pyx/base.py

   1 #!/usr/bin/env python
   2 # -*- coding: ISO-8859-1 -*-
   3 #
   4 #
   5 # Copyright (C) 2002 Jörg Lehmann <joergl@users.sourceforge.net>
   6 # Copyright (C) 2002 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 #
  25 # Postscript operators
  26 #
  27
  28 class PSOp:
  29
  30     """Poscript Operators
  31
  32     Everything, you can write in a (E)PS file
  33
  34     """
  35
  36     def write(self, file):
  37         """writing into a file is the only routine, a PSOp has to supply"""
  38         raise NotImplementedError, "cannot call virtual method write()"
  39
  40     def prolog(self):
  41         """return list of prolog items"""
  42         return []
  43
  44 #
  45 # PSCmd class
  46 #
  47
  48 class PSCmd(PSOp):
  49
  50     """ PSCmd is the base class of all visible elements
  51
  52     Visible elements are those, that can be embedded in the Canvas
  53     and posses a bbox.
  54
  55     """
  56
  57     def bbox(self):
  58         raise NotImplementedError, "cannot call virtual method bbox()"
  59
  60 #
  61 # PyX Exception class
  62 #
  63
  64 class PyXExcept(Exception):
  65
  66     """base class for all PyX Exceptions"""
  67
  68     pass