colour_text

colour_text and colour-print command

colour-print is a command that makes printing coloured text easier to do on Unix, macOS and Windows. It uses the ColourText class to colour the text.

The command uses markup using <>colour-name text<>.

    $ colour-print "<>info Info:<> this is an <>em informational<> message"
    $ colour-print "<>error Error: This is an error message<>"

The first argument is treated as a format string if there are more arguments.

    $ colour-print "<>info Info:<> Home folder is %s" "$HOME"

class ColourText

The ColourText class converts strings with colour markup into a form suitable for printing on a terminal that support colour text. This include most terminal emulators on macOS, Windows and Unix.

To colour a section of text use the marker followed by the colour name a space and the text to be coloured ending with the marker.

    from colour_text import ColourText

    ct = ColourText()
    ct.initTerminal()

    print( ct.convert( "The next section is in green: <>green example<>." ) )

To include the marker as literal text use two adjacent markers.

    from colour_text import ColourText

    ct = ColourText()
    ct.initTerminal()

    print( ct("A <>red literal marker<> <><> in the string") )

ColoutText can be use with gettext for internationalized applications.

    from colour_text import ColourText

    ct = ColourText()
    ct.initTerminal()

    message = "<>red Error: cannot open file %s<>"
    i18n_message = _(message)
    coloured_i18n_message = ct(i18n_message)
    formatted_message = coloured_i18n_message % (file_name,)

    print( formatted_message )

    # or in one line
    print ct( _("<>red Error: cannot open file %s<>") ) % (file_name,) )

class ColourText

• __init__( marker='<>' )

  The marker is the string used to markup the colour sections which defaults to <>.

• initTerminal()

  Ensure the terminal can display coloured text.

  Must be called on Windows and can be safely called on macOS and Unix systems.

• define( name, colour_def )

  Define a colour name for use in the marked up sections. The colour_def is a list of existing colour names or a single name.

  The builtin foreground colour names are:

    bold, black, brown, green, yellow, blue,
    magenta, cyan, gray, red, lightred, lightgreen,
    lightyellow, lightblue, lightmagenta, lightcyan
    and white.
  

  The builtin background colour names are:

    bg-black, bg-brown, bg-green, bg-yellow,
    bg-blue, bg-magenta, bg-cyan, bg-gray
    and bg-white.
  

  For example add the name info as green text and error as to be red text on a white background:

        ct = ColourText()
        ct.define( 'info', 'green' )
        ct.define( 'error', ('red', 'bg-white') )

        ct( "Error messages are <>error shown like this<>" ) 

• convert( colour_text )

  Interpret the colour markup in the colour_text string and return a string suitable for printing on the terminal.

• __call__( colour_text )

  Call convert( colour_text ) in a concise way.