pyx/unit.py

   1 #!/usr/bin/env python
   2 #
   3 #
   4 # Copyright (C) 2002, 2003 Jörg Lehmann <joergl@users.sourceforge.net>
   5 # Copyright (C) 2002, 2003 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  22
  23 import types
  24 import re
  25 import helper
  26
  27 unit_ps = 1.0
  28
  29 scale = { 't':1, 'u':1, 'v':1, 'w':1 }
  30
  31 _default_unit = "cm"
  32
  33 unit_pattern = re.compile(r"""^\s*([+-]?\d*((\d\.?)|(\.?\d))\d*(E[+-]?\d+)?)
  34                               (\s+([t-w]))?
  35                               (\s+(([a-z][a-z]+)|[^t-w]))?\s*$""",
  36                           re.IGNORECASE | re.VERBOSE)
  37
  38
  39 _m = {
  40       'm' :   1,
  41       'cm':   0.01,
  42       'mm':   0.001,
  43       'inch': 0.01*2.54,
  44       'pt':   0.01*2.54/72,
  45     }
  46
  47 def set(uscale=None, vscale=None, wscale=None, defaultunit=None):
  48     if uscale:
  49         scale['u'] = uscale
  50     if vscale:
  51         scale['v'] = vscale
  52     if wscale:
  53         scale['w'] = wscale
  54     if defaultunit:
  55         global _default_unit
  56         _default_unit = defaultunit
  57
  58
  59 def _convert_to(l, dest_unit="m"):
  60     if type(l) in (types.IntType, types.LongType, types.FloatType):
  61         return l*_m[_default_unit]*scale['u']/_m[dest_unit]
  62     elif not isinstance(l, length):
  63         l=length(l)       # convert to length instance if necessary
  64
  65     return ( l.length['t']            +
  66              l.length['u']*scale['u'] +
  67              l.length['v']*scale['v'] +
  68              l.length['w']*scale['w'] ) / _m[dest_unit]
  69
  70 def tom(l):
  71     return _convert_to(l, "m")
  72
  73 def tocm(l):
  74     return _convert_to(l, "cm")
  75
  76 def tomm(l):
  77     return _convert_to(l, "mm")
  78
  79 def toinch(l):
  80     return _convert_to(l, "inch")
  81
  82 def topt(l):
  83     return _convert_to(l, "pt")
  84
  85 ################################################################################
  86 # class for generic length
  87 ################################################################################
  88
  89 class length:
  90     """ general lengths
  91
  92     Lengths can either be a initialized with a number or a string:
  93
  94      - a length specified as a number corresponds to the default values of
  95        unit_type and unit_name
  96      - a string has to consist of a maximum of three parts:
  97        -quantifier: integer/float value
  98        -unit_type:  "t", "u", "v", or "w".
  99                     Optional, defaults to "u"
 100        -unit_name:  "m", "cm", "mm", "inch", "pt".
 101                     Optional, defaults to _default_unit
 102
 103     Internally all length are stored in units of m as a quadruple of the four
 104     unit_types.
 105
 106     """
 107
 108     def __init__(self, l=1, default_type="u", dunit=None):
 109         self.length = { 't': 0 , 'u': 0, 'v': 0, 'v':0, 'w':0 }
 110
 111         if isinstance(l, length):
 112             self.length = l.length
 113         elif helper.isstring(l):
 114             unit_match = re.match(unit_pattern, l)
 115             if unit_match is None:
 116                 assert 0, "expecting number or string of the form 'number [u|v|w] unit'"
 117             else:
 118                 self.prefactor = float(unit_match.group(1))
 119                 self.unit_type = unit_match.group(7) or default_type
 120                 self.unit_name = unit_match.group(9) or dunit or _default_unit
 121
 122                 self.length[self.unit_type] = self.prefactor*_m[self.unit_name]
 123         elif helper.isnumber(l):
 124             self.length[default_type] = l*_m[dunit or _default_unit]
 125         else:
 126             raise ( NotImplementedError,
 127                     "cannot convert given argument to length type" )
 128
 129     def __mul__(self, factor):
 130         newlength = self.__class__()
 131         for unit_type in newlength.length.keys():
 132            newlength.length[unit_type] = self.length[unit_type]*factor
 133         return newlength
 134
 135     __rmul__=__mul__
 136
 137     def __div__(self, factor):
 138         newlength = self.__class__()
 139         for unit_type in newlength.length.keys():
 140            newlength.length[unit_type] = self.length[unit_type]/factor
 141         return newlength
 142
 143     def __add__(self, l):
 144         # convert to length if necessary
 145         ll = length(l)
 146         newlength = self.__class__()
 147         for unit_type in newlength.length.keys():
 148            newlength.length[unit_type] = self.length[unit_type] + ll.length[unit_type]
 149         return newlength
 150
 151     __radd__=__add__
 152
 153     def __sub__(self, l):
 154         # convert to length if necessary
 155         ll = length(l)
 156         newlength = self.__class__()
 157         for unit_type in newlength.length.keys():
 158            newlength.length[unit_type] = self.length[unit_type] - ll.length[unit_type]
 159         return newlength
 160
 161     def __rsub__(self, l):
 162         # convert to length if necessary
 163         ll = length(l)
 164         newlength = self.__class__()
 165         for unit_type in newlength.length.keys():
 166            newlength.length[unit_type] = ll.length[unit_type] - self.length[unit_type]
 167         return newlength
 168
 169     def __neg__(self):
 170         newlength = self.__class__()
 171         for unit_type in newlength.length.keys():
 172            newlength.length[unit_type] = -self.length[unit_type]
 173         return newlength
 174
 175     def __str__(self):
 176         return "(%(t)f t + %(u)f u + %(v)f v + %(w)f w) m" % self.length
 177
 178
 179 ################################################################################
 180 # class for more specialized lengths
 181 ################################################################################
 182
 183 # lengths with user units as default
 184
 185 class u_pt(length):
 186     def __init__(self, l=1, default_type="u"):
 187        length.__init__(self, l, default_type=default_type, dunit="pt")
 188
 189
 190 class u_m(length):
 191     def __init__(self, l=1, default_type="u"):
 192        length.__init__(self, l, default_type=default_type, dunit="m")
 193
 194
 195 class u_mm(length):
 196     def __init__(self, l=1, default_type="u"):
 197        length.__init__(self, l, default_type=default_type, dunit="mm")
 198
 199
 200 class u_cm(length):
 201     def __init__(self, l=1, default_type="u"):
 202        length.__init__(self, l, default_type=default_type, dunit="cm")
 203
 204
 205 class u_inch(length):
 206     def __init__(self, l=1, default_type="u"):
 207        length.__init__(self, l, default_type=default_type, dunit="inch")
 208
 209 # without further specification, length are user length. Hence we
 210 # define the following aliases
 211
 212 pt = u_pt
 213 m = u_m
 214 cm = u_cm
 215 mm = u_mm
 216 inch = u_inch
 217
 218 # true lengths
 219
 220 class t_pt(length):
 221     def __init__(self, l=1):
 222        length.__init__(self, l, default_type="t", dunit="pt")
 223
 224
 225 class t_m(length):
 226     def __init__(self, l=1):
 227        length.__init__(self, l, default_type="t", dunit="m")
 228
 229
 230 class t_cm(length):
 231     def __init__(self, l=1):
 232        length.__init__(self, l, default_type="t", dunit="cm")
 233
 234
 235 class t_mm(length):
 236     def __init__(self, l=1):
 237        length.__init__(self, l, default_type="t", dunit="mm")
 238
 239
 240 class t_inch(length):
 241     def __init__(self, l=1):
 242        length.__init__(self, l, default_type="t", dunit="inch")
 243
 244 # visual lengths
 245
 246 class v_pt(length):
 247     def __init__(self, l=1):
 248        length.__init__(self, l, default_type="v", dunit="pt")
 249
 250
 251 class v_m(length):
 252     def __init__(self, l=1):
 253        length.__init__(self, l, default_type="v", dunit="m")
 254
 255
 256 class v_cm(length):
 257     def __init__(self, l=1):
 258        length.__init__(self, l, default_type="v", dunit="cm")
 259
 260
 261 class v_mm(length):
 262     def __init__(self, l=1):
 263        length.__init__(self, l, default_type="v", dunit="mm")
 264
 265
 266 class v_inch(length):
 267     def __init__(self, l=1):
 268        length.__init__(self, l, default_type="v", dunit="inch")
 269
 270 # width lengths
 271
 272 class w_pt(length):
 273     def __init__(self, l=1):
 274        length.__init__(self, l, default_type="w", dunit="pt")
 275
 276
 277 class w_m(length):
 278     def __init__(self, l=1):
 279        length.__init__(self, l, default_type="w", dunit="m")
 280
 281
 282 class w_cm(length):
 283     def __init__(self, l=1):
 284        length.__init__(self, l, default_type="w", dunit="cm")
 285
 286
 287 class w_mm(length):
 288     def __init__(self, l=1):
 289        length.__init__(self, l, default_type="w", dunit="mm")
 290
 291
 292 class w_inch(length):
 293     def __init__(self, l=1):
 294        length.__init__(self, l, default_type="w", dunit="inch")