/web/text_layer_builder.js
JavaScript | 365 lines | 252 code | 38 blank | 75 comment | 43 complexity | 277345f5c317a2f45e3a9a753ee6cf8b MD5 | raw file
- /* 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.
- */
- 'use strict';
- (function (root, factory) {
- if (typeof define === 'function' && define.amd) {
- define('pdfjs-web/text_layer_builder', ['exports', 'pdfjs-web/dom_events',
- 'pdfjs-web/pdfjs'],
- factory);
- } else if (typeof exports !== 'undefined') {
- factory(exports, require('./dom_events.js'), require('./pdfjs.js'));
- } else {
- factory((root.pdfjsWebTextLayerBuilder = {}), root.pdfjsWebDOMEvents,
- root.pdfjsWebPDFJS);
- }
- }(this, function (exports, domEvents, pdfjsLib) {
- /**
- * @typedef {Object} TextLayerBuilderOptions
- * @property {HTMLDivElement} textLayerDiv - The text layer container.
- * @property {EventBus} eventBus - The application event bus.
- * @property {number} pageIndex - The page index.
- * @property {PageViewport} viewport - The viewport of the text layer.
- * @property {PDFFindController} findController
- */
- /**
- * TextLayerBuilder provides text-selection functionality for the PDF.
- * It does this by creating overlay divs over the PDF text. These divs
- * contain text that matches the PDF text they are overlaying. This object
- * also provides a way to highlight text that is being searched for.
- * @class
- */
- var TextLayerBuilder = (function TextLayerBuilderClosure() {
- function TextLayerBuilder(options) {
- this.textLayerDiv = options.textLayerDiv;
- this.eventBus = options.eventBus || domEvents.getGlobalEventBus();
- this.renderingDone = false;
- this.divContentDone = false;
- this.pageIdx = options.pageIndex;
- this.pageNumber = this.pageIdx + 1;
- this.matches = [];
- this.viewport = options.viewport;
- this.textDivs = [];
- this.findController = options.findController || null;
- this.textLayerRenderTask = null;
- this._bindMouse();
- }
- TextLayerBuilder.prototype = {
- _finishRendering: function TextLayerBuilder_finishRendering() {
- this.renderingDone = true;
- var endOfContent = document.createElement('div');
- endOfContent.className = 'endOfContent';
- this.textLayerDiv.appendChild(endOfContent);
- this.eventBus.dispatch('textlayerrendered', {
- source: this,
- pageNumber: this.pageNumber
- });
- },
- /**
- * Renders the text layer.
- * @param {number} timeout (optional) if specified, the rendering waits
- * for specified amount of ms.
- */
- render: function TextLayerBuilder_render(timeout) {
- if (!this.divContentDone || this.renderingDone) {
- return;
- }
- if (this.textLayerRenderTask) {
- this.textLayerRenderTask.cancel();
- this.textLayerRenderTask = null;
- }
- this.textDivs = [];
- var textLayerFrag = document.createDocumentFragment();
- this.textLayerRenderTask = pdfjsLib.renderTextLayer({
- textContent: this.textContent,
- container: textLayerFrag,
- viewport: this.viewport,
- textDivs: this.textDivs,
- timeout: timeout
- });
- this.textLayerRenderTask.promise.then(function () {
- this.textLayerDiv.appendChild(textLayerFrag);
- this._finishRendering();
- this.updateMatches();
- }.bind(this), function (reason) {
- // canceled or failed to render text layer -- skipping errors
- });
- },
- setTextContent: function TextLayerBuilder_setTextContent(textContent) {
- if (this.textLayerRenderTask) {
- this.textLayerRenderTask.cancel();
- this.textLayerRenderTask = null;
- }
- this.textContent = textContent;
- this.divContentDone = true;
- },
- convertMatches: function TextLayerBuilder_convertMatches(matches) {
- var i = 0;
- var iIndex = 0;
- var bidiTexts = this.textContent.items;
- var end = bidiTexts.length - 1;
- var queryLen = (this.findController === null ?
- 0 : this.findController.state.query.length);
- var ret = [];
- for (var m = 0, len = matches.length; m < len; m++) {
- // Calculate the start position.
- var matchIdx = matches[m];
- // Loop over the divIdxs.
- while (i !== end && matchIdx >= (iIndex + bidiTexts[i].str.length)) {
- iIndex += bidiTexts[i].str.length;
- i++;
- }
- if (i === bidiTexts.length) {
- console.error('Could not find a matching mapping');
- }
- var match = {
- begin: {
- divIdx: i,
- offset: matchIdx - iIndex
- }
- };
- // Calculate the end position.
- matchIdx += queryLen;
- // Somewhat the same array as above, but use > instead of >= to get
- // the end position right.
- while (i !== end && matchIdx > (iIndex + bidiTexts[i].str.length)) {
- iIndex += bidiTexts[i].str.length;
- i++;
- }
- match.end = {
- divIdx: i,
- offset: matchIdx - iIndex
- };
- ret.push(match);
- }
- return ret;
- },
- renderMatches: function TextLayerBuilder_renderMatches(matches) {
- // Early exit if there is nothing to render.
- if (matches.length === 0) {
- return;
- }
- var bidiTexts = this.textContent.items;
- var textDivs = this.textDivs;
- var prevEnd = null;
- var pageIdx = this.pageIdx;
- var isSelectedPage = (this.findController === null ?
- false : (pageIdx === this.findController.selected.pageIdx));
- var selectedMatchIdx = (this.findController === null ?
- -1 : this.findController.selected.matchIdx);
- var highlightAll = (this.findController === null ?
- false : this.findController.state.highlightAll);
- var infinity = {
- divIdx: -1,
- offset: undefined
- };
- function beginText(begin, className) {
- var divIdx = begin.divIdx;
- textDivs[divIdx].textContent = '';
- appendTextToDiv(divIdx, 0, begin.offset, className);
- }
- function appendTextToDiv(divIdx, fromOffset, toOffset, className) {
- var div = textDivs[divIdx];
- var content = bidiTexts[divIdx].str.substring(fromOffset, toOffset);
- var node = document.createTextNode(content);
- if (className) {
- var span = document.createElement('span');
- span.className = className;
- span.appendChild(node);
- div.appendChild(span);
- return;
- }
- div.appendChild(node);
- }
- var i0 = selectedMatchIdx, i1 = i0 + 1;
- if (highlightAll) {
- i0 = 0;
- i1 = matches.length;
- } else if (!isSelectedPage) {
- // Not highlighting all and this isn't the selected page, so do nothing.
- return;
- }
- for (var i = i0; i < i1; i++) {
- var match = matches[i];
- var begin = match.begin;
- var end = match.end;
- var isSelected = (isSelectedPage && i === selectedMatchIdx);
- var highlightSuffix = (isSelected ? ' selected' : '');
- if (this.findController) {
- this.findController.updateMatchPosition(pageIdx, i, textDivs,
- begin.divIdx, end.divIdx);
- }
- // Match inside new div.
- if (!prevEnd || begin.divIdx !== prevEnd.divIdx) {
- // If there was a previous div, then add the text at the end.
- if (prevEnd !== null) {
- appendTextToDiv(prevEnd.divIdx, prevEnd.offset, infinity.offset);
- }
- // Clear the divs and set the content until the starting point.
- beginText(begin);
- } else {
- appendTextToDiv(prevEnd.divIdx, prevEnd.offset, begin.offset);
- }
- if (begin.divIdx === end.divIdx) {
- appendTextToDiv(begin.divIdx, begin.offset, end.offset,
- 'highlight' + highlightSuffix);
- } else {
- appendTextToDiv(begin.divIdx, begin.offset, infinity.offset,
- 'highlight begin' + highlightSuffix);
- for (var n0 = begin.divIdx + 1, n1 = end.divIdx; n0 < n1; n0++) {
- textDivs[n0].className = 'highlight middle' + highlightSuffix;
- }
- beginText(end, 'highlight end' + highlightSuffix);
- }
- prevEnd = end;
- }
- if (prevEnd) {
- appendTextToDiv(prevEnd.divIdx, prevEnd.offset, infinity.offset);
- }
- },
- updateMatches: function TextLayerBuilder_updateMatches() {
- // Only show matches when all rendering is done.
- if (!this.renderingDone) {
- return;
- }
- // Clear all matches.
- var matches = this.matches;
- var textDivs = this.textDivs;
- var bidiTexts = this.textContent.items;
- var clearedUntilDivIdx = -1;
- // Clear all current matches.
- for (var i = 0, len = matches.length; i < len; i++) {
- var match = matches[i];
- var begin = Math.max(clearedUntilDivIdx, match.begin.divIdx);
- for (var n = begin, end = match.end.divIdx; n <= end; n++) {
- var div = textDivs[n];
- div.textContent = bidiTexts[n].str;
- div.className = '';
- }
- clearedUntilDivIdx = match.end.divIdx + 1;
- }
- if (this.findController === null || !this.findController.active) {
- return;
- }
- // Convert the matches on the page controller into the match format
- // used for the textLayer.
- this.matches = this.convertMatches(this.findController === null ?
- [] : (this.findController.pageMatches[this.pageIdx] || []));
- this.renderMatches(this.matches);
- },
- /**
- * Fixes text selection: adds additional div where mouse was clicked.
- * This reduces flickering of the content if mouse slowly dragged down/up.
- * @private
- */
- _bindMouse: function TextLayerBuilder_bindMouse() {
- var div = this.textLayerDiv;
- div.addEventListener('mousedown', function (e) {
- var end = div.querySelector('.endOfContent');
- if (!end) {
- return;
- }
- //#if !(MOZCENTRAL || FIREFOX)
- // On non-Firefox browsers, the selection will feel better if the height
- // of the endOfContent div will be adjusted to start at mouse click
- // location -- this will avoid flickering when selections moves up.
- // However it does not work when selection started on empty space.
- var adjustTop = e.target !== div;
- //#if GENERIC
- adjustTop = adjustTop && window.getComputedStyle(end).
- getPropertyValue('-moz-user-select') !== 'none';
- //#endif
- if (adjustTop) {
- var divBounds = div.getBoundingClientRect();
- var r = Math.max(0, (e.pageY - divBounds.top) / divBounds.height);
- end.style.top = (r * 100).toFixed(2) + '%';
- }
- //#endif
- end.classList.add('active');
- });
- div.addEventListener('mouseup', function (e) {
- var end = div.querySelector('.endOfContent');
- if (!end) {
- return;
- }
- //#if !(MOZCENTRAL || FIREFOX)
- end.style.top = '';
- //#endif
- end.classList.remove('active');
- });
- },
- };
- return TextLayerBuilder;
- })();
- /**
- * @constructor
- * @implements IPDFTextLayerFactory
- */
- function DefaultTextLayerFactory() {}
- DefaultTextLayerFactory.prototype = {
- /**
- * @param {HTMLDivElement} textLayerDiv
- * @param {number} pageIndex
- * @param {PageViewport} viewport
- * @returns {TextLayerBuilder}
- */
- createTextLayerBuilder: function (textLayerDiv, pageIndex, viewport) {
- return new TextLayerBuilder({
- textLayerDiv: textLayerDiv,
- pageIndex: pageIndex,
- viewport: viewport
- });
- }
- };
- exports.TextLayerBuilder = TextLayerBuilder;
- exports.DefaultTextLayerFactory = DefaultTextLayerFactory;
- }));