Scenes

Scenes are very usefull. You can make a game inside a game with this feature. Scenes have their own ui refresh and keyboard handler function. You may use that for a minigame, boss fight, puzzle or something like that.

Scenes are very simple for their job. Let's look cr.obj.scene's fields again:

Field	Type	Description
exit_key	integer	Exit key. (default: `string.byte('q')')
ui_refresh()	Function	Functions to refresh UI.
key_handler(key)	Function takes 1 integer	Function to handle keyboard
run()	Function	Run method

ui_refresh() and run() does not take an argument or return a value. key_handler(key) gets an integer containing a key number and returns a bool value (is scene finished?). Use string.byte(char) to convert char to integer, and string.char(key) to convert key to character. You can use cr.curses.KEY_ constants in key_handler. When user presses the exit_key scene ends and exits. 0 to disable.

And look at the cr.create_scene example:

local last_key = 0;
local scene = cr.create_scene({
    ui_refresh = function()
        cr.curses.clear();
        if last_key == 0 then
            cr.curses.mvprintw(0, 0, "Press a key")
        else
            cr.curses.mvprintw(0, 0, "You pressed: " .. string.char(last_key))
        end
        cr.curses.refresh()
    end,

    key_handler = function(key)
        if key == string.byte('r') then
            -- Make things red
            cr.curses.attron(cr.curses.ansi2attr("31m"))

        elseif key == string.byte('R') then
            -- Disable red
            cr.curses.attroff(cr.curses.ansi2attr("31m"))

        elseif key == 27 then
            -- ESC pressed! Make italic!
            cr.curses.attron(cr.curses.ansi2attr("3m"))

        elseif key == cr.curses.KEY_ENTER then
            -- enter pressed. disable italic
            cr.curses.attroff(cr.curses.ansi2attr("3m"))
 
        elseif key == cr.curses.KEY_BACKSPACE then
            -- backspace pressed . that is an alternative way to finish scene
            return true;
        end

        last_key = key
        return false; -- scene not finished
    end
})

-- After creating scene run it:
scene:run()