pdfjs-dist/lib/web/pdf_thumbnail_view.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.PDFThumbnailView = undefined;

var _ui_utils = require('pdfjs-web/ui_utils');

var _pdf_rendering_queue = require('pdfjs-web/pdf_rendering_queue');

var THUMBNAIL_WIDTH = 98;
var THUMBNAIL_CANVAS_BORDER_WIDTH = 1;
var PDFThumbnailView = function PDFThumbnailViewClosure() {
  function getTempCanvas(width, height) {
    var tempCanvas = PDFThumbnailView.tempImageCache;
    if (!tempCanvas) {
      tempCanvas = document.createElement('canvas');
      PDFThumbnailView.tempImageCache = 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;
  }
  function PDFThumbnailView(options) {
    var container = options.container;
    var id = options.id;
    var defaultViewport = options.defaultViewport;
    var linkService = options.linkService;
    var renderingQueue = options.renderingQueue;
    var disableCanvasToImageConversion = options.disableCanvasToImageConversion || false;
    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;
    var anchor = document.createElement('a');
    anchor.href = linkService.getAnchorUrl('#page=' + id);
    anchor.title = _ui_utils.mozL10n.get('thumb_page_title', { page: id }, 'Page {{page}}');
    anchor.onclick = function stopNavigation() {
      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;
    if (id === 1) {
      div.classList.add('selected');
    }
    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);
  }
  PDFThumbnailView.prototype = {
    setPdfPage: function PDFThumbnailView_setPdfPage(pdfPage) {
      this.pdfPage = pdfPage;
      this.pdfPageRotate = pdfPage.rotate;
      var totalRotation = (this.rotation + this.pdfPageRotate) % 360;
      this.viewport = pdfPage.getViewport(1, totalRotation);
      this.reset();
    },
    reset: function PDFThumbnailView_reset() {
      this.cancelRendering();
      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;
      }
    },
    update: function PDFThumbnailView_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();
    },
    cancelRendering: function PDFThumbnailView_cancelRendering() {
      if (this.renderTask) {
        this.renderTask.cancel();
        this.renderTask = null;
      }
      this.renderingState = _pdf_rendering_queue.RenderingStates.INITIAL;
      this.resume = null;
    },
    _getPageDrawContext: function PDFThumbnailView_getPageDrawContext(noCtxScale) {
      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;
    },
    _convertCanvasToImage: function PDFThumbnailView_convertCanvasToImage() {
      if (!this.canvas) {
        return;
      }
      if (this.renderingState !== _pdf_rendering_queue.RenderingStates.FINISHED) {
        return;
      }
      var id = this.renderingId;
      var className = 'thumbnailImage';
      var ariaLabel = _ui_utils.mozL10n.get('thumb_page_canvas', { page: this.pageId }, 'Thumbnail of Page {{page}}');
      if (this.disableCanvasToImageConversion) {
        this.canvas.id = id;
        this.canvas.className = className;
        this.canvas.setAttribute('aria-label', ariaLabel);
        this.div.setAttribute('data-loaded', true);
        this.ring.appendChild(this.canvas);
        return;
      }
      var image = document.createElement('img');
      image.id = id;
      image.className = className;
      image.setAttribute('aria-label', ariaLabel);
      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;
    },
    draw: function PDFThumbnailView_draw() {
      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 resolveRenderPromise, rejectRenderPromise;
      var promise = new Promise(function (resolve, reject) {
        resolveRenderPromise = resolve;
        rejectRenderPromise = reject;
      });
      var self = this;
      function thumbnailDrawCallback(error) {
        if (renderTask === self.renderTask) {
          self.renderTask = null;
        }
        if (error === 'cancelled') {
          rejectRenderPromise(error);
          return;
        }
        self.renderingState = _pdf_rendering_queue.RenderingStates.FINISHED;
        self._convertCanvasToImage();
        if (!error) {
          resolveRenderPromise(undefined);
        } else {
          rejectRenderPromise(error);
        }
      }
      var ctx = this._getPageDrawContext();
      var drawViewport = this.viewport.clone({ scale: this.scale });
      var renderContinueCallback = function renderContinueCallback(cont) {
        if (!self.renderingQueue.isHighestPriority(self)) {
          self.renderingState = _pdf_rendering_queue.RenderingStates.PAUSED;
          self.resume = function resumeCallback() {
            self.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 pdfPageRenderCallback() {
        thumbnailDrawCallback(null);
      }, function pdfPageRenderError(error) {
        thumbnailDrawCallback(error);
      });
      return promise;
    },
    setImage: function PDFThumbnailView_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 MAX_NUM_SCALING_STEPS = 3;
      var reducedWidth = canvas.width << MAX_NUM_SCALING_STEPS;
      var reducedHeight = canvas.height << MAX_NUM_SCALING_STEPS;
      var reducedImage = getTempCanvas(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();
    },
    get pageId() {
      return this.pageLabel !== null ? this.pageLabel : this.id;
    },
    setPageLabel: function PDFThumbnailView_setPageLabel(label) {
      this.pageLabel = typeof label === 'string' ? label : null;
      this.anchor.title = _ui_utils.mozL10n.get('thumb_page_title', { page: this.pageId }, 'Page {{page}}');
      if (this.renderingState !== _pdf_rendering_queue.RenderingStates.FINISHED) {
        return;
      }
      var ariaLabel = _ui_utils.mozL10n.get('thumb_page_canvas', { page: this.pageId }, 'Thumbnail of Page {{page}}');
      if (this.image) {
        this.image.setAttribute('aria-label', ariaLabel);
      } else if (this.disableCanvasToImageConversion && this.canvas) {
        this.canvas.setAttribute('aria-label', ariaLabel);
      }
    }
  };
  return PDFThumbnailView;
}();
PDFThumbnailView.tempImageCache = null;
exports.PDFThumbnailView = PDFThumbnailView;