425 lines
14 KiB
JavaScript
425 lines
14 KiB
JavaScript
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/* Copyright 2012 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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'use strict';
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(function (root, factory) {
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if (typeof define === 'function' && define.amd) {
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define('pdfjs-web/text_layer_builder', ['exports', 'pdfjs-web/dom_events',
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'pdfjs-web/pdfjs'], factory);
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} else if (typeof exports !== 'undefined') {
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factory(exports, require('./dom_events.js'), require('./pdfjs.js'));
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} else {
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factory((root.pdfjsWebTextLayerBuilder = {}), root.pdfjsWebDOMEvents,
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root.pdfjsWebPDFJS);
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}
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}(this, function (exports, domEvents, pdfjsLib) {
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var EXPAND_DIVS_TIMEOUT = 300; // ms
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/**
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* @typedef {Object} TextLayerBuilderOptions
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* @property {HTMLDivElement} textLayerDiv - The text layer container.
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* @property {EventBus} eventBus - The application event bus.
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* @property {number} pageIndex - The page index.
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* @property {PageViewport} viewport - The viewport of the text layer.
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* @property {PDFFindController} findController
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* @property {boolean} enhanceTextSelection - Option to turn on improved
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* text selection.
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*/
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/**
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* TextLayerBuilder provides text-selection functionality for the PDF.
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* It does this by creating overlay divs over the PDF text. These divs
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* contain text that matches the PDF text they are overlaying. This object
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* also provides a way to highlight text that is being searched for.
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* @class
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*/
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var TextLayerBuilder = (function TextLayerBuilderClosure() {
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function TextLayerBuilder(options) {
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this.textLayerDiv = options.textLayerDiv;
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this.eventBus = options.eventBus || domEvents.getGlobalEventBus();
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this.textContent = null;
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this.renderingDone = false;
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this.pageIdx = options.pageIndex;
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this.pageNumber = this.pageIdx + 1;
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this.matches = [];
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this.viewport = options.viewport;
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this.textDivs = [];
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this.findController = options.findController || null;
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this.textLayerRenderTask = null;
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this.enhanceTextSelection = options.enhanceTextSelection;
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this._bindMouse();
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}
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TextLayerBuilder.prototype = {
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/**
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* @private
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*/
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_finishRendering: function TextLayerBuilder_finishRendering() {
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this.renderingDone = true;
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if (!this.enhanceTextSelection) {
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var endOfContent = document.createElement('div');
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endOfContent.className = 'endOfContent';
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this.textLayerDiv.appendChild(endOfContent);
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}
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this.eventBus.dispatch('textlayerrendered', {
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source: this,
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pageNumber: this.pageNumber,
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numTextDivs: this.textDivs.length,
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});
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},
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/**
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* Renders the text layer.
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* @param {number} timeout (optional) if specified, the rendering waits
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* for specified amount of ms.
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*/
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render: function TextLayerBuilder_render(timeout) {
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if (!this.textContent || this.renderingDone) {
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return;
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}
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this.cancel();
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this.textDivs = [];
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var textLayerFrag = document.createDocumentFragment();
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this.textLayerRenderTask = pdfjsLib.renderTextLayer({
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textContent: this.textContent,
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container: textLayerFrag,
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viewport: this.viewport,
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textDivs: this.textDivs,
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timeout: timeout,
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enhanceTextSelection: this.enhanceTextSelection,
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});
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this.textLayerRenderTask.promise.then(function () {
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this.textLayerDiv.appendChild(textLayerFrag);
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this._finishRendering();
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this.updateMatches();
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}.bind(this), function (reason) {
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// cancelled or failed to render text layer -- skipping errors
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});
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},
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/**
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* Cancels rendering of the text layer.
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*/
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cancel: function TextLayerBuilder_cancel() {
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if (this.textLayerRenderTask) {
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this.textLayerRenderTask.cancel();
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this.textLayerRenderTask = null;
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}
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},
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setTextContent: function TextLayerBuilder_setTextContent(textContent) {
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this.cancel();
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this.textContent = textContent;
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},
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convertMatches: function TextLayerBuilder_convertMatches(matches,
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matchesLength) {
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var i = 0;
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var iIndex = 0;
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var bidiTexts = this.textContent.items;
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var end = bidiTexts.length - 1;
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var queryLen = (this.findController === null ?
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0 : this.findController.state.query.length);
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var ret = [];
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if (!matches) {
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return ret;
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}
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for (var m = 0, len = matches.length; m < len; m++) {
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// Calculate the start position.
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var matchIdx = matches[m];
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// Loop over the divIdxs.
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while (i !== end && matchIdx >= (iIndex + bidiTexts[i].str.length)) {
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iIndex += bidiTexts[i].str.length;
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i++;
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}
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if (i === bidiTexts.length) {
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console.error('Could not find a matching mapping');
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}
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var match = {
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begin: {
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divIdx: i,
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offset: matchIdx - iIndex
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}
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};
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// Calculate the end position.
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if (matchesLength) { // multiterm search
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matchIdx += matchesLength[m];
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} else { // phrase search
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matchIdx += queryLen;
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}
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// Somewhat the same array as above, but use > instead of >= to get
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// the end position right.
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while (i !== end && matchIdx > (iIndex + bidiTexts[i].str.length)) {
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iIndex += bidiTexts[i].str.length;
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i++;
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}
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match.end = {
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divIdx: i,
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offset: matchIdx - iIndex
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};
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ret.push(match);
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}
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return ret;
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},
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renderMatches: function TextLayerBuilder_renderMatches(matches) {
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// Early exit if there is nothing to render.
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if (matches.length === 0) {
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return;
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}
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var bidiTexts = this.textContent.items;
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var textDivs = this.textDivs;
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var prevEnd = null;
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var pageIdx = this.pageIdx;
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var isSelectedPage = (this.findController === null ?
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false : (pageIdx === this.findController.selected.pageIdx));
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var selectedMatchIdx = (this.findController === null ?
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-1 : this.findController.selected.matchIdx);
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var highlightAll = (this.findController === null ?
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false : this.findController.state.highlightAll);
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var infinity = {
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divIdx: -1,
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offset: undefined
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};
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function beginText(begin, className) {
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var divIdx = begin.divIdx;
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textDivs[divIdx].textContent = '';
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appendTextToDiv(divIdx, 0, begin.offset, className);
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}
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function appendTextToDiv(divIdx, fromOffset, toOffset, className) {
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var div = textDivs[divIdx];
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var content = bidiTexts[divIdx].str.substring(fromOffset, toOffset);
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var node = document.createTextNode(content);
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if (className) {
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var span = document.createElement('span');
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span.className = className;
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span.appendChild(node);
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div.appendChild(span);
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return;
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}
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div.appendChild(node);
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}
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var i0 = selectedMatchIdx, i1 = i0 + 1;
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if (highlightAll) {
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i0 = 0;
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i1 = matches.length;
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} else if (!isSelectedPage) {
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// Not highlighting all and this isn't the selected page, so do nothing.
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return;
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}
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for (var i = i0; i < i1; i++) {
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var match = matches[i];
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var begin = match.begin;
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var end = match.end;
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var isSelected = (isSelectedPage && i === selectedMatchIdx);
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var highlightSuffix = (isSelected ? ' selected' : '');
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if (this.findController) {
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this.findController.updateMatchPosition(pageIdx, i, textDivs,
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begin.divIdx);
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}
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// Match inside new div.
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if (!prevEnd || begin.divIdx !== prevEnd.divIdx) {
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// If there was a previous div, then add the text at the end.
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if (prevEnd !== null) {
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appendTextToDiv(prevEnd.divIdx, prevEnd.offset, infinity.offset);
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}
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// Clear the divs and set the content until the starting point.
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beginText(begin);
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} else {
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appendTextToDiv(prevEnd.divIdx, prevEnd.offset, begin.offset);
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}
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if (begin.divIdx === end.divIdx) {
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appendTextToDiv(begin.divIdx, begin.offset, end.offset,
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'highlight' + highlightSuffix);
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} else {
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appendTextToDiv(begin.divIdx, begin.offset, infinity.offset,
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'highlight begin' + highlightSuffix);
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for (var n0 = begin.divIdx + 1, n1 = end.divIdx; n0 < n1; n0++) {
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textDivs[n0].className = 'highlight middle' + highlightSuffix;
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}
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beginText(end, 'highlight end' + highlightSuffix);
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}
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prevEnd = end;
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}
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if (prevEnd) {
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appendTextToDiv(prevEnd.divIdx, prevEnd.offset, infinity.offset);
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}
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},
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updateMatches: function TextLayerBuilder_updateMatches() {
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// Only show matches when all rendering is done.
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if (!this.renderingDone) {
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return;
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}
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// Clear all matches.
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var matches = this.matches;
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var textDivs = this.textDivs;
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var bidiTexts = this.textContent.items;
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var clearedUntilDivIdx = -1;
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// Clear all current matches.
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for (var i = 0, len = matches.length; i < len; i++) {
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var match = matches[i];
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var begin = Math.max(clearedUntilDivIdx, match.begin.divIdx);
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for (var n = begin, end = match.end.divIdx; n <= end; n++) {
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var div = textDivs[n];
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div.textContent = bidiTexts[n].str;
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div.className = '';
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}
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clearedUntilDivIdx = match.end.divIdx + 1;
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}
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if (this.findController === null || !this.findController.active) {
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return;
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}
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// Convert the matches on the page controller into the match format
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// used for the textLayer.
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var pageMatches, pageMatchesLength;
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if (this.findController !== null) {
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pageMatches = this.findController.pageMatches[this.pageIdx] || null;
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pageMatchesLength = (this.findController.pageMatchesLength) ?
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this.findController.pageMatchesLength[this.pageIdx] || null : null;
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}
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this.matches = this.convertMatches(pageMatches, pageMatchesLength);
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this.renderMatches(this.matches);
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},
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/**
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* Fixes text selection: adds additional div where mouse was clicked.
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* This reduces flickering of the content if mouse slowly dragged down/up.
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* @private
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*/
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_bindMouse: function TextLayerBuilder_bindMouse() {
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var div = this.textLayerDiv;
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var self = this;
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var expandDivsTimer = null;
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div.addEventListener('mousedown', function (e) {
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if (self.enhanceTextSelection && self.textLayerRenderTask) {
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self.textLayerRenderTask.expandTextDivs(true);
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if ((typeof PDFJSDev === 'undefined' ||
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!PDFJSDev.test('FIREFOX || MOZCENTRAL')) &&
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expandDivsTimer) {
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clearTimeout(expandDivsTimer);
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expandDivsTimer = null;
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}
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return;
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}
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var end = div.querySelector('.endOfContent');
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if (!end) {
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return;
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}
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if (typeof PDFJSDev === 'undefined' ||
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!PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
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// On non-Firefox browsers, the selection will feel better if the height
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// of the endOfContent div will be adjusted to start at mouse click
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// location -- this will avoid flickering when selections moves up.
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// However it does not work when selection started on empty space.
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var adjustTop = e.target !== div;
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if (typeof PDFJSDev === 'undefined' || PDFJSDev.test('GENERIC')) {
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adjustTop = adjustTop && window.getComputedStyle(end).
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getPropertyValue('-moz-user-select') !== 'none';
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}
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if (adjustTop) {
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var divBounds = div.getBoundingClientRect();
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var r = Math.max(0, (e.pageY - divBounds.top) / divBounds.height);
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end.style.top = (r * 100).toFixed(2) + '%';
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}
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}
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end.classList.add('active');
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});
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div.addEventListener('mouseup', function (e) {
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if (self.enhanceTextSelection && self.textLayerRenderTask) {
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if (typeof PDFJSDev === 'undefined' ||
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!PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
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expandDivsTimer = setTimeout(function() {
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if (self.textLayerRenderTask) {
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self.textLayerRenderTask.expandTextDivs(false);
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}
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|
|
expandDivsTimer = null;
|
||
|
|
}, EXPAND_DIVS_TIMEOUT);
|
||
|
|
} else {
|
||
|
|
self.textLayerRenderTask.expandTextDivs(false);
|
||
|
|
}
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
var end = div.querySelector('.endOfContent');
|
||
|
|
if (!end) {
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
if (typeof PDFJSDev === 'undefined' ||
|
||
|
|
!PDFJSDev.test('FIREFOX || MOZCENTRAL')) {
|
||
|
|
end.style.top = '';
|
||
|
|
}
|
||
|
|
end.classList.remove('active');
|
||
|
|
});
|
||
|
|
},
|
||
|
|
};
|
||
|
|
return TextLayerBuilder;
|
||
|
|
})();
|
||
|
|
|
||
|
|
/**
|
||
|
|
* @constructor
|
||
|
|
* @implements IPDFTextLayerFactory
|
||
|
|
*/
|
||
|
|
function DefaultTextLayerFactory() {}
|
||
|
|
DefaultTextLayerFactory.prototype = {
|
||
|
|
/**
|
||
|
|
* @param {HTMLDivElement} textLayerDiv
|
||
|
|
* @param {number} pageIndex
|
||
|
|
* @param {PageViewport} viewport
|
||
|
|
* @param {boolean} enhanceTextSelection
|
||
|
|
* @returns {TextLayerBuilder}
|
||
|
|
*/
|
||
|
|
createTextLayerBuilder: function (textLayerDiv, pageIndex, viewport,
|
||
|
|
enhanceTextSelection) {
|
||
|
|
return new TextLayerBuilder({
|
||
|
|
textLayerDiv: textLayerDiv,
|
||
|
|
pageIndex: pageIndex,
|
||
|
|
viewport: viewport,
|
||
|
|
enhanceTextSelection: enhanceTextSelection
|
||
|
|
});
|
||
|
|
}
|
||
|
|
};
|
||
|
|
|
||
|
|
exports.TextLayerBuilder = TextLayerBuilder;
|
||
|
|
exports.DefaultTextLayerFactory = DefaultTextLayerFactory;
|
||
|
|
}));
|