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Colors

Doing colors with blessed is easy, pick a color name from the Color chart below, any of these named are also attributes of the terminal!

These attributes can be printed directly, causing the terminal to switch into the given color. Or, as a callable, which terminates the string with the normal attribute. The following three statements are equivalent:

>>> print(term.orangered + 'All systems are offline' + term.normal) >>> print(f'{term.orangered}All systems are offline{term.normal}') >>> print(term.orangered('All systems are offline'))

To use a background color, prefix any color with on_:

>>> print(term.on_darkolivegreen('welcome to the army'))

And combine two colors using "_on_", as in "foreground_on_background":

>>> print(term.peru_on_seagreen('All systems functioning within defined parameters.'))

24-bit Colors

Most Terminal emulators, even Windows, has supported 24-bit colors since roughly 2016. To test or force-set whether the terminal emulator supports 24-bit colors, check or set the terminal attribute ~Terminal.number_of_colors:

>>> print(term.number_of_colors == 1 << 24) True

Even if the terminal only supports 256, or worse, 16 colors, the nearest color supported by the terminal is automatically mapped:

>>> term.number_of_colors = 1 << 24 >>> term.darkolivegreen 'x1b[38;2;85;107;47m'

>>> term.number_of_colors = 256 >>> term.darkolivegreen 'x1b[38;5;58m'

>>> term.number_of_colors = 16 >>> term.darkolivegreen 'x1b[90m'

And finally, the direct (r, g, b) values of 0-255 can be used for ~.Terminal.color_rgb and ~.Terminal.on_color_rgb for foreground and background colors, to access each and every color!

256 Colors

The built-in capability ~.Terminal.color accepts a numeric index of any value between 0 and 254, I guess you could call this "Color by number...", it not recommended, there are many common cases where the colors do not match across terminals!

16 Colors

Recommended for common CLI applications.

Traditional terminals are only capable of 8 colors:

  • black
  • red
  • green
  • yellow
  • blue
  • magenta
  • cyan
  • white

Prefixed with on_, the given color is used as the background color:

  • on_black
  • on_red
  • on_green
  • on_yellow
  • on_blue
  • on_magenta
  • on_cyan
  • on_white

The same colors, prefixed with bright_ or bold_, such as bright_blue, provides the other 8 colors of a 16-color terminal:

  • bright_black
  • bright_red
  • bright_green
  • bright_yellow
  • bright_blue
  • bright_magenta
  • bright_cyan
  • bright_white

Combined, there are actually three shades of grey for 16-color terminals, in ascending order of intensity:

  • bright_black: is dark grey.
  • white: a mild white.
  • bright_white: pure white (#ffffff).

Note

  • bright_black is actually a very dark shade of grey!
  • yellow is brown, only high-intensity yellow (bright_yellow) is yellow!
  • purple is magenta.

Warning

Terminal emulators use different values for any of these 16 colors, the most common of these are displayed at https://en.wikipedia.org/wiki/ANSI_escape_code#3/4_bit. Users can customize these 16 colors as a common "theme", so that one CLI application appears of the same color theme as the next.

When exact color values are needed, 24-bit Colors should be preferred, by their name or RGB value.

Monochrome

One small consideration for targeting legacy terminals, such as a vt220, which do not support colors but do support reverse video: select a foreground color, followed by reverse video, rather than selecting a background color directly:: the same desired background color effect as on_background:

>>> print(term.on_green('This will not standout on a vt220')) >>> print(term.green_reverse('Though some terminals standout more than others'))

The second phrase appears as black on green on both color terminals and a green monochrome vt220.