pyx/epsfile.py

   1 #!/usr/bin/env python
   2 # -*- coding: ISO-8859-1 -*-
   3 #
   4 #
   5 # Copyright (C) 2002-2004 Jörg Lehmann <joergl@users.sourceforge.net>
   6 # Copyright (C) 2002-2004 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 import string
  25 import canvas, bbox, pykpathsea, unit, trafo, pswriter
  26
  27 # PostScript-procedure definitions (cf. 5002.EPSF_Spec_v3.0.pdf)
  28 # with important correction in EndEPSF:
  29 #   end operator is missing in the spec!
  30
  31 _BeginEPSF = pswriter.PSdefinition("BeginEPSF", """{
  32   /b4_Inc_state save def
  33   /dict_count countdictstack def
  34   /op_count count 1 sub def
  35   userdict begin
  36   /showpage { } def
  37   0 setgray 0 setlinecap
  38   1 setlinewidth 0 setlinejoin
  39   10 setmiterlimit [ ] 0 setdash newpath
  40   /languagelevel where
  41   {pop languagelevel
  42   1 ne
  43     {false setstrokeadjust false setoverprint
  44     } if
  45   } if
  46 } bind""")
  47
  48 _EndEPSF = pswriter.PSdefinition("EndEPSF", """{
  49   end
  50   count op_count sub {pop} repeat
  51   countdictstack dict_count sub {end} repeat
  52   b4_Inc_state restore
  53 } bind""")
  54
  55
  56 class linefilereader:
  57     """a line by line file reader
  58
  59     This line by line file reader allows for '\n', '\r' and
  60     '\r\n' as line separation characters. Line separation
  61     characters are not modified (binary mode). It implements
  62     a readline, a read and a close method similar to a regular
  63     file object."""
  64
  65     # note: '\n\r' is not considered to be a linebreak as its documented
  66     #       in the DSC spec #5001, while '\n\r' *is* a *single* linebreak
  67     #       according to the EPSF spec #5002
  68
  69     def __init__(self, filename, typicallinelen=257):
  70         """Opens the file filename for reading.
  71
  72         typicallinelen defines the default buffer increase
  73         to find the next linebreak."""
  74
  75         # note: The maximal line size in an EPS is 255 plus the
  76         #       linebreak characters. However, we also handle
  77         #       lines longer than that.
  78
  79         self.file = open(filename, "rb")
  80         self.buffer = ""
  81         self.typicallinelen = typicallinelen
  82
  83     def read(self, count=None, EOFmsg="unexpected end of file"):
  84         """read bytes from the file
  85
  86         count is the number of bytes to be read when set. Then count
  87         is unset, the rest of the file is returned. EOFmsg is used
  88         to raise a IOError, when the end of the file is reached while
  89         reading count bytes or when the rest of the file is empty when
  90         count is unset. When EOFmsg is set to None, less than the
  91         requested number of bytes might be returned."""
  92         if count is not None:
  93             if count > len(self.buffer):
  94                 self.buffer += self.file.read(count - len(self.buffer))
  95             if EOFmsg is not None and len(buffer) < count:
  96                 raise IOError(EOFmsg)
  97             result = self.buffer[:count]
  98             self.buffer = self.buffer[count:]
  99             return result
 100         else:
 101             self.buffer += self.file.read()
 102             if EOFmsg is not None and not len(self.buffer):
 103                 raise IOError(EOFmsg)
 104             result = self.buffer
 105             self.buffer = ""
 106             return result
 107
 108     def readline(self, EOFmsg="unexpected end of file"):
 109         """reads a line from the file
 110
 111         Lines are separated by '\n', '\r' or '\r\n'. The line separation
 112         strings are included in the return value. The last line might not
 113         end with an line separation string. Reading beyond the file generates
 114         an IOError with the EOFmsg message. When EOFmsg is None, an empty
 115         string is returned when reading beyond the end of the file."""
 116         EOF = 0
 117         while 1:
 118             crpos = self.buffer.find("\r")
 119             nlpos = self.buffer.find("\n")
 120             if nlpos == -1 and (crpos == -1 or crpos == len(self.buffer) - 1) and not EOF:
 121                 newbuffer = self.file.read(self.typicallinelen)
 122                 if not len(newbuffer):
 123                     EOF = 1
 124                 self.buffer += newbuffer
 125             else:
 126                 eol = len(self.buffer)
 127                 if not eol and EOFmsgo is not None:
 128                     raise IOError(EOFmsg)
 129                 if nlpos != -1:
 130                     eol = nlpos + 1
 131                 if crpos != -1 and crpos < nlpos - 1:
 132                     eol = crpos + 1
 133                 result = self.buffer[:eol]
 134                 self.buffer = self.buffer[eol:]
 135                 return result
 136
 137     def close(self):
 138         "closes the file"
 139         self.file.close()
 140
 141
 142 def _readbbox(filename):
 143     """returns bounding box of EPS file filename"""
 144
 145     file = linefilereader(filename)
 146
 147     # check the %! header comment
 148     if not file.readline().startswith("%!"):
 149         raise IOError("file doesn't start with a '%!' header comment")
 150
 151     bboxatend = 0
 152     # parse the header (use the first BoundingBox)
 153     while 1:
 154         line = file.readline()
 155         if not line:
 156             break
 157         if line.startswith("%%BoundingBox:") and not bboxatend:
 158             values = line.split(":", 1)[1].split()
 159             if values == ["(atend)"]:
 160                 bboxatend = 1
 161             else:
 162                 if len(values) != 4:
 163                     raise IOError("invalid number of bounding box values")
 164                 return bbox.bbox_pt(*map(int, values))
 165         elif (line.rstrip() == "%%EndComments" or
 166               (len(line) >= 2 and line[0] != "%" and line[1] not in string.whitespace)):
 167             # implicit end of comments section
 168             break
 169     if not bboxatend:
 170         raise IOError("no bounding box information found")
 171
 172     # parse the body
 173     nesting = 0 # allow for nested documents
 174     while 1:
 175         line = file.readline()
 176         if line.startswith("%%BeginData:"):
 177             values = line.split(":", 1)[1].split()
 178             if len(values) > 3:
 179                 raise IOError("invalid number of arguments")
 180             if len(values) == 3:
 181                 if values[2] == "Lines":
 182                     for i in xrange(int(values[0])):
 183                         file.readline()
 184                 elif values[2] != "Bytes":
 185                     raise IOError("invalid bytesorlines-value")
 186                 else:
 187                     file.read(int(values[0]))
 188             else:
 189                 file.read(int(values[0]))
 190             line = file.readline()
 191             # ignore tailing whitespace/newline for binary data
 192             if (len(values) < 3 or values[2] != "Lines") and not len(line.strip()):
 193                 line = file.readline()
 194             if line.rstrip() != "%%EndData":
 195                 raise IOError("missing EndData")
 196         elif line.startswith("%%BeginBinary:"):
 197             file.read(int(line.split(":", 1)[1]))
 198             line = file.readline()
 199             # ignore tailing whitespace/newline
 200             if not len(line.strip()):
 201                 line = file.readline()
 202             if line.rstrip() != "%%EndBinary":
 203                 raise IOError("missing EndBinary")
 204         elif line.startswith("%%BeginDocument:"):
 205             nesting += 1
 206         elif line.rstrip() == "%%EndDocument":
 207             if nesting < 1:
 208                 raise IOError("unmatched EndDocument")
 209             nesting -= 1
 210         elif not nesting and line.rstrip() == "%%Trailer":
 211             break
 212
 213     usebbox = None
 214     # parse the trailer (use the last BoundingBox)
 215     while 1:
 216         line = file.readline(EOFmsg=None)
 217         if line.startswith("%%BoundingBox:"):
 218             values = line.split(":", 1)[1].split()
 219             if len(values) != 4:
 220                 raise IOError("invalid number of bounding box values")
 221             usebbox = bbox.bbox_pt(*map(int, values))
 222     if not usebbox:
 223         raise IOError("missing bounding box information in document trailer")
 224     return usebbox
 225
 226
 227 class epsfile(canvas.canvasitem):
 228
 229     """class for epsfiles"""
 230
 231     def __init__(self,
 232                  x, y, filename,
 233                  width=None, height=None, scale=None, align="bl",
 234                  clip=1, translatebbox=1, bbox=None,
 235                  kpsearch=0):
 236         """inserts epsfile
 237
 238         Object for an EPS file named filename at position (x,y). Width, height,
 239         scale and aligment can be adjusted by the corresponding parameters. If
 240         clip is set, the result gets clipped to the bbox of the EPS file. If
 241         translatebbox is not set, the EPS graphics is not translated to the
 242         corresponding origin. If bbox is not None, it overrides the bounding
 243         box in the epsfile itself. If kpsearch is set then filename is searched
 244         using the kpathsea library.
 245         """
 246
 247         self.x_pt = unit.topt(x)
 248         self.y_pt = unit.topt(y)
 249         if kpsearch:
 250             self.filename = pykpathsea.find_file(filename, pykpathsea.kpse_pict_format)
 251         else:
 252             self.filename = filename
 253         self.mybbox = bbox or _readbbox(self.filename)
 254
 255         # determine scaling in x and y direction
 256         self.scalex = self.scaley = scale
 257
 258         if width is not None or height is not None:
 259             if scale is not None:
 260                 raise ValueError("cannot set both width and/or height and scale simultaneously")
 261             if height is not None:
 262                 self.scaley = unit.topt(height)/(self.mybbox.ury_pt-self.mybbox.lly_pt)
 263             if width is not None:
 264                 self.scalex = unit.topt(width)/(self.mybbox.urx_pt-self.mybbox.llx_pt)
 265
 266             if self.scalex is None:
 267                 self.scalex = self.scaley
 268             if self.scaley is None:
 269                 self.scaley = self.scalex
 270
 271         # set the actual width and height of the eps file (after a
 272         # possible scaling)
 273         self.width_pt  = self.mybbox.urx_pt-self.mybbox.llx_pt
 274         if self.scalex:
 275             self.width_pt *= self.scalex
 276
 277         self.height_pt = self.mybbox.ury_pt-self.mybbox.lly_pt
 278         if self.scaley:
 279             self.height_pt *= self.scaley
 280
 281         # take alignment into account
 282         self.align       = align
 283         if self.align[0]=="b":
 284             pass
 285         elif self.align[0]=="c":
 286             self.y_pt -= self.height_pt/2.0
 287         elif self.align[0]=="t":
 288             self.y_pt -= self.height_pt
 289         else:
 290             raise ValueError("vertical alignment can only be b (bottom), c (center), or t (top)")
 291
 292         if self.align[1]=="l":
 293             pass
 294         elif self.align[1]=="c":
 295             self.x_pt -= self.width_pt/2.0
 296         elif self.align[1]=="r":
 297             self.x_pt -= self.width_pt
 298         else:
 299             raise ValueError("horizontal alignment can only be l (left), c (center), or r (right)")
 300
 301         self.clip = clip
 302         self.translatebbox = translatebbox
 303
 304         self.trafo = trafo.translate_pt(self.x_pt, self.y_pt)
 305
 306         if self.scalex is not None:
 307             self.trafo = self.trafo * trafo.scale_pt(self.scalex, self.scaley)
 308
 309         if translatebbox:
 310             self.trafo = self.trafo * trafo.translate_pt(-self.mybbox.llx_pt, -self.mybbox.lly_pt)
 311
 312     def bbox(self):
 313         return self.mybbox.transformed(self.trafo)
 314
 315     def registerPS(self, registry):
 316         registry.add(_BeginEPSF)
 317         registry.add(_EndEPSF)
 318
 319     def outputPS(self, file, writer, context):
 320         try:
 321             epsfile=open(self.filename,"rb")
 322         except:
 323             raise IOError, "cannot open EPS file '%s'" % self.filename
 324
 325         file.write("BeginEPSF\n")
 326
 327         bbrect = self.mybbox.rect().transformed(self.trafo)
 328
 329         if self.clip:
 330             file.write("newpath\n")
 331             bbrect.outputPS(file, writer, context)
 332             file.write("clip\n")
 333
 334         self.trafo.outputPS(file, writer, context)
 335
 336         file.write("%%%%BeginDocument: %s\n" % self.filename)
 337         file.write(epsfile.read())
 338         file.write("%%EndDocument\n")
 339         file.write("EndEPSF\n")