ANSI graphic codes and Python

Question

I was browsing the Django source code and I saw this function:

def colorize(text='', opts=(), **kwargs):
    """
    Returns your text, enclosed in ANSI graphics codes.

    Depends on the keyword arguments 'fg' and 'bg', and the contents of
    the opts tuple/list.

    Returns the RESET code if no parameters are given.

    Valid colors:
    'black', 'red', 'green', 'yellow', 'blue', 'magenta', 'cyan', 'white'

    Valid options:
    'bold'
    'underscore'
    'blink'
    'reverse'
    'conceal'
    'noreset' - string will not be auto-terminated with the RESET code

    Examples:
    colorize('hello', fg='red', bg='blue', opts=('blink',))
    colorize()
    colorize('goodbye', opts=('underscore',))
    print colorize('first line', fg='red', opts=('noreset',))
    print 'this should be red too'
    print colorize('and so should this')
    print 'this should not be red'
    """
    code_list = []
    if text == '' and len(opts) == 1 and opts[0] == 'reset':
        return '\x1b[%sm' % RESET       
    for k, v in kwargs.iteritems(): 
        if k == 'fg':
            code_list.append(foreground[v]) 
        elif k == 'bg':
            code_list.append(background[v]) 
    for o in opts:
        if o in opt_dict:
            code_list.append(opt_dict[o])   
    if 'noreset' not in opts:
        text = text + '\x1b[%sm' % RESET
    return ('\x1b[%sm' % ';'.join(code_list)) + text

I removed it out of the context and placed in another file just to try it, the thing is that it doesn't seem to colour the text I pass it. It might be that I don't understand it correctly but isn't it supposed to just return the text surrounded with ANSI graphics codes which than the terminal will convert to actual colours.

I tried all the given examples of calling it, but it just returned the argument I specified as a text.

I'm using Ubuntu so I think the terminal should support colours.

Answer 1

It's that you have many terms undefined, because it relies on several variables defined outside of the function.

Instead just

import django.utils.termcolors as termcolors
red_hello = termcolors.colorize("Hello", fg='red') # '\x1b[31mHello\x1b[0m'
print red_hello

Or just also copy the first few lines of django/utils/termcolors.py specifically:

color_names = ('black', 'red', 'green', 'yellow', 'blue', 'magenta', 'cyan', 'white')
foreground = dict([(color_names[x], '3%s' % x) for x in range(8)])
background = dict([(color_names[x], '4%s' % x) for x in range(8)])
RESET = '0'

def colorize( ... ):
    ...
print colorize("Hello", fg='red') # '\x1b[31mHello\x1b[0m'

Also note:

>>> from django.utils.termcolors import colorize
>>> red_hello = colorize("Hello", fg="red")
>>> red_hello # by not printing; it will not appear red; special characters are escaped
'\x1b[31mHello\x1b[0m'
>>> print red_hello # by print it will appear red; special characters are not escaped
Hello