pyx/unit.py

   1 #!/usr/bin/env python
   2 # -*- coding: ISO-8859-1 -*-
   3 #
   4 #
   5 # Copyright (C) 2002, 2003 Jörg Lehmann <joergl@users.sourceforge.net>
   6 # Copyright (C) 2002, 2003 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 import types
  25 import re
  26 import helper
  27
  28 unit_ps = 1.0
  29
  30 scale = { 't':1, 'u':1, 'v':1, 'w':1 }
  31
  32 _default_unit = "cm"
  33
  34 unit_pattern = re.compile(r"""^\s*([+-]?\d*((\d\.?)|(\.?\d))\d*(E[+-]?\d+)?)
  35                               (\s+([t-w]))?
  36                               (\s+(([a-z][a-z]+)|[^t-w]))?\s*$""",
  37                           re.IGNORECASE | re.VERBOSE)
  38
  39
  40 _m = {
  41       'm' :   1,
  42       'cm':   0.01,
  43       'mm':   0.001,
  44       'inch': 0.01*2.54,
  45       'pt':   0.01*2.54/72,
  46     }
  47
  48 def set(uscale=None, vscale=None, wscale=None, defaultunit=None):
  49     if uscale:
  50         scale['u'] = uscale
  51     if vscale:
  52         scale['v'] = vscale
  53     if wscale:
  54         scale['w'] = wscale
  55     if defaultunit:
  56         global _default_unit
  57         _default_unit = defaultunit
  58
  59
  60 def _convert_to(l, dest_unit="m"):
  61     if type(l) in (types.IntType, types.LongType, types.FloatType):
  62         return l*_m[_default_unit]*scale['u']/_m[dest_unit]
  63     elif not isinstance(l, length):
  64         l=length(l)       # convert to length instance if necessary
  65
  66     return ( l.length['t']            +
  67              l.length['u']*scale['u'] +
  68              l.length['v']*scale['v'] +
  69              l.length['w']*scale['w'] ) / _m[dest_unit]
  70
  71 def tom(l):
  72     return _convert_to(l, "m")
  73
  74 def tocm(l):
  75     return _convert_to(l, "cm")
  76
  77 def tomm(l):
  78     return _convert_to(l, "mm")
  79
  80 def toinch(l):
  81     return _convert_to(l, "inch")
  82
  83 def topt(l):
  84     return _convert_to(l, "pt")
  85
  86 ################################################################################
  87 # class for generic length
  88 ################################################################################
  89
  90 class length:
  91     """ general lengths
  92
  93     Lengths can either be a initialized with a number or a string:
  94
  95      - a length specified as a number corresponds to the default values of
  96        unit_type and unit_name
  97      - a string has to consist of a maximum of three parts:
  98        -quantifier: integer/float value
  99        -unit_type:  "t", "u", "v", or "w".
 100                     Optional, defaults to "u"
 101        -unit_name:  "m", "cm", "mm", "inch", "pt".
 102                     Optional, defaults to _default_unit
 103
 104     Internally all length are stored in units of m as a quadruple of the four
 105     unit_types.
 106
 107     """
 108
 109     def __init__(self, l=1, default_type="u", dunit=None):
 110         self.length = { 't': 0 , 'u': 0, 'v': 0, 'v':0, 'w':0 }
 111
 112         if isinstance(l, length):
 113             self.length = l.length
 114         elif helper.isstring(l):
 115             unit_match = re.match(unit_pattern, l)
 116             if unit_match is None:
 117                 raise ValueError("expecting number or string of the form 'number [u|v|w] unit'")
 118             else:
 119                 self.prefactor = float(unit_match.group(1))
 120                 self.unit_type = unit_match.group(7) or default_type
 121                 self.unit_name = unit_match.group(9) or dunit or _default_unit
 122
 123                 self.length[self.unit_type] = self.prefactor*_m[self.unit_name]
 124         elif helper.isnumber(l):
 125             self.length[default_type] = l*_m[dunit or _default_unit]
 126         else:
 127             raise ( NotImplementedError,
 128                     "cannot convert given argument to length type" )
 129
 130     def __mul__(self, factor):
 131         newlength = self.__class__()
 132         for unit_type in newlength.length.keys():
 133            newlength.length[unit_type] = self.length[unit_type]*factor
 134         return newlength
 135
 136     __rmul__=__mul__
 137
 138     def __div__(self, factor):
 139         newlength = self.__class__()
 140         for unit_type in newlength.length.keys():
 141            newlength.length[unit_type] = self.length[unit_type]/factor
 142         return newlength
 143
 144     def __add__(self, l):
 145         # convert to length if necessary
 146         ll = length(l)
 147         newlength = self.__class__()
 148         for unit_type in newlength.length.keys():
 149            newlength.length[unit_type] = self.length[unit_type] + ll.length[unit_type]
 150         return newlength
 151
 152     __radd__=__add__
 153
 154     def __sub__(self, l):
 155         # convert to length if necessary
 156         ll = length(l)
 157         newlength = self.__class__()
 158         for unit_type in newlength.length.keys():
 159            newlength.length[unit_type] = self.length[unit_type] - ll.length[unit_type]
 160         return newlength
 161
 162     def __rsub__(self, l):
 163         # convert to length if necessary
 164         ll = length(l)
 165         newlength = self.__class__()
 166         for unit_type in newlength.length.keys():
 167            newlength.length[unit_type] = ll.length[unit_type] - self.length[unit_type]
 168         return newlength
 169
 170     def __neg__(self):
 171         newlength = self.__class__()
 172         for unit_type in newlength.length.keys():
 173            newlength.length[unit_type] = -self.length[unit_type]
 174         return newlength
 175
 176     def __str__(self):
 177         return "(%(t)f t + %(u)f u + %(v)f v + %(w)f w) m" % self.length
 178
 179
 180 ################################################################################
 181 # class for more specialized lengths
 182 ################################################################################
 183
 184 # lengths with user units as default
 185
 186 class u_pt(length):
 187     def __init__(self, l=1, default_type="u"):
 188        length.__init__(self, l, default_type=default_type, dunit="pt")
 189
 190
 191 class u_m(length):
 192     def __init__(self, l=1, default_type="u"):
 193        length.__init__(self, l, default_type=default_type, dunit="m")
 194
 195
 196 class u_mm(length):
 197     def __init__(self, l=1, default_type="u"):
 198        length.__init__(self, l, default_type=default_type, dunit="mm")
 199
 200
 201 class u_cm(length):
 202     def __init__(self, l=1, default_type="u"):
 203        length.__init__(self, l, default_type=default_type, dunit="cm")
 204
 205
 206 class u_inch(length):
 207     def __init__(self, l=1, default_type="u"):
 208        length.__init__(self, l, default_type=default_type, dunit="inch")
 209
 210 # without further specification, length are user length. Hence we
 211 # define the following aliases
 212
 213 pt = u_pt
 214 m = u_m
 215 cm = u_cm
 216 mm = u_mm
 217 inch = u_inch
 218
 219 # true lengths
 220
 221 class t_pt(length):
 222     def __init__(self, l=1):
 223        length.__init__(self, l, default_type="t", dunit="pt")
 224
 225
 226 class t_m(length):
 227     def __init__(self, l=1):
 228        length.__init__(self, l, default_type="t", dunit="m")
 229
 230
 231 class t_cm(length):
 232     def __init__(self, l=1):
 233        length.__init__(self, l, default_type="t", dunit="cm")
 234
 235
 236 class t_mm(length):
 237     def __init__(self, l=1):
 238        length.__init__(self, l, default_type="t", dunit="mm")
 239
 240
 241 class t_inch(length):
 242     def __init__(self, l=1):
 243        length.__init__(self, l, default_type="t", dunit="inch")
 244
 245 # visual lengths
 246
 247 class v_pt(length):
 248     def __init__(self, l=1):
 249        length.__init__(self, l, default_type="v", dunit="pt")
 250
 251
 252 class v_m(length):
 253     def __init__(self, l=1):
 254        length.__init__(self, l, default_type="v", dunit="m")
 255
 256
 257 class v_cm(length):
 258     def __init__(self, l=1):
 259        length.__init__(self, l, default_type="v", dunit="cm")
 260
 261
 262 class v_mm(length):
 263     def __init__(self, l=1):
 264        length.__init__(self, l, default_type="v", dunit="mm")
 265
 266
 267 class v_inch(length):
 268     def __init__(self, l=1):
 269        length.__init__(self, l, default_type="v", dunit="inch")
 270
 271 # width lengths
 272
 273 class w_pt(length):
 274     def __init__(self, l=1):
 275        length.__init__(self, l, default_type="w", dunit="pt")
 276
 277
 278 class w_m(length):
 279     def __init__(self, l=1):
 280        length.__init__(self, l, default_type="w", dunit="m")
 281
 282
 283 class w_cm(length):
 284     def __init__(self, l=1):
 285        length.__init__(self, l, default_type="w", dunit="cm")
 286
 287
 288 class w_mm(length):
 289     def __init__(self, l=1):
 290        length.__init__(self, l, default_type="w", dunit="mm")
 291
 292
 293 class w_inch(length):
 294     def __init__(self, l=1):
 295        length.__init__(self, l, default_type="w", dunit="inch")