metanohi-misc-subsites/subsites/natur/subtitler.js

/* 
  This program is free software. It comes without any warranty, to
  the extent permitted by applicable law. You can redistribute it
  and/or modify it under the terms of the Do What The Fuck You Want
  To Public License, Version 2, as published by Sam Hocevar. See
  http://sam.zoy.org/wtfpl/COPYING for more details.
*/

/* It's very simple and not perfect. I'm not going to develop more on this code.
 */

function subtitle(vid, subs_url, alt) {
	
	this.videoElement = vid
	this.subtitles = null
	if (alt != undefined)
		this.rootElement = alt
	else
		this.rootElement = document.body
	
	this.fetchSubtitles(subs_url)
}

subtitle.prototype.fetchSubtitles = function(subs_url) {
	var req = new XMLHttpRequest()
	req.open('GET', subs_url, true)
	req.onreadystatechange = function() {
		if (req.readyState == 4) {
			if (req.status == 200)
				this.subtitleObject.extractSubtitles(req.responseText)
			else
				this.subtitleObject.err()
		}
	}
	req.subtitleObject = this
	req.send(null)
}

subtitle.prototype.extractSubtitles = function(subs) {
	var subs = subs
	while (subs.indexOf('\n') == 0)
		subs = subs.substr(1)
	while (subs.substr(subs.length-1) == '\n')
		subs = subs.substr(0, subs.length-1)
	subs = subs.split('\n\n')
	
	var subs_arr = new Array()
	var x, i, txt, times, start, end, msg
	for (x in subs) {
		txt = subs[x].split('\n')
		times = txt[1].split(' --> ')
		
		start = this.toSeconds(times[0])
		end = this.toSeconds(times[1])
		msg = ''
		for (i = 2; i < txt.length; i++)
			msg += '\n' + txt[i]
		msg = msg.substr(1)
		
		subs_arr.push([start, end, msg])
	}
	this.start(subs_arr)
}

subtitle.prototype.toSeconds = function(time_str) {
	var t = 0
	t += time_str.substr(0, 2) * 3600
	t += time_str.substr(3, 2) * 60
	t += time_str.substr(6, 2) * 1
	t += time_str.substr(9, 3) * 0.001
	return t
}

subtitle.prototype.err = function() {
	this.start([[0, 4000, 'It wasn\t possible to load the subtitles.']])
}

/**********************/

subtitle.prototype.start = function(subs_arr) {
	this.subtitles = subs_arr
	this.textLength = this.subtitles.length
	this.currentSubtitle = 0
	this.currentSubtitleOn = false
	
	var elem = document.createElement('div')
	elem.style.position = 'absolute'
	var subelem = document.createElement('div')
	subelem.id = 'subtitle'
	elem.appendChild(subelem)
	
	this.rootElement.appendChild(elem)
	this.subtitleElement = elem
	this.subtitleTextElement = subelem
	
	this.updateSubtitleElement()
	
	this.videoElement.subtitlesObject = this
	this.videoElement.onmouseover = function() {
		this.subtitlesObject.subtitleElement.style.display = 'none'
	}
	this.videoElement.onmouseout = function() {
		this.subtitlesObject.subtitleElement.style.display = ''
	}
	this.resume()
}

subtitle.prototype.resume = function() {
	this.videoElement.addEventListener('timeupdate', this.check, true)
}

subtitle.prototype.stop = function() {
	this.removeCurrentSubtitle()
	this.videoElement.removeEventListener('timeupdate', this.check, true)
}

subtitle.prototype.updateSubtitleElement = function() {
	var x = this.videoElement.offsetLeft
	var y = this.videoElement.offsetTop
	var w = this.videoElement.width
	var h = this.videoElement.height
	this.subtitleElement.style.left = x + 10 + 'px'
	this.subtitleElement.style.width = w - 20 + 'px'
	this.subtitleElement.style.top = y + h - 50 + 'px'
	this.subtitleElement.style.height = '40px'
}

subtitle.prototype.check = function(event) {
	var self = event.target.subtitlesObject
	var time = event.target.currentTime
	
	var csub = self.subtitles[self.currentSubtitle]
	if (time >= csub[0] && time <= csub[1]) {
		if (!self.currentSubtitleOn)
			self.updateSubtitle()
	}
	else {
		self.removeCurrentSubtitle()
		if (time < csub[0] && self.currentSubtitle > 0)
			self.currentSubtitle -= 1
		else if (time > csub[1] && self.currentSubtitle < self.textLength)
			self.currentSubtitle += 1
	}
}

subtitle.prototype.updateSubtitle = function() {
	this.subtitleTextElement.innerHTML = this.subtitles[this.currentSubtitle][2]
	this.subtitleTextElement.style.display = ''
	this.currentSubtitleOn = true
}

subtitle.prototype.removeCurrentSubtitle = function() {
	this.subtitleTextElement.style.display = 'none'
	this.subtitleTextElement.innerHTML = ''
	this.currentSubtitleOn = false
}