pyx/unit.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 import copy
  25 import types
  26 import helper
  27
  28 scale = { 't':1, 'u':1, 'v':1, 'w':1, 'x':1 }
  29
  30 _default_unit = "cm"
  31
  32 _m = {
  33       'm' :   1,
  34       'cm':   0.01,
  35       'mm':   0.001,
  36       'inch': 0.01*2.54,
  37       'pt':   0.01*2.54/72,
  38     }
  39
  40 def set(uscale=None, vscale=None, wscale=None, xscale=None, defaultunit=None):
  41     if uscale is not None:
  42         scale['u'] = uscale
  43     if vscale is not None:
  44         scale['v'] = vscale
  45     if wscale is not None:
  46         scale['w'] = wscale
  47     if xscale is not None:
  48         scale['x'] = xscale
  49     if defaultunit is not None:
  50         global _default_unit
  51         _default_unit = defaultunit
  52
  53
  54 def _convert_to(l, dest_unit="m"):
  55     if type(l) in (types.IntType, types.LongType, types.FloatType):
  56         return l * _m[_default_unit] * scale['u'] / _m[dest_unit]
  57     elif not isinstance(l, length):
  58         l = length(l)       # convert to length instance if necessary
  59
  60     return (l.t + l.u*scale['u'] + l.v*scale['v'] + l.w*scale['w'] + l.x*scale['x']) / _m[dest_unit]
  61
  62 def tom(l):
  63     return _convert_to(l, "m")
  64
  65 def tocm(l):
  66     return _convert_to(l, "cm")
  67
  68 def tomm(l):
  69     return _convert_to(l, "mm")
  70
  71 def toinch(l):
  72     return _convert_to(l, "inch")
  73
  74 def topt(l):
  75     return _convert_to(l, "pt")
  76
  77 ################################################################################
  78 # class for generic length
  79 ################################################################################
  80
  81 class length:
  82     """ general lengths
  83
  84     XXX write me
  85
  86     """
  87
  88     def __init__(self, f, type="u", unit=None):
  89         self.t = self.u = self.v = self.w = self.x = 0
  90         l = f * _m[unit or _default_unit]
  91         if type == "t":
  92             self.t = l
  93         elif type == "u":
  94             self.u = l
  95         elif type == "v":
  96             self.v = l
  97         elif type == "w":
  98             self.w = l
  99         elif type == "x":
 100             self.x = l
 101
 102     def __cmp__(self, other):
 103         return cmp(tom(self), tom(other))
 104
 105     def __mul__(self, factor):
 106         result = copy.copy(self)
 107         result.t *= factor
 108         result.u *= factor
 109         result.v *= factor
 110         result.w *= factor
 111         result.x *= factor
 112         return result
 113
 114     __rmul__=__mul__
 115
 116     def __div__(self, factor):
 117         result = copy.copy(self)
 118         result.t /= factor
 119         result.u /= factor
 120         result.v /= factor
 121         result.w /= factor
 122         result.x /= factor
 123         return result
 124
 125     def __add__(self, other):
 126         # convert to length if necessary
 127         if not isinstance(other, length):
 128             other = length(other)
 129         result = copy.copy(self)
 130         result.t += other.t
 131         result.u += other.u
 132         result.v += other.v
 133         result.w += other.w
 134         result.x += other.x
 135         return result
 136
 137     __radd__=__add__
 138
 139     def __sub__(self, other):
 140         # convert to length if necessary
 141         if not isinstance(other, length):
 142             other = length(other)
 143         result = copy.copy(self)
 144         result.t -= other.t
 145         result.u -= other.u
 146         result.v -= other.v
 147         result.w -= other.w
 148         result.x -= other.x
 149         return result
 150
 151     def __rsub__(self, other):
 152         # convert to length if necessary
 153         if not isinstance(other, length):
 154             other = length(other)
 155         result = copy.copy(self)
 156         result.t = other.t - self.t
 157         result.u = other.u - self.u
 158         result.v = other.v - self.v
 159         result.w = other.w - self.w
 160         result.x = other.x - self.x
 161         return result
 162
 163     def __neg__(self):
 164         result = copy.copy(self)
 165         result.t *= -1
 166         result.u *= -1
 167         result.v *= -1
 168         result.w *= -1
 169         result.x *= -1
 170         return result
 171
 172     def __str__(self):
 173         return "(%(t)f t + %(u)f u + %(v)f v + %(w)f w + %(x)f x) m" % self.length.__dict__
 174
 175
 176 ################################################################################
 177 # predefined instances which can be used as length units
 178 ################################################################################
 179
 180 # user lengths and unqualified length which are also user length
 181 u_pt   = pt   = length(1, type="u", unit="pt")
 182 u_m    = m    = length(1, type="u", unit="m")
 183 u_mm   = mm   = length(1, type="u", unit="mm")
 184 u_cm   = cm   = length(1, type="u", unit="cm")
 185 u_inch = inch = length(1, type="u", unit="inch")
 186
 187 # true lengths
 188 t_pt   = length(1, type="t", unit="pt")
 189 t_m    = length(1, type="t", unit="m")
 190 t_mm   = length(1, type="t", unit="mm")
 191 t_cm   = length(1, type="t", unit="cm")
 192 t_inch = length(1, type="t", unit="inch")
 193
 194 # visual lengths
 195 v_pt   = length(1, type="v", unit="pt")
 196 v_m    = length(1, type="v", unit="m")
 197 v_mm   = length(1, type="v", unit="mm")
 198 v_cm   = length(1, type="v", unit="cm")
 199 v_inch = length(1, type="v", unit="inch")
 200
 201 # width lengths
 202 w_pt   = length(1, type="w", unit="pt")
 203 w_m    = length(1, type="w", unit="m")
 204 w_mm   = length(1, type="w", unit="mm")
 205 w_cm   = length(1, type="w", unit="cm")
 206 w_inch = length(1, type="w", unit="inch")
 207
 208 # TeX lengths
 209 x_pt   = length(1, type="x", unit="pt")
 210 x_m    = length(1, type="x", unit="m")
 211 x_mm   = length(1, type="x", unit="mm")
 212 x_cm   = length(1, type="x", unit="cm")
 213 x_inch = length(1, type="x", unit="inch")