pyx/base.py

   1 #!/usr/bin/env python
   2 #
   3 #
   4 # Copyright (C) 2002 Jörg Lehmann <joergl@users.sourceforge.net>
   5 # Copyright (C) 2002 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22
  23 #
  24 # Postscript operators
  25 #
  26
  27 class PSOp:
  28
  29     """Poscript Operators
  30
  31     Everything, you can write in a (E)PS file
  32
  33     """
  34
  35     def write(self, file):
  36         """writing into a file is the only routine, a PSOp has to supply"""
  37         raise NotImplementedError, "cannot call virtual method write()"
  38
  39 #
  40 # PSCmd class
  41 #
  42
  43 class PSCmd(PSOp):
  44
  45     """ PSCmd is the base class of all visible elements
  46
  47     Visible elements are those, that can be embedded in the Canvas
  48     and posses a bbox.
  49
  50     """
  51
  52     def bbox(self):
  53         raise NotImplementedError, "cannot call virtual method bbox()"
  54
  55 #
  56 # PSText class
  57 #
  58
  59 class PSText(PSCmd):
  60
  61     """ PSText is the base class of all text elements
  62
  63     Text elements are those, that (may) contain text and thus provide a
  64     writefontheader method.
  65
  66     """
  67
  68     def writefontheader(self, file, containsfonts):
  69         raise NotImplementedError, "cannot call virtual method writefontheader()"
  70
  71 #
  72 # Path style classes
  73 #
  74 # note that as usual in PyX most classes have default instances as members
  75
  76 class PathStyle(PSOp):
  77
  78     """style modifiers for paths
  79     """
  80
  81
  82     pass
  83
  84
  85
  86 #
  87 # PyX Exception class
  88 #
  89
  90 class PyXExcept(Exception):
  91
  92     """base class for all PyX Exceptions"""
  93
  94     pass