Find The Colour Name From A Hexadecimal Colour Code
i want to find the name of a colour from the hexadecimal colour code. When i get a hex colour code i want to find the most matching colour name. for example for the code #c06040 ,
Solution 1:
There is a program distributed with the Python source called pynche which can do this
The functionality you need is in the method ColorDB.nearest() in ColorDB.py
From Python/Tools/README
Introduction
Pynche is a color editor based largely on a similar program that I
originally wrote back in 1987 for the Sunview window system. That
editor was called ICE, the Interactive Color Editor. I'd always
wanted to port this program to X but didn't feel like hacking X
and C code to do it. Fast forward many years, to where Python +
Tkinter provides such a nice programming environment, with enough
power, that I finally buckled down and re-implemented it. I
changed the name because these days, too many other systems have
the acronym `ICE'.
Pynche should work with any variant of Python after 1.5.2
(e.g. 2.0.1 and 2.1.1), using Tk 8.0.x. It's been tested on
Solaris 2.6, Windows NT 4, and various Linux distros. You'll want
to be sure to have at least Tk 8.0.3 for Windows. Also, Pynche is
very colormap intensive, so it doesn't work very well on 8-bit
graphics cards; 24bit+ graphics cards are so cheap these days,
I'll probably never "fix" that.
Pynche must find a text database of colors names in order to
provide `nearest' color matching. Pynche is distributed with an
rgb.txt file from the X11R6.4 distribution for this reason, along
with other "Web related" database (see below). You can use a
different file with the -d option. The file xlicense.txt contains
the license only for rgb.txt and both files are in the X/
subdirectory.
Pynche is pronounced: Pin'-chee
Running Standalone
On Unix, start it by running the `pynche' script. On Windows, run
pynche.pyw to inhibit the console window. When run from the
command line, the following options are recognized:
--database file
-d file
Alternate location of the color database file. Without this
option, the first valid file found will be used (see below).
--initfile file
-i file
Alternate location of the persistent initialization file. See
the section on Persistency below.
--ignore
-X
Ignore the persistent initialization file when starting up.
Pynche will still write the current option settings to the
persistent init file when it quits.
--help
-h
Print the help message.
initialcolor
a Tk color name or #rrggbb color spec to be used as the
initially selected color. This overrides any color saved in
the persistent init file. Since `#' needs to be escaped in
many shells, it is optional in the spec (e.g. #45dd1f is the
same as 45dd1f).
Running as a Modal Dialog
Pynche can be run as a modal dialog, inside another application,
say as a general color chooser. In fact, Grail 0.6 uses Pynche
and a future version of IDLE may as well. Pynche supports the API
implemented by the Tkinter standard tkColorChooser module, with a
few changes as described below. By importing pyColorChooser from
the Pynche package, you can run
pyColorChooser.askcolor()
which will popup Pynche as a modal dialog, and return the selected
color.
There are some UI differences when running as a modal
vs. standalone. When running as a modal, there is no "Quit" menu
item under the "File" menu. Instead there are "Okay" and "Cancel"
buttons.
When "Okay" is hit, askcolor() returns the tuple
((r, g, b), "name")
where r, g, and b are red, green, and blue color values
respectively (in the range 0 to 255). "name" will be a color name
from the color database if there is an exact match, otherwise it
will be an X11 color spec of the form "#rrggbb". Note that this
is different than tkColorChooser, which doesn't know anything
about color names.
askcolor() supports the following optional keyword arguments:
color
the color to set as the initial selected color
master[*]
the master window to use as the parent of the modal
dialog. Without this argument, pyColorChooser will create
its own Tkinter.Tk instance as the master. This may not
be what you want.
databasefile
similar to the --database option, the value must be a
file name
initfile[*]
similar to the --initfile option, the value must be a
file name
ignore[*]
similar to the --ignore flag, the value is a boolean
wantspec
When this is true, the "name" field in the return tuple
will always be a color spec of the form "#rrggbb". It
will not return a color name even if there is a match;
this is so pyColorChooser can exactly match the API of
tkColorChooser.
[*] these arguments must be specified the first time
askcolor() is used and cannot be changed on subsequent calls.
The Colorstrip Window
The top part of the main Pynche window contains the "variation
strips". Each strip contains a number of "color chips". The
strips always indicate the currently selected color by a highlight
rectangle around the selected color chip, with an arrow pointing
to the chip. Each arrow has an associated number giving you the
color value along the variation's axis. Each variation strip
shows you the colors that are reachable from the selected color by
varying just one axis of the color solid.
For example, when the selected color is (in Red/Green/Blue
notation) 127/127/127, the Red Variations strip shows you every
color in the range 0/127/127 to 255/127/127. Similarly for the
green and blue axes. You can select any color by clicking on its
chip. This will update the highlight rectangle and the arrow, as
well as other displays in Pynche.
Click on "Update while dragging" if you want Pynche to update the
selected color while you drag along any variation strip (this will
be a bit slower). Click on "Hexadecimal" to display the arrow
numbers in hex.
There are also two shortcut buttons in this window, which
auto-select Black (0/0/0) and White (255/255/255).
The Proof Window
In the lower left corner of the main window you see two larger
color chips. The Selected chip shows you a larger version of the
color selected in the variation strips, along with its X11 color
specification. The Nearest chip shows you the closest color in
the X11 database to the selected color, giving its X11 color
specification, and below that, its X11 color name. When the
Selected chip color exactly matches the Nearest chip color, you
will see the color name appear below the color specification for
the Selected chip.
Clicking on the Nearest color chip selects that color. Color
distance is calculated in the 3D space of the RGB color solid and
if more than one color name is the same distance from the selected
color, the first one found will be chosen.
Note that there may be more than one X11 color name for the same
RGB value. In that case, the first one found in the text database
is designated the "primary" name, and this is shown under the
Nearest chip. The other names are "aliases" and they are visible
in the Color List Window (see below).
Both the color specifications and color names are selectable for
copying and pasting into another window.
The Type-in Window
At the lower right of the main window are three entry fields.
Here you can type numeric values for any of the three color axes.
Legal values are between 0 and 255, and these fields do not allow
you to enter illegal values. You must hit Enter or Tab to select
the new color.
Click on "Update while typing" if you want Pynche to select the
color on every keystroke (well, every one that produces a legal
value!) Click on "Hexadecimal" to display and enter color values
in hex.
Other Views
There are three secondary windows which are not displayed by
default. You can bring these up via the "View" menu on the main
Pynche window.
The Text Window
The "Text Window" allows you to see what effects various colors
have on the standard Tk text widget elements. In the upper part
of the window is a plain Tk text widget and here you can edit the
text, select a region of text, etc. Below this is a button "Track
color changes". When this is turned on, any colors selected in
the other windows will change the text widget element specified in
the radio buttons below. When this is turned off, text widget
elements are not affected by color selection.
You can choose which element gets changed by color selection by
clicking on one of the radio buttons in the bottom part of this
window. Text foreground and background affect the text in the
upper part of the window. Selection foreground and background
affect the colors of the primary selection which is what you see
when you click the middle button (depending on window system) and
drag it through some text.
The Insertion is the insertion cursor in the text window, where
new text will be inserted as you type. The insertion cursor only
has a background.
The Color List Window
The "Color List" window shows every named color in the color name
database (this window may take a while to come up). In the upper
part of the window you see a scrolling list of all the color names
in the database, in alphabetical order. Click on any color to
select it. In the bottom part of the window is displayed any
aliases for the selected color (those color names that have the
same RGB value, but were found later in the text database). For
example, find the color "Black" and you'll see that its aliases
are "gray0" and "grey0".
If the color has no aliases you'll see "<no aliases>" here. If you
just want to see if a color has an alias, and do not want to select a
color when you click on it, turn off "Update on Click".
Note that the color list is always updated when a color is selected
from the main window. There's no way to turn this feature off. If
the selected color has no matching color name you'll see
"<no matching color>" in the Aliases window.
The Details Window
The "Details" window gives you more control over color selection
than just clicking on a color chip in the main window. The row of
buttons along the top apply the specified increment and decrement
amounts to the selected color. These delta amounts are applied to
the variation strips specified by the check boxes labeled "Move
Sliders". Thus if just Red and Green are selected, hitting -10
will subtract 10 from the color value along the red and green
variation only. Note the message under the checkboxes; this
indicates the primary color level being changed when more than one
slider is tied together. For example, if Red and Green are
selected, you will be changing the Yellow level of the selected
color.
The "At Boundary" behavior determines what happens when any color
variation hits either the lower or upper boundaries (0 or 255) as
a result of clicking on the top row buttons:
Stop
When the increment or decrement would send any of the tied
variations out of bounds, the entire delta is discarded.
Wrap Around
When the increment or decrement would send any of the tied
variations out of bounds, the out of bounds value is wrapped
around to the other side. Thus if red were at 238 and +25
were clicked, red would have the value 7.
Preserve Distance
When the increment or decrement would send any of the tied
variations out of bounds, all tied variations are wrapped as
one, so as to preserve the distance between them. Thus if
green and blue were tied, and green was at 238 while blue was
at 223, and +25 were clicked, green would be at 15 and blue
would be at 0.
Squash
When the increment or decrement would send any of the tied
variations out of bounds, the out of bounds variation is set
to the ceiling of 255 or floor of 0, as appropriate. In this
way, all tied variations are squashed to one edge or the
other.
The top row buttons have the following keyboard accelerators:
-25 == Shift Left Arrow
-10 == Control Left Arrow
-1 == Left Arrow
+1 == Right Arrow
+10 == Control Right Arrow
+25 == Shift Right Arrow
Keyboard Accelerators
Alt-w in any secondary window dismisses the window. In the main
window it exits Pynche (except when running as a modal).
Alt-q in any window exits Pynche (except when running as a modal).
Persistency
Pynche remembers various settings of options and colors between
invocations, storing these values in a `persistent initialization
file'. The actual location of this file is specified by the
--initfile option (see above), and defaults to ~/.pynche.
When Pynche exits, it saves these values in the init file, and
re-reads them when it starts up. There is no locking on this
file, so if you run multiple instances of Pynche at a time, you
may clobber the init file.
The actual options stored include
- the currently selected color
- all settings of checkbox and radio button options in all windows
- the contents of the text window, the current text selection and
insertion point, and all current text widget element color
settings.
- the name of the color database file (but not its contents)
You can inhibit Pynche from reading the init file by supplying the
--ignore option on the command line. However, you cannot suppress
the storing of the settings in the init file on Pynche exit. If
you really want to do this, use /dev/null as the init file, using
--initfile.
Color Name Database Files
Pynche uses a color name database file to calculate the nearest
color to the selected color, and to display in the Color List
view. Several files are distributed with Pynche, described
below. By default, the X11 color name database file is selected.
Other files:
html40colors.txt -- the HTML 4.0 guaranteed color names
websafe.txt -- the 216 "Web-safe" colors that Netscape and MSIE
guarantee will not be dithered. These are specified in #rrggbb
format for both values and names
webcolors.txt -- The 140 color names that Tim Peters and his
sister say NS and MSIE both understand (with some controversy over
AliceBlue).
namedcolors.txt -- an alternative set of Netscape colors.
You can switch between files by choosing "Load palette..." from
the "File" menu. This brings up a standard Tk file dialog.
Choose the file you want and then click "Ok". If Pynche
understands the format in this file, it will load the database and
update the appropriate windows. If not, it will bring up an error
dialog.
To Do
Here's a brief list of things I want to do (some mythical day):
- Better support for resizing the top level windows
- More output views, e.g. color solids
- Have the notion of a `last color selected'; this may require a
new output view
- Support setting the font in the text view
- Support distutils setup.py for installation
I'm open to suggestions!
Local Variables:
indent-tabs-mode: nil
End:
Solution 2:
Hexadecimal web colour values are just a form of RGB. Convert your RGB values to HSL, and then partition the Hue space into the different colours.
For example, a Hue value of about 0-19 would be "red", 20-39 "orange", 40-59 "yellow", etc. (These numbers are not exact, I just had a quick glance at the Hue chart on the Wikipedia page.)
For a more complex analysis of the colour name, use the Lightness value also. For example, "brown" is just a darker yellow.
Solution 3:
You can build dict of hex codes as keys and human readable color names as values.
Here is a heuristic/fuzzy function for guessing what a color might look like ;)
colorof = {'f0f8ff':"Alice Blue",
'faebd7':"Antique White",
'000000':"Black"}
def get_color_name(hx):
# if color is found in dict
if colorof.has_key(hx):return colorof[hx]
# else return its closest available color
m = 16777215
k = '000000'
for key in colorof.keys():
a = int(hx[:2],16)-int(key[:2],16)
b = int(hx[2:4],16)-int(key[2:4],16)
c = int(hx[4:],16)-int(key[4:],16)
v = a*a+b*b+c*c # simple measure for distance between colors
# v = (r1 - r2)^2 + (g1 - g2)^2 + (b1 - b2)^2
if v <= m:
m = v
k = key
return colorof[k]
print get_color_name('f0f8ff') # found in dict
print get_color_name('faeb11') # closest to Antique white
Solution 4:
Here is a small example I have written, which uses the pearson coefficient to compare two colors and chooses the most similar color from a dict. This solution is probably not the most efficient one, but the results should be quite good:
import re
re_color = re.compile('#([0-9a-f]{2})([0-9a-f]{2})([0-9a-f]{2})')
from math import sqrt
def color_to_rgb(color):
return tuple(int(x, 16) / 255.0 for x in re_color.match(color).groups())
def similarity(color1, color2):
"""Computes the pearson correlation coefficient for two colors. The result
will be between 1.0 (very similar) and -1.0 (no similarity)."""
c1 = color_to_rgb(color1)
c2 = color_to_rgb(color2)
s1 = sum(c1)
s2 = sum(c2)
sp1 = sum(map(lambda c: pow(c, 2), c1))
sp2 = sum(map(lambda c: pow(c, 2), c2))
sp = sum(map(lambda x: x[0] * x[1], zip(c1, c2)))
return (sp - (s1 * s2 / 3.0)) / sqrt((sp1 - pow(s1, 2) / 3.0) * (sp2 - pow(s2, 2) / 3.0))
color_names = {
'#ff0000': 'red',
'#00ff00': 'green',
'#0000ff': 'blue'
# add more color definitions here
}
def find_name(color):
sim = [(similarity(color, c), name) for c, name in color_names.items()]
return max(sim, key=lambda x: x[0])[1]
print find_name('#cc0000') # returns "red"
Solution 5:
Your code is precious @tux21b, but it fails with more color_names and non really approaching web-color value. It crashes with a Divide by Zero Error on this line :
return (sp - (s1 * s2 / 3.0)) / sqrt((sp1 - pow(s1, 2) / 3.0) * (sp2 - pow(s2, 2) / 3.0))
I'm not a good mathematician, but I was thinking that, if the similarity function returns a value from -1 (not similar) to +1 (exact color), then if a divide by zero occured, it should return 0 ? So I've fixed your code like this :
try:
computed = (sp - (s1 * s2 / 3.0)) / sqrt((sp1 - pow(s1, 2) / 3.0) * (sp2 - pow(s2, 2) / 3.0))
except:
computed = 0
return computed
Then, it works well and returns the good approaching values, even with a larger set of predefined colors like this:
color_names = {
'#000000': 'black',
'#ffffff': 'white',
'#808080': 'dark gray',
'#b0b0b0': 'light gray',
'#ff0000': 'red',
'#800000': 'dark red',
'#00ff00': 'green',
'#008000': 'darkgreen',
'#0000ff': 'blue',
'#000080': 'dark blue',
'#ffff00': 'yellow',
'#808000': 'olive',
'#00ffff': 'cyan',
'#ff00ff': 'magenta',
'#800080': 'purple'
}
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