Ffi-ncurses v0.4.0 released

Ruby
1

Hi,

I’m pleased to announce version 0.4.0 of the ffi-ncurses gem which
provides an FFI wrapper to the ncursesw library for creating
fullscreen terminal applications with cursor positioning, colour and
text windows.

This release has much better support for Unicode (aka widechars) both
on input and output and fully implements the ncursesw widechar
routines. It has been tested on Ubuntu 10.04 and 11.04 with MRI 1.8.7,
1.9.2 and jruby-head in 1.8.7 and 1.9.2 modes. A previous version was
tested on Mac OS X 10.4 - this version should still work but I have
not been able to test it yet.

It also contains some more substantial examples, in particular
showing how to handle Unicode input (in examples/getkey.rb), how to
temporarily leaves ncurses (examples/temp_leave.rb) and how to use
pads and popup windows (examples/viewer.rb).

I’ve tried to retain backward compatibility for those libraries that
depend on it but if I’ve missed something, please let me know on the
github issues page (Issues · seanohalpin/ffi-ncurses · GitHub).

To install:

$ [sudo] gem install ffi-ncurses

To run the examples, change to a scratch directory then

$ gem unpack ffi-ncurses
$ cd ffi-ncurses-0.4.0/examples
$ ./run-all.sh

Main Changes

  • Uses the ncursesw (widechar) version of ncurses by default.

  • Supports all functions in ncursesw except the =vwprintw/vwscanw=
    family.

  • Added =ACS= constants (box characters). See =examples/acs.rb= and
    =examples/wacs.rb=.

  • Added support for =libpanelw=. See =examples/panel_simple.rb=.

  • Methods with boolean arguments now accept =true= or =false= as well
    as 1 or 0.

  • Better examples. See =examples/viewer.rb= for a simple but complete
    file viewing application.

  • Sets the locale (using FFI::Locale.setlocale(LC_ALL, “”)) in ruby
    1.8.x to enable UTF-8 input. This adds a dependency on the
    ffi-locale gem. See =examples/getkey.rb= to see how to distinguish
    between function keys and Unicode characters.

  • Start of a compatibility layer for the existing C extension-based
    Ncurses Ruby libraries - require ‘ffi-ncurses/ncurses’. Runs all
    the examples from ncurses-ruby without changes (except those relying
    on menus and forms). See =examples/ncurses/*.rb=.

Source code available at GitHub - seanohalpin/ffi-ncurses: Interface to ncurses using Ruby FFI (Foreign Function Interface).

Regards,
Sean

2

On Sun, Sep 25, 2011 at 5:25 PM, Sean O’Halpin
[email protected]wrote:

1.9.2 and jruby-head in 1.8.7 and 1.9.2 modes. A previous version was
github issues page (Issues · seanohalpin/ffi-ncurses · GitHub).

ffi-locale gem. See =examples/getkey.rb= to see how to distinguish
Sean

This is really cool :slight_smile:

Could you add an example with nonblocking input? (ie for a game loop
that
gets input from user but continues playing even if user doesn’t do
anything)
I don’t seem to be able to figure out how to do it, my efforts were
based on
threads like this:

require ‘ffi-ncurses’
include FFI::NCurses

begin
initscr
raw
keypad stdscr, true
noecho
curs_set 0
ch = 0

key_getter = Thread.new do
while ch != KEY_CTRL_Q
ch = getch
addstr “You pressed #{ch}\n”
refresh
end
end

1.upto 5 do |i|
sleep 1
addstr “Running for #{i} seconds\n”
end

key_getter.kill

ensure
endwin
end

This approach works for the equivalent gets/puts:

line = “”
line_getter = Thread.new do
while line != “quit\n”
line = gets
puts “You wrote #{line}\n”
end
end

1.upto 5 do |i|
sleep 1
puts “Running for #{i} seconds\n”
end

line_getter.kill

3

Hi Josh,

To get non-blocking input in ncurses you have to change the input mode
using either nodelay or timeout. For example:

require ‘ffi-ncurses’

def KEY(ch)
ch[0].ord
end

include FFI::NCurses
initscr
begin
cbreak
noecho
curs_set 0
timeout(100) # delay in milliseconds
counter = 0
move 0, 0
scrollok(stdscr, true)
while (ch = getch) != KEY(“q”)
flushinp
addstr sprintf(“You pressed %d\n”, ch)
refresh
end
ensure
endwin
end

See “man timeout” for more details. Thanks for the feedback. I’ll add
this (and a threaded example) to the examples directory.

Regards,
Sean

4

On Mon, Sep 26, 2011 at 3:05 AM, Sean O’Halpin
[email protected]wrote:

while (ch = getch) != KEY(“q”)

Regards,
Sean

Thanks a lot, Sean :slight_smile: