mouse-over video thumbnail to preview video by cycling through the storyboard
当前为
// ==UserScript==
// @name Youtube Storyboard
// @namespace hbb_works
// @description mouse-over video thumbnail to preview video by cycling through the storyboard
// @version 1.2r1407080550
// @include http://*youtube.com*
// @include https://*youtube.com*
// @grant none
// ==/UserScript==
const INTERVAL = 200; // default interval in milliseconds
var div;
var loader;
function getPos(element) {
var ref = document.body.getBoundingClientRect();
var rel = element.getBoundingClientRect();
return {
left: rel.left - ref.left,
top: rel.top - ref.top
};
}
(function init() {
document.addEventListener('mouseover', onMouseOver, false);
loader = document.createElement('img');
div = document.createElement('div');
div.id = 'storyboardPlayer';
div.style.display = 'none';
div.style.position = 'absolute';
div.style.zIndex = 99;
document.getElementById('page') .appendChild(div)
})();
function onMouseOver(event) {
var target = event.target;
var src = target.src;
if (target.nodeName == 'IMG' && src && (/default\.jpg$/.exec(src) || /0\.jpg$/.exec(src)))
{
var a = new Animator(target);
var onMouseOut = function () {
if (div.style.display == 'none') {
a.stop();
}
target.removeEventListener('mouseout', onMouseOut);
};
target.addEventListener('mouseout', onMouseOut);
a.getStoryboardSpecs(function () {
a.start();
});
}
}
var Animator = function (target) {
this.target = target;
this.frame = 0;
this.sheet = 0;
this.interval = INTERVAL;
this.src = target.src
this.isMouseOver = true;
// get video id
this.v = (/vi\/(.*?)\//.exec(this.src) || []) [1];
if (this.v) {
this.width = target.width;
this.height = target.height;
}
var p = getPos(target);
div.style.top = p.top + 'px';
div.style.left = p.left + 'px';
div.style.width = this.width + 'px';
div.style.height = this.height + 'px';
// adjustments for small thumbnails in list of related videos
if (target.parentElement.classList.contains('yt-uix-simple-thumb-wrap')) {
var spanHeight = target.parentElement.getBoundingClientRect() .height;
div.style.top = p.top + ((target.height - spanHeight) / 2) + 'px';
div.style.height = spanHeight + 'px';
this.height = spanHeight;
}
};
Animator.prototype.parseSpec = function (storyboard_spec) {
var lines = storyboard_spec.split('|');
var q;
if (!this.quality) {
this.quality = - 1;
do {
this.quality++;
q = lines[this.quality + 1].split('#');
} while (parseInt(q[0], 10) < this.width && this.quality + 2 < lines.length);
}
var q = lines[this.quality + 1].split('#');
var s = {
url: lines[0].replace('$L', this.quality) .replace('$N', q[6]),
width: parseInt(q[0], 10),
height: parseInt(q[1], 10),
count: parseInt(q[2], 10),
cols: parseInt(q[3], 10),
rows: parseInt(q[4], 10),
sigh: q[7]
};
s.sheetSize = s.cols * s.rows;
s.sheetCount = ((s.count / s.sheetSize) | 0) + 1; // bitwise OR to loose decimals
s.countOnLastSheet = ((s.count - 1) % s.sheetSize) + 1;
return this.spec = s;
};
Animator.prototype.loadImage = function (callback) {
clearInterval(this.token);
var onLoad = (function () {
div.style.backgroundImage = 'url(' + loader.src + ')';
loader.removeEventListener('load', onLoad);
callback.apply(this);
}).bind(this);
loader.addEventListener('load', onLoad);
loader.src = this.spec.url.replace('$M', this.sheet) + '?sigh=' + this.spec.sigh;
};
Animator.prototype.getStoryboardSpecs = function (callback, fromWatch) {
this.xhr = new XMLHttpRequest();
this.xhr.onreadystatechange = (function () {
if (this.isMouseOver && this.xhr.readyState == 4 && this.xhr.status == 200) {
if (fromWatch)
var spec = (/"storyboard_spec":\s*(".*?")/.exec(this.xhr.responseText) || []) [1];
else
var spec = (/&storyboard_spec=(.*?)&/.exec(this.xhr.responseText) || []) [1];
if (spec) {
if (fromWatch)
spec = eval(spec); // remove backslashes
this.parseSpec(decodeURIComponent(spec));
callback.apply(this);
}
else if (!fromWatch) {
this.getStoryboardSpecs(callback, true);
}
}
}).bind(this);
if (fromWatch)
this.xhr.open('GET', '/watch?v=' + this.v, true);
else
this.xhr.open('GET', '/get_video_info?video_id=' + this.v, true);
this.xhr.send();
};
Animator.prototype.start = function () {
this.frame = 0;
this.sheet = 0;
var lastTick;
var next = function () {
if (this.isMouseOver) {
if (this.spec.fit == 'height') {
var w = this.spec.width * this.height / this.spec.height;
var offset = (this.width - w) / 2;
div.style.backgroundPosition = -((this.frame % this.spec.cols) * w - offset) + 'px ' +
-(((this.frame / this.spec.cols) | 0) * this.height) + 'px'; // bitwise OR with 0 to loose decimals
}
else {
var h = this.spec.height * this.width / this.spec.width;
var offset = (this.height - h) / 2;
div.style.backgroundPosition = -((this.frame % this.spec.cols) * this.width) + 'px ' +
-(((this.frame / this.spec.cols) | 0) * h - offset) + 'px';
}
this.frame++;
if ((this.frame == this.spec.sheetSize) || (this.sheet == this.spec.sheetCount - 1 && this.frame == this.spec.countOnLastSheet))
{
clearInterval(this.token);
this.frame = 0;
this.sheet = (this.sheet + 1) % this.spec.sheetCount;
this.loadImage(function () {
this.token = setInterval(next, this.interval);
});
}
}
else {
this.stop();
}
}.bind(this);
this.loadImage(function () {
if (this.isMouseOver) {
div.style.display = null;
var onMouseOut = (function () {
this.stop();
div.removeEventListener('mouseout', onMouseOut);
}).bind(this);
div.addEventListener('mouseout', onMouseOut);
if ((this.width / this.height) <= (this.spec.width / this.spec.height)) {
this.spec.fit = 'height';
div.style.backgroundSize = ((this.spec.width * this.height / this.spec.height) * this.spec.cols) + 'px ' +
(this.height * this.spec.rows) + 'px';
}
else {
this.spec.fit = 'width';
div.style.backgroundSize = (this.width * this.spec.cols) + 'px ' +
((this.spec.height * this.width / this.spec.width) * this.spec.rows) + 'px';
}
next();
this.token = setInterval(next, this.interval);
}
});
};
Animator.prototype.stop = function () {
this.isMouseOver = false;
clearInterval(this.token);
div.style.display = 'none';
}