canvas.py

   1 # -*- encoding: utf-8 -*-
   2 #
   3 #
   4 # Copyright (C) 2002-2011 Jörg Lehmann <joergl@users.sourceforge.net>
   5 # Copyright (C) 2002-2011 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 os, tempfile
  29 import attr, canvasitem, deco, deformer, document, font, pycompat, style, trafo
  30 import bbox as bboxmodule
  31
  32
  33 #
  34 # clipping class
  35 #
  36
  37 class clip(canvasitem.canvasitem):
  38
  39     """class for use in canvas constructor which clips to a path"""
  40
  41     def __init__(self, path):
  42         """construct a clip instance for a given path"""
  43         self.path = path
  44
  45     def bbox(self):
  46         # as a canvasitem a clipping path has NO influence on the bbox...
  47         return bboxmodule.empty()
  48
  49     def clipbbox(self):
  50         # ... but for clipping, we nevertheless need the bbox
  51         return self.path.bbox()
  52
  53     def processPS(self, file, writer, context, registry, bbox):
  54         file.write("newpath\n")
  55         self.path.outputPS(file, writer)
  56         file.write("clip\n")
  57
  58     def processPDF(self, file, writer, context, registry, bbox):
  59         self.path.outputPDF(file, writer)
  60         file.write("W n\n")
  61
  62
  63 #
  64 # general canvas class
  65 #
  66
  67 class _canvas(canvasitem.canvasitem):
  68
  69     """a canvas holds a collection of canvasitems"""
  70
  71     def __init__(self, attrs=None, texrunner=None):
  72
  73         """construct a canvas
  74
  75         The canvas can be modfied by supplying a list of attrs, which have
  76         to be instances of one of the following classes:
  77          - trafo.trafo (leading to a global transformation of the canvas)
  78          - canvas.clip (clips the canvas)
  79          - style.strokestyle, style.fillstyle (sets some global attributes of the canvas)
  80
  81         Note that, while the first two properties are fixed for the
  82         whole canvas, the last one can be changed via canvas.set().
  83
  84         The texrunner instance used for the text method can be specified
  85         using the texrunner argument. It defaults to text.defaulttexrunner
  86
  87         """
  88
  89         self.items     = []
  90         self.trafo     = trafo.trafo()
  91         self.clipbbox  = None
  92         if attrs is None:
  93             attrs = []
  94         if texrunner is not None:
  95             self.texrunner = texrunner
  96         else:
  97             # prevent cyclic imports
  98             import text
  99             self.texrunner = text.defaulttexrunner
 100
 101         attr.checkattrs(attrs, [trafo.trafo_pt, clip, style.strokestyle, style.fillstyle])
 102         # We have to reverse the trafos such that the PostScript concat operators
 103         # are in the right order. Correspondingly, we below multiply the current self.trafo
 104         # from the right.
 105         # Note that while for the stroke and fill styles the order doesn't matter at all,
 106         # this is not true for the clip operation.
 107         for aattr in attrs[::-1]:
 108             if isinstance(aattr, trafo.trafo_pt):
 109                 self.trafo = self.trafo * aattr
 110             elif isinstance(aattr, clip):
 111                 if self.clipbbox is None:
 112                     self.clipbbox = aattr.clipbbox().transformed(self.trafo)
 113                 else:
 114                     self.clippbox *= aattr.clipbbox().transformed(self.trafo)
 115             self.items.append(aattr)
 116
 117     def __len__(self):
 118         return len(self.items)
 119
 120     def __getitem__(self, i):
 121         return self.items[i]
 122
 123     def bbox(self):
 124         """returns bounding box of canvas
 125
 126         Note that this bounding box doesn't take into account the linewidths, so
 127         is less accurate than the one used when writing the output to a file.
 128         """
 129         obbox = bboxmodule.empty()
 130         for cmd in self.items:
 131             obbox += cmd.bbox()
 132
 133         # transform according to our global transformation and
 134         # intersect with clipping bounding box (which has already been
 135         # transformed in canvas.__init__())
 136         obbox.transform(self.trafo)
 137         if self.clipbbox is not None:
 138             obbox *= self.clipbbox
 139         return obbox
 140
 141     def processPS(self, file, writer, context, registry, bbox):
 142         context = context()
 143         if self.items:
 144             file.write("gsave\n")
 145             nbbox = bboxmodule.empty()
 146             for item in self.items:
 147                 item.processPS(file, writer, context, registry, nbbox)
 148             # update bounding bbox
 149             nbbox.transform(self.trafo)
 150             if self.clipbbox is not None:
 151                 nbbox *= self.clipbbox
 152             bbox += nbbox
 153             file.write("grestore\n")
 154
 155     def processPDF(self, file, writer, context, registry, bbox):
 156         context = context()
 157         context.trafo = context.trafo * self.trafo
 158         if self.items:
 159             file.write("q\n") # gsave
 160             nbbox = bboxmodule.empty()
 161             for item in self.items:
 162                 if isinstance(item, style.fillstyle):
 163                     context.fillstyles.append(item)
 164                 if not writer.text_as_path:
 165                     if isinstance(item, font.text_pt):
 166                         if not context.textregion:
 167                             file.write("BT\n")
 168                             context.textregion = 1
 169                     else:
 170                         if context.textregion:
 171                             file.write("ET\n")
 172                             context.textregion = 0
 173                             context.selectedfont = None
 174                 item.processPDF(file, writer, context, registry, nbbox)
 175             if context.textregion:
 176                 file.write("ET\n")
 177                 context.textregion = 0
 178                 context.selectedfont = None
 179             # update bounding bbox
 180             nbbox.transform(self.trafo)
 181             if self.clipbbox is not None:
 182                 nbbox *= self.clipbbox
 183             bbox += nbbox
 184             file.write("Q\n") # grestore
 185
 186     def insert(self, item, attrs=None):
 187         """insert item in the canvas.
 188
 189         If attrs are passed, a canvas containing the item is inserted applying attrs.
 190
 191         returns the item
 192
 193         """
 194
 195         if not isinstance(item, canvasitem.canvasitem):
 196             raise RuntimeError("only instances of canvasitem.canvasitem can be inserted into a canvas")
 197
 198         if attrs:
 199             sc = _canvas(attrs)
 200             sc.insert(item)
 201             self.items.append(sc)
 202         else:
 203             self.items.append(item)
 204         return item
 205
 206     def draw(self, path, attrs):
 207         """draw path on canvas using the style given by args
 208
 209         The argument attrs consists of PathStyles, which modify
 210         the appearance of the path, PathDecos, which add some new
 211         visual elements to the path, or trafos, which are applied
 212         before drawing the path.
 213
 214         """
 215
 216         attrs = attr.mergeattrs(attrs)
 217         attr.checkattrs(attrs, [deco.deco, deformer.deformer, style.fillstyle, style.strokestyle, style.fillrule])
 218
 219         for adeformer in attr.getattrs(attrs, [deformer.deformer]):
 220             path = adeformer.deform(path)
 221
 222         styles = attr.getattrs(attrs, [style.fillstyle, style.strokestyle])
 223         fillrule, = attr.getattrs(attrs, [style.fillrule]) or [style.fillrule.nonzero_winding]
 224         dp = deco.decoratedpath(path, styles=styles, fillrule=fillrule)
 225
 226         # add path decorations and modify path accordingly
 227         for adeco in attr.getattrs(attrs, [deco.deco]):
 228             adeco.decorate(dp, self.texrunner)
 229
 230         self.insert(dp)
 231
 232     def stroke(self, path, attrs=[]):
 233         """stroke path on canvas using the style given by args
 234
 235         The argument attrs consists of PathStyles, which modify
 236         the appearance of the path, PathDecos, which add some new
 237         visual elements to the path, or trafos, which are applied
 238         before drawing the path.
 239
 240         """
 241
 242         self.draw(path, [deco.stroked]+list(attrs))
 243
 244     def fill(self, path, attrs=[]):
 245         """fill path on canvas using the style given by args
 246
 247         The argument attrs consists of PathStyles, which modify
 248         the appearance of the path, PathDecos, which add some new
 249         visual elements to the path, or trafos, which are applied
 250         before drawing the path.
 251
 252         """
 253
 254         self.draw(path, [deco.filled]+list(attrs))
 255
 256     def settexrunner(self, texrunner):
 257         """sets the texrunner to be used to within the text and text_pt methods"""
 258
 259         self.texrunner = texrunner
 260
 261     def text(self, x, y, atext, *args, **kwargs):
 262         """insert a text into the canvas
 263
 264         inserts a textbox created by self.texrunner.text into the canvas
 265
 266         returns the inserted textbox"""
 267
 268         return self.insert(self.texrunner.text(x, y, atext, *args, **kwargs))
 269
 270
 271     def text_pt(self, x, y, atext, *args):
 272         """insert a text into the canvas
 273
 274         inserts a textbox created by self.texrunner.text_pt into the canvas
 275
 276         returns the inserted textbox"""
 277
 278         return self.insert(self.texrunner.text_pt(x, y, atext, *args))
 279
 280 #
 281 # user canvas class which adds a few convenience methods for single page output
 282 #
 283
 284 def _wrappedindocument(method):
 285     def wrappedindocument(self, file=None, **kwargs):
 286         d = document.document([document.page(self, **kwargs)])
 287         self.__name__ = method.__name__
 288         self.__doc__ = method.__doc__
 289         return method(d, file)
 290     return wrappedindocument
 291
 292
 293 class canvas(_canvas):
 294
 295     """a canvas holds a collection of canvasitems"""
 296
 297     writeEPSfile = _wrappedindocument(document.document.writeEPSfile)
 298     writePSfile = _wrappedindocument(document.document.writePSfile)
 299     writePDFfile = _wrappedindocument(document.document.writePDFfile)
 300     writetofile = _wrappedindocument(document.document.writetofile)
 301
 302     def pipeGS(self, filename="-", device=None, resolution=100,
 303                gscommand="gs", gsoptions="",
 304                textalphabits=4, graphicsalphabits=4,
 305                ciecolor=False, input="eps", **kwargs):
 306         if device is None:
 307             if filename.endswith(".png"):
 308                 device = "png16m"
 309             if filename.endswith(".jpg"):
 310                 device = "jpeg"
 311         gscommand += " -dEPSCrop -dNOPAUSE -dQUIET -dBATCH -r%i -sDEVICE=%s -sOutputFile=%s" % (resolution, device, filename)
 312         if gsoptions:
 313             gscommand += " %s" % gsoptions
 314         if textalphabits is not None:
 315             gscommand += " -dTextAlphaBits=%i" % textalphabits
 316         if graphicsalphabits is not None:
 317             gscommand += " -dGraphicsAlphaBits=%i" % graphicsalphabits
 318         if ciecolor:
 319             gscommand += " -dUseCIEColor"
 320         if input == "eps":
 321             gscommand += " -"
 322             pipe = pycompat.popen(gscommand, "wb")
 323             self.writeEPSfile(pipe, **kwargs)
 324             pipe.close()
 325         elif input == "pdf":
 326             fd, fname = tempfile.mkstemp()
 327             f = os.fdopen(fd, "wb")
 328             gscommand += " %s" % fname
 329             self.writePDFfile(f, **kwargs)
 330             f.close()
 331             os.system(gscommand)
 332             os.unlink(fname)
 333         else:
 334             raise RuntimeError("input 'eps' or 'pdf' expected")