var pics
var area

var interval
var speed = 20
var max_speed = 5
var min_speed = 50

var start_position = 10
var spacing = 10
var positions = new Array()
var full_width

var start_step = 1
var step

var running = false

function setup_scroll(image_names, area_name) {
	step = start_step
	pics = document.getElementsByName(image_names)
	area = document.getElementById(area_name)
	
	area_width = get_window_width() - 300
	area.style.width = area_width+'px'
	area.style.overflow = 'hidden'

	positions[0] = start_position
	pics[0].style.position = 'absolute'
	pics[0].style.left = positions[0]+'px'

	for(i=1; i<pics.length; i++) {
		// I really dont know why, but I have to set til image width to 131
		// manualy, since IE somehow cant understand img.width properly
		positions[i] = positions[i-1] + 131 + spacing
		pics[i].style.position = 'absolute'
		pics[i].style.left = positions[i]+'px'
	}
	
	full_width = positions[positions.length - 1] + spacing
	if(full_width < area_width) {
		full_width = area_width
	}

	scroll()
}

function get_window_width() {

	width = 800
	if (parseInt(navigator.appVersion)>3) {
		if (navigator.appName=="Netscape") {
			width = window.innerWidth;
	  	}
		if (navigator.appName.indexOf("Microsoft")!=-1) {
		    width = document.body.offsetWidth + 20;
		}
	}
	return width
}

function scroll() {
	if(!running) {
		running = true
		disable_button('play')
		enable_button('stop')
		enable_button('plus')
		enable_button('minus')
		interval = setInterval('move()', speed)
	}
}

function stop() {
	running = false
	disable_button('stop')
	enable_button('play')
	disable_button('plus')
	disable_button('minus')
	clearInterval(interval)
}

function move() {
	for(i = 0; i < pics.length; i++) {
		positions[i] = positions[i] + step
		if(positions[i] > full_width) {
			positions[i] = start_position - pics[i].width
		}
		pics[i].style.left = positions[i]+'px'

	}			
}

function increase_speed(speed_step) {
	if(running) {
		new_speed = speed - speed_step
		if(new_speed > max_speed) {
			change_speed(new_speed)
			enable_button('minus')
		} else {
			disable_button('plus')
		}
	}
}

function decrease_speed(speed_step) {
	if(running) {
		new_speed = speed + speed_step
		if(new_speed < min_speed) {
			change_speed(new_speed)
			enable_button('plus')
		} else {
			disable_button('minus')
		}
	}
}

function change_speed(new_speed) {
	if(running) {
		stop()
		speed = new_speed
		scroll()
	}
}

function disable_button(button) {
//	img = document.getElementById(button+'_button')
//	img.src = 'images/'+button+'_off.png'
}

function enable_button(button) {
//	img = document.getElementById(button+'_button')
//	img.src = 'images/'+button+'.png'
}