healthbar.rb

require 'RMagick'

class HealthBar
	attr_accessor :health, :x, :y, :z

	def initialize (window, width, height, max_health, starting_health, x, y, z, text = "", foreground_colour = 'red', border_colour = 'white', empty_callback) 
		@window = window
		@width = width
		@height = height
		@max_health = max_health
		self.health = starting_health
		self.x = x
		self.y = y
		self.z = z
		@text = text
		@foreground = foreground_colour
		@border = border_colour
		@empty_callback = empty_callback
		@fixed_width = nil
	end

	def draw
		update_bar	
		@bar.draw(self.x, self.y, self.z)
	end

	def update_bar
		@gc = Magick::Draw.new
		@gc.fill_opacity(0)
		@gc.stroke(@border)
		@gc.stroke_width(1)

		@gc.rectangle(0,0, @width, @height)

		@gc.fill_opacity(1)
		@gc.fill(@foreground)
		@gc.stroke(@foreground)
		@gc.stroke_width(1)
		@gc.rectangle(1,1, (@fixed_width == nil ? bar_width - 1 : @fixed_width), @height - 1)

		if @text.length > 0 then
			@gc.fill('black')
			@gc.stroke('black')
			@gc.text(25, 15, @text)
		end
       		background = Magick::Image.new(@width + 1, @height + 1)
		@gc.draw background
		@bar = Gosu::Image.new(@window, background, true)

		if @fixed_width == nil and bar_width == 1 then
			@empty_callback.call()
			@fixed_width = 1
		end
	end

	def bar_width
		w = Float(health) / Float(@max_health) * @width
		return (w > 0 ? w : 1)
	end
end