ColorConsole

ColorConsole is a small cross-platform library for outputting color text to the console on both Linux and Windows, as well as providing utilities for drawing progress bars and outputting tabular data.

On Windows, Fiddler (under MRI) or FFI (other engines) is used to dynamically link to the Windows Console API functions, while on other platforms, ANSI escape sequences are used. As such, there are no dependencies and no libraries to install other than this gem.

ColorConsole is supplied as a gem, and has no dependencies. To use it, simply:

gem install color-console

ColorConsole provides methods for outputting lines of text in different colors, using the Console.write and Console.puts functions.

require 'color-console'

Console.puts "Some text"                    # Outputs text using the current console colours
Console.puts "Some other text", :red        # Outputs red text with the current background
Console.puts "Yet more text", nil, :blue    # Outputs text using the current foreground and a blue background

# The following lines output BlueRedGreen on a single line, each word in the appropriate color
Console.write "Blue ", :blue
Console.write "Red ", :red
Console.write "Green", :green

In addition to Console.puts and Console.write for outputting text in color, ColorConsole also supports:

• Setting the console title: The title bar of the console window can be set using Console.title = 'My title'.

• Status messages: Status messages (i.e. a line of text at the current scroll position) can be output and updated at any time. The status message will remain at the current scroll point even as new text is output using Console.puts.

• Progress bars: A progress bar can be rendered like a status message, but with a pseudo-graphical representation of the current completion percentage:

  (0..100).do |i|
      Console.show_progress('Processing data', i)
  end
  Console.clear_progress

  Output:

  [==============    35%                   ]  Processing data
  

• Tables: Data can be output in a tabular representation:

  HEADER_ROW = ['Column 1', 'Column 2', 'Column 3', 'Column 4']
  MIXED_ROW = [17,
               'A somewhat longer column',
               'A very very very long column that should wrap multple lines',
               'Another medium length column']
  SECOND_ROW = [24,
                'Lorem ipsum',
                'Some more text',
                'Lorem ipsum dolor sit amet']
  
  Console.display_table([HEADER_ROW, MIXED_ROW, SECOND_ROW], width: 100,
                        col_sep: '|', row_sep: '-')

  Output:

  +----------+--------------------------+-----------------------------+-----------------------------+
  | Column 1 | Column 2                 | Column 3                    | Column 4                    |
  +----------+--------------------------+-----------------------------+-----------------------------+
  |       17 | A somewhat longer column | A very very very long       | Another medium length       |
  |          |                          | column that should wrap     | column                      |
  |          |                          | multple lines               |                             |
  +----------+--------------------------+-----------------------------+-----------------------------+
  |       24 | Lorem ipsum              | Some more text              | Lorem ipsum dolor sit amet  |
  +----------+--------------------------+-----------------------------+-----------------------------+
  

• Color Logging: If you are using java.util.logging under JRuby, or the Ruby logging library Log4r, you can obtain colour log messages by replacing the console handler with one provided by this gem:

  # If using Log4r for logging...
  require 'color_console/log4r_logger'
  Console.replace_console_logger(level: :info)
  
  # Or under JRuby with java.util.logging...
  require 'color_console/java_util_logger'
  Console.replace_console_logger(level: :fine, format: '%4$-6s %5$s%n')