/Tools/pynche/ColorDB.py

http://unladen-swallow.googlecode.com/ · Python · 276 lines · 182 code · 38 blank · 56 comment · 34 complexity · ae25195489fb4dccabce6f032bb457cc MD5 · raw file

  1. """Color Database.
  2. This file contains one class, called ColorDB, and several utility functions.
  3. The class must be instantiated by the get_colordb() function in this file,
  4. passing it a filename to read a database out of.
  5. The get_colordb() function will try to examine the file to figure out what the
  6. format of the file is. If it can't figure out the file format, or it has
  7. trouble reading the file, None is returned. You can pass get_colordb() an
  8. optional filetype argument.
  9. Supporte file types are:
  10. X_RGB_TXT -- X Consortium rgb.txt format files. Three columns of numbers
  11. from 0 .. 255 separated by whitespace. Arbitrary trailing
  12. columns used as the color name.
  13. The utility functions are useful for converting between the various expected
  14. color formats, and for calculating other color values.
  15. """
  16. import sys
  17. import re
  18. from types import *
  19. import operator
  20. class BadColor(Exception):
  21. pass
  22. DEFAULT_DB = None
  23. SPACE = ' '
  24. COMMASPACE = ', '
  25. # generic class
  26. class ColorDB:
  27. def __init__(self, fp):
  28. lineno = 2
  29. self.__name = fp.name
  30. # Maintain several dictionaries for indexing into the color database.
  31. # Note that while Tk supports RGB intensities of 4, 8, 12, or 16 bits,
  32. # for now we only support 8 bit intensities. At least on OpenWindows,
  33. # all intensities in the /usr/openwin/lib/rgb.txt file are 8-bit
  34. #
  35. # key is (red, green, blue) tuple, value is (name, [aliases])
  36. self.__byrgb = {}
  37. # key is name, value is (red, green, blue)
  38. self.__byname = {}
  39. # all unique names (non-aliases). built-on demand
  40. self.__allnames = None
  41. for line in fp:
  42. # get this compiled regular expression from derived class
  43. mo = self._re.match(line)
  44. if not mo:
  45. print >> sys.stderr, 'Error in', fp.name, ' line', lineno
  46. lineno += 1
  47. continue
  48. # extract the red, green, blue, and name
  49. red, green, blue = self._extractrgb(mo)
  50. name = self._extractname(mo)
  51. keyname = name.lower()
  52. # BAW: for now the `name' is just the first named color with the
  53. # rgb values we find. Later, we might want to make the two word
  54. # version the `name', or the CapitalizedVersion, etc.
  55. key = (red, green, blue)
  56. foundname, aliases = self.__byrgb.get(key, (name, []))
  57. if foundname <> name and foundname not in aliases:
  58. aliases.append(name)
  59. self.__byrgb[key] = (foundname, aliases)
  60. # add to byname lookup
  61. self.__byname[keyname] = key
  62. lineno = lineno + 1
  63. # override in derived classes
  64. def _extractrgb(self, mo):
  65. return [int(x) for x in mo.group('red', 'green', 'blue')]
  66. def _extractname(self, mo):
  67. return mo.group('name')
  68. def filename(self):
  69. return self.__name
  70. def find_byrgb(self, rgbtuple):
  71. """Return name for rgbtuple"""
  72. try:
  73. return self.__byrgb[rgbtuple]
  74. except KeyError:
  75. raise BadColor(rgbtuple)
  76. def find_byname(self, name):
  77. """Return (red, green, blue) for name"""
  78. name = name.lower()
  79. try:
  80. return self.__byname[name]
  81. except KeyError:
  82. raise BadColor(name)
  83. def nearest(self, red, green, blue):
  84. """Return the name of color nearest (red, green, blue)"""
  85. # BAW: should we use Voronoi diagrams, Delaunay triangulation, or
  86. # octree for speeding up the locating of nearest point? Exhaustive
  87. # search is inefficient, but seems fast enough.
  88. nearest = -1
  89. nearest_name = ''
  90. for name, aliases in self.__byrgb.values():
  91. r, g, b = self.__byname[name.lower()]
  92. rdelta = red - r
  93. gdelta = green - g
  94. bdelta = blue - b
  95. distance = rdelta * rdelta + gdelta * gdelta + bdelta * bdelta
  96. if nearest == -1 or distance < nearest:
  97. nearest = distance
  98. nearest_name = name
  99. return nearest_name
  100. def unique_names(self):
  101. # sorted
  102. if not self.__allnames:
  103. self.__allnames = []
  104. for name, aliases in self.__byrgb.values():
  105. self.__allnames.append(name)
  106. # sort irregardless of case
  107. def nocase_cmp(n1, n2):
  108. return cmp(n1.lower(), n2.lower())
  109. self.__allnames.sort(nocase_cmp)
  110. return self.__allnames
  111. def aliases_of(self, red, green, blue):
  112. try:
  113. name, aliases = self.__byrgb[(red, green, blue)]
  114. except KeyError:
  115. raise BadColor((red, green, blue))
  116. return [name] + aliases
  117. class RGBColorDB(ColorDB):
  118. _re = re.compile(
  119. '\s*(?P<red>\d+)\s+(?P<green>\d+)\s+(?P<blue>\d+)\s+(?P<name>.*)')
  120. class HTML40DB(ColorDB):
  121. _re = re.compile('(?P<name>\S+)\s+(?P<hexrgb>#[0-9a-fA-F]{6})')
  122. def _extractrgb(self, mo):
  123. return rrggbb_to_triplet(mo.group('hexrgb'))
  124. class LightlinkDB(HTML40DB):
  125. _re = re.compile('(?P<name>(.+))\s+(?P<hexrgb>#[0-9a-fA-F]{6})')
  126. def _extractname(self, mo):
  127. return mo.group('name').strip()
  128. class WebsafeDB(ColorDB):
  129. _re = re.compile('(?P<hexrgb>#[0-9a-fA-F]{6})')
  130. def _extractrgb(self, mo):
  131. return rrggbb_to_triplet(mo.group('hexrgb'))
  132. def _extractname(self, mo):
  133. return mo.group('hexrgb').upper()
  134. # format is a tuple (RE, SCANLINES, CLASS) where RE is a compiled regular
  135. # expression, SCANLINES is the number of header lines to scan, and CLASS is
  136. # the class to instantiate if a match is found
  137. FILETYPES = [
  138. (re.compile('Xorg'), RGBColorDB),
  139. (re.compile('XConsortium'), RGBColorDB),
  140. (re.compile('HTML'), HTML40DB),
  141. (re.compile('lightlink'), LightlinkDB),
  142. (re.compile('Websafe'), WebsafeDB),
  143. ]
  144. def get_colordb(file, filetype=None):
  145. colordb = None
  146. fp = open(file)
  147. try:
  148. line = fp.readline()
  149. if not line:
  150. return None
  151. # try to determine the type of RGB file it is
  152. if filetype is None:
  153. filetypes = FILETYPES
  154. else:
  155. filetypes = [filetype]
  156. for typere, class_ in filetypes:
  157. mo = typere.search(line)
  158. if mo:
  159. break
  160. else:
  161. # no matching type
  162. return None
  163. # we know the type and the class to grok the type, so suck it in
  164. colordb = class_(fp)
  165. finally:
  166. fp.close()
  167. # save a global copy
  168. global DEFAULT_DB
  169. DEFAULT_DB = colordb
  170. return colordb
  171. _namedict = {}
  172. def rrggbb_to_triplet(color):
  173. """Converts a #rrggbb color to the tuple (red, green, blue)."""
  174. rgbtuple = _namedict.get(color)
  175. if rgbtuple is None:
  176. if color[0] <> '#':
  177. raise BadColor(color)
  178. red = color[1:3]
  179. green = color[3:5]
  180. blue = color[5:7]
  181. rgbtuple = int(red, 16), int(green, 16), int(blue, 16)
  182. _namedict[color] = rgbtuple
  183. return rgbtuple
  184. _tripdict = {}
  185. def triplet_to_rrggbb(rgbtuple):
  186. """Converts a (red, green, blue) tuple to #rrggbb."""
  187. global _tripdict
  188. hexname = _tripdict.get(rgbtuple)
  189. if hexname is None:
  190. hexname = '#%02x%02x%02x' % rgbtuple
  191. _tripdict[rgbtuple] = hexname
  192. return hexname
  193. _maxtuple = (256.0,) * 3
  194. def triplet_to_fractional_rgb(rgbtuple):
  195. return map(operator.__div__, rgbtuple, _maxtuple)
  196. def triplet_to_brightness(rgbtuple):
  197. # return the brightness (grey level) along the scale 0.0==black to
  198. # 1.0==white
  199. r = 0.299
  200. g = 0.587
  201. b = 0.114
  202. return r*rgbtuple[0] + g*rgbtuple[1] + b*rgbtuple[2]
  203. if __name__ == '__main__':
  204. colordb = get_colordb('/usr/openwin/lib/rgb.txt')
  205. if not colordb:
  206. print 'No parseable color database found'
  207. sys.exit(1)
  208. # on my system, this color matches exactly
  209. target = 'navy'
  210. red, green, blue = rgbtuple = colordb.find_byname(target)
  211. print target, ':', red, green, blue, triplet_to_rrggbb(rgbtuple)
  212. name, aliases = colordb.find_byrgb(rgbtuple)
  213. print 'name:', name, 'aliases:', COMMASPACE.join(aliases)
  214. r, g, b = (1, 1, 128) # nearest to navy
  215. r, g, b = (145, 238, 144) # nearest to lightgreen
  216. r, g, b = (255, 251, 250) # snow
  217. print 'finding nearest to', target, '...'
  218. import time
  219. t0 = time.time()
  220. nearest = colordb.nearest(r, g, b)
  221. t1 = time.time()
  222. print 'found nearest color', nearest, 'in', t1-t0, 'seconds'
  223. # dump the database
  224. for n in colordb.unique_names():
  225. r, g, b = colordb.find_byname(n)
  226. aliases = colordb.aliases_of(r, g, b)
  227. print '%20s: (%3d/%3d/%3d) == %s' % (n, r, g, b,
  228. SPACE.join(aliases[1:]))