This week I was playing around with creating a complex terminal game. I immediately though about Curses.
If you don’t know Curses is an old C library for manipulating text in the terminal. It, and its newer brother NCurses, has been used to create applications from famous games to text editors.
The Good
I found out that Curses is actually built into most distributions of Ruby. That means getting started with Curses is only a require away.
The Bad
Seeing how Curses is a 30+ year old library, its syntax is very un-ruby like and needs a bit of knowhow.
The first thing to when learning how to use Curses with Ruby is read the documentation on ruby-doc.org. The documentation there gives some sample problems, and an intro to the syntax. Unfortunately, other than the sample problems the documentation is sadly lacking. Here’s some features that the docs don’t cover.
Colors
Colors in Curses a defined in terms of color_pairs. A color_pair is two colors, the first being the foreground color and the second being the background. Color pairs must be defined before they are used.
Curses.init_pair(COLOR_BLUE,COLOR_BLUE,COLOR_BLACK)This will create the COLOR_BLUE color pair with a blue foreground and a black background. Using this color pairs have a funny syntax as well.
Curses.attron(color_pair(COLOR_BLUE)|A_NORMAL) {
Curses.addstr("I'm in blue!!")
}Curses.attron takes a hash of attributes that it then applies to the block it receives. The color_pair and the A_NORMAL constant work together to create a full attributes hash thats needed.
It my next post I’ll talk about speed.