pyx/bbox.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 # TODO: - it would be nice to have a real bbox.transform
  25 #       - what about __iadd__, ...
  26
  27 import math
  28 import unit
  29
  30 # helper routine for bbox manipulations
  31
  32 def _nmin(*args):
  33     """minimum of a list of values, where None represents +infinity, not -infinity as
  34     in standard min implementation of python"""
  35     args = [x for x in args if x is not None]
  36     if len(args):
  37         return min(args)
  38     else:
  39         return None
  40
  41 def _nmax(*args):
  42     """maximum of a list of values, where None represents +infinity, not -infinity as
  43     in standard max implementation of python 2.0"""
  44     args = [x for x in args if x is not None]
  45     if len(args):
  46         return max(args)
  47     else:
  48         return None
  49
  50 #
  51 # classes representing bounding boxes
  52 #
  53
  54 class _bbox:
  55
  56     """class for bounding boxes
  57
  58     This variant requires points in the constructor, and is used for internal
  59     purposes."""
  60
  61     def __init__(self, llx=None, lly=None, urx=None, ury=None):
  62         self.llx = llx
  63         self.lly = lly
  64         self.urx = urx
  65         self.ury = ury
  66
  67     def __add__(self, other):
  68         """join two bboxes"""
  69
  70         return _bbox(_nmin(self.llx, other.llx), _nmin(self.lly, other.lly),
  71                      _nmax(self.urx, other.urx), _nmax(self.ury, other.ury))
  72
  73     def __mul__(self, other):
  74         """return intersection of two bboxes"""
  75
  76         return _bbox(_nmax(self.llx, other.llx), _nmax(self.lly, other.lly),
  77                      _nmin(self.urx, other.urx), _nmin(self.ury, other.ury))
  78
  79     def __str__(self):
  80         return "%s %s %s %s" % (self.llx, self.lly, self.urx, self.ury)
  81
  82     def write(self, file):
  83         file.write("%%%%BoundingBox: %d %d %d %d\n" %
  84                    (math.floor(self.llx), math.floor(self.lly),
  85                     math.ceil(self.urx), math.ceil(self.ury)))
  86         file.write("%%%%HiResBoundingBox: %g %g %g %g\n" %
  87                    (self.llx, self.lly, self.urx, self.ury))
  88
  89     def intersects(self, other):
  90         """check, if two bboxes intersect eachother"""
  91
  92         return not (self.llx > other.urx or
  93                     self.lly > other.ury or
  94                     self.urx < other.llx or
  95                     self.ury < other.lly)
  96
  97     def transformed(self, trafo):
  98         """return bbox transformed by trafo"""
  99         # we have to transform all four corner points of the bbox
 100         # method correctly handles bboxes with None entries at the corners
 101         if None not in (self.llx, self.lly):
 102             llx, lly = trafo._apply(self.llx, self.lly)
 103         else:
 104             llx = lly = None
 105         if None not in (self.urx, self.lly):
 106             lrx, lry = trafo._apply(self.urx, self.lly)
 107         else:
 108             lrx = lry = None
 109         if None not in (self.urx, self.ury):
 110             urx, ury = trafo._apply(self.urx, self.ury)
 111         else:
 112             urx = ury = None
 113         if None not in (self.llx, self.ury):
 114             ulx, uly = trafo._apply(self.llx, self.ury)
 115         else:
 116             ulx = uly = None
 117
 118         # now, by sorting, we obtain the lower left and upper right corner
 119         # of the new bounding box.
 120
 121         return _bbox(_nmin(llx, lrx, urx, ulx), _nmin(lly, lry, ury, uly),
 122                      _nmax(llx, lrx, urx, ulx), _nmax(lly, lry, ury, uly))
 123
 124     def enlarged(self, all=0, bottom=None, left=None, top=None, right=None):
 125         """return bbox enlarged
 126
 127         all is used, if bottom, left, top and/or right are not given.
 128
 129         """
 130         _bottom = _left = _top = _right = unit.topt(unit.length(all, default_type="v"))
 131         if bottom is not None:
 132            _bottom = unit.topt(unit.length(bottom, default_type="v"))
 133         if left is not None:
 134            _left = unit.topt(unit.length(left, default_type="v"))
 135         if top is not None:
 136            _top = unit.topt(unit.length(top, default_type="v"))
 137         if right is not None:
 138            _right = unit.topt(unit.length(right, default_type="v"))
 139         return _bbox(self.llx-_left, self.lly-_bottom, self.urx+_right, self.ury+_top)
 140
 141     def rect(self):
 142         """return rectangle corresponding to bbox"""
 143         import path
 144         return path.rect_pt(self.llx, self.lly, self.urx-self.llx, self.ury-self.lly)
 145
 146     path = rect
 147
 148     def height(self):
 149         """return height of bbox"""
 150         return unit.t_pt(self.ury-self.lly)
 151
 152     def width(self):
 153         """return width of bbox"""
 154         return unit.t_pt(self.urx-self.llx)
 155
 156     def top(self):
 157         """return top coordinate of bbox"""
 158         return unit.t_pt(self.ury)
 159
 160     def bottom(self):
 161         """return bottom coordinate of bbox"""
 162         return unit.t_pt(self.lly)
 163
 164     def left(self):
 165         """return left coordinate of bbox"""
 166         return unit.t_pt(self.llx)
 167
 168     def right(self):
 169         """return right coordinate of bbox"""
 170         return unit.t_pt(self.urx)
 171
 172
 173 class bbox(_bbox):
 174
 175     """class for bounding boxes"""
 176
 177     def __init__(self, llx=None, lly=None, urx=None, ury=None):
 178         if llx is not None:
 179             llx = unit.topt(llx)
 180         if lly is not None:
 181             lly = unit.topt(lly)
 182         if urx is not None:
 183             urx = unit.topt(urx)
 184         if ury is not None:
 185             ury = unit.topt(ury)
 186         _bbox.__init__(self, llx, lly, urx, ury)
 187