pdfjs-dist/lib/web/pdf_thumbnail_view.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.PDFThumbnailView = void 0;

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

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

var _pdf_rendering_queue = require("./pdf_rendering_queue");

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 MAX_NUM_SCALING_STEPS = 3;
var THUMBNAIL_CANVAS_BORDER_WIDTH = 1;
var THUMBNAIL_WIDTH = 98;

var TempImageFactory = function TempImageFactoryClosure() {
  var tempCanvasCache = null;
  return {
    getCanvas: function getCanvas(width, height) {
      var tempCanvas = tempCanvasCache;

      if (!tempCanvas) {
        tempCanvas = document.createElement('canvas');
        tempCanvasCache = tempCanvas;
      }

      tempCanvas.width = width;
      tempCanvas.height = height;
      tempCanvas.mozOpaque = true;
      var ctx = tempCanvas.getContext('2d', {
        alpha: false
      });
      ctx.save();
      ctx.fillStyle = 'rgb(255, 255, 255)';
      ctx.fillRect(0, 0, width, height);
      ctx.restore();
      return tempCanvas;
    },
    destroyCanvas: function destroyCanvas() {
      var tempCanvas = tempCanvasCache;

      if (tempCanvas) {
        tempCanvas.width = 0;
        tempCanvas.height = 0;
      }

      tempCanvasCache = null;
    }
  };
}();

var PDFThumbnailView =
/*#__PURE__*/
function () {
  function PDFThumbnailView(_ref) {
    var container = _ref.container,
        id = _ref.id,
        defaultViewport = _ref.defaultViewport,
        linkService = _ref.linkService,
        renderingQueue = _ref.renderingQueue,
        _ref$disableCanvasToI = _ref.disableCanvasToImageConversion,
        disableCanvasToImageConversion = _ref$disableCanvasToI === void 0 ? false : _ref$disableCanvasToI,
        _ref$l10n = _ref.l10n,
        l10n = _ref$l10n === void 0 ? _ui_utils.NullL10n : _ref$l10n;

    _classCallCheck(this, PDFThumbnailView);

    this.id = id;
    this.renderingId = 'thumbnail' + id;
    this.pageLabel = null;
    this.pdfPage = null;
    this.rotation = 0;
    this.viewport = defaultViewport;
    this.pdfPageRotate = defaultViewport.rotation;
    this.linkService = linkService;
    this.renderingQueue = renderingQueue;
    this.renderTask = null;
    this.renderingState = _pdf_rendering_queue.RenderingStates.INITIAL;
    this.resume = null;
    this.disableCanvasToImageConversion = disableCanvasToImageConversion;
    this.pageWidth = this.viewport.width;
    this.pageHeight = this.viewport.height;
    this.pageRatio = this.pageWidth / this.pageHeight;
    this.canvasWidth = THUMBNAIL_WIDTH;
    this.canvasHeight = this.canvasWidth / this.pageRatio | 0;
    this.scale = this.canvasWidth / this.pageWidth;
    this.l10n = l10n;
    var anchor = document.createElement('a');
    anchor.href = linkService.getAnchorUrl('#page=' + id);
    this.l10n.get('thumb_page_title', {
      page: id
    }, 'Page {{page}}').then(function (msg) {
      anchor.title = msg;
    });

    anchor.onclick = function () {
      linkService.page = id;
      return false;
    };

    this.anchor = anchor;
    var div = document.createElement('div');
    div.className = 'thumbnail';
    div.setAttribute('data-page-number', this.id);
    this.div = div;
    var ring = document.createElement('div');
    ring.className = 'thumbnailSelectionRing';
    var borderAdjustment = 2 * THUMBNAIL_CANVAS_BORDER_WIDTH;
    ring.style.width = this.canvasWidth + borderAdjustment + 'px';
    ring.style.height = this.canvasHeight + borderAdjustment + 'px';
    this.ring = ring;
    div.appendChild(ring);
    anchor.appendChild(div);
    container.appendChild(anchor);
  }

  _createClass(PDFThumbnailView, [{
    key: "setPdfPage",
    value: function setPdfPage(pdfPage) {
      this.pdfPage = pdfPage;
      this.pdfPageRotate = pdfPage.rotate;
      var totalRotation = (this.rotation + this.pdfPageRotate) % 360;
      this.viewport = pdfPage.getViewport({
        scale: 1,
        rotation: totalRotation
      });
      this.reset();
    }
  }, {
    key: "reset",
    value: function reset() {
      this.cancelRendering();
      this.renderingState = _pdf_rendering_queue.RenderingStates.INITIAL;
      this.pageWidth = this.viewport.width;
      this.pageHeight = this.viewport.height;
      this.pageRatio = this.pageWidth / this.pageHeight;
      this.canvasHeight = this.canvasWidth / this.pageRatio | 0;
      this.scale = this.canvasWidth / this.pageWidth;
      this.div.removeAttribute('data-loaded');
      var ring = this.ring;
      var childNodes = ring.childNodes;

      for (var i = childNodes.length - 1; i >= 0; i--) {
        ring.removeChild(childNodes[i]);
      }

      var borderAdjustment = 2 * THUMBNAIL_CANVAS_BORDER_WIDTH;
      ring.style.width = this.canvasWidth + borderAdjustment + 'px';
      ring.style.height = this.canvasHeight + borderAdjustment + 'px';

      if (this.canvas) {
        this.canvas.width = 0;
        this.canvas.height = 0;
        delete this.canvas;
      }

      if (this.image) {
        this.image.removeAttribute('src');
        delete this.image;
      }
    }
  }, {
    key: "update",
    value: function update(rotation) {
      if (typeof rotation !== 'undefined') {
        this.rotation = rotation;
      }

      var totalRotation = (this.rotation + this.pdfPageRotate) % 360;
      this.viewport = this.viewport.clone({
        scale: 1,
        rotation: totalRotation
      });
      this.reset();
    }
  }, {
    key: "cancelRendering",
    value: function cancelRendering() {
      if (this.renderTask) {
        this.renderTask.cancel();
        this.renderTask = null;
      }

      this.resume = null;
    }
  }, {
    key: "_getPageDrawContext",
    value: function _getPageDrawContext() {
      var noCtxScale = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : false;
      var canvas = document.createElement('canvas');
      this.canvas = canvas;
      canvas.mozOpaque = true;
      var ctx = canvas.getContext('2d', {
        alpha: false
      });
      var outputScale = (0, _ui_utils.getOutputScale)(ctx);
      canvas.width = this.canvasWidth * outputScale.sx | 0;
      canvas.height = this.canvasHeight * outputScale.sy | 0;
      canvas.style.width = this.canvasWidth + 'px';
      canvas.style.height = this.canvasHeight + 'px';

      if (!noCtxScale && outputScale.scaled) {
        ctx.scale(outputScale.sx, outputScale.sy);
      }

      return ctx;
    }
  }, {
    key: "_convertCanvasToImage",
    value: function _convertCanvasToImage() {
      var _this = this;

      if (!this.canvas) {
        return;
      }

      if (this.renderingState !== _pdf_rendering_queue.RenderingStates.FINISHED) {
        return;
      }

      var id = this.renderingId;
      var className = 'thumbnailImage';

      if (this.disableCanvasToImageConversion) {
        this.canvas.id = id;
        this.canvas.className = className;
        this.l10n.get('thumb_page_canvas', {
          page: this.pageId
        }, 'Thumbnail of Page {{page}}').then(function (msg) {
          _this.canvas.setAttribute('aria-label', msg);
        });
        this.div.setAttribute('data-loaded', true);
        this.ring.appendChild(this.canvas);
        return;
      }

      var image = document.createElement('img');
      image.id = id;
      image.className = className;
      this.l10n.get('thumb_page_canvas', {
        page: this.pageId
      }, 'Thumbnail of Page {{page}}').then(function (msg) {
        image.setAttribute('aria-label', msg);
      });
      image.style.width = this.canvasWidth + 'px';
      image.style.height = this.canvasHeight + 'px';
      image.src = this.canvas.toDataURL();
      this.image = image;
      this.div.setAttribute('data-loaded', true);
      this.ring.appendChild(image);
      this.canvas.width = 0;
      this.canvas.height = 0;
      delete this.canvas;
    }
  }, {
    key: "draw",
    value: function draw() {
      var _this2 = this;

      if (this.renderingState !== _pdf_rendering_queue.RenderingStates.INITIAL) {
        console.error('Must be in new state before drawing');
        return Promise.resolve(undefined);
      }

      this.renderingState = _pdf_rendering_queue.RenderingStates.RUNNING;
      var renderCapability = (0, _pdf.createPromiseCapability)();

      var finishRenderTask = function finishRenderTask(error) {
        if (renderTask === _this2.renderTask) {
          _this2.renderTask = null;
        }

        if (error instanceof _pdf.RenderingCancelledException) {
          renderCapability.resolve(undefined);
          return;
        }

        _this2.renderingState = _pdf_rendering_queue.RenderingStates.FINISHED;

        _this2._convertCanvasToImage();

        if (!error) {
          renderCapability.resolve(undefined);
        } else {
          renderCapability.reject(error);
        }
      };

      var ctx = this._getPageDrawContext();

      var drawViewport = this.viewport.clone({
        scale: this.scale
      });

      var renderContinueCallback = function renderContinueCallback(cont) {
        if (!_this2.renderingQueue.isHighestPriority(_this2)) {
          _this2.renderingState = _pdf_rendering_queue.RenderingStates.PAUSED;

          _this2.resume = function () {
            _this2.renderingState = _pdf_rendering_queue.RenderingStates.RUNNING;
            cont();
          };

          return;
        }

        cont();
      };

      var renderContext = {
        canvasContext: ctx,
        viewport: drawViewport
      };
      var renderTask = this.renderTask = this.pdfPage.render(renderContext);
      renderTask.onContinue = renderContinueCallback;
      renderTask.promise.then(function () {
        finishRenderTask(null);
      }, function (error) {
        finishRenderTask(error);
      });
      return renderCapability.promise;
    }
  }, {
    key: "setImage",
    value: function setImage(pageView) {
      if (this.renderingState !== _pdf_rendering_queue.RenderingStates.INITIAL) {
        return;
      }

      var img = pageView.canvas;

      if (!img) {
        return;
      }

      if (!this.pdfPage) {
        this.setPdfPage(pageView.pdfPage);
      }

      this.renderingState = _pdf_rendering_queue.RenderingStates.FINISHED;

      var ctx = this._getPageDrawContext(true);

      var canvas = ctx.canvas;

      if (img.width <= 2 * canvas.width) {
        ctx.drawImage(img, 0, 0, img.width, img.height, 0, 0, canvas.width, canvas.height);

        this._convertCanvasToImage();

        return;
      }

      var reducedWidth = canvas.width << MAX_NUM_SCALING_STEPS;
      var reducedHeight = canvas.height << MAX_NUM_SCALING_STEPS;
      var reducedImage = TempImageFactory.getCanvas(reducedWidth, reducedHeight);
      var reducedImageCtx = reducedImage.getContext('2d');

      while (reducedWidth > img.width || reducedHeight > img.height) {
        reducedWidth >>= 1;
        reducedHeight >>= 1;
      }

      reducedImageCtx.drawImage(img, 0, 0, img.width, img.height, 0, 0, reducedWidth, reducedHeight);

      while (reducedWidth > 2 * canvas.width) {
        reducedImageCtx.drawImage(reducedImage, 0, 0, reducedWidth, reducedHeight, 0, 0, reducedWidth >> 1, reducedHeight >> 1);
        reducedWidth >>= 1;
        reducedHeight >>= 1;
      }

      ctx.drawImage(reducedImage, 0, 0, reducedWidth, reducedHeight, 0, 0, canvas.width, canvas.height);

      this._convertCanvasToImage();
    }
  }, {
    key: "setPageLabel",
    value: function setPageLabel(label) {
      var _this3 = this;

      this.pageLabel = typeof label === 'string' ? label : null;
      this.l10n.get('thumb_page_title', {
        page: this.pageId
      }, 'Page {{page}}').then(function (msg) {
        _this3.anchor.title = msg;
      });

      if (this.renderingState !== _pdf_rendering_queue.RenderingStates.FINISHED) {
        return;
      }

      this.l10n.get('thumb_page_canvas', {
        page: this.pageId
      }, 'Thumbnail of Page {{page}}').then(function (ariaLabel) {
        if (_this3.image) {
          _this3.image.setAttribute('aria-label', ariaLabel);
        } else if (_this3.disableCanvasToImageConversion && _this3.canvas) {
          _this3.canvas.setAttribute('aria-label', ariaLabel);
        }
      });
    }
  }, {
    key: "pageId",
    get: function get() {
      return this.pageLabel !== null ? this.pageLabel : this.id;
    }
  }], [{
    key: "cleanup",
    value: function cleanup() {
      TempImageFactory.destroyCanvas();
    }
  }]);

  return PDFThumbnailView;
}();

exports.PDFThumbnailView = PDFThumbnailView;