gistfile1.rb

require 'rubygems'
require 'gosu'

include Gosu

class GameWindow < Window
  
  # Word Wrap method shamelessly stolen from: http://www.libgosu.org/cgi-bin/mwf/topic_show.pl?tid=94
  def wordwrap(message,width,font)
    #split the message into multiple words
    word_array = message.split(' ')
    
    #begin the lines array with the first word; this will be an array of strings
    lines = [word_array.shift]
    
    #Loop over each word...
    word_array.each do |word|
      #as long as the line + this word doesn't exceed the width...
      if font.text_width("#{lines[-1]} #{word}") < width
        #push the word onto the last string in the array with a space
        lines[-1] << ' ' << word
      else
        #otherwise, push the current word onto the next line
        lines.push(word)
      end
    end
    
    return lines
  end
  
  def initialize
    super(640, 480, false)
    self.caption = "Gosu Text Scrolling Example"
    
    #Setup the font to be used
    @font = Font.new(self,default_font_name,20)
    
    #Create a long string for wrapping
    @message = "Hello and welcome to my very long text string which is also pretty boring and stupid, but oh well I guess there is a time and a place for lorum ipsum, and this was probably it, but I didn't have any handy so we get this crap instead, which is too bad really, because Lorem Ipsum is kinda nice, but oh well, what can you do, other than end this damn string already?"
    
    #Set the margin to be used for the window
    @margin = 20
    
    #Set the width of the body of the message
    body_width = self.width - 2*@margin
    
    #Generate the wrapped lines
    @lines = wordwrap(@message,body_width,@font)
    
    #This will be used to auto-scroll the message
    @start = Time.now.to_i
  end

  def update
    
  end

  def draw
    #determine the offset of the text and speed at which we scroll
    speed = 5
    
    #The offset will be a negative number to pull the text upward per second passed
    offset = ( @start - Time.now.to_i  ) * speed
    
    #Set the clipping region. We're going to clip 1/7th of the screen height
    self.clip_to(0, 0, self.width, self.height / 7) do
      
      #Draw each line
      @lines.each_with_index do |line,index|
        #determine where this line will be drawn and factor in the offset
        height = @margin + (index * @font.height + offset)
        
        #draw the line
        @font.draw(line,@margin,height,0)
      end
    end
  end
end

window = GameWindow.new
window.show