There are 147 standard color names for use in HTML. here is a simple Python code to find the nearest matching color name given input R,G, B values (from 0-255). The minimization criterion is the sum of absolute vaues of the differences from the color r, g, b values of the colornames.
"""
File colornames.py
Author Ernesto P. Adorio, Ph.D
Version 0.0.1 February 1, 2012
"""
# Src: http://www.w3schools.com/html/html_colornames.asp
lines = """AliceBlue #F0F8FF Shades Mix
AntiqueWhite #FAEBD7 Shades Mix
Aqua #00FFFF Shades Mix
Aquamarine #7FFFD4 Shades Mix
Azure #F0FFFF Shades Mix
Beige #F5F5DC Shades Mix
Bisque #FFE4C4 Shades Mix
Black #000000 Shades Mix
BlanchedAlmond #FFEBCD Shades Mix
Blue #0000FF Shades Mix
BlueViolet #8A2BE2 Shades Mix
Brown #A52A2A Shades Mix
BurlyWood #DEB887 Shades Mix
CadetBlue #5F9EA0 Shades Mix
Chartreuse #7FFF00 Shades Mix
Chocolate #D2691E Shades Mix
Coral #FF7F50 Shades Mix
CornflowerBlue #6495ED Shades Mix
Cornsilk #FFF8DC Shades Mix
Crimson #DC143C Shades Mix
Cyan #00FFFF Shades Mix
DarkBlue #00008B Shades Mix
DarkCyan #008B8B Shades Mix
DarkGoldenRod #B8860B Shades Mix
DarkGray #A9A9A9 Shades Mix
DarkGrey #A9A9A9 Shades Mix
DarkGreen #006400 Shades Mix
DarkKhaki #BDB76B Shades Mix
DarkMagenta #8B008B Shades Mix
DarkOliveGreen #556B2F Shades Mix
Darkorange #FF8C00 Shades Mix
DarkOrchid #9932CC Shades Mix
DarkRed #8B0000 Shades Mix
DarkSalmon #E9967A Shades Mix
DarkSeaGreen #8FBC8F Shades Mix
DarkSlateBlue #483D8B Shades Mix
DarkSlateGray #2F4F4F Shades Mix
DarkSlateGrey #2F4F4F Shades Mix
DarkTurquoise #00CED1 Shades Mix
DarkViolet #9400D3 Shades Mix
DeepPink #FF1493 Shades Mix
DeepSkyBlue #00BFFF Shades Mix
DimGray #696969 Shades Mix
DimGrey #696969 Shades Mix
DodgerBlue #1E90FF Shades Mix
FireBrick #B22222 Shades Mix
FloralWhite #FFFAF0 Shades Mix
ForestGreen #228B22 Shades Mix
Fuchsia #FF00FF Shades Mix
Gainsboro #DCDCDC Shades Mix
GhostWhite #F8F8FF Shades Mix
Gold #FFD700 Shades Mix
GoldenRod #DAA520 Shades Mix
Gray #808080 Shades Mix
Grey #808080 Shades Mix
Green #008000 Shades Mix
GreenYellow #ADFF2F Shades Mix
HoneyDew #F0FFF0 Shades Mix
HotPink #FF69B4 Shades Mix
IndianRed #CD5C5C Shades Mix
Indigo #4B0082 Shades Mix
Ivory #FFFFF0 Shades Mix
Khaki #F0E68C Shades Mix
Lavender #E6E6FA Shades Mix
LavenderBlush #FFF0F5 Shades Mix
LawnGreen #7CFC00 Shades Mix
LemonChiffon #FFFACD Shades Mix
LightBlue #ADD8E6 Shades Mix
LightCoral #F08080 Shades Mix
LightCyan #E0FFFF Shades Mix
LightGoldenRodYellow #FAFAD2 Shades Mix
LightGray #D3D3D3 Shades Mix
LightGrey #D3D3D3 Shades Mix
LightGreen #90EE90 Shades Mix
LightPink #FFB6C1 Shades Mix
LightSalmon #FFA07A Shades Mix
LightSeaGreen #20B2AA Shades Mix
LightSkyBlue #87CEFA Shades Mix
LightSlateGray #778899 Shades Mix
LightSlateGrey #778899 Shades Mix
LightSteelBlue #B0C4DE Shades Mix
LightYellow #FFFFE0 Shades Mix
Lime #00FF00 Shades Mix
LimeGreen #32CD32 Shades Mix
Linen #FAF0E6 Shades Mix
Magenta #FF00FF Shades Mix
Maroon #800000 Shades Mix
MediumAquaMarine #66CDAA Shades Mix
MediumBlue #0000CD Shades Mix
MediumOrchid #BA55D3 Shades Mix
MediumPurple #9370D8 Shades Mix
MediumSeaGreen #3CB371 Shades Mix
MediumSlateBlue #7B68EE Shades Mix
MediumSpringGreen #00FA9A Shades Mix
MediumTurquoise #48D1CC Shades Mix
MediumVioletRed #C71585 Shades Mix
MidnightBlue #191970 Shades Mix
MintCream #F5FFFA Shades Mix
MistyRose #FFE4E1 Shades Mix
Moccasin #FFE4B5 Shades Mix
NavajoWhite #FFDEAD Shades Mix
Navy #000080 Shades Mix
OldLace #FDF5E6 Shades Mix
Olive #808000 Shades Mix
OliveDrab #6B8E23 Shades Mix
Orange #FFA500 Shades Mix
OrangeRed #FF4500 Shades Mix
Orchid #DA70D6 Shades Mix
PaleGoldenRod #EEE8AA Shades Mix
PaleGreen #98FB98 Shades Mix
PaleTurquoise #AFEEEE Shades Mix
PaleVioletRed #D87093 Shades Mix
PapayaWhip #FFEFD5 Shades Mix
PeachPuff #FFDAB9 Shades Mix
Peru #CD853F Shades Mix
Pink #FFC0CB Shades Mix
Plum #DDA0DD Shades Mix
PowderBlue #B0E0E6 Shades Mix
Purple #800080 Shades Mix
Red #FF0000 Shades Mix
RosyBrown #BC8F8F Shades Mix
RoyalBlue #4169E1 Shades Mix
SaddleBrown #8B4513 Shades Mix
Salmon #FA8072 Shades Mix
SandyBrown #F4A460 Shades Mix
SeaGreen #2E8B57 Shades Mix
SeaShell #FFF5EE Shades Mix
Sienna #A0522D Shades Mix
Silver #C0C0C0 Shades Mix
SkyBlue #87CEEB Shades Mix
SlateBlue #6A5ACD Shades Mix
SlateGray #708090 Shades Mix
SlateGrey #708090 Shades Mix
Snow #FFFAFA Shades Mix
SpringGreen #00FF7F Shades Mix
SteelBlue #4682B4 Shades Mix
Tan #D2B48C Shades Mix
Teal #008080 Shades Mix
Thistle #D8BFD8 Shades Mix
Tomato #FF6347 Shades Mix
Turquoise #40E0D0 Shades Mix
Violet #EE82EE Shades Mix
Wheat #F5DEB3 Shades Mix
White #FFFFFF Shades Mix
WhiteSmoke #F5F5F5 Shades Mix
Yellow #FFFF00 Shades Mix
YellowGreen #9ACD32"""
def rgbfromstr(s):
# s starts with a #.
r, g, b = int(s[1:3],16), int(s[3:5], 16),int(s[5:7], 16)
return r, g, b
def findnearestcolorname(R,G, B, colorD):
mindiff = None
for d in colorD:
r, g, b = rgbfromstr(colorD[d])
diff = abs(R -r)*256 + abs(G-g)* 256 + abs(B- b)* 256
if mindiff is None or diff < mindiff:
mindiff = diff
mincolorname = d
return mincolorname
if __name__ == "__main__":
D={}
for line in lines.split("\n"):
tokens = line.split()
if len(tokens) > 1:
D[tokens[0]]= tokens[1]
R, G, B = 0, 127, 127
colorname = findnearestcolorname(0, 127, 127, D)
print hex(R), hex(G), hex(B)
print colorname, D[colorname]
When the above program runs, it outputs
$ python colornames.py
0x0 0x7f 0x7f
Teal #008080
Questions.
1. Modify the minimizaiton criterion to use least sum of squares of the differences.
2. Provide error checking for input R, G, B values to be within the interval [0, 255].
3. Procide different ways to specify the input RGB values, aside from the (R, G, B) values as done in the program above.
