PythonCAD/Generic/color.py

   1 #
   2 # Copyright (c) 2002, 2003, 2004, 2005 Art Haas
   3 #
   4 # This file is part of PythonCAD.
   5 #
   6 # PythonCAD is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License as published by
   8 # the Free Software Foundation; either version 2 of the License, or
   9 # (at your option) any later version.
  10 #
  11 # PythonCAD is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with PythonCAD; if not, write to the Free Software
  18 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  19 #
  20 #
  21 # classes for colors
  22 #
  23
  24 from PythonCAD.Generic import globals
  25
  26 #
  27 # a seemingly good way to convert from string to integer
  28 # for a couple of common ways of expressing colors ...
  29 #
  30
  31 def color_str_to_int(cstr):
  32     if cstr.startswith('0x') or cstr.startswith('0X'):
  33         _val = int(cstr, 16)
  34     elif cstr.startswith('#'):
  35         _val = int(cstr[1:], 16)
  36     else:
  37         _val = int(cstr)
  38     return _val
  39
  40 class Color(object):
  41     """An object representing an RGB color.
  42
  43 The class purpose is self evident.
  44
  45 A Color object has three attributes:
  46
  47 r: Red (0-255)
  48 g: Green (0-255)
  49 b: Blue (0-255)
  50
  51 There is no alpha-channel attribute (yet)...
  52
  53 A Color object has the following methods:
  54
  55 getRed(): Get the Red value in the Color.
  56 getBlue(): Get the Blue value in the Color.
  57 getGreen(): Get the Green value in the Color.
  58 clone(): Return an identical copy of a Color.
  59
  60 Once a color object is created, the values it
  61 contains may not be changed.
  62     """
  63     def __init__(self, r=None, g=None, b=None):
  64         """Initialize a Color object.
  65
  66 There are several ways to create a color object:
  67
  68 Color(r,g,b) => r, g, and b values are all integers 0 <= value <= 255
  69 Color(0xxxxx) => A hexidecimal value - it must begin with 0x. The color
  70                  is computed as follows:
  71                  r = (0xff0000 & value) >> 16
  72                  g = (0xff00 & value) >> 8
  73                  b = (0xff & value)
  74 Color('#hexvalue') => A string prefixed with '#', with the remaining
  75                       characters representing a hexidecimal value.
  76 Color() => A default color with r = g = b = 255.
  77         """
  78         _r = r
  79         _g = g
  80         _b = b
  81         if isinstance(_r, str):
  82             _val = color_str_to_int(_r)
  83             _r = (0xff0000 & _val) >> 16
  84             _g = (0xff00 & _val) >> 8
  85             _b = (0xff & _val)
  86         elif isinstance(_r, int) and _g is None and _b is None:
  87             _r = (0xff0000 & r) >> 16
  88             _g = (0xff00 & r) >> 8
  89             _b = (0xff & r)
  90         elif (isinstance(_r, int) and
  91               isinstance(_g, int) and
  92               isinstance(_b, int)):
  93             if _r < 0 or _r > 255:
  94                 raise ValueError, "Invalid Red value: %d" % _r
  95             if _g < 0 or _g > 255:
  96                 raise ValueError, "Invalid Green value: %d" % _g
  97             if _b < 0 or _b > 255:
  98                 raise ValueError, "Invalid Blue value: %d" % _b
  99         elif _r is None and _g is None and _b is None:
 100             _r = 255
 101             _g = 255
 102             _b = 255
 103         else:
 104             raise SyntaxError, "Invalid call to Color()."
 105         self.__color = (_r << 16) | (_g << 8) | _b
 106
 107     def __eq__(self, obj):
 108         """Compare two Color objects for equivalence.
 109         """
 110         if not isinstance(obj, Color):
 111             return False
 112         return self.getColors() == obj.getColors()
 113
 114     def __ne__(self, obj):
 115         """Compare two Color objects for equivalence.
 116         """
 117         if not isinstance(obj, Color):
 118             return True
 119         return self.getColors() != obj.getColors()
 120
 121     def __cmp__(self, obj):
 122         """Compare two Color objects.
 123
 124 The comparison is done based on the RGB values.
 125
 126 red value of C1 < red value of C2 ==> return -1
 127 red value of C1 > red value of C2 ==> return 1
 128
 129 Then green values are compared, then blue. If
 130 all values are equal, return 0.
 131         """
 132         if not isinstance(obj, Color):
 133             raise TypeError, "Invalid object for color comparison: " + `obj`
 134         _val = self.__color
 135         _objval = hash(obj)
 136         return cmp(_val, _objval)
 137
 138     def __hash__(self):
 139         """Return a hash value for the Color object.
 140
 141 Providing this method means that Color objects can be used
 142 as keys in dictionaries.
 143         """
 144         return self.__color
 145
 146     def __repr__(self):
 147         _val = self.__color
 148         _r = (_val & 0xff0000) >> 16
 149         _g = (_val & 0xff00) >> 8
 150         _b = (_val & 0xff)
 151         return "Color(%d,%d,%d)" % (_r, _g, _b)
 152
 153     def __str__(self):
 154         return "#%06x" % self.__color
 155
 156     def getColors(self):
 157         """Return a three-item tuple with the values comprising this color.
 158
 159 getColors()
 160         """
 161         _val = self.__color
 162         _r = (_val & 0xff0000) >> 16
 163         _g = (_val & 0xff00) >> 8
 164         _b = (_val & 0xff)
 165         return _r, _g, _b
 166
 167     def getRed(self):
 168         """Return the red value of the color.
 169
 170 getRed()
 171         """
 172         return (self.__color & 0xff0000) >> 16
 173
 174     r = property(getRed, None, None, "Red value of the color.")
 175
 176     def getGreen(self):
 177         """Return the green value of the color.
 178
 179 getGreen()
 180         """
 181         return (self.__color & 0xff00) >> 8
 182
 183     g = property(getGreen, None, None, "Green value of the color.")
 184
 185     def getBlue(self):
 186         """Return the blue value of the color.
 187
 188 getBlue()
 189         """
 190         return (self.__color & 0xff)
 191
 192     b = property(getBlue, None, None, "Blue value of the color.")
 193
 194     def clone(self):
 195         """Return a new Color object with the same color values.
 196
 197 clone()
 198         """
 199         _val = self.__color
 200         return Color(_val)
 201
 202 #
 203 # ColorDict Class
 204 #
 205 # The ColorDict is built from the dict object. Using instances
 206 # of this class will guarantee than only Color objects will be
 207 # stored in the instance
 208 #
 209
 210 class ColorDict(dict):
 211     def __init__(self):
 212         super(ColorDict, self).__init__()
 213
 214     def __setitem__(self, key, value):
 215         if not isinstance(key, Color):
 216             raise TypeError, "ColorDict keys must be color objects: " + `key`
 217         if not isinstance(value, Color):
 218             raise TypeError, "ColorDict values must be Color objects: " + `value`
 219         super(ColorDict, self).__setitem__(key, value)
 220
 221 #
 222 # find a Color object stored in the global color dictionary
 223 # or make a new one and store it
 224 #
 225
 226 def get_color(r, g, b):
 227     if not isinstance(r, int):
 228         raise TypeError, "Invalid red value:" + `r`
 229     if r < 0 or r > 255:
 230         raise ValueError, "Invalid red value: %d" % r
 231     if not isinstance(g, int):
 232         raise TypeError, "Invalid green value:" + `g`
 233     if g < 0 or g > 255:
 234         raise ValueError, "Invalid green value: %d" % g
 235     if not isinstance(b, int):
 236         raise TypeError, "Invalid blue value:" + `b`
 237     if b < 0 or b > 255:
 238         raise ValueError, "Invalid blue value: %d" % b
 239     _color = Color(r, g, b)
 240     if _color in globals.colors:
 241         _color = globals.colors[_color]
 242     else:
 243         globals.colors[_color] = _color
 244     return _color