/* eslint-disable prettier/prettier */
/* Copyright 2012 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
const CSS_UNITS = 96.0 / 72.0;
const DEFAULT_SCALE_VALUE = "auto";
const DEFAULT_SCALE = 1.0;
const MIN_SCALE = 0.1;
const MAX_SCALE = 10.0;
const UNKNOWN_SCALE = 0;
const MAX_AUTO_SCALE = 1.25;
const SCROLLBAR_PADDING = 40;
const VERTICAL_PADDING = 5;
const LOADINGBAR_END_OFFSET_VAR = "--loadingBar-end-offset";
const PresentationModeState = {
UNKNOWN: 0,
NORMAL: 1,
CHANGING: 2,
FULLSCREEN: 3,
};
const SidebarView = {
UNKNOWN: -1,
NONE: 0,
THUMBS: 1, // Default value.
OUTLINE: 2,
ATTACHMENTS: 3,
LAYERS: 4,
};
const RendererType = {
CANVAS: "canvas",
SVG: "svg",
};
const TextLayerMode = {
DISABLE: 0,
ENABLE: 1,
ENABLE_ENHANCE: 2,
};
const ScrollMode = {
UNKNOWN: -1,
VERTICAL: 0, // Default value.
HORIZONTAL: 1,
WRAPPED: 2,
};
const SpreadMode = {
UNKNOWN: -1,
NONE: 0, // Default value.
ODD: 1,
EVEN: 2,
};
/**
* Returns scale factor for the canvas. It makes sense for the HiDPI displays.
* @returns {Object} The object with horizontal (sx) and vertical (sy)
* scales. The scaled property is set to false if scaling is
* not required, true otherwise.
* @ignore
*/
function getOutputScale(ctx) {
const devicePixelRatio = window.devicePixelRatio || 1;
const backingStoreRatio =
ctx.webkitBackingStorePixelRatio ||
ctx.mozBackingStorePixelRatio ||
ctx.backingStorePixelRatio ||
1;
const pixelRatio = devicePixelRatio / backingStoreRatio;
return {
sx: pixelRatio,
sy: pixelRatio,
scaled: pixelRatio !== 1,
};
}
/**
* Scrolls specified element into view of its parent.
* @param {Object} element - The element to be visible.
* @param {Object} spot - An object with optional top and left properties,
* specifying the offset from the top left edge.
* @param {boolean} skipOverflowHiddenElements - Ignore elements that have
* the CSS rule `overflow: hidden;` set. The default is false.
* @ignore
*/
function scrollIntoView(element, spot, skipOverflowHiddenElements = false) {
// Assuming offsetParent is available (it's not available when viewer is in
// hidden iframe or object). We have to scroll: if the offsetParent is not set
// producing the error. See also animationStarted.
let parent = element.offsetParent;
if (!parent) {
console.error("offsetParent is not set -- cannot scroll");
return;
}
let offsetY = element.offsetTop + element.clientTop;
let offsetX = element.offsetLeft + element.clientLeft;
while (
(parent.clientHeight === parent.scrollHeight &&
parent.clientWidth === parent.scrollWidth) ||
(skipOverflowHiddenElements &&
getComputedStyle(parent).overflow === "hidden")
) {
if (parent.dataset._scaleY) {
offsetY /= parent.dataset._scaleY;
offsetX /= parent.dataset._scaleX;
}
offsetY += parent.offsetTop;
offsetX += parent.offsetLeft;
parent = parent.offsetParent;
if (!parent) {
return; // no need to scroll
}
}
if (spot) {
if (spot.top !== undefined) {
offsetY += spot.top;
}
if (spot.left !== undefined) {
offsetX += spot.left;
parent.scrollLeft = offsetX;
}
}
parent.scrollTop = offsetY;
}
/**
* Helper function to start monitoring the scroll event and converting them into
* PDF.js friendly one: with scroll debounce and scroll direction.
* @ignore
*/
function watchScroll(viewAreaElement, callback) {
const debounceScroll = function (evt) {
if (rAF) {
return;
}
// schedule an invocation of scroll for next animation frame.
rAF = window.requestAnimationFrame(function viewAreaElementScrolled() {
rAF = null;
const currentX = viewAreaElement.scrollLeft;
const lastX = state.lastX;
if (currentX !== lastX) {
state.right = currentX > lastX;
}
state.lastX = currentX;
const currentY = viewAreaElement.scrollTop;
const lastY = state.lastY;
if (currentY !== lastY) {
state.down = currentY > lastY;
}
state.lastY = currentY;
callback(state);
});
};
const state = {
right: true,
down: true,
lastX: viewAreaElement.scrollLeft,
lastY: viewAreaElement.scrollTop,
_eventHandler: debounceScroll,
};
let rAF = null;
viewAreaElement.addEventListener("scroll", debounceScroll, true);
return state;
}
/**
* Helper function to parse query string (e.g. ?param1=value&parm2=...).
*/
function parseQueryString(query) {
const parts = query.split("&");
const params = Object.create(null);
for (let i = 0, ii = parts.length; i < ii; ++i) {
const param = parts[i].split("=");
const key = param[0].toLowerCase();
const value = param.length > 1 ? param[1] : null;
params[decodeURIComponent(key)] = decodeURIComponent(value);
}
return params;
}
/**
* Use binary search to find the index of the first item in a given array which
* passes a given condition. The items are expected to be sorted in the sense
* that if the condition is true for one item in the array, then it is also true
* for all following items.
*
* @returns {number} Index of the first array element to pass the test,
* or |items.length| if no such element exists.
*/
function binarySearchFirstItem(items, condition) {
let minIndex = 0;
let maxIndex = items.length - 1;
if (maxIndex < 0 || !condition(items[maxIndex])) {
return items.length;
}
if (condition(items[minIndex])) {
return minIndex;
}
while (minIndex < maxIndex) {
const currentIndex = (minIndex + maxIndex) >> 1;
const currentItem = items[currentIndex];
if (condition(currentItem)) {
maxIndex = currentIndex;
} else {
minIndex = currentIndex + 1;
}
}
return minIndex; /* === maxIndex */
}
/**
* Approximates float number as a fraction using Farey sequence (max order
* of 8).
* @param {number} x - Positive float number.
* @returns {Array} Estimated fraction: the first array item is a numerator,
* the second one is a denominator.
*/
function approximateFraction(x) {
// Fast paths for int numbers or their inversions.
if (Math.floor(x) === x) {
return [x, 1];
}
const xinv = 1 / x;
const limit = 8;
if (xinv > limit) {
return [1, limit];
} else if (Math.floor(xinv) === xinv) {
return [1, xinv];
}
const x_ = x > 1 ? xinv : x;
// a/b and c/d are neighbours in Farey sequence.
let a = 0,
b = 1,
c = 1,
d = 1;
// Limiting search to order 8.
while (true) {
// Generating next term in sequence (order of q).
const p = a + c,
q = b + d;
if (q > limit) {
break;
}
if (x_ <= p / q) {
c = p;
d = q;
} else {
a = p;
b = q;
}
}
let result;
// Select closest of the neighbours to x.
if (x_ - a / b < c / d - x_) {
result = x_ === x ? [a, b] : [b, a];
} else {
result = x_ === x ? [c, d] : [d, c];
}
return result;
}
function roundToDivide(x, div) {
const r = x % div;
return r === 0 ? x : Math.round(x - r + div);
}
/**
* Gets the size of the specified page, converted from PDF units to inches.
* @param {Object} An Object containing the properties: {Array} `view`,
* {number} `userUnit`, and {number} `rotate`.
* @returns {Object} An Object containing the properties: {number} `width`
* and {number} `height`, given in inches.
*/
function getPageSizeInches({ view, userUnit, rotate }) {
const [x1, y1, x2, y2] = view;
// We need to take the page rotation into account as well.
const changeOrientation = rotate % 180 !== 0;
const width = ((x2 - x1) / 72) * userUnit;
const height = ((y2 - y1) / 72) * userUnit;
return {
width: changeOrientation ? height : width,
height: changeOrientation ? width : height,
};
}
/**
* Helper function for getVisibleElements.
*
* @param {number} index - initial guess at the first visible element
* @param {Array} views - array of pages, into which `index` is an index
* @param {number} top - the top of the scroll pane
* @returns {number} less than or equal to `index` that is definitely at or
* before the first visible element in `views`, but not by too much. (Usually,
* this will be the first element in the first partially visible row in
* `views`, although sometimes it goes back one row further.)
*/
function backtrackBeforeAllVisibleElements(index, views, top) {
// binarySearchFirstItem's assumption is that the input is ordered, with only
// one index where the conditions flips from false to true: [false ...,
// true...]. With vertical scrolling and spreads, it is possible to have
// [false ..., true, false, true ...]. With wrapped scrolling we can have a
// similar sequence, with many more mixed true and false in the middle.
//
// So there is no guarantee that the binary search yields the index of the
// first visible element. It could have been any of the other visible elements
// that were preceded by a hidden element.
// Of course, if either this element or the previous (hidden) element is also
// the first element, there's nothing to worry about.
if (index < 2) {
return index;
}
// That aside, the possible cases are represented below.
//
// **** = fully hidden
// A*B* = mix of partially visible and/or hidden pages
// CDEF = fully visible
//
// (1) Binary search could have returned A, in which case we can stop.
// (2) Binary search could also have returned B, in which case we need to
// check the whole row.
// (3) Binary search could also have returned C, in which case we need to
// check the whole previous row.
//
// There's one other possibility:
//
// **** = fully hidden
// ABCD = mix of fully and/or partially visible pages
//
// (4) Binary search could only have returned A.
// Initially assume that we need to find the beginning of the current row
// (case 1, 2, or 4), which means finding a page that is above the current
// page's top. If the found page is partially visible, we're definitely not in
// case 3, and this assumption is correct.
let elt = views[index].div;
let pageTop = elt.offsetTop + elt.clientTop;
if (pageTop >= top) {
// The found page is fully visible, so we're actually either in case 3 or 4,
// and unfortunately we can't tell the difference between them without
// scanning the entire previous row, so we just conservatively assume that
// we do need to backtrack to that row. In both cases, the previous page is
// in the previous row, so use its top instead.
elt = views[index - 1].div;
pageTop = elt.offsetTop + elt.clientTop;
}
// Now we backtrack to the first page that still has its bottom below
// `pageTop`, which is the top of a page in the first visible row (unless
// we're in case 4, in which case it's the row before that).
// `index` is found by binary search, so the page at `index - 1` is
// invisible and we can start looking for potentially visible pages from
// `index - 2`. (However, if this loop terminates on its first iteration,
// which is the case when pages are stacked vertically, `index` should remain
// unchanged, so we use a distinct loop variable.)
for (let i = index - 2; i >= 0; --i) {
elt = views[i].div;
if (elt.offsetTop + elt.clientTop + elt.clientHeight <= pageTop) {
// We have reached the previous row, so stop now.
// This loop is expected to terminate relatively quickly because the
// number of pages per row is expected to be small.
break;
}
index = i;
}
return index;
}
/**
* @typedef {Object} GetVisibleElementsParameters
* @property {HTMLElement} scrollEl - A container that can possibly scroll.
* @property {Array} views - Objects with a `div` property that contains an
* HTMLElement, which should all be descendants of `scrollEl` satisfying the
* relevant layout assumptions.
* @property {boolean} sortByVisibility - If `true`, the returned elements are
* sorted in descending order of the percent of their padding box that is
* visible. The default value is `false`.
* @property {boolean} horizontal - If `true`, the elements are assumed to be
* laid out horizontally instead of vertically. The default value is `false`.
* @property {boolean} rtl - If `true`, the `scrollEl` container is assumed to
* be in right-to-left mode. The default value is `false`.
*/
/**
* Generic helper to find out what elements are visible within a scroll pane.
*
* Well, pretty generic. There are some assumptions placed on the elements
* referenced by `views`:
* - If `horizontal`, no left of any earlier element is to the right of the
* left of any later element.
* - Otherwise, `views` can be split into contiguous rows where, within a row,
* no top of any element is below the bottom of any other element, and
* between rows, no bottom of any element in an earlier row is below the
* top of any element in a later row.
*
* (Here, top, left, etc. all refer to the padding edge of the element in
* question. For pages, that ends up being equivalent to the bounding box of the
* rendering canvas. Earlier and later refer to index in `views`, not page
* layout.)
*
* @param {GetVisibleElementsParameters}
* @returns {Object} `{ first, last, views: [{ id, x, y, view, percent }] }`
*/
function getVisibleElements({
scrollEl,
views,
sortByVisibility = false,
horizontal = false,
rtl = false,
}) {
const top = scrollEl.scrollTop,
bottom = top + scrollEl.clientHeight;
const left = scrollEl.scrollLeft,
right = left + scrollEl.clientWidth;
// Throughout this "generic" function, comments will assume we're working with
// PDF document pages, which is the most important and complex case. In this
// case, the visible elements we're actually interested is the page canvas,
// which is contained in a wrapper which adds no padding/border/margin, which
// is itself contained in `view.div` which adds no padding (but does add a
// border). So, as specified in this function's doc comment, this function
// does all of its work on the padding edge of the provided views, starting at
// offsetLeft/Top (which includes margin) and adding clientLeft/Top (which is
// the border). Adding clientWidth/Height gets us the bottom-right corner of
// the padding edge.
function isElementBottomAfterViewTop(view) {
const element = view.div;
const elementBottom =
element.offsetTop + element.clientTop + element.clientHeight;
return elementBottom > top;
}
function isElementNextAfterViewHorizontally(view) {
const element = view.div;
const elementLeft = element.offsetLeft + element.clientLeft;
const elementRight = elementLeft + element.clientWidth;
return rtl ? elementLeft < right : elementRight > left;
}
const visible = [],
numViews = views.length;
let firstVisibleElementInd = binarySearchFirstItem(
views,
horizontal
? isElementNextAfterViewHorizontally
: isElementBottomAfterViewTop
);
// Please note the return value of the `binarySearchFirstItem` function when
// no valid element is found (hence the `firstVisibleElementInd` check below).
if (
firstVisibleElementInd > 0 &&
firstVisibleElementInd < numViews &&
!horizontal
) {
// In wrapped scrolling (or vertical scrolling with spreads), with some page
// sizes, isElementBottomAfterViewTop doesn't satisfy the binary search
// condition: there can be pages with bottoms above the view top between
// pages with bottoms below. This function detects and corrects that error;
// see it for more comments.
firstVisibleElementInd = backtrackBeforeAllVisibleElements(
firstVisibleElementInd,
views,
top
);
}
// lastEdge acts as a cutoff for us to stop looping, because we know all
// subsequent pages will be hidden.
//
// When using wrapped scrolling or vertical scrolling with spreads, we can't
// simply stop the first time we reach a page below the bottom of the view;
// the tops of subsequent pages on the same row could still be visible. In
// horizontal scrolling, we don't have that issue, so we can stop as soon as
// we pass `right`, without needing the code below that handles the -1 case.
let lastEdge = horizontal ? right : -1;
for (let i = firstVisibleElementInd; i < numViews; i++) {
const view = views[i],
element = view.div;
const currentWidth = element.offsetLeft + element.clientLeft;
const currentHeight = element.offsetTop + element.clientTop;
const viewWidth = element.clientWidth,
viewHeight = element.clientHeight;
const viewRight = currentWidth + viewWidth;
const viewBottom = currentHeight + viewHeight;
if (lastEdge === -1) {
// As commented above, this is only needed in non-horizontal cases.
// Setting lastEdge to the bottom of the first page that is partially
// visible ensures that the next page fully below lastEdge is on the
// next row, which has to be fully hidden along with all subsequent rows.
if (viewBottom >= bottom) {
lastEdge = viewBottom;
}
} else if ((horizontal ? currentWidth : currentHeight) > lastEdge) {
break;
}
if (
viewBottom <= top ||
currentHeight >= bottom ||
viewRight <= left ||
currentWidth >= right
) {
continue;
}
const hiddenHeight =
Math.max(0, top - currentHeight) + Math.max(0, viewBottom - bottom);
const hiddenWidth =
Math.max(0, left - currentWidth) + Math.max(0, viewRight - right);
const fractionHeight = (viewHeight - hiddenHeight) / viewHeight,
fractionWidth = (viewWidth - hiddenWidth) / viewWidth;
const percent = (fractionHeight * fractionWidth * 100) | 0;
visible.push({
id: view.id,
x: currentWidth,
y: currentHeight,
view,
percent,
widthPercent: (fractionWidth * 100) | 0,
});
}
const first = visible[0],
last = visible[visible.length - 1];
if (sortByVisibility) {
visible.sort(function (a, b) {
const pc = a.percent - b.percent;
if (Math.abs(pc) > 0.001) {
return -pc;
}
return a.id - b.id; // ensure stability
});
}
return { first, last, views: visible };
}
/**
* Event handler to suppress context menu.
*/
function noContextMenuHandler(evt) {
evt.preventDefault();
}
function normalizeWheelEventDirection(evt) {
let delta = Math.hypot(evt.deltaX, evt.deltaY);
const angle = Math.atan2(evt.deltaY, evt.deltaX);
if (-0.25 * Math.PI < angle && angle < 0.75 * Math.PI) {
// All that is left-up oriented has to change the sign.
delta = -delta;
}
return delta;
}
function normalizeWheelEventDelta(evt) {
let delta = normalizeWheelEventDirection(evt);
const MOUSE_DOM_DELTA_PIXEL_MODE = 0;
const MOUSE_DOM_DELTA_LINE_MODE = 1;
const MOUSE_PIXELS_PER_LINE = 30;
const MOUSE_LINES_PER_PAGE = 30;
// Converts delta to per-page units
if (evt.deltaMode === MOUSE_DOM_DELTA_PIXEL_MODE) {
delta /= MOUSE_PIXELS_PER_LINE * MOUSE_LINES_PER_PAGE;
} else if (evt.deltaMode === MOUSE_DOM_DELTA_LINE_MODE) {
delta /= MOUSE_LINES_PER_PAGE;
}
return delta;
}
function isValidRotation(angle) {
return Number.isInteger(angle) && angle % 90 === 0;
}
function isValidScrollMode(mode) {
return (
Number.isInteger(mode) &&
Object.values(ScrollMode).includes(mode) &&
mode !== ScrollMode.UNKNOWN
);
}
function isValidSpreadMode(mode) {
return (
Number.isInteger(mode) &&
Object.values(SpreadMode).includes(mode) &&
mode !== SpreadMode.UNKNOWN
);
}
function isPortraitOrientation(size) {
return size.width <= size.height;
}
/**
* Promise that is resolved when DOM window becomes visible.
*/
const animationStarted = new Promise(function (resolve) {
if (
typeof PDFJSDev !== "undefined" &&
PDFJSDev.test("LIB") &&
typeof window === "undefined"
) {
// Prevent "ReferenceError: window is not defined" errors when running the
// unit-tests in Node.js environments.
setTimeout(resolve, 20);
return;
}
window.requestAnimationFrame(resolve);
});
function clamp(v, min, max) {
return Math.min(Math.max(v, min), max);
}
class ProgressBar {
constructor(id, { height, width, units } = {}) {
this.visible = true;
// Fetch the sub-elements for later.
this.div = document.querySelector(id + " .progress");
// Get the loading bar element, so it can be resized to fit the viewer.
this.bar = this.div.parentNode;
// Get options, with sensible defaults.
this.height = height || 100;
this.width = width || 100;
this.units = units || "%";
// Initialize heights.
this.div.style.height = this.height + this.units;
this.percent = 0;
}
_updateBar() {
if (this._indeterminate) {
this.div.classList.add("indeterminate");
this.div.style.width = this.width + this.units;
return;
}
this.div.classList.remove("indeterminate");
const progressSize = (this.width * this._percent) / 100;
this.div.style.width = progressSize + this.units;
}
get percent() {
return this._percent;
}
set percent(val) {
this._indeterminate = isNaN(val);
this._percent = clamp(val, 0, 100);
this._updateBar();
}
setWidth(viewer) {
if (!viewer) {
return;
}
const container = viewer.parentNode;
const scrollbarWidth = container.offsetWidth - viewer.offsetWidth;
if (scrollbarWidth > 0) {
const doc = document.documentElement;
doc.style.setProperty(LOADINGBAR_END_OFFSET_VAR, `${scrollbarWidth}px`);
}
}
hide() {
if (!this.visible) {
return;
}
this.visible = false;
this.bar.classList.add("hidden");
}
show() {
if (this.visible) {
return;
}
this.visible = true;
this.bar.classList.remove("hidden");
}
}
/**
* Moves all elements of an array that satisfy condition to the end of the
* array, preserving the order of the rest.
*/
function moveToEndOfArray(arr, condition) {
const moved = [],
len = arr.length;
let write = 0;
for (let read = 0; read < len; ++read) {
if (condition(arr[read])) {
moved.push(arr[read]);
} else {
arr[write] = arr[read];
++write;
}
}
for (let read = 0; write < len; ++read, ++write) {
arr[write] = moved[read];
}
}
/**
* Get the active or focused element in current DOM.
*
* Recursively search for the truly active or focused element in case there are
* shadow DOMs.
*
* @returns {Element} the truly active or focused element.
*/
function getActiveOrFocusedElement() {
let curRoot = document;
let curActiveOrFocused =
curRoot.activeElement || curRoot.querySelector(":focus");
while (curActiveOrFocused?.shadowRoot) {
curRoot = curActiveOrFocused.shadowRoot;
curActiveOrFocused =
curRoot.activeElement || curRoot.querySelector(":focus");
}
return curActiveOrFocused;
}
/**
* Converts API PageLayout values to the format used by `BaseViewer`.
* NOTE: This is supported to the extent that the viewer implements the
* necessary Scroll/Spread modes (since SinglePage, TwoPageLeft,
* and TwoPageRight all suggests using non-continuous scrolling).
* @param {string} mode - The API PageLayout value.
* @returns {number} A value from {SpreadMode}.
*/
function apiPageLayoutToSpreadMode(layout) {
switch (layout) {
case "SinglePage":
case "OneColumn":
return SpreadMode.NONE;
case "TwoColumnLeft":
case "TwoPageLeft":
return SpreadMode.ODD;
case "TwoColumnRight":
case "TwoPageRight":
return SpreadMode.EVEN;
}
return SpreadMode.NONE; // Default value.
}
/**
* Converts API PageMode values to the format used by `PDFSidebar`.
* NOTE: There's also a "FullScreen" parameter which is not possible to support,
* since the Fullscreen API used in browsers requires that entering
* fullscreen mode only occurs as a result of a user-initiated event.
* @param {string} mode - The API PageMode value.
* @returns {number} A value from {SidebarView}.
*/
function apiPageModeToSidebarView(mode) {
switch (mode) {
case "UseNone":
return SidebarView.NONE;
case "UseThumbs":
return SidebarView.THUMBS;
case "UseOutlines":
return SidebarView.OUTLINE;
case "UseAttachments":
return SidebarView.ATTACHMENTS;
case "UseOC":
return SidebarView.LAYERS;
}
return SidebarView.NONE; // Default value.
}
export {
animationStarted,
apiPageLayoutToSpreadMode,
apiPageModeToSidebarView,
approximateFraction,
backtrackBeforeAllVisibleElements, // only exported for testing
binarySearchFirstItem,
CSS_UNITS,
DEFAULT_SCALE,
DEFAULT_SCALE_VALUE,
getActiveOrFocusedElement,
getOutputScale,
getPageSizeInches,
getVisibleElements,
isPortraitOrientation,
isValidRotation,
isValidScrollMode,
isValidSpreadMode,
MAX_AUTO_SCALE,
MAX_SCALE,
MIN_SCALE,
moveToEndOfArray,
noContextMenuHandler,
normalizeWheelEventDelta,
normalizeWheelEventDirection,
parseQueryString,
PresentationModeState,
ProgressBar,
RendererType,
roundToDivide,
SCROLLBAR_PADDING,
scrollIntoView,
ScrollMode,
SidebarView,
SpreadMode,
TextLayerMode,
UNKNOWN_SCALE,
VERTICAL_PADDING,
watchScroll,
};