin = self.nostrokeranges[ibegin][0]
 100             if end < self.nostrokeranges[iend][1]:
 101                 end = self.nostrokeranges[iend][1]
 102
 103             self.nostrokeranges[ibegin:iend+1] = [(begin, end)]
 104
 105     def bbox(self):
 106         pathbbox = self.path.bbox()
 107         ornamentsbbox = self.ornaments.bbox()
 108         if ornamentsbbox is not None:
 109             return ornamentsbbox + pathbbox
 110         else:
 111             return pathbbox
 112
 113     def registerPS(self, registry):
 114         if self.styles:
 115             for style in self.styles:
 116                 style.registerPS(registry)
 117         if self.fillstyles:
 118             for style in self.fillstyles:
 119                 style.registerPS(registry)
 120         if self.strokestyles:
 121             for style in self.strokestyles:
 122                 style.registerPS(registry)
 123         self.ornaments.registerPS(registry)
 124
 125     def registerPDF(self, registry):
 126         if self.styles:
 127             for style in self.styles:
 128                 style.registerPDF(registry)
 129         if self.fillstyles:
 130             for style in self.fillstyles:
 131                 style.registerPDF(registry)
 132         if self.strokestyles:
 133             for style in self.strokestyles:
 134                 style.registerPDF(registry)
 135         self.ornaments.registerPDF(registry)
 136
 137     def strokepath(self):
 138         if self.nostrokeranges:
 139             splitlist = []
 140             for begin, end in self.nostrokeranges:
 141                 splitlist.append(begin)
 142                 splitlist.append(end)
 143             split = self.path.split(splitlist)
 144             # XXX properly handle closed paths?
 145             result = split[0]
 146             for i in range(2, len(split), 2):
 147                 result += split[i]
 148             return result
 149         else:
 150             return self.path
 151
 152     def outputPS(self, file):
 153         # draw (stroke and/or fill) the decoratedpath on the canvas
 154         # while trying to produce an efficient output, e.g., by
 155         # not writing one path two times
 156
 157         # small helper
 158         def _writestyles(styles, file=file):
 159             for style in styles:
 160                 style.outputPS(file)
 161
 162         if self.strokestyles is None and self.fillstyles is None:
 163             raise RuntimeError("Path neither to be stroked nor filled")
 164
 165         strokepath = self.strokepath()
 166         fillpath = self.path
 167
 168         # apply global styles
 169         if self.styles:
 170             file.write("gsave\n")
 171             _writestyles(self.styles)
 172
 173         if self.fillstyles is not None:
 174             file.write("newpath\n")
 175             fillpath.outputPS(file)
 176
 177             if self.strokestyles is not None and strokepath is fillpath:
 178                 # do efficient stroking + filling if respective paths are identical
 179                 file.write("gsave\n")
 180
 181                 if self.fillstyles:
 182                     _writestyles(self.fillstyles)
 183
 184                 file.write("fill\n")
 185                 file.write("grestore\n")
 186
 187                 if self.strokestyles:
 188                     file.write("gsave\n")
 189                     _writestyles(self.strokestyles)
 190
 191                 file.write("stroke\n")
 192
 193                 if self.strokestyles:
 194                     file.write("grestore\n")
 195             else:
 196                 # only fill fillpath - for the moment
 197                 if self.fillstyles:
 198                     file.write("gsave\n")
 199                     _writestyles(self.fillstyles)
 200
 201                 file.write("fill\n")
 202
 203                 if self.fillstyles:
 204                     file.write("grestore\n")
 205
 206         if self.strokestyles is not None and (strokepath is not fillpath or self.fillstyles is None):
 207             # this is the only relevant case still left
 208             # Note that a possible stroking has already been done.
 209
 210             if self.strokestyles:
 211                 file.write("gsave\n")
 212                 _writestyles(self.strokestyles)
 213
 214             file.write("newpath\n")
 215             strokepath.outputPS(file)
 216             file.write("stroke\n")
 217
 218             if self.strokestyles:
 219                 file.write("grestore\n")
 220
 221         # now, draw additional elements of decoratedpath
 222         self.ornaments.outputPS(file)
 223
 224         # restore global styles
 225         if self.styles:
 226             file.write("grestore\n")
 227
 228     def outputPDF(self, file, writer, context):
 229         # draw (stroke and/or fill) the decoratedpath on the canvas
 230
 231         def _writestyles(styles, file=file):
 232             for style in styles:
 233                 style.outputPDF(file, writer, context)
 234
 235         def _writestrokestyles(strokestyles, file=file):
 236             for style in strokestyles:
 237                 if isinstance(style, color.color):
 238                     style.outputPDF(file, writer, context(fillattr=0))
 239                 else:
 240                     style.outputPDF(file, writer, context)
 241
 242         def _writefillstyles(fillstyles, file=file):
 243             for style in fillstyles:
 244                 if isinstance(style, color.color):
 245                     style.outputPDF(file, writer, context(strokeattr=0))
 246                 else:
 247                     style.outputPDF(file, writer, context)
 248
 249         if self.strokestyles is None and self.fillstyles is None:
 250             raise RuntimeError("Path neither to be stroked nor filled")
 251
 252         strokepath = self.strokepath()
 253         fillpath = self.path
 254
 255         # apply global styles
 256         if self.styles:
 257             file.write("q\n") # gsave
 258             _writestyles(self.styles)
 259
 260         if self.fillstyles is not None:
 261             fillpath.outputPDF(file, writer, context)
 262
 263             if self.strokestyles is not None and strokepath is fillpath:
 264                 # do efficient stroking + filling
 265                 file.write("q\n") # gsave
 266
 267                 if self.fillstyles:
 268                     _writefillstyles(self.fillstyles)
 269                 if self.strokestyles:
 270                     _writestrokestyles(self.strokestyles)
 271
 272                 file.write("B\n") # both stroke and fill
 273                 file.write("Q\n") # grestore
 274             else:
 275                 # only fill fillpath - for the moment
 276                 if self.fillstyles:
 277                     file.write("q\n") # gsave
 278                     _writefillstyles(self.fillstyles)
 279
 280                 file.write("f\n") # fill
 281
 282                 if self.fillstyles:
 283                     file.write("Q\n") # grestore
 284
 285         if self.strokestyles is not None and (strokepath is not fillpath or self.fillstyles is None):
 286             # this is the only relevant case still left
 287             # Note that a possible stroking has already been done.
 288
 289             if self.strokestyles:
 290                 file.write("q\n") # gsave
 291                 _writestrokestyles(self.strokestyles)
 292
 293             strokepath.outputPDF(file, writer, context)
 294             file.write("S\n") # stroke
 295
 296             if self.strokestyles:
 297                 file.write("Q\n") # grestore
 298
 299         # now, draw additional elements of decoratedpath
 300         self.ornaments.outputPDF(file, writer, context)
 301
 302         # restore global styles
 303         if self.styles:
 304             file.write("Q\n") # grestore
 305
 306 #
 307 # Path decorators
 308 #
 309
 310 class deco:
 311
 312     """decorators
 313
 314     In contrast to path styles, path decorators depend on the concrete
 315     path to which they are applied. In particular, they don't make
 316     sense without any path and can thus not be used in canvas.set!
 317
 318     """
 319
 320     def decorate(self, dp):
 321         """apply a style to a given decoratedpath object dp
 322
 323         decorate accepts a decoratedpath object dp, applies PathStyle
 324         by modifying dp in place and returning the new dp.
 325         """
 326
 327         pass
 328
 329 #
 330 # stroked and filled: basic decos which stroked and fill,
 331 # respectively the path
 332 #
 333
 334 class _stroked(deco, attr.exclusiveattr):
 335
 336     """stroked is a decorator, which draws the outline of the path"""
 337
 338     def __init__(self, styles=[]):
 339         attr.exclusiveattr.__init__(self, _stroked)
 340         self.styles = attr.mergeattrs(styles)
 341         attr.checkattrs(self.styles, [style.strokestyle])
 342
 343     def __call__(self, styles=[]):
 344         # XXX or should we also merge self.styles
 345         return _stroked(styles)
 346
 347     def decorate(self, dp):
 348         if dp.strokestyles is not None:
 349             raise RuntimeError("Cannot stroke an already stroked path")
 350         dp.strokestyles = self.styles
 351         return dp
 352
 353 stroked = _stroked()
 354 stroked.clear = attr.clearclass(_stroked)
 355
 356
 357 class _filled(deco, attr.exclusiveattr):
 358
 359     """filled is a decorator, which fills the interior of the path"""
 360
 361     def __init__(self, styles=[]):
 362         attr.exclusiveattr.__init__(self, _filled)
 363         self.styles = attr.mergeattrs(styles)
 364         attr.checkattrs(self.styles, [style.fillstyle])
 365
 366     def __call__(self, styles=[]):
 367         # XXX or should we also merge self.styles
 368         return _filled(styles)
 369
 370     def decorate(self, dp):
 371         if dp.fillstyles is not None:
 372             raise RuntimeError("Cannot fill an already filled path")
 373         dp.fillstyles = self.styles
 374         return dp
 375
 376 filled = _filled()
 377 filled.clear = attr.clearclass(_filled)
 378
 379 #
 380 # Arrows
 381 #
 382
 383 # helper function which constructs the arrowhead
 384
 385 def _arrowhead(anormpath, size, angle, constrictionlen, reversed):
 386
 387     """helper routine, which returns an arrowhead from a given anormpath
 388
 389     returns arrowhead at begin of anormpath with size,
 390     opening angle and constriction length constrictionlen. If constrictionlen is None, we
 391     do not add a constriction.
 392     """
 393
 394     if reversed:
 395         anormpath = anormpath.reversed()
 396     alen = anormpath.arclentoparam(size)
 397     tx, ty = anormpath.atbegin()
 398
 399     # now we construct the template for our arrow but cutting
 400     # the path a the corresponding length
 401     arrowtemplate = anormpath.split(alen)[0]
 402
 403     # from this template, we construct the two outer curves
 404     # of the arrow
 405     arrowl = arrowtemplate.transformed(trafo.rotate(-angle/2.0, tx, ty))
 406     arrowr = arrowtemplate.transformed(trafo.rotate( angle/2.0, tx, ty))
 407
 408     # now come the joining backward parts
 409
 410     if constrictionlen is not None:
 411         # constriction point (cx, cy) lies on path
 412         cx, cy = anormpath.at(anormpath.arclentoparam(constrictionlen))
 413         arrowcr= path.line(*(arrowr.atend() + (cx,cy)))
 414         arrow = arrowl.reversed() << arrowr << arrowcr
 415     else:
 416         arrow = arrowl.reversed() << arrowr
 417
 418     arrow[-1].close()
 419
 420     return arrow
 421
 422
 423 _base = 6 * unit.v_pt
 424
 425 class arrow(deco, attr.attr):
 426
 427     """arrow is a decorator which adds an arrow to either side of the path"""
 428
 429     def __init__(self, attrs=[], position=0, size=_base, angle=45, constriction=0.8):
 430         self.attrs = attr.mergeattrs([style.linestyle.solid, filled] + attrs)
 431         attr.checkattrs(self.attrs, [deco, style.fillstyle, style.strokestyle])
 432         self.position = position
 433         self.size = size
 434         self.angle = angle
 435         self.constriction = constriction
 436
 437     def __call__(self, attrs=None, position=None, size=None, angle=None, constriction=helper.nodefault):
 438         if attrs is None:
 439             attrs = self.attrs
 440         if position is None:
 441             position = self.position
 442         if size is None:
 443             size = self.size
 444         if angle is None:
 445             angle = self.angle
 446         if constriction is helper.nodefault:
 447             constriction = self.constriction
 448         return arrow(attrs=attrs, position=position, size=size, angle=angle, constriction=constriction)
 449
 450     def decorate(self, dp):
 451         dp.ensurenormpath()
 452         anormpath = dp.path
 453
 454         # calculate absolute arc length of constricition
 455         # Note that we have to correct this length because the arrowtemplates are rotated
 456         # by self.angle/2 to the left and right. Hence, if we want no constriction, i.e., for
 457         # self.constriction = 1, we actually have a length which is approximately shorter
 458         # by the given geometrical factor.
 459         if self.constriction is not None:
 460             constrictionlen = arrowheadconstrictionlen = self.size * self.constriction * math.cos(radians(self.angle/2.0))
 461         else:
 462             # if we do not want a constriction, i.e. constriction is None, we still
 463             # need constrictionlen for cutting the path
 464             constrictionlen = self.size * 1 * math.cos(radians(self.angle/2.0))
 465             arrowheadconstrictionlen = None
 466
 467         if self.position == 0:
 468             arrowhead = _arrowhead(anormpath, self.size, self.angle, arrowheadconstrictionlen, reversed=0)
 469         else:
 470             arrowhead = _arrowhead(anormpath, self.size, self.angle, arrowheadconstrictionlen, reversed=1)
 471
 472         # add arrowhead to decoratedpath
 473         dp.ornaments.draw(arrowhead, self.attrs)
 474
 475         if self.position == 0:
 476             # exclude first part of the first normsubpath from stroking
 477             dp.excluderange(0, min(self.size, constrictionlen))
 478         else:
 479             dp.excluderange(anormpath.end() - min(self.size, constrictionlen), anormpath.end())
 480
 481         return dp
 482
 483 arrow.clear = attr.clearclass(arrow)
 484
 485 # arrows at begin of path
 486 barrow = arrow(position=0)
 487 barrow.SMALL = barrow(size=_base/math.sqrt(64))
 488 barrow.SMALl = barrow(size=_base/math.sqrt(32))
 489 barrow.SMAll = barrow(size=_base/math.sqrt(16))
 490 barrow.SMall = barrow(size=_base/math.sqrt(8))
 491 barrow.Small = barrow(size=_base/math.sqrt(4))
 492 barrow.small = barrow(size=_base/math.sqrt(2))
 493 barrow.normal = barrow(size=_base)
 494 barrow.large = barrow(size=_base*math.sqrt(2))
 495 barrow.Large = barrow(size=_base*math.sqrt(4))
 496 barrow.LArge = barrow(size=_base*math.sqrt(8))
 497 barrow.LARge = barrow(size=_base*math.sqrt(16))
 498 barrow.LARGe = barrow(size=_base*math.sqrt(32))
 499 barrow.LARGE = barrow(size=_base*math.sqrt(64))
 500
 501 # arrows at end of path
 502 earrow = arrow(position=1)
 503 earrow.SMALL = earrow(size=_base/math.sqrt(64))
 504 earrow.SMALl = earrow(size=_base/math.sqrt(32))
 505 earrow.SMAll = earrow(size=_base/math.sqrt(16))
 506 earrow.SMall = earrow(size=_base/math.sqrt(8))
 507 earrow.Small = earrow(size=_base/math.sqrt(4))
 508 earrow.small = earrow(size=_base/math.sqrt(2))
 509 earrow.normal = earrow(size=_base)
 510 earrow.large = earrow(size=_base*math.sqrt(2))
 511 earrow.Large = earrow(size=_base*math.sqrt(4))
 512 earrow.LArge = earrow(size=_base*math.sqrt(8))
 513 earrow.LARge = earrow(size=_base*math.sqrt(16))
 514 earrow.LARGe = earrow(size=_base*math.sqrt(32))
 515 earrow.LARGE = earrow(size=_base*math.sqrt(64))
 516