344 lines
8.6 KiB
JavaScript
344 lines
8.6 KiB
JavaScript
//============
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// CONTROLS
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//============
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MOVE_NEXT = "ArrowRight"
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MOVE_BACK = "ArrowLeft"
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TOGGLE_FULLSCREEN = "F"
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//========================
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// NAVIGATION CONSTANTS
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//========================
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PAGE_TRANSITION_SPEED = "1.5s"
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MOUSEWHELL_MIN_DELAY = 50
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DELAY_BEFORE_HIDDING_CONTROLS = 4000;
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//====================
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// STATES CONSTANTS
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//====================
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READER_FRAME = document.getElementById("reader-frame")
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READER_PAGES = document.getElementById("reader-pages")
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FOCUS_OVERLAY = document.getElementById("focus-overlay")
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HELP_CONTROLS = document.getElementById("help-controls")
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CURRENT_ZOOM = 0
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CURRENT_PAGE = 1
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CURRENT_WIDTH = 0
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CURRENT_HEIGHT = 0
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CURRENT_X = 0
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CURRENT_Y = 0
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IS_PAGE_MODE = false
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MOUSEWHELL_WAIT = false
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// =============
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// UTILITIES
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// =============
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// Zooms utilites
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// --------------
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function getFirstZoomOfPage(pageNumber){
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for (var zoom_idx = 0; zoom_idx < zooms.length; zoom_idx++){
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if (zooms[zoom_idx][0] == pageNumber) {
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return zoom_idx
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}
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}
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}
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function getLastZoomOfPage(pageNumber){
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let res = null
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for (var zoom_idx = 0; zoom_idx < zooms.length; zoom_idx++){
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if (zooms[zoom_idx][0] == pageNumber) {
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res = zoom_idx
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}
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if (res != null && zooms[zoom_idx][0] != pageNumber) {
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break
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}
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}
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return res
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}
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// Dimensions utilites
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// -------------------
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function getPagesCount() {
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return READER_PAGES.childElementCount
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}
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function pageOriginalHeight() {
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return parseInt(READER_PAGES.dataset.pagesHeight)
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}
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function pageOriginalWidth() {
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return parseInt(READER_PAGES.dataset.pagesWidth)
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}
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function readerFrameRatio() {
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return READER_FRAME.clientWidth / READER_FRAME.clientHeight
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}
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function pageRatio() {
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return READER_PAGES.dataset.pagesWidth / READER_PAGES.dataset.pagesHeight
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}
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function isFrameRatioWiderThanPage(){
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return readerFrameRatio() > pageRatio()
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}
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function pageToFrameScaleFactor(useHeight){
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// The scale factor to apply to a page so it exactly fit in the reader frame
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if (useHeight) {
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return READER_FRAME.clientHeight / pageOriginalHeight()
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}
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return READER_FRAME.clientWidth / pageOriginalWidth()
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}
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function totalPagesWidth() {
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// The width of all cumuled pages with scale factor applied
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return pageOriginalWidth() * getPagesCount()
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}
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// =========
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// ACTIONS
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// =========
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function initReader(){
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moveReaderDisplayToZoom(0)
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// Smoothly show pictures when they intersect with the viewport
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let visibilityObserver = new IntersectionObserver((entries, observer) => {
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entries.forEach((entry) => {
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if (entry.isIntersecting) {
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entry.target.style.opacity = 1
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entry.target.style.visibility = "visible"
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} else {
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entry.target.style.opacity = 0
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entry.target.style.visibility = "hidden"
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}
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});
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}, { root: READER_FRAME, rootMargin: "-10px" });
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for (var i = 0; i < READER_PAGES.children.length; i++) {
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let img = READER_PAGES.children[i];
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img.style.width = 100 / getPagesCount() + "%"
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visibilityObserver.observe(img)
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}
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READER_PAGES.style.display = "flex"
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setTimeout(() => {
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READER_PAGES.hidden = false
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}, "300")
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setTimeout(() => {
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HELP_CONTROLS.style.opacity = null;
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}, DELAY_BEFORE_HIDDING_CONTROLS)
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}
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function moveReaderDisplayToArea(pageNumber, width, height, posx, posy){
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if (width == 0){
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width = pageOriginalWidth()
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}
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if (height == 0){
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height = pageOriginalHeight()
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}
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zoomRatio = width / height
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if (readerFrameRatio() > zoomRatio) {
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// Frame wider than zoom
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var zoomToFrameScaleFactor = pageToFrameScaleFactor(true) * pageOriginalHeight() / height
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var zoomToFrameCenteringOffset = [(READER_FRAME.clientWidth - width * zoomToFrameScaleFactor) / 2, 0]
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updateFocusByWidth(width * zoomToFrameScaleFactor)
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} else {
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var zoomToFrameScaleFactor = pageToFrameScaleFactor(false) * pageOriginalWidth() / width
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var zoomToFrameCenteringOffset = [0, (READER_FRAME.clientHeight - height * zoomToFrameScaleFactor) / 2]
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updateFocusByHeight(height * zoomToFrameScaleFactor)
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}
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previousPagesOffset = pageOriginalWidth() * (pageNumber - 1) * zoomToFrameScaleFactor
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READER_PAGES.style.width = totalPagesWidth() * zoomToFrameScaleFactor + "px"
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READER_PAGES.style.height = pageOriginalHeight() * zoomToFrameScaleFactor + "px"
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READER_PAGES.style.left = (- posx * zoomToFrameScaleFactor + zoomToFrameCenteringOffset[0] - previousPagesOffset) + "px"
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READER_PAGES.style.top = (- posy * zoomToFrameScaleFactor + zoomToFrameCenteringOffset[1]) + "px"
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CURRENT_PAGE = pageNumber
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CURRENT_WIDTH = width
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CURRENT_HEIGHT = height
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CURRENT_X = posx
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CURRENT_Y = posy
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}
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function moveReaderDisplayToPage(pageNumber) {
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moveReaderDisplayToArea(pageNumber, 0, 0, 0, 0)
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}
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function moveReaderDisplayToZoom(index) {
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moveReaderDisplayToArea(zooms[index][0], zooms[index][1], zooms[index][2], zooms[index][3], zooms[index][4])
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CURRENT_ZOOM = index
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}
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function updateFocusByWidth(width){
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side_width = (READER_FRAME.clientWidth - width) / 2
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FOCUS_OVERLAY.style.gridTemplateColumns = side_width +"px auto " + side_width + "px"
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FOCUS_OVERLAY.style.gridTemplateRows = "0px auto 0px";
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}
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function updateFocusByHeight(height){
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side_width = (READER_FRAME.clientHeight - height) / 2
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FOCUS_OVERLAY.style.gridTemplateRows = side_width +"px auto " + side_width + "px"
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FOCUS_OVERLAY.style.gridTemplateColumns = "0px auto 0px";
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}
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function moveReader(to_next, move_page) {
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if (move_page){
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if (IS_PAGE_MODE){
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if (to_next && CURRENT_PAGE < getPagesCount()) {
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moveReaderDisplayToPage(CURRENT_PAGE + 1)
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IS_PAGE_MODE = true
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}
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else if (CURRENT_PAGE > 1) {
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moveReaderDisplayToPage(CURRENT_PAGE - 1)
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IS_PAGE_MODE = true
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}
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}
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else {
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if (to_next && CURRENT_PAGE < getPagesCount()) {
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moveReaderDisplayToPage(CURRENT_PAGE + 1)
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IS_PAGE_MODE = true
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}
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else {
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moveReaderDisplayToPage(CURRENT_PAGE)
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IS_PAGE_MODE = true
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}
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}
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} else {
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if (IS_PAGE_MODE){
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if (to_next) {
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moveReaderDisplayToZoom(getFirstZoomOfPage(CURRENT_PAGE))
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IS_PAGE_MODE = false
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}
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else {
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if (CURRENT_PAGE == 1) {
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moveReaderDisplayToZoom(0)
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IS_PAGE_MODE = false
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} else {
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moveReaderDisplayToZoom(getLastZoomOfPage(CURRENT_PAGE - 1))
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IS_PAGE_MODE = false
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}
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}
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} else {
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if (to_next && CURRENT_ZOOM < zooms.length - 1) {
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moveReaderDisplayToZoom(CURRENT_ZOOM + 1)
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IS_PAGE_MODE = false
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}
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else if (CURRENT_ZOOM > 0) {
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moveReaderDisplayToZoom(CURRENT_ZOOM - 1)
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IS_PAGE_MODE = false
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}
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}
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}
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}
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// =============
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// CALLBACKS
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// =============
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function handleKeyPress(key, has_shift){
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if (key == MOVE_NEXT) {
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moveReader(true, has_shift)
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}
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else if (key == MOVE_BACK) {
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moveReader(false, has_shift)
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}
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else if (key.toUpperCase() == TOGGLE_FULLSCREEN){
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if (document.fullscreenElement == null){
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READER_FRAME.requestFullscreen();
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} else {
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document.exitFullscreen();
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}
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}
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}
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function handleMouseWhell(deltaY){
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if (MOUSEWHELL_WAIT){
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return
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} else {
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MOUSEWHELL_WAIT = true
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setTimeout(() => {
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MOUSEWHELL_WAIT = false
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}, MOUSEWHELL_MIN_DELAY)
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}
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if (deltaY > 0) {
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moveReader(true, false)
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}
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else {
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moveReader(false, false)
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}
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}
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// ======
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// INIT
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// ======
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window.addEventListener("load", (event) => {
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initReader()
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});
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addEventListener("resize", (event) => {
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moveReaderDisplayToArea(CURRENT_PAGE, CURRENT_WIDTH, CURRENT_HEIGHT, CURRENT_X, CURRENT_Y)
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});
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addEventListener("keydown", (event) => {
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handleKeyPress(event.key, event.shiftKey)
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});
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addEventListener("wheel", (event) => {
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handleMouseWhell(event.deltaY)
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});
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