pyx/graph/axis/tick.py

   1 # -*- encoding: utf-8 -*-
   2 #
   3 #
   4 # Copyright (C) 2002-2004 Jörg Lehmann <joergl@users.sourceforge.net>
   5 # Copyright (C) 2003-2004 Michael Schindler <m-schindler@users.sourceforge.net>
   6 # Copyright (C) 2002-2005 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
  23
  24
  25 import sys, functools
  26
  27 # test automatic long conversion
  28 try:
  29     sys.maxsize+1
  30     autolong = 1
  31 except OverflowError:
  32     autolong = 0
  33
  34
  35 @functools.total_ordering
  36 class rational:
  37     """rational class performing some basic rational arithmetics
  38     the axis partitioning uses rational arithmetics (with infinite accuracy)
  39     basically it contains self.num and self.denom"""
  40
  41     def initfromstring(self, s):
  42         "converts a string 0.123 into a rational"
  43         expparts = s.strip().replace("E", "e").split("e")
  44         if len(expparts) > 2:
  45             raise ValueError("multiple 'e' found in '%s'" % s)
  46         commaparts = expparts[0].split(".")
  47         if len(commaparts) > 2:
  48             raise ValueError("multiple '.' found in '%s'" % expparts[0])
  49         if len(commaparts) == 1:
  50             commaparts = [commaparts[0], ""]
  51         self.num = 1
  52         if autolong:
  53             self.denom = 10 ** len(commaparts[1])
  54         else:
  55             self.denom = 10 ** len(commaparts[1])
  56         neg = len(commaparts[0]) and commaparts[0][0] == "-"
  57         if neg:
  58             commaparts[0] = commaparts[0][1:]
  59         elif len(commaparts[0]) and commaparts[0][0] == "+":
  60             commaparts[0] = commaparts[0][1:]
  61         if len(commaparts[0]):
  62             if not commaparts[0].isdigit():
  63                 raise ValueError("unrecognized characters in '%s'" % s)
  64             try:
  65                 x = int(commaparts[0])
  66             except:
  67                 x = int(commaparts[0])
  68         else:
  69             x = 0
  70         if len(commaparts[1]):
  71             if not commaparts[1].isdigit():
  72                 raise ValueError("unrecognized characters in '%s'" % s)
  73             try:
  74                 y = int(commaparts[1])
  75             except:
  76                 y = int(commaparts[1])
  77         else:
  78             y = 0
  79         self.num = x*self.denom + y
  80         if neg:
  81             self.num = -self.num
  82         if len(expparts) == 2:
  83             neg = expparts[1][0] == "-"
  84             if neg:
  85                 expparts[1] = expparts[1][1:]
  86             elif expparts[1][0] == "+":
  87                 expparts[1] = expparts[1][1:]
  88             if not expparts[1].isdigit():
  89                 raise ValueError("unrecognized characters in '%s'" % s)
  90             if neg:
  91                 if autolong:
  92                     self.denom *= 10 ** int(expparts[1])
  93                 else:
  94                     self.denom *= 10 ** int(expparts[1])
  95             else:
  96                 if autolong:
  97                     self.num *= 10 ** int(expparts[1])
  98                 else:
  99                     self.num *= 10 ** int(expparts[1])
 100
 101     def initfromfloat(self, x, floatprecision):
 102         "converts a float into a rational with finite resolution"
 103         if floatprecision < 0:
 104             raise RuntimeError("float resolution must be non-negative")
 105         self.initfromstring(("%%.%ig" % floatprecision) % x)
 106
 107     def __init__(self, x, power=1, floatprecision=10):
 108         """initializes a rational
 109         - rational=(num/denom)**power
 110         - x must be one of:
 111           - a string (like "1.2", "1.2e3", "1.2/3.4", etc.)
 112           - a float (converted using floatprecision)
 113           - a sequence of two integers
 114           - a rational instance"""
 115         if power == 0:
 116             self.num = 1
 117             self.denom = 1
 118             return
 119         try:
 120             # does x behave like a number
 121             x + 0
 122         except:
 123             try:
 124                 # does x behave like a string
 125                 x + ""
 126             except:
 127                 try:
 128                     # x might be a tuple
 129                     self.num, self.denom = x
 130                 except:
 131                     # otherwise it should have a num and denom
 132                     self.num, self.denom = x.num, x.denom
 133             else:
 134                 # x is a string
 135                 fraction = x.split("/")
 136                 if len(fraction) > 2:
 137                     raise ValueError("multiple '/' found in '%s'" % x)
 138                 self.initfromstring(fraction[0])
 139                 if len(fraction) == 2:
 140                     self /= rational(fraction[1])
 141         else:
 142             # x is a number
 143             self.initfromfloat(x, floatprecision)
 144         if not self.denom: raise ZeroDivisionError("zero denominator")
 145         if power == -1:
 146             self.num, self.denom = self.denom, self.num
 147         elif power < -1:
 148             if autolong:
 149                 self.num, self.denom = self.denom ** (-power), self.num ** (-power)
 150             else:
 151                 self.num, self.denom = int(self.denom) ** (-power), int(self.num) ** (-power)
 152         elif power > 1:
 153             if autolong:
 154                 self.num = self.num ** power
 155                 self.denom = self.denom ** power
 156             else:
 157                 self.num = int(self.num) ** power
 158                 self.denom = int(self.denom) ** power
 159
 160     def __lt__(self, other):
 161         try:
 162             return self.num * other.denom < other.num * self.denom
 163         except:
 164             return float(self) < other
 165
 166     def __eq__(self, other):
 167         try:
 168             return self.num * other.denom == other.num * self.denom
 169         except:
 170             return float(self) == other
 171
 172     def __abs__(self):
 173         return rational((abs(self.num), abs(self.denom)))
 174
 175     def __add__(self, other):
 176         assert abs(other) < 1e-10
 177         return float(self)
 178
 179     def __mul__(self, other):
 180         return rational((self.num * other.num, self.denom * other.denom))
 181
 182     def __imul__(self, other):
 183         self.num *= other.num
 184         self.denom *= other.denom
 185         return self
 186
 187     def __div__(self, other):
 188         return rational((self.num * other.denom, self.denom * other.num))
 189
 190     __truediv__ = __div__
 191
 192     def __idiv__(self, other):
 193         self.num *= other.denom
 194         self.denom *= other.num
 195         return self
 196
 197     __itruediv__ = __idiv__
 198
 199     def __float__(self):
 200         "caution: avoid final precision of floats"
 201         return float(self.num) / self.denom
 202
 203     def __str__(self):
 204         return "%i/%i" % (self.num, self.denom)
 205
 206
 207 class tick(rational):
 208     """tick class
 209     a tick is a rational enhanced by
 210     - self.ticklevel (0 = tick, 1 = subtick, etc.)
 211     - self.labellevel (0 = label, 1 = sublabel, etc.)
 212     - self.label (a string) and self.labelattrs (a list, defaults to [])
 213     When ticklevel or labellevel is None, no tick or label is present at that value.
 214     When label is None, it should be automatically created (and stored), once the
 215     an axis painter needs it. Classes, which implement _Itexter do precisely that."""
 216
 217     def __init__(self, x, ticklevel=0, labellevel=0, label=None, labelattrs=[], **kwargs):
 218         """initializes the instance
 219         - see class description for the parameter description
 220         - **kwargs are passed to the rational constructor"""
 221         rational.__init__(self, x, **kwargs)
 222         self.ticklevel = ticklevel
 223         self.labellevel = labellevel
 224         self.label = label
 225         self.labelattrs = labelattrs
 226
 227     def merge(self, other):
 228         """merges two ticks together:
 229           - the lower ticklevel/labellevel wins
 230           - the ticks should be at the same position (otherwise it doesn't make sense)
 231             -> this is NOT checked"""
 232         if self.ticklevel is None or (other.ticklevel is not None and other.ticklevel < self.ticklevel):
 233             self.ticklevel = other.ticklevel
 234         if self.labellevel is None or (other.labellevel is not None and other.labellevel < self.labellevel):
 235             self.labellevel = other.labellevel
 236         if self.label is None:
 237             self.label = other.label
 238
 239
 240 def mergeticklists(list1, list2, mergeequal=1):
 241     """helper function to merge tick lists
 242     - return a merged list of ticks out of list1 and list2
 243     - CAUTION: original lists have to be ordered
 244       (the returned list is also ordered)"""
 245     # TODO: improve along the lines of http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/305269
 246
 247     # do not destroy original lists
 248     list1 = list1[:]
 249     i = 0
 250     j = 0
 251     try:
 252         while True: # we keep on going until we reach an index error
 253             while list2[j] < list1[i]: # insert tick
 254                list1.insert(i, list2[j])
 255                i += 1
 256                j += 1
 257             if list2[j] == list1[i]: # merge tick
 258                if mergeequal:
 259                    list1[i].merge(list2[j])
 260                j += 1
 261             i += 1
 262     except IndexError:
 263         if j < len(list2):
 264             list1 += list2[j:]
 265     return list1
 266
 267
 268 def maxlevels(ticks):
 269     "returns a tuple maxticklevel, maxlabellevel from a list of tick instances"
 270     maxticklevel = maxlabellevel = 0
 271     for tick in ticks:
 272         if tick.ticklevel is not None and tick.ticklevel >= maxticklevel:
 273             maxticklevel = tick.ticklevel + 1
 274         if tick.labellevel is not None and tick.labellevel >= maxlabellevel:
 275             maxlabellevel = tick.labellevel + 1
 276     return maxticklevel, maxlabellevel