pdfjs-dist/lib/web/text_layer_builder.js

/* Copyright 2017 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';
var domEvents = require('./dom_events.js');
var pdfjsLib = require('./pdfjs.js');
var EXPAND_DIVS_TIMEOUT = 300;
var TextLayerBuilder = function TextLayerBuilderClosure() {
 function TextLayerBuilder(options) {
  this.textLayerDiv = options.textLayerDiv;
  this.eventBus = options.eventBus || domEvents.getGlobalEventBus();
  this.textContent = null;
  this.renderingDone = 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.enhanceTextSelection = options.enhanceTextSelection;
  this._bindMouse();
 }
 TextLayerBuilder.prototype = {
  _finishRendering: function TextLayerBuilder_finishRendering() {
   this.renderingDone = true;
   if (!this.enhanceTextSelection) {
    var endOfContent = document.createElement('div');
    endOfContent.className = 'endOfContent';
    this.textLayerDiv.appendChild(endOfContent);
   }
   this.eventBus.dispatch('textlayerrendered', {
    source: this,
    pageNumber: this.pageNumber,
    numTextDivs: this.textDivs.length
   });
  },
  render: function TextLayerBuilder_render(timeout) {
   if (!this.textContent || this.renderingDone) {
    return;
   }
   this.cancel();
   this.textDivs = [];
   var textLayerFrag = document.createDocumentFragment();
   this.textLayerRenderTask = pdfjsLib.renderTextLayer({
    textContent: this.textContent,
    container: textLayerFrag,
    viewport: this.viewport,
    textDivs: this.textDivs,
    timeout: timeout,
    enhanceTextSelection: this.enhanceTextSelection
   });
   this.textLayerRenderTask.promise.then(function () {
    this.textLayerDiv.appendChild(textLayerFrag);
    this._finishRendering();
    this.updateMatches();
   }.bind(this), function (reason) {
   });
  },
  cancel: function TextLayerBuilder_cancel() {
   if (this.textLayerRenderTask) {
    this.textLayerRenderTask.cancel();
    this.textLayerRenderTask = null;
   }
  },
  setTextContent: function TextLayerBuilder_setTextContent(textContent) {
   this.cancel();
   this.textContent = textContent;
  },
  convertMatches: function TextLayerBuilder_convertMatches(matches, matchesLength) {
   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 = [];
   if (!matches) {
    return ret;
   }
   for (var m = 0, len = matches.length; m < len; m++) {
    var matchIdx = matches[m];
    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
     }
    };
    if (matchesLength) {
     matchIdx += matchesLength[m];
    } else {
     matchIdx += queryLen;
    }
    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) {
   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) {
    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);
    }
    if (!prevEnd || begin.divIdx !== prevEnd.divIdx) {
     if (prevEnd !== null) {
      appendTextToDiv(prevEnd.divIdx, prevEnd.offset, infinity.offset);
     }
     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() {
   if (!this.renderingDone) {
    return;
   }
   var matches = this.matches;
   var textDivs = this.textDivs;
   var bidiTexts = this.textContent.items;
   var clearedUntilDivIdx = -1;
   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;
   }
   var pageMatches, pageMatchesLength;
   if (this.findController !== null) {
    pageMatches = this.findController.pageMatches[this.pageIdx] || null;
    pageMatchesLength = this.findController.pageMatchesLength ? this.findController.pageMatchesLength[this.pageIdx] || null : null;
   }
   this.matches = this.convertMatches(pageMatches, pageMatchesLength);
   this.renderMatches(this.matches);
  },
  _bindMouse: function TextLayerBuilder_bindMouse() {
   var div = this.textLayerDiv;
   var self = this;
   var expandDivsTimer = null;
   div.addEventListener('mousedown', function (e) {
    if (self.enhanceTextSelection && self.textLayerRenderTask) {
     self.textLayerRenderTask.expandTextDivs(true);
     if (expandDivsTimer) {
      clearTimeout(expandDivsTimer);
      expandDivsTimer = null;
     }
     return;
    }
    var end = div.querySelector('.endOfContent');
    if (!end) {
     return;
    }
    var adjustTop = e.target !== div;
    adjustTop = adjustTop && window.getComputedStyle(end).getPropertyValue('-moz-user-select') !== 'none';
    if (adjustTop) {
     var divBounds = div.getBoundingClientRect();
     var r = Math.max(0, (e.pageY - divBounds.top) / divBounds.height);
     end.style.top = (r * 100).toFixed(2) + '%';
    }
    end.classList.add('active');
   });
   div.addEventListener('mouseup', function (e) {
    if (self.enhanceTextSelection && self.textLayerRenderTask) {
     expandDivsTimer = setTimeout(function () {
      if (self.textLayerRenderTask) {
       self.textLayerRenderTask.expandTextDivs(false);
      }
      expandDivsTimer = null;
     }, EXPAND_DIVS_TIMEOUT);
     return;
    }
    var end = div.querySelector('.endOfContent');
    if (!end) {
     return;
    }
    end.style.top = '';
    end.classList.remove('active');
   });
  }
 };
 return TextLayerBuilder;
}();
function DefaultTextLayerFactory() {
}
DefaultTextLayerFactory.prototype = {
 createTextLayerBuilder: function (textLayerDiv, pageIndex, viewport, enhanceTextSelection) {
  return new TextLayerBuilder({
   textLayerDiv: textLayerDiv,
   pageIndex: pageIndex,
   viewport: viewport,
   enhanceTextSelection: enhanceTextSelection
  });
 }
};
exports.TextLayerBuilder = TextLayerBuilder;
exports.DefaultTextLayerFactory = DefaultTextLayerFactory;