Source Code for Module colors

  1  #colors.py 
  2  #A part of NonVisual Desktop Access (NVDA) 
  3  #Copyright (C) 2006-2008 NVDA Contributors <http://www.nvda-project.org/> 
  4  #This file is covered by the GNU General Public License. 
  5  #See the file COPYING for more details. 
  6   
  7  from collections import namedtuple 
  8  import math 
  9  from ctypes.wintypes import COLORREF 
 10  import re 
 11   
 12 -class RGB(namedtuple('RGB',('red','green','blue'))): 
 13          """Represents a color as an RGB (red green blue) value""" 
 14   
 15          @classmethod 
 16 -        def fromCOLORREF(cls,c): 
 17                  """factory method to create an RGB from a COLORREF ctypes instance""" 
 18                  if isinstance(c,COLORREF): 
 19                          c=c.value 
 20                  return cls(c&0xff,(c>>8)&0xff,(c>>16)&0xff) 
 21   
 22          _re_RGBFunctionString=re.compile(r'rgb\(\s*(\d+%?)\s*,\s*(\d+%?)\s*,\s*(\d+%?)\s*\)',re.I) 
 23          _re_RGBAFunctionString=re.compile(r'rgba\(\s*(\d+%?)\s*,\s*(\d+%?)\s*,\s*(\d+%?)\s*,\s*\d+(\.\d+)?\s*\)',re.I) 
 24   
 25          @staticmethod 
 26 -        def _RGBStringValToInt(s): 
 27                  val=int(round(int(s[:-1])*2.55)) if s.endswith('%') else int(s) 
 28                  if val<0 or val>255: 
 29                          raise ValueError("%s out of range"%val) 
 30                  return val 
 31   
 32          @classmethod 
 33 -        def fromString(cls,s): 
 34                  """ 
 35                  Factory method to create an RGB instance from a css RGB string representation. 
 36                  """ 
 37                  s=s.strip() 
 38                  #Try to match on the form RGB(x,y,z) 
 39                  m=cls._re_RGBFunctionString.match(s) or cls._re_RGBAFunctionString.match(s) 
 40                  if m: 
 41                          r=cls._RGBStringValToInt(m.group(1)) 
 42                          g=cls._RGBStringValToInt(m.group(2)) 
 43                          b=cls._RGBStringValToInt(m.group(3)) 
 44                          return RGB(r,g,b) 
 45                  if s.startswith('#'): 
 46                          sLen=len(s) 
 47                          try: 
 48                                  val=int(s[1:],16) 
 49                          except ValueError: 
 50                                  val=None 
 51                          if val is not None: 
 52                                  #Perhaps its a #aarrggbb or #rrggbb hex string 
 53                                  if sLen==7 or sLen==9: 
 54                                          r=(val>>16)&0xff 
 55                                          g=(val>>8)&0xff 
 56                                          b=val&0xff 
 57                                          return RGB(r,g,b) 
 58                                  #Perhaps its a #argb or #rgb hex string 
 59                                  if sLen==4 or sLen==5: 
 60                                          r=((val>>8)&0xf)+(((val>>8)&0xf)<<4) 
 61                                          g=((val>>4)&0xf)+(((val>>4)&0xf)<<4) 
 62                                          b=(val&0xf)+((val&0xf)<<4) 
 63                                          return RGB(r,g,b) 
 64                  raise ValueError("invalid RGB string: %s"%s) 
 65   
 66          @property 
 67 -        def name(self): 
 68                  foundName=RGBToNames.get(self,None) 
 69                  if foundName: 
 70                          return foundName 
 71                  foundName=RGBToNamesCache.get(self,None) 
 72                  if foundName: 
 73                          return foundName 
 74                  longestDistance=255.0 
 75                  closestName=_("unknown color") 
 76                  for possibleRGB,possibleName  in RGBToNames.iteritems(): 
 77                          distance=math.sqrt(abs(self.red-possibleRGB.red)**2+abs(self.green-possibleRGB.green)**2+abs(self.blue-possibleRGB.blue)**2) 
 78                          if distance<longestDistance: 
 79                                  longestDistance=distance 
 80                                  closestName=possibleName 
 81                  RGBToNamesCache[self]=closestName 
 82                  return closestName 
 83   
 84  RGBToNamesCache={} 
 85   
 86  RGBToNames={ 
 87          #Standard 16 HTML 4 colors 
 88          RGB(0x00,0x00,0x00):_('black'), 
 89          RGB(0x00,0x80,0x00):_('green'), 
 90          RGB(0xc0,0xc0,0xc0):_('light grey'), 
 91          RGB(0x00,0xff,0x00):_('lime'), 
 92          RGB(0x80,0x80,0x80):_('grey'), 
 93          RGB(0x80,0x80,0x00):_('olive'), 
 94          RGB(0xff,0xff,0xff):_('white'), 
 95          RGB(0xff,0xff,0x00):_('yellow'), 
 96          RGB(0x80,0x00,0x00):_('dark red'), 
 97          RGB(0x00,0x00,0xa0):_('navy blue'), 
 98          RGB(0xff,0x00,0x00):_('red'), 
 99          RGB(0x00,0x00,0xff):_('blue'), 
100          RGB(0x80,0x00,0x80):_('purple'), 
101          RGB(0x00,0x80,0x80):_('teal'), 
102          RGB(0xff,0x00,0xff):_('fuchsia'), 
103          RGB(0x00,0xff,0xff):_('aqua'), 
104          #Extra CSS 2.1 color 
105          RGB(0xff,0xa5,0x00):_('orange'), 
106  } 
107