pyx/canvas.py

   1 #!/usr/bin/env python
   2 # -*- coding: ISO-8859-1 -*-
   3 #
   4 #
   5 # Copyright (C) 2002, 2003 Jörg Lehmann <joergl@users.sourceforge.net>
   6 # Copyright (C) 2002, 2003 André Wobst <wobsta@users.sourceforge.net>
   7 #
   8 # This file is part of PyX (http://pyx.sourceforge.net/).
   9 #
  10 # PyX is free software; you can redistribute it and/or modify
  11 # it under the terms of the GNU General Public License as published by
  12 # the Free Software Foundation; either version 2 of the License, or
  13 # (at your option) any later version.
  14 #
  15 # PyX is distributed in the hope that it will be useful,
  16 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 # GNU General Public License for more details.
  19 #
  20 # You should have received a copy of the GNU General Public License
  21 # along with PyX; if not, write to the Free Software
  22 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23
  24 # XXX remove string module
  25 # XXX what is a pattern
  26 # XXX what is a color
  27
  28
  29 """The canvas module provides a PostScript canvas class and related classes
  30
  31 A canvas holds a collection of all elements that should be displayed together
  32 with their attributes.
  33 """
  34
  35 import string, cStringIO, time
  36 import attr, base, bbox, color, deco, path, unit, prolog, style, trafo, version
  37
  38 # known paperformats as tuple(width, height)
  39
  40 _paperformats = { "A4"      : ("210 t mm",  "297 t mm"),
  41                   "A3"      : ("297 t mm",  "420 t mm"),
  42                   "A2"      : ("420 t mm",  "594 t mm"),
  43                   "A1"      : ("594 t mm",  "840 t mm"),
  44                   "A0"      : ("840 t mm", "1188 t mm"),
  45                   "A0B"     : ("910 t mm", "1370 t mm"),
  46                   "LETTER"  : ("8.5 t inch", "11 t inch"),
  47                   "LEGAL"   : ("8.5 t inch", "14 t inch")}
  48
  49
  50 #
  51 # clipping class
  52 #
  53
  54 # XXX help me find my identity
  55
  56 class clip(base.PSCmd):
  57
  58     """class for use in canvas constructor which clips to a path"""
  59
  60     def __init__(self, path):
  61         """construct a clip instance for a given path"""
  62         self.path = path
  63
  64     def bbox(self):
  65         # as a PSCmd a clipping path has NO influence on the bbox...
  66         return bbox._bbox()
  67
  68     def clipbbox(self):
  69         # ... but for clipping, we nevertheless need the bbox
  70         return self.path.bbox()
  71
  72     def write(self, file):
  73         _newpath().write(file)
  74         self.path.write(file)
  75         _clip().write(file)
  76
  77 #
  78 # some very primitive Postscript operators
  79 #
  80
  81 class _newpath(base.PSOp):
  82     def write(self, file):
  83        file.write("newpath\n")
  84
  85
  86 class _stroke(base.PSOp):
  87     def write(self, file):
  88        file.write("stroke\n")
  89
  90
  91 class _fill(base.PSOp):
  92     def write(self, file):
  93         file.write("fill\n")
  94
  95
  96 class _clip(base.PSOp):
  97     def write(self, file):
  98        file.write("clip\n")
  99
 100
 101 class _gsave(base.PSOp):
 102     def write(self, file):
 103        file.write("gsave\n")
 104
 105
 106 class _grestore(base.PSOp):
 107     def write(self, file):
 108        file.write("grestore\n")
 109
 110 #
 111 #
 112 #
 113
 114 class _canvas(base.PSCmd):
 115
 116     """a canvas is a collection of PSCmds together with PSAttrs"""
 117
 118     def __init__(self, *args):
 119
 120         """construct a canvas
 121
 122         The canvas can be modfied by supplying args, which have
 123         to be instances of one of the following classes:
 124          - trafo.trafo (leading to a global transformation of the canvas)
 125          - canvas.clip (clips the canvas)
 126          - base.PathStyle (sets some global attributes of the canvas)
 127
 128         Note that, while the first two properties are fixed for the
 129         whole canvas, the last one can be changed via canvas.set()
 130
 131         """
 132
 133         self.PSOps     = []
 134         self.trafo     = trafo.trafo()
 135         self.clipbbox  = bbox._bbox()
 136
 137         # prevent cyclic imports
 138         import text
 139         self.texrunner = text.defaulttexrunner
 140
 141         for arg in args:
 142             if isinstance(arg, trafo._trafo):
 143                 self.trafo = self.trafo*arg
 144                 self.PSOps.append(arg)
 145             elif isinstance(arg, clip):
 146                 self.clipbbox=(self.clipbbox*
 147                                arg.clipbbox().transformed(self.trafo))
 148                 self.PSOps.append(arg)
 149             else:
 150                 self.set(arg)
 151
 152     def bbox(self):
 153         """returns bounding box of canvas"""
 154         obbox = reduce(lambda x,y:
 155                        isinstance(y, base.PSCmd) and x+y.bbox() or x,
 156                        self.PSOps,
 157                        bbox._bbox())
 158
 159         # transform according to our global transformation and
 160         # intersect with clipping bounding box (which have already been
 161         # transformed in canvas.__init__())
 162         return obbox.transformed(self.trafo)*self.clipbbox
 163
 164     def prolog(self):
 165         result = []
 166         for cmd in self.PSOps:
 167             result.extend(cmd.prolog())
 168         return result
 169
 170     def write(self, file):
 171         if self.PSOps:
 172             _gsave().write(file)
 173             for cmd in self.PSOps:
 174                 cmd.write(file)
 175             _grestore().write(file)
 176
 177     def insert(self, PSOp, *args):
 178         """insert PSOp in the canvas.
 179
 180         If args are given, then insert a canvas containing PSOp applying args.
 181
 182         returns the PSOp
 183
 184         """
 185
 186         # XXX check for PSOp
 187
 188         if args:
 189             sc = _canvas(*args)
 190             sc.insert(PSOp)
 191             self.PSOps.append(sc)
 192         else:
 193             self.PSOps.append(PSOp)
 194
 195         return PSOp
 196
 197     def set(self, *attrs):
 198         """sets styles args globally for the rest of the canvas
 199
 200         returns canvas
 201
 202         """
 203
 204         attr.checkattrs(attrs, [style.strokestyle, style.fillstyle])
 205         for astyle in attrs:
 206             self.insert(astyle)
 207         return self
 208
 209     def draw(self, path, *attrs):
 210         """draw path on canvas using the style given by args
 211
 212         The argument list args consists of PathStyles, which modify
 213         the appearance of the path, PathDecos, which add some new
 214         visual elements to the path, or trafos, which are applied
 215         before drawing the path.
 216
 217         returns the canvas
 218
 219         """
 220
 221         attr.mergeattrs(attrs)
 222         attr.checkattrs(attrs, [deco.deco, style.fillstyle, style.strokestyle, trafo._trafo])
 223
 224         for t in attr.getattrs(attrs, [trafo._trafo]):
 225             path = path.transformed(t)
 226
 227         dp = deco.decoratedpath(path)
 228
 229         # set global styles
 230         dp.styles = attr.getattrs(attrs, [style.fillstyle, style.strokestyle])
 231
 232         # add path decorations and modify path accordingly
 233         for adeco in attr.getattrs(attrs, [deco.deco]):
 234             dp = adeco.decorate(dp)
 235
 236         self.insert(dp)
 237
 238         return self
 239
 240     def stroke(self, path, *attrs):
 241         """stroke path on canvas using the style given by args
 242
 243         The argument list args consists of PathStyles, which modify
 244         the appearance of the path, PathDecos, which add some new
 245         visual elements to the path, or trafos, which are applied
 246         before drawing the path.
 247
 248         returns the canvas
 249
 250         """
 251
 252         return self.draw(path, deco.stroked(), *attrs)
 253
 254     def fill(self, path, *attrs):
 255         """fill path on canvas using the style given by args
 256
 257         The argument list args consists of PathStyles, which modify
 258         the appearance of the path, PathDecos, which add some new
 259         visual elements to the path, or trafos, which are applied
 260         before drawing the path.
 261
 262         returns the canvas
 263
 264         """
 265
 266         return self.draw(path, deco.filled(), *attrs)
 267
 268     def settexrunner(self, texrunner):
 269         """sets the texrunner to be used to within the text and text_pt methods"""
 270
 271         self.texrunner = texrunner
 272
 273     def text(self, x, y, atext, *args):
 274         """insert a text into the canvas
 275
 276         inserts a textbox created by self.texrunner.text into the canvas
 277
 278         returns the inserted textbox"""
 279
 280         return self.insert(self.texrunner.text(x, y, atext, *args))
 281
 282
 283     def text_pt(self, x, y, atext, *args):
 284         """insert a text into the canvas
 285
 286         inserts a textbox created by self.texrunner.text_pt into the canvas
 287
 288         returns the inserted textbox"""
 289
 290         return self.insert(self.texrunner.text_pt(x, y, atext, *args))
 291
 292 #
 293 # canvas for patterns
 294 #
 295
 296 class pattern(_canvas, style.fillstyle):
 297
 298     def __init__(self, painttype=1, tilingtype=1, xstep=None, ystep=None, bbox=None, trafo=None):
 299         _canvas.__init__(self)
 300         self.id = "pattern%d" % id(self)
 301         # XXX: some checks are in order
 302         if painttype not in (1,2):
 303             raise ValueError("painttype must be 1 or 2")
 304         self.painttype = painttype
 305         if tilingtype not in (1,2,3):
 306             raise ValueError("tilingtype must be 1, 2 or 3")
 307         self.tilingtype = tilingtype
 308         self.xstep = xstep
 309         self.ystep = ystep
 310         self.patternbbox = bbox
 311         self.patterntrafo = trafo
 312
 313     def bbox(self):
 314         return bbox._bbox()
 315
 316     def write(self, file):
 317         file.write("%s setpattern\n" % self.id)
 318
 319     def prolog(self):
 320         realpatternbbox = _canvas.bbox(self)
 321         if self.xstep is None:
 322            xstep = unit.topt(realpatternbbox.width())
 323         else:
 324            xstep = unit.topt(unit.length(self.xstep))
 325         if self.ystep is None:
 326             ystep = unit.topt(realpatternbbox.height())
 327         else:
 328            ystep = unit.topt(unit.length(self.ystep))
 329         if not xstep:
 330             raise ValueError("xstep in pattern cannot be zero")
 331         if not ystep:
 332             raise ValueError("ystep in pattern cannot be zero")
 333         patternbbox = self.patternbbox or realpatternbbox.enlarged("5 pt")
 334
 335         patternprefix = string.join(("<<",
 336                                      "/PatternType 1",
 337                                      "/PaintType %d" % self.painttype,
 338                                      "/TilingType %d" % self.tilingtype,
 339                                      "/BBox[%s]" % str(patternbbox),
 340                                      "/XStep %g" % xstep,
 341                                      "/YStep %g" % ystep,
 342                                      "/PaintProc {\nbegin\n"),
 343                                     sep="\n")
 344         stringfile = cStringIO.StringIO()
 345         _canvas.write(self, stringfile)
 346         patternproc = stringfile.getvalue()
 347         stringfile.close()
 348         patterntrafostring = self.patterntrafo is None and "matrix" or str(self.patterntrafo)
 349         patternsuffix = "end\n} bind\n>>\n%s\nmakepattern" % patterntrafostring
 350
 351         pr = _canvas.prolog(self)
 352         pr.append(prolog.definition(self.id, string.join((patternprefix, patternproc, patternsuffix), "")))
 353         return pr
 354
 355 #
 356 # The main canvas class
 357 #
 358
 359 class canvas(_canvas):
 360
 361     """a canvas is a collection of PSCmds together with PSAttrs"""
 362
 363     def writetofile(self, filename, paperformat=None, rotated=0, fittosize=0, margin="1 t cm",
 364                     bbox=None, bboxenlarge="1 t pt"):
 365         """write canvas to EPS file
 366
 367         If paperformat is set to a known paperformat, the output will be centered on
 368         the page.
 369
 370         If rotated is set, the output will first be rotated by 90 degrees.
 371
 372         If fittosize is set, then the output is scaled to the size of the
 373         page (minus margin). In that case, the paperformat the specification
 374         of the paperformat is obligatory.
 375
 376         The bbox parameter overrides the automatic bounding box determination.
 377         bboxenlarge may be used to enlarge the bbox of the canvas (or the
 378         manually specified bbox).
 379         """
 380
 381         if filename[-4:]!=".eps":
 382             filename = filename + ".eps"
 383
 384         try:
 385             file = open(filename, "w")
 386         except IOError:
 387             raise IOError("cannot open output file")
 388
 389         abbox = bbox is not None and bbox or self.bbox()
 390         abbox = abbox.enlarged(bboxenlarge)
 391         ctrafo = None     # global transformation of canvas
 392
 393         if rotated:
 394             ctrafo = trafo._rotate(90,
 395                                      0.5*(abbox.llx+abbox.urx),
 396                                      0.5*(abbox.lly+abbox.ury))
 397
 398         if paperformat:
 399             # center (optionally rotated) output on page
 400             try:
 401                 width, height = _paperformats[paperformat.upper()]
 402             except KeyError:
 403                 raise KeyError, "unknown paperformat '%s'" % paperformat
 404             width = unit.topt(width)
 405             height = unit.topt(height)
 406
 407             if not ctrafo: ctrafo=trafo.trafo()
 408
 409             ctrafo = ctrafo._translated(0.5*(width -(abbox.urx-abbox.llx))-
 410                                        abbox.llx,
 411                                        0.5*(height-(abbox.ury-abbox.lly))-
 412                                        abbox.lly)
 413
 414             if fittosize:
 415                 # scale output to pagesize - margins
 416                 margin = unit.topt(margin)
 417                 if 2*margin > min(width, height):
 418                     raise RuntimeError("Margins too broad for selected paperformat. Aborting.")
 419
 420                 if rotated:
 421                     sfactor = min((height-2*margin)/(abbox.urx-abbox.llx),
 422                                   (width-2*margin)/(abbox.ury-abbox.lly))
 423                 else:
 424                     sfactor = min((width-2*margin)/(abbox.urx-abbox.llx),
 425                                   (height-2*margin)/(abbox.ury-abbox.lly))
 426
 427                 ctrafo = ctrafo._scaled(sfactor, sfactor, 0.5*width, 0.5*height)
 428
 429
 430         elif fittosize:
 431             raise ValueError("must specify paper size for fittosize")
 432
 433         # if there has been a global transformation, adjust the bounding box
 434         # accordingly
 435         if ctrafo: abbox = abbox.transformed(ctrafo)
 436
 437         file.write("%!PS-Adobe-3.0 EPSF 3.0\n")
 438         abbox.write(file)
 439         file.write("%%%%Creator: PyX %s\n" % version.version)
 440         file.write("%%%%Title: %s\n" % filename)
 441         file.write("%%%%CreationDate: %s\n" %
 442                    time.asctime(time.localtime(time.time())))
 443         file.write("%%EndComments\n")
 444
 445         file.write("%%BeginProlog\n")
 446
 447         mergedprolog = []
 448
 449         for pritem in self.prolog():
 450             for mpritem in mergedprolog:
 451                 if mpritem.merge(pritem) is None: break
 452             else:
 453                 mergedprolog.append(pritem)
 454
 455         for pritem in mergedprolog:
 456             pritem.write(file)
 457
 458         file.write("%%EndProlog\n")
 459
 460         # again, if there has occured global transformation, apply it now
 461         if ctrafo: ctrafo.write(file)
 462
 463         file.write("%f setlinewidth\n" % unit.topt(style.linewidth.normal))
 464
 465         # here comes the actual content
 466         self.write(file)
 467
 468         file.write("showpage\n")
 469         file.write("%%Trailer\n")
 470         file.write("%%EOF\n")