baseclasses.py

   1 # -*- encoding: utf-8 -*-
   2 #
   3 #
   4 # Copyright (C) 2002-2007 Jörg Lehmann <joergl@users.sourceforge.net>
   5 # Copyright (C) 2002-2007 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 from . import attr
  24
  25 class canvasitem:
  26
  27     """Base class for everything which can be inserted into a canvas"""
  28
  29     def bbox(self):
  30         """return bounding box of canvasitem"""
  31         raise NotImplementedError()
  32
  33     def requiretextregion(self):
  34         """indicates whether a canvasitem needs to be part of a PDF text
  35         region"""
  36         return False
  37
  38     def processPS(self, file, writer, context, registry, bbox):
  39         """process canvasitem by writing the corresponding PS code to file and
  40         by updating context, registry as well as bbox
  41
  42         - the PS code corresponding to the canvasitem has to be written in the
  43           stream file, which provides a write(string) method
  44         - writer is the PSwriter used for the output
  45         - context is an instance of pswriter.context which is used for keeping
  46           track of the graphics state (current linewidth, colorspace and font,
  47           etc.)
  48         - registry is used for tracking resources needed by the canvasitem
  49         - bbox has to be updated to include the bounding box of the canvasitem
  50         """
  51         raise NotImplementedError()
  52
  53     def processPDF(self, file, writer, context, registry, bbox):
  54         """process canvasitem by writing the corresponding PDF code to file and
  55         by updating context, registry as well as bbox
  56
  57         - the PDF code corresponding to the canvasitem has to be written in the
  58           stream file, which provides a write(string) method
  59         - writer is the PDFwriter used for the output, which contains properties
  60           like whether streamcompression is used
  61         - context is an instance of pdfwriter.context which is used for keeping
  62           track of the graphics state, in particular for the emulation of PS
  63           behaviour regarding fill and stroke styles, for keeping track of the
  64           currently selected font as well as of text regions.
  65         - registry is used for tracking resources needed by the canvasitem
  66         - bbox has to be updated to include the bounding box of the canvasitem
  67         """
  68         raise NotImplementedError()
  69
  70
  71 class deformer(attr.attr):
  72
  73     def deform (self, basepath):
  74         raise NotImplementedError()
  75