ruby based curses widgets: fields, buttons, textarea. menus, message boxes, tabbed panes, tables, listboxes, splitpanes, scrollpanes. Event based, MVC architecture.
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rbcurse (for ruby 1.9.x)

  • Version that works with ruby 1.9 (backward compatible with 1.8.7)

  • 1.2.0: many additions (See CHANGELOG for details)

    • App class that wraps the environment and makes application development very easy
    • New controls such as:
      • vimsplit: allows multiple vertical and horizontal splits in one component
      • progress bar
      • Tree control
      • Divider (can grab and move, so as to visually resize components)
      • Scrollbar class that can be easily attached to lists, tables etc
      • Tabular data widgets and data converters

    Please see CHANGELOG for changes.

  • rbcurse 1.1.4 works with 1.9.2 and also contains some files that got missed out in gemspec.

  • Corrections due to 1.9.2:

    • hash_update: rwidget.rb and rtable.rb Please report any more errors due to this
    • $: does not contain "." (affects some examples only)

Check downloads at

test2.rb works - i always give it a quick run after making changes. All the testsplit* and testscroll* examples are working. If using ruby1.9.2, you might say: ruby -I. test2.rb.


A small but comprehensive widget library written in ruby for creating ncurses applications.


  • Field : text/entry fields in pure ruby (not ncurses)
  • scrollable list box (also editable lists with Field, checkbox and combos)
  • Textarea : multi-line editable area
  • togglebutton, radio and check buttons (with mnemonics)
  • message box
  • menubar - with submenu and CheckBoxMenuItem
  • popup list
  • tabbedpane (multiple forms using tabbed metaphor)
  • combobox
  • labels with mnemonics (hotkeys)
  • Table: multi-column table - with cell selection and editing, horizontal and vertical scrolling
  • Scrollpanes which can contain textviews, textareas, listboxes.
  • Splitpanes which can contain scrollpanes, textviews/areas, listboxes or splitpanes ...
  • MultiContainer = add any number of objects to it (such as tables or text objects) and cycle through them (saves screen estate)
  • MultiTextView - have multiple files open for viewing in one component. Since these are readonly files, one can map a lot of single-keys as in vim for operating and cycling through buffers.
  • Textview - editable option using vim like keys.
  • PromptMenu - A simple interactive menu like the most application. Saves on allocating keybindings and memorizing them.
  • multiple key bindings for Procs, block and symbols (as in vim and emacs: C-x C-f or 15dd)
  • Kill-ring concept of emacs for cut-paste operations
  • Unlimited undo and redo in TextArea (needs to be switched on at present on instance basis)
  • Numeric arguments. (vim: 25dd etc. Or in an editable box, emacs's C-u or Alt-1..9)
  • Various others, too

Above may be created using DSL like syntax, or hashes, and modified at runtime. Very flexible unlike ncurses forms and fields.

Current work

I've just added vi and emacs key bindings to some classes, multiple object containers such as MultiContainer and MultiTextView. Emacs like kill-ring in TextArea and TextView. Tabbedpane can have unlimited tabs, we can scroll the tabs. Bunch of other stuff. Multiple keys can be bound to a Proc or symbol as in emacs and vim (dd or C-x C-f).

I've made a demo using ScrollForm (testscroller.rb)- a form that takes more fields/objects than can be viewed at a go. Meta keys scroll the form. Then onto testing what's there, before making a stable release.

Sample programs:

  • test2.rb most widgets (including menus)
  • sqlc.rb is a ruby sql client demo (using sqlite3-ruby)
  • rfe : file explorer or Finder like app
  • testcombo.rb combos with various insert policies and vertical alignments
  • testtodo.rb : a todo app based on a yaml file (now csv)
  • testmenu.rb : popup menu with multiple levels
  • testtabp.rb tabbed pane
  • test1.rb various kinds of messageboxes (input, list, custom) pass 1,2,3,4, or 5 as argument on command line ruby test1.rb 1 ruby test1.rb 2
  • test2.rb most widgets (including menus)

    • partially tested, many widgets, needs thorough testing.
  • testscroll*.rb - various demos of scrollpanes with listboxes, text areas, tables etc

  • testsplit*.rb - various splitpanes with scrollpanes and other objects placed inside See screenshots on blog.

  • testtpane.rb - tabbedpane sample with a scrollpane and a textobject.


General terminal related issues.

The following are issues with terminals (or with ncurses-ruby in some cases) not with rbcurse.

  • Some terminals may not show underlines (e.g screen).

  • Some terminals (xterm-color) do not process Function keys, avoid declaring F1 etc if unsure of client terminals. I have put in fixes for xterm-color F1 and backtab.

  • To use ALT/META keys on a Mac OS X, in Terminal preferences, under Keyboard, select "use Option as Meta key". All hotkeys are automatically, ALT combinations.

  • Some screens do not display window background color under spaces. This is okay under "screen" and "xterm-color" but not under "xterm". You will notice this in the message box samples.

I am developing and testing under "screen" under OS X Leopard 10.5.8 PPC (now 10.6.x Snow Leopard).


See lib/rbcurse/rwidgets.rb. For test programs, see test1, test2, testcombo etc in examples folder.

This depends only on "window" provided by ncurses. Does not use forms and fields. Minor changes and improvements may have happened to sample code below. See test programs for latest, working code.

THE following samples are only demonstrative of how widgets are built. See samples in examples folder for initialization of ncurses etc which is necessary before the following code can be run. The following samples may be slightly obsolete.

create a window and a form based on window

  @layout = { :height => 0, :width => 0, :top => 0, :left => 0 } 
  @win =

  @form = @win

create a bunch of fields with dependent labels

  r = 1; c = 22;
  %w[ name age company].each do |w|
    field = @form do
      name   w 
      row  r 
      col  c 
      display_length  30
      set_buffer "abcd #{w}" 
      set_label @form, {'text' => w}
    r += 1

create a variable (like TkVariable) and tie a label to it.

  $results =
  $results.value = "A variable"
  var = @form, {'text_variable' => $results, "row" => r, "col" => 22}
    r += 1

create a list and a list box based on the list.

    mylist = []
    0.upto(100) { |v| mylist << "#{v} scrollable data" }

    field = @form do
      name   "mylist" 
      row  r 
      col  1 
      width 40
      height 10
      list mylist
    field.insert 5, "hello ruby", "so long python", "farewell java", "RIP .Net"

create a textarea for entry

    texta = @form do
      name   "mytext" 
      row  1 
      col  52 
      width 40
      height 20
    texta << "hello there" << "Some text to go into textarea."
    texta << "HELLO ruby" << "Some text to go into textarea."

create a check box, updates a Variable

  checkbutton = @form do
    text_variable $results
    #value = true
    onvalue "selected cb"
    offvalue "UNselected cb"
    text "Please click me"
    row 17
    col 22

change field properties at any time by referring to them by name

  @form.by_name["age"].display_length = 3
  @form.by_name["age"].maxlen = 3
  @form.by_name["age"].set_buffer  "24"
  @form.by_name["name"].set_buffer  "Not focusable"
  @form.by_name["age"].chars_allowed = /\d/

  @form.by_name["password"].color 'red'
  @form.by_name["password"].bgcolor 'blue'

  # restrict entry to some values
  password.values(%w[ scotty tiger secret qwerty])

  # validation using ruby's regular expressions


bind events to forms, and fields

  @form.bind(:ENTER) { |f|   f.label.bgcolor = $promptcolor if f.instance_of? RubyCurses::Field}
  @form.bind(:LEAVE) { |f|  f.label.bgcolor = $datacolor  if f.instance_of? RubyCurses::Field}

create buttons

  ok_button = @form do
    text "OK"
    name "OK"
    row 18
    col 22
  ok_button.command { |form| $results.value = "OK PRESS:";form.printstr(@window, 23,45, "OK CALLED") }
    #text "Cancel"
  cancel_button = @form do
    text_variable $results
    row 18
    col 28
  cancel_button.command { |form| form.printstr(@window, 23,45, "Cancel CALLED"); throw(:close); }

create radio buttons

  colorlabel = @form, {'text' => "Select a color:", "row" => 20,
      "col" => 22, "color"=> "cyan"}
  $radio =
  radio1 = @form do
    text_variable $radio
    text "red"
    value "red"
    color "red"
    row 21
    col 22
  radio2 = @form do
    text_variable $radio
    text  "green"
    value  "green"
    color "green"
    row 22
    col 22

create a messagebox

  @mb = do
    title "Enter your name"
    message "Enter your name"
    type :input
    default_value "rahul"
    default_button 0
    #title "Color selector"
    #type :custom
    #buttons %w[red green blue yellow]
    #underlines [0,0,0,0]

 $log.debug "MBOX : #{@mb.selected_index} "
 $log.debug "MBOX : #{@mb.input_value} "

create a read-only scrollable view of data

    @textview = @form do
      name   "myView" 
      row  16 
      col  52 
      width 40
      height 7
    content ="../../README.markdown","r").readlines
    @textview.set_content content

    ## set it to point to row 21
    @textview.top_row 21

    # lets scroll the text view as we scroll the listbox

    listb.bind(:ENTER_ROW, @textview) { |arow, tview| tview.top_row arow }

    # lets scroll the text view to the line you enter in the numeric
    # field
    @form.by_name["line"].bind(:LEAVE, @textview) { |fld, tv| tv.top_row(fld.getvalue.to_i) }

    # lets scroll the text view to the first match of the regex you
    # enter
    @form.by_name["regex"].bind(:LEAVE, @textview) { |fld, tv| tv.top_row(tv.find_first_match(fld.getvalue)) }

    # change the value of colorlabel to the selected radiobutton
    # (red or green)

    $radio.update_command(colorlabel) {|tv, label|  label.color tv.value}

    # change the attribute of colorlabel to bold or normal

    $results.update_command(colorlabel,checkbutton) {|tv, label, cb| 
        attrs =  cb.value ? 'bold' : nil; label.attrs(attrs)}

  # during menu creation, create a checkboxmenuitem

  item = "CheckMe"

  # when selected, make colorlabel attribute reverse.

  item.command(colorlabel){|it, label| att = it.getvalue ? 'reverse' :
      nil; label.attrs(att); label.repaint}


  • ruby 1.9.1, 1.9.2 (I believe it is working on 1.8.7, 1.8.6 as well).

  • ncurses-ruby (1.2.4)

(Note: 1.8.6 users: pls report any issues and suggest a fix or alternative if you encounter a method_missing)


STEP 1. (In following commands, use sudo if installing gems in readonly are such as /opt/local/).

gem install ncurses

Often this gives compilation errors, or runtime errors when you run the examples. If so, please download ncurses-1.2.4.gem from and do a:

gem install --local ncurses-1.2.4.gem.

This should have installed an ncurses.rb and ncurses_bin.bundle in the site directory. Goto examples directory and run some examples:

ruby rain.rb
ruby examples.rb


gem install rbcurse

Now go to the the examples folder and execute some examples. Each sample writes to a log file named view.log. If the examples folder is readonly, you will have to set LOGDIR to a writable folder as below.

cd examples 
ruby test2.rb
LOGDIR=~/tmp ruby test1.rb

Note: Please use rbcurse gem version 1.1.3 or higher. I have just created this gem, so let me know if there are missing files.

Installing ncurses-ruby on Mac OS X Snow Leopard

ncurses-ruby has been failing on OSX Snow Leopard. Please get 1.2.4 or 0.9.2 from Ensure that the examples are working before trying rbcurse.

I have uploaded a modified ncurses gem here . Download this and then run:

gem install --local ncurses-1.2.4.gem

OR gem install --local ncurses-0.9.2.gem

Thanks to Ralf Papenkordt for providing me with a working tar.bz2 file (see download folder).

Update: I've uploaded a gem for Snow Leopard onto

gem install snowleopard-ncurses


Copyright (c) 2008 -2010 rkumar

Same as ruby license.