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';

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.DefaultTextLayerFactory = exports.TextLayerBuilder = undefined;

var _dom_events = require('./dom_events');

var _pdf = require('../pdf');

var EXPAND_DIVS_TIMEOUT = 300;
var TextLayerBuilder = function TextLayerBuilderClosure() {
  function TextLayerBuilder(options) {
    this.textLayerDiv = options.textLayerDiv;
    this.eventBus = options.eventBus || (0, _dom_events.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) {
      var _this = this;

      if (!this.textContent || this.renderingDone) {
        return;
      }
      this.cancel();
      this.textDivs = [];
      var textLayerFrag = document.createDocumentFragment();
      this.textLayerRenderTask = (0, _pdf.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();
      }, 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 createTextLayerBuilder(textLayerDiv, pageIndex, viewport) {
    var enhanceTextSelection = arguments.length > 3 && arguments[3] !== undefined ? arguments[3] : false;

    return new TextLayerBuilder({
      textLayerDiv: textLayerDiv,
      pageIndex: pageIndex,
      viewport: viewport,
      enhanceTextSelection: enhanceTextSelection
    });
  }
};
exports.TextLayerBuilder = TextLayerBuilder;
exports.DefaultTextLayerFactory = DefaultTextLayerFactory;