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