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require 'sdl'

class Rect
	attr_accessor :x, :y, :w, :h
	def initialize( x, y, w, h )
		@x = x
		@y = y
		@w = w
		@h = h
	end
	
	def contain( x, y )
		x > @x and x < @x + @w and y > @y and y < @y + @h
	end
end

class Button
	def initialize( x, y, w, h, image )
		@box = Rect.new( x, y, w, h )
		@clips = [ Rect.new( 0, 0, 320, 240 ),
				  Rect.new( 320, 0, 320, 240 ),
				  Rect.new( 0, 240, 320, 240 ),
				  Rect.new( 320, 240, 320, 240 ) ]	
		@image = image
		@clip = @clips[1]
	end
	
	def handle_events( event )
		case event
		when SDL::Event::MouseMotion
			x = event.x
			y = event.y
			
			if @box.contain( x, y )
				@clip = @clips[0]  
			else
				@clip = @clips[1]  
			end
		when SDL::Event::MouseButtonDown
			x = event.x
			y = event.y
			
			@clip = @clips[2] if @box.contain( x, y )
		when SDL::Event::MouseButtonUp
			x = event.x
			y = event.y
			
			@clip = @clips[3] if @box.contain( x, y )
		end
	end
	
	def show( screen )
		apply_surface( @box.x, @box.y, @image, screen, @clip )
	end
end

def load_image( filename, color_key = nil )
	loaded_image = SDL::Surface.load( filename )
	
	optimized_image = loaded_image.display_format
	
	if color_key
		color_key = optimized_image.map_rgb( color_key[0], color_key[1], color_key[2] )
		optimized_image.set_color_key( SDL::SRCCOLORKEY, color_key ) 
	end
	
	return optimized_image
end

def apply_surface( x, y, source, destination, rect  = nil)
	rect = Rect.new( 0, 0, source.w, source.h ) unless rect
	
	SDL::Surface.blit( source, rect.x, rect.y, rect.w, rect.h, destination, x, y )
end

def init_video( screen_width, screen_height, screen_bpp, caption = "Hello World" )
	SDL.init( SDL::INIT_VIDEO )
	screen = SDL::set_video_mode( screen_width, screen_height, screen_bpp, SDL::HWSURFACE )
	SDL::WM.set_caption( caption, "" )
	
	return screen
end

def init_ttf( filename, size )
	SDL::TTF.init
	font = SDL::TTF.open( filename, size, index = 0 )
	
	return font
end

def clean_up
	# do nothing
end

def main 
	screen_width = 640
	screen_height = 480
	screen_bpp = 32
		
	########################################################
	screen = init_video( screen_width, screen_height, screen_bpp, "Button Test" )
	########################################################
	
	button_sheets = load_image( "button.png" )
	button = Button.new( 170, 120, 320, 240, button_sheets )
	########################################################		
	quit = false
	
	while !quit
	########################################################
		screen.fill_rect( 0, 0, screen.w, screen.h, screen.map_rgb( 0xff, 0xff, 0xff ) )
		button.show( screen )
	########################################################				   
		screen.flip	
		while event = SDL::Event.poll
	########################################################
			button.handle_events( event )
			case event
			when SDL::Event::Quit
				quit = true
			end
	########################################################
		end
	end
	
	clean_up
	########################################################
end

main