pdfjs-dist/lib/web/text_layer_builder.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2019 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.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.DefaultTextLayerFactory = exports.TextLayerBuilder = void 0;

var _ui_utils = require("./ui_utils");

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

function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }

function _defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } }

function _createClass(Constructor, protoProps, staticProps) { if (protoProps) _defineProperties(Constructor.prototype, protoProps); if (staticProps) _defineProperties(Constructor, staticProps); return Constructor; }

var EXPAND_DIVS_TIMEOUT = 300;

var TextLayerBuilder =
/*#__PURE__*/
function () {
  function TextLayerBuilder(_ref) {
    var textLayerDiv = _ref.textLayerDiv,
        eventBus = _ref.eventBus,
        pageIndex = _ref.pageIndex,
        viewport = _ref.viewport,
        _ref$findController = _ref.findController,
        findController = _ref$findController === void 0 ? null : _ref$findController,
        _ref$enhanceTextSelec = _ref.enhanceTextSelection,
        enhanceTextSelection = _ref$enhanceTextSelec === void 0 ? false : _ref$enhanceTextSelec;

    _classCallCheck(this, TextLayerBuilder);

    this.textLayerDiv = textLayerDiv;
    this.eventBus = eventBus || (0, _ui_utils.getGlobalEventBus)();
    this.textContent = null;
    this.textContentItemsStr = [];
    this.textContentStream = null;
    this.renderingDone = false;
    this.pageIdx = pageIndex;
    this.pageNumber = this.pageIdx + 1;
    this.matches = [];
    this.viewport = viewport;
    this.textDivs = [];
    this.findController = findController;
    this.textLayerRenderTask = null;
    this.enhanceTextSelection = enhanceTextSelection;
    this._onUpdateTextLayerMatches = null;

    this._bindMouse();
  }

  _createClass(TextLayerBuilder, [{
    key: "_finishRendering",
    value: function _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
      });
    }
  }, {
    key: "render",
    value: function render() {
      var _this = this;

      var timeout = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 0;

      if (!(this.textContent || this.textContentStream) || this.renderingDone) {
        return;
      }

      this.cancel();
      this.textDivs = [];
      var textLayerFrag = document.createDocumentFragment();
      this.textLayerRenderTask = (0, _pdf.renderTextLayer)({
        textContent: this.textContent,
        textContentStream: this.textContentStream,
        container: textLayerFrag,
        viewport: this.viewport,
        textDivs: this.textDivs,
        textContentItemsStr: this.textContentItemsStr,
        timeout: timeout,
        enhanceTextSelection: this.enhanceTextSelection
      });
      this.textLayerRenderTask.promise.then(function () {
        _this.textLayerDiv.appendChild(textLayerFrag);

        _this._finishRendering();

        _this._updateMatches();
      }, function (reason) {});

      if (!this._onUpdateTextLayerMatches) {
        this._onUpdateTextLayerMatches = function (evt) {
          if (evt.pageIndex === _this.pageIdx || evt.pageIndex === -1) {
            _this._updateMatches();
          }
        };

        this.eventBus.on('updatetextlayermatches', this._onUpdateTextLayerMatches);
      }
    }
  }, {
    key: "cancel",
    value: function cancel() {
      if (this.textLayerRenderTask) {
        this.textLayerRenderTask.cancel();
        this.textLayerRenderTask = null;
      }

      if (this._onUpdateTextLayerMatches) {
        this.eventBus.off('updatetextlayermatches', this._onUpdateTextLayerMatches);
        this._onUpdateTextLayerMatches = null;
      }
    }
  }, {
    key: "setTextContentStream",
    value: function setTextContentStream(readableStream) {
      this.cancel();
      this.textContentStream = readableStream;
    }
  }, {
    key: "setTextContent",
    value: function setTextContent(textContent) {
      this.cancel();
      this.textContent = textContent;
    }
  }, {
    key: "_convertMatches",
    value: function _convertMatches(matches, matchesLength) {
      if (!matches) {
        return [];
      }

      var findController = this.findController,
          textContentItemsStr = this.textContentItemsStr;
      var i = 0,
          iIndex = 0;
      var end = textContentItemsStr.length - 1;
      var queryLen = findController.state.query.length;
      var result = [];

      for (var m = 0, mm = matches.length; m < mm; m++) {
        var matchIdx = matches[m];

        while (i !== end && matchIdx >= iIndex + textContentItemsStr[i].length) {
          iIndex += textContentItemsStr[i].length;
          i++;
        }

        if (i === textContentItemsStr.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 + textContentItemsStr[i].length) {
          iIndex += textContentItemsStr[i].length;
          i++;
        }

        match.end = {
          divIdx: i,
          offset: matchIdx - iIndex
        };
        result.push(match);
      }

      return result;
    }
  }, {
    key: "_renderMatches",
    value: function _renderMatches(matches) {
      if (matches.length === 0) {
        return;
      }

      var findController = this.findController,
          pageIdx = this.pageIdx,
          textContentItemsStr = this.textContentItemsStr,
          textDivs = this.textDivs;
      var isSelectedPage = pageIdx === findController.selected.pageIdx;
      var selectedMatchIdx = findController.selected.matchIdx;
      var highlightAll = findController.state.highlightAll;
      var prevEnd = null;
      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 = textContentItemsStr[divIdx].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 (isSelected) {
          findController.scrollMatchIntoView({
            element: textDivs[begin.divIdx],
            pageIndex: pageIdx,
            matchIndex: selectedMatchIdx
          });
        }

        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);
      }
    }
  }, {
    key: "_updateMatches",
    value: function _updateMatches() {
      if (!this.renderingDone) {
        return;
      }

      var findController = this.findController,
          matches = this.matches,
          pageIdx = this.pageIdx,
          textContentItemsStr = this.textContentItemsStr,
          textDivs = this.textDivs;
      var clearedUntilDivIdx = -1;

      for (var i = 0, ii = matches.length; i < ii; 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 = textContentItemsStr[n];
          div.className = '';
        }

        clearedUntilDivIdx = match.end.divIdx + 1;
      }

      if (!findController || !findController.highlightMatches) {
        return;
      }

      var pageMatches = findController.pageMatches[pageIdx] || null;
      var pageMatchesLength = findController.pageMatchesLength[pageIdx] || null;
      this.matches = this._convertMatches(pageMatches, pageMatchesLength);

      this._renderMatches(this.matches);
    }
  }, {
    key: "_bindMouse",
    value: function _bindMouse() {
      var _this2 = this;

      var div = this.textLayerDiv;
      var expandDivsTimer = null;
      div.addEventListener('mousedown', function (evt) {
        if (_this2.enhanceTextSelection && _this2.textLayerRenderTask) {
          _this2.textLayerRenderTask.expandTextDivs(true);

          if (expandDivsTimer) {
            clearTimeout(expandDivsTimer);
            expandDivsTimer = null;
          }

          return;
        }

        var end = div.querySelector('.endOfContent');

        if (!end) {
          return;
        }

        var adjustTop = evt.target !== div;
        adjustTop = adjustTop && window.getComputedStyle(end).getPropertyValue('-moz-user-select') !== 'none';

        if (adjustTop) {
          var divBounds = div.getBoundingClientRect();
          var r = Math.max(0, (evt.pageY - divBounds.top) / divBounds.height);
          end.style.top = (r * 100).toFixed(2) + '%';
        }

        end.classList.add('active');
      });
      div.addEventListener('mouseup', function () {
        if (_this2.enhanceTextSelection && _this2.textLayerRenderTask) {
          expandDivsTimer = setTimeout(function () {
            if (_this2.textLayerRenderTask) {
              _this2.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;
}();

exports.TextLayerBuilder = TextLayerBuilder;

var DefaultTextLayerFactory =
/*#__PURE__*/
function () {
  function DefaultTextLayerFactory() {
    _classCallCheck(this, DefaultTextLayerFactory);
  }

  _createClass(DefaultTextLayerFactory, [{
    key: "createTextLayerBuilder",
    value: 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
      });
    }
  }]);

  return DefaultTextLayerFactory;
}();

exports.DefaultTextLayerFactory = DefaultTextLayerFactory;