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epubreader/vendor/pdfjs/controllers/toc_controller.js

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JavaScript
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2020-04-21 20:37:42 +00:00
PDFJS.reader.TocController = function() {
var reader = this,
book = this.book,
settings = reader.settings,
toc = document.getElementById("toc"),
tovView = document.getElementById("tocView"),
$toc_populate = $("#toc_populate"),
timeout;
var isVisible = function (element) {
var viewport = element.getBoundingClientRect(),
visible,
offset = settings.preloadOffset;
visible = (
viewport.top >= (0 - offset)
&& viewport.left >= (0 - offset)
&& viewport.right < (window.innerWidth + offset)
&& viewport.bottom < (window.innerHeight + offset)
);
return visible;
};
var lazyLoad = function () {
var elements = toc.querySelectorAll('img[data-pagenum]'),
pagenum,
count;
for (var i = 0; i < elements.length; i++) {
if (isVisible(elements[i])) {
pagenum = elements[i].getAttribute("data-pagenum");
elements[i].removeAttribute("data-pagenum");
reader.getThumb(parseInt(pagenum), true);
count++;
}
}
if (!elements.length || count === elements.length ) {
removeLazyLoader(tocView);
}
};
var lazyLoader = function () {
timeout = setTimeout( function () {
lazyLoad();
}, settings.lazyDelay);
};
var addLazyLoader = function (_element) {
var element = _element || window;
element.addEventListener("scroll", lazyLoader, false);
element.addEventListener("load", lazyLoader, false);
};
var removeLazyLoader = function (_element) {
var element = _element || window;
element.removeEventListener("scroll", lazyLoader);
element.removeEventListener("load", lazyLoader);
};
var tocCreate = function (no_pages, width, height, populate) {
var canvas = document.createElement("canvas"),
ctx = canvas.getContext("2d"),
aspect,
imgsrc,
preloadcount,
scale,
timeout;
aspect = parseFloat(width / height);
// create small placeholder image
canvas.width = 10;
canvas.height = parseInt(canvas.width / aspect);
placeholder_width = reader.settings.thumbnailWidth;
placeholder_height = parseInt(reader.settings.thumbnailWidth / aspect);
// fill with transparent black, style in CSS
ctx.fillStyle = "rgba(0, 0, 0, 0)";
ctx.fillRect(0, 0, canvas.width, canvas.height);
imgsrc = canvas.toDataURL();
for(var i = 0; i < no_pages; i++) {
var item = document.createElement('li'),
placeholder = new Image(),
label = document.createElement('span'),
page_label = reader.pageLabels[i + 1];
item.setAttribute("id", "page_" + parseInt(i + 1));
placeholder.src = imgsrc;
placeholder.style.width = reader.settings.thumbnailWidth;
placeholder.style.height = parseInt(reader.settings.thumbnailWidth / aspect);
placeholder.classList.add("placeholder");
label.innerHTML = page_label || (i + 1).toString();
label.classList.add("page_label");
//label.style.left = width;
item.appendChild(placeholder);
item.appendChild(label);
toc.appendChild(item);
if (populate) {
reader.getThumb(i + 1, true);
} else {
placeholder.setAttribute("data-pagenum", parseInt(i + 1));
}
}
if (!populate) {
// preload first screenfull of thumbnails
scale = parseFloat(settings.thumbnailWidth / width);
preloadcount = parseInt(window.innerHeight / placeholder_height) + 2;
if (preloadcount > settings.numPages)
preloadcount = settings.numPages;
var _timeout = setTimeout(function () {
for (var i = 1; i <= preloadcount; i++) {
reader.getThumb(i, true);
}
}, settings.initialLazyDelay);
}
};
var tocInsert = function (image, page, replace) {
var placeholder = toc.children[page - 1].firstChild;
if (replace === true) {
placeholder.parentNode.replaceChild(image, placeholder);
}
toc.children[page - 1].addEventListener('click', function (e) {
reader.queuePage(page);
});
};
var tocPopulate = function () {
var i = 0;
while (i < reader.settings.numPages) {
reader.getThumb(i, true);
i++;
}
reader.thumbnails = true;
$toc_populate.addClass("hide");
remove_lazy_loader();
};
if (!settings.thumbnails) {
addLazyLoader(tocView);
}
reader.book.getPage(1).then(function(page) {
var width,
height,
viewport,
page_rotation,
rotation;
page_rotation = page.rotate;
rotation = (page_rotation + reader.settings.rotation) % 360;
viewport = page.getViewport(1, rotation);
width = viewport.width;
height = viewport.height;
tocCreate(settings.numPages, width, height, settings.thumbnails);
});
var onShow = function() {
tocView.classList.add('open');
scrollToPage(settings.currentPage);
};
var onHide = function() {
tocView.classList.remove('open');
};
var scrollToPage = function (pageNum) {
if (pageNum > 0 && pageNum <= settings.numPages) {
thumb = document.getElementById("page_" + pageNum);
if (thumb)
thumb.scrollIntoView();
}
};
return {
"show" : onShow,
"hide" : onHide,
"tocInsert": tocInsert,
"totPopulate": tocPopulate,
"scrollToPage": scrollToPage
};
};