canvas.py

   1 # -*- encoding: utf-8 -*-
   2 #
   3 #
   4 # Copyright (C) 2002-2012 Jörg Lehmann <joergl@users.sourceforge.net>
   5 # Copyright (C) 2002-2012 André Wobst <wobsta@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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  22
  23 """The canvas module provides a PostScript canvas class and related classes
  24
  25 A canvas holds a collection of all elements and corresponding attributes to be
  26 displayed. """
  27
  28 import io, logging, os, sys, string, tempfile
  29 from . import attr, baseclasses, config, document, style, trafo
  30 from . import bbox as bboxmodule
  31
  32 logger = logging.getLogger("pyx")
  33
  34 def _wrappedindocument(method):
  35     def wrappedindocument(self, file=None, **kwargs):
  36         page_kwargs = {}
  37         write_kwargs = {}
  38         for name, value in list(kwargs.items()):
  39             if name.startswith("page_"):
  40                 page_kwargs[name[5:]] = value
  41             elif name.startswith("write_"):
  42                 write_kwargs[name[6:]] = value
  43             else:
  44                 logger.warning("implicit page keyword argument passing is deprecated; keyword argument '%s' of %s method should be changed to 'page_%s'" %
  45                                (name, method.__name__, name))
  46                 page_kwargs[name] = value
  47         d = document.document([document.page(self, **page_kwargs)])
  48         self.__name__ = method.__name__
  49         self.__doc__ = method.__doc__
  50         return method(d, file, **write_kwargs)
  51     return wrappedindocument
  52
  53 #
  54 # clipping class
  55 #
  56
  57 class clip(attr.attr):
  58
  59     """class for use in canvas constructor which clips to a path"""
  60
  61     def __init__(self, path):
  62         """construct a clip instance for a given path"""
  63         self.path = path
  64
  65     def processPS(self, file, writer, context, registry):
  66         file.write("newpath\n")
  67         self.path.outputPS(file, writer)
  68         file.write("clip\n")
  69
  70     def processPDF(self, file, writer, context, registry):
  71         self.path.outputPDF(file, writer)
  72         file.write("W n\n")
  73
  74
  75 #
  76 # general canvas class
  77 #
  78
  79 class canvas(baseclasses.canvasitem):
  80
  81     """a canvas holds a collection of canvasitems"""
  82
  83     def __init__(self, attrs=None, texrunner=None):
  84
  85         """construct a canvas
  86
  87         The canvas can be modfied by supplying a list of attrs, which have
  88         to be instances of one of the following classes:
  89          - trafo.trafo (leading to a global transformation of the canvas)
  90          - canvas.clip (clips the canvas)
  91          - style.strokestyle, style.fillstyle (sets some global attributes of the canvas)
  92
  93         Note that, while the first two properties are fixed for the
  94         whole canvas, the last one can be changed via canvas.set().
  95
  96         The texrunner instance used for the text method can be specified
  97         using the texrunner argument. It defaults to text.defaulttexrunner
  98
  99         """
 100
 101         self.items = []
 102         self.trafo = trafo.identity
 103         self.clip = None
 104         self.layers = {}
 105         if attrs is None:
 106             attrs = []
 107         if texrunner is not None:
 108             self.texrunner = texrunner
 109         else:
 110             # prevent cyclic imports
 111             from . import text
 112             self.texrunner = text.defaulttexrunner
 113
 114         attr.checkattrs(attrs, [trafo.trafo_pt, clip, style.style])
 115         attrs = attr.mergeattrs(attrs)
 116         self.modifies_state = bool(attrs)
 117
 118         self.styles = attr.getattrs(attrs, [style.style])
 119
 120         # trafos (and one possible clip operation) are applied from left to
 121         # right in the attrs list -> reverse for calculating total trafo
 122         for aattr in reversed(attr.getattrs(attrs, [trafo.trafo_pt, clip])):
 123             if isinstance(aattr, trafo.trafo_pt):
 124                 self.trafo = self.trafo * aattr
 125                 if self.clip is not None:
 126                     self.clip = clip(self.clip.path.transformed(aattr))
 127             else:
 128                 if self.clip is not None:
 129                     raise ValueError("single clipping allowed only")
 130                 self.clip = aattr
 131
 132     def __len__(self):
 133         return len(self.items)
 134
 135     def __getitem__(self, i):
 136         return self.items[i]
 137
 138     def _repr_png_(self):
 139         """
 140         Automatically represent as PNG graphic when evaluated in IPython notebook.
 141         """
 142         return self.pipeGS(device="png16m").getvalue()
 143
 144     def bbox(self):
 145         """returns bounding box of canvas
 146
 147         Note that this bounding box doesn't take into account the linewidths, so
 148         is less accurate than the one used when writing the output to a file.
 149         """
 150         obbox = bboxmodule.empty()
 151         for cmd in self.items:
 152             obbox += cmd.bbox()
 153
 154         # transform according to our global transformation and
 155         # intersect with clipping bounding box (which has already been
 156         # transformed in canvas.__init__())
 157         obbox.transform(self.trafo)
 158         if self.clip is not None:
 159             obbox *= self.clip.path.bbox()
 160         return obbox
 161
 162     def processPS(self, file, writer, context, registry, bbox):
 163         context = context()
 164         if self.items:
 165             if self.modifies_state:
 166                 file.write("gsave\n")
 167                 for attr in self.styles:
 168                     attr.processPS(file, writer, context, registry)
 169                 if self.trafo is not trafo.identity:
 170                     self.trafo.processPS(file, writer, context, registry)
 171                 if self.clip is not None:
 172                     self.clip.processPS(file, writer, context, registry)
 173             nbbox = bboxmodule.empty()
 174             for item in self.items:
 175                 item.processPS(file, writer, context, registry, nbbox)
 176             # update bounding bbox
 177             nbbox.transform(self.trafo)
 178             if self.clip is not None:
 179                 nbbox *= self.clip.path.bbox()
 180             bbox += nbbox
 181             if self.modifies_state:
 182                 file.write("grestore\n")
 183
 184     def processPDF(self, file, writer, context, registry, bbox):
 185         context = context()
 186         textregion = False
 187         context.trafo = context.trafo * self.trafo
 188         if self.items:
 189             if self.modifies_state:
 190                 file.write("q\n") # gsave
 191                 for attr in self.styles:
 192                     if isinstance(attr, style.fillstyle):
 193                         context.fillstyles.append(attr)
 194                     attr.processPDF(file, writer, context, registry)
 195                 if self.trafo is not trafo.identity:
 196                     self.trafo.processPDF(file, writer, context, registry)
 197                 if self.clip is not None:
 198                     self.clip.processPDF(file, writer, context, registry)
 199             nbbox = bboxmodule.empty()
 200             for item in self.items:
 201                 if not writer.text_as_path:
 202                     if item.requiretextregion():
 203                         if not textregion:
 204                             file.write("BT\n")
 205                             textregion = True
 206                     else:
 207                         if textregion:
 208                             file.write("ET\n")
 209                             textregion = False
 210                             context.selectedfont = None
 211                 item.processPDF(file, writer, context, registry, nbbox)
 212             if textregion:
 213                 file.write("ET\n")
 214                 textregion = False
 215                 context.selectedfont = None
 216             # update bounding bbox
 217             nbbox.transform(self.trafo)
 218             if self.clip is not None:
 219                 nbbox *= self.clip.path.bbox()
 220             bbox += nbbox
 221             if self.modifies_state:
 222                 file.write("Q\n") # grestore
 223
 224     def layer(self, name, above=None, below=None):
 225         """create or get a layer with name
 226
 227         A layer is a canvas itself and can be used to combine drawing
 228         operations for ordering purposes, i.e., what is above and below each
 229         other. The layer name is a dotted string, where dots are used to form
 230         a hierarchy of layer groups. When inserting a layer, it is put on top
 231         of its layer group except when another layer of this group is specified
 232         by means of the parameters above or below.
 233
 234         """
 235         if above is not None and below is not None:
 236             raise ValueError("above and below cannot be specified at the same time")
 237         try:
 238             group, layer = name.split(".", 1)
 239         except ValueError:
 240             if name in self.layers:
 241                 if above is not None or below is not None:
 242                     # remove for repositioning
 243                     self.items.remove(self.layers[name])
 244             else:
 245                 # create new layer
 246                 self.layers[name] = canvas(texrunner=self.texrunner)
 247                 if above is None and below is None:
 248                     self.items.append(self.layers[name])
 249
 250             # (re)position layer
 251             if above is not None:
 252                 self.items.insert(self.items.index(self.layers[above])+1, self.layers[name])
 253             elif below is not None:
 254                 self.items.insert(self.items.index(self.layers[below]), self.layers[name])
 255
 256             return self.layers[name]
 257         else:
 258             if not group in self.layers:
 259                 self.layers[group] = self.insert(canvas(texrunner=self.texrunner))
 260             if above is not None:
 261                 abovegroup, above = above.split(".", 1)
 262                 assert abovegroup == group
 263             if below is not None:
 264                 belowgroup, below = below.split(".", 1)
 265                 assert belowgroup == group
 266             return self.layers[group].layer(layer, above=above, below=below)
 267
 268     def insert(self, item, attrs=None):
 269         """insert item in the canvas.
 270
 271         If attrs are passed, a canvas containing the item is inserted applying
 272         attrs. If replace is not None, the new item is
 273         positioned accordingly in the canvas.
 274
 275         returns the item, possibly wrapped in a canvas
 276
 277         """
 278
 279         if not isinstance(item, baseclasses.canvasitem):
 280             raise ValueError("only instances of baseclasses.canvasitem can be inserted into a canvas")
 281
 282         if attrs:
 283             sc = canvas(attrs)
 284             sc.insert(item)
 285             item = sc
 286
 287         self.items.append(item)
 288         return item
 289
 290     def draw(self, path, attrs):
 291         """draw path on canvas using the style given by args
 292
 293         The argument attrs consists of PathStyles, which modify
 294         the appearance of the path, PathDecos, which add some new
 295         visual elements to the path, or trafos, which are applied
 296         before drawing the path.
 297
 298         """
 299         from . import deco
 300         attrs = attr.mergeattrs(attrs)
 301         attr.checkattrs(attrs, [deco.deco, baseclasses.deformer, style.style])
 302
 303         for adeformer in attr.getattrs(attrs, [baseclasses.deformer]):
 304             path = adeformer.deform(path)
 305
 306         styles = attr.getattrs(attrs, [style.style])
 307         dp = deco.decoratedpath(path, styles=styles)
 308
 309         # add path decorations and modify path accordingly
 310         for adeco in attr.getattrs(attrs, [deco.deco]):
 311             adeco.decorate(dp, self.texrunner)
 312
 313         self.insert(dp)
 314
 315     def stroke(self, path, attrs=[]):
 316         """stroke path on canvas using the style given by args
 317
 318         The argument attrs consists of PathStyles, which modify
 319         the appearance of the path, PathDecos, which add some new
 320         visual elements to the path, or trafos, which are applied
 321         before drawing the path.
 322
 323         """
 324         from . import deco
 325         self.draw(path, [deco.stroked]+list(attrs))
 326
 327     def fill(self, path, attrs=[]):
 328         """fill path on canvas using the style given by args
 329
 330         The argument attrs consists of PathStyles, which modify
 331         the appearance of the path, PathDecos, which add some new
 332         visual elements to the path, or trafos, which are applied
 333         before drawing the path.
 334
 335         """
 336         from . import deco
 337         self.draw(path, [deco.filled]+list(attrs))
 338
 339     def settexrunner(self, texrunner):
 340         """sets the texrunner to be used to within the text and text_pt methods"""
 341
 342         self.texrunner = texrunner
 343
 344     def text(self, x, y, atext, *args, **kwargs):
 345         """insert a text into the canvas
 346
 347         inserts a textbox created by self.texrunner.text into the canvas
 348
 349         returns the inserted textbox"""
 350
 351         return self.insert(self.texrunner.text(x, y, atext, *args, **kwargs))
 352
 353
 354     def text_pt(self, x, y, atext, *args):
 355         """insert a text into the canvas
 356
 357         inserts a textbox created by self.texrunner.text_pt into the canvas
 358
 359         returns the inserted textbox"""
 360
 361         return self.insert(self.texrunner.text_pt(x, y, atext, *args))
 362
 363     writeEPSfile = _wrappedindocument(document.document.writeEPSfile)
 364     writePSfile = _wrappedindocument(document.document.writePSfile)
 365     writePDFfile = _wrappedindocument(document.document.writePDFfile)
 366     writetofile = _wrappedindocument(document.document.writetofile)
 367
 368
 369     def _gscmd(self, device, filename, resolution=100, gs="gs", gsoptions=[],
 370                textalphabits=4, graphicsalphabits=4, ciecolor=False, **kwargs):
 371
 372         cmd = [gs, "-dEPSCrop", "-dNOPAUSE", "-dQUIET", "-dBATCH", "-r%d" % resolution, "-sDEVICE=%s" % device, "-sOutputFile=%s" % filename]
 373         if textalphabits is not None:
 374             cmd.append("-dTextAlphaBits=%i" % textalphabits)
 375         if graphicsalphabits is not None:
 376             cmd.append("-dGraphicsAlphaBits=%i" % graphicsalphabits)
 377         if ciecolor:
 378             cmd.append("-dUseCIEColor")
 379         cmd.extend(gsoptions)
 380
 381         return cmd, kwargs
 382
 383     def writeGSfile(self, filename=None, device=None, input="eps", **kwargs):
 384         """
 385         convert EPS or PDF output to a file via Ghostscript
 386
 387         If filename is None it is auto-guessed from the script name. If
 388         filename is "-", the output is written to stdout. In both cases, a
 389         device needs to be specified to define the format.
 390
 391         If device is None, but a filename with suffix is given, PNG files will
 392         be written using the png16m device and JPG files using the jpeg device.
 393         """
 394         if filename is None:
 395             if not sys.argv[0].endswith(".py"):
 396                 raise RuntimeError("could not auto-guess filename")
 397             if device.startswith("png"):
 398                 filename = sys.argv[0][:-2] + "png"
 399             elif device.startswith("jpeg"):
 400                 filename = sys.argv[0][:-2] + "jpg"
 401             else:
 402                 filename = sys.argv[0][:-2] + device
 403         if device is None:
 404             if filename.endswith(".png"):
 405                 device = "png16m"
 406             elif filename.endswith(".jpg"):
 407                 device = "jpeg"
 408             else:
 409                 raise RuntimeError("could not auto-guess device")
 410
 411         cmd, kwargs = self._gscmd(device, filename, **kwargs)
 412
 413         if input == "eps":
 414             cmd.append("-")
 415             p = config.Popen(cmd, stdin=config.PIPE)
 416             self.writeEPSfile(p.stdin, **kwargs)
 417             p.stdin.close()
 418             p.wait()
 419         elif input == "pdf":
 420             # PDF files need to be accesible by random access and thus we need to create
 421             # a temporary file
 422             with tempfile.NamedTemporaryFile("wb", delete=False) as f:
 423                 self.writePDFfile(f, **kwargs)
 424                 fname = f.name
 425             cmd.append(fname)
 426             config.Popen(cmd).wait()
 427             os.unlink(fname)
 428         else:
 429             raise RuntimeError("input 'eps' or 'pdf' expected")
 430
 431
 432     def pipeGS(self, device, input="eps", **kwargs):
 433         """
 434         returns a BytesIO instance with the Ghostscript output of the EPS or PDF
 435         """
 436
 437         cmd, kwargs = self._gscmd(device, "-", **kwargs)
 438
 439         with tempfile.NamedTemporaryFile("wb", delete=False) as f:
 440             if input == "eps":
 441                 self.writeEPSfile(f, **kwargs)
 442             elif input == "pdf":
 443                 self.writePDFfile(f, **kwargs)
 444             else:
 445                 raise RuntimeError("input 'eps' or 'pdf' expected")
 446             fname = f.name
 447
 448         cmd.append(fname)
 449         p = config.Popen(cmd, stdout=config.PIPE)
 450         data, error = p.communicate()
 451         os.unlink(fname)
 452
 453         if error:
 454             raise ValueError("error received while waiting for ghostscript")
 455         return io.BytesIO(data)