pdfjs-dist/lib/web/pdf_thumbnail_viewer.js

/**
 * @licstart The following is the entire license notice for the
 * JavaScript code in this page
 *
 * Copyright 2022 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.PDFThumbnailViewer = void 0;

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

var _pdf_thumbnail_view = require("./pdf_thumbnail_view.js");

const THUMBNAIL_SCROLL_MARGIN = -19;
const THUMBNAIL_SELECTED_CLASS = "selected";

class PDFThumbnailViewer {
  constructor({
    container,
    eventBus,
    linkService,
    renderingQueue,
    l10n,
    pageColors
  }) {
    this.container = container;
    this.linkService = linkService;
    this.renderingQueue = renderingQueue;
    this.l10n = l10n;
    this.pageColors = pageColors || null;

    if (this.pageColors && !(CSS.supports("color", this.pageColors.background) && CSS.supports("color", this.pageColors.foreground))) {
      if (this.pageColors.background || this.pageColors.foreground) {
        console.warn("PDFThumbnailViewer: Ignoring `pageColors`-option, since the browser doesn't support the values used.");
      }

      this.pageColors = null;
    }

    this.scroll = (0, _ui_utils.watchScroll)(this.container, this._scrollUpdated.bind(this));

    this._resetView();
  }

  _scrollUpdated() {
    this.renderingQueue.renderHighestPriority();
  }

  getThumbnail(index) {
    return this._thumbnails[index];
  }

  _getVisibleThumbs() {
    return (0, _ui_utils.getVisibleElements)({
      scrollEl: this.container,
      views: this._thumbnails
    });
  }

  scrollThumbnailIntoView(pageNumber) {
    if (!this.pdfDocument) {
      return;
    }

    const thumbnailView = this._thumbnails[pageNumber - 1];

    if (!thumbnailView) {
      console.error('scrollThumbnailIntoView: Invalid "pageNumber" parameter.');
      return;
    }

    if (pageNumber !== this._currentPageNumber) {
      const prevThumbnailView = this._thumbnails[this._currentPageNumber - 1];
      prevThumbnailView.div.classList.remove(THUMBNAIL_SELECTED_CLASS);
      thumbnailView.div.classList.add(THUMBNAIL_SELECTED_CLASS);
    }

    const {
      first,
      last,
      views
    } = this._getVisibleThumbs();

    if (views.length > 0) {
      let shouldScroll = false;

      if (pageNumber <= first.id || pageNumber >= last.id) {
        shouldScroll = true;
      } else {
        for (const {
          id,
          percent
        } of views) {
          if (id !== pageNumber) {
            continue;
          }

          shouldScroll = percent < 100;
          break;
        }
      }

      if (shouldScroll) {
        (0, _ui_utils.scrollIntoView)(thumbnailView.div, {
          top: THUMBNAIL_SCROLL_MARGIN
        });
      }
    }

    this._currentPageNumber = pageNumber;
  }

  get pagesRotation() {
    return this._pagesRotation;
  }

  set pagesRotation(rotation) {
    if (!(0, _ui_utils.isValidRotation)(rotation)) {
      throw new Error("Invalid thumbnails rotation angle.");
    }

    if (!this.pdfDocument) {
      return;
    }

    if (this._pagesRotation === rotation) {
      return;
    }

    this._pagesRotation = rotation;
    const updateArgs = {
      rotation
    };

    for (const thumbnail of this._thumbnails) {
      thumbnail.update(updateArgs);
    }
  }

  cleanup() {
    for (const thumbnail of this._thumbnails) {
      if (thumbnail.renderingState !== _ui_utils.RenderingStates.FINISHED) {
        thumbnail.reset();
      }
    }

    _pdf_thumbnail_view.TempImageFactory.destroyCanvas();
  }

  _resetView() {
    this._thumbnails = [];
    this._currentPageNumber = 1;
    this._pageLabels = null;
    this._pagesRotation = 0;
    this.container.textContent = "";
  }

  setDocument(pdfDocument) {
    if (this.pdfDocument) {
      this._cancelRendering();

      this._resetView();
    }

    this.pdfDocument = pdfDocument;

    if (!pdfDocument) {
      return;
    }

    const firstPagePromise = pdfDocument.getPage(1);
    const optionalContentConfigPromise = pdfDocument.getOptionalContentConfig();
    firstPagePromise.then(firstPdfPage => {
      const pagesCount = pdfDocument.numPages;
      const viewport = firstPdfPage.getViewport({
        scale: 1
      });

      for (let pageNum = 1; pageNum <= pagesCount; ++pageNum) {
        const thumbnail = new _pdf_thumbnail_view.PDFThumbnailView({
          container: this.container,
          id: pageNum,
          defaultViewport: viewport.clone(),
          optionalContentConfigPromise,
          linkService: this.linkService,
          renderingQueue: this.renderingQueue,
          l10n: this.l10n,
          pageColors: this.pageColors
        });

        this._thumbnails.push(thumbnail);
      }

      const firstThumbnailView = this._thumbnails[0];

      if (firstThumbnailView) {
        firstThumbnailView.setPdfPage(firstPdfPage);
      }

      const thumbnailView = this._thumbnails[this._currentPageNumber - 1];
      thumbnailView.div.classList.add(THUMBNAIL_SELECTED_CLASS);
    }).catch(reason => {
      console.error("Unable to initialize thumbnail viewer", reason);
    });
  }

  _cancelRendering() {
    for (const thumbnail of this._thumbnails) {
      thumbnail.cancelRendering();
    }
  }

  setPageLabels(labels) {
    if (!this.pdfDocument) {
      return;
    }

    if (!labels) {
      this._pageLabels = null;
    } else if (!(Array.isArray(labels) && this.pdfDocument.numPages === labels.length)) {
      this._pageLabels = null;
      console.error("PDFThumbnailViewer_setPageLabels: Invalid page labels.");
    } else {
      this._pageLabels = labels;
    }

    for (let i = 0, ii = this._thumbnails.length; i < ii; i++) {
      this._thumbnails[i].setPageLabel(this._pageLabels?.[i] ?? null);
    }
  }

  async #ensurePdfPageLoaded(thumbView) {
    if (thumbView.pdfPage) {
      return thumbView.pdfPage;
    }

    try {
      const pdfPage = await this.pdfDocument.getPage(thumbView.id);

      if (!thumbView.pdfPage) {
        thumbView.setPdfPage(pdfPage);
      }

      return pdfPage;
    } catch (reason) {
      console.error("Unable to get page for thumb view", reason);
      return null;
    }
  }

  #getScrollAhead(visible) {
    if (visible.first?.id === 1) {
      return true;
    } else if (visible.last?.id === this._thumbnails.length) {
      return false;
    }

    return this.scroll.down;
  }

  forceRendering() {
    const visibleThumbs = this._getVisibleThumbs();

    const scrollAhead = this.#getScrollAhead(visibleThumbs);
    const thumbView = this.renderingQueue.getHighestPriority(visibleThumbs, this._thumbnails, scrollAhead);

    if (thumbView) {
      this.#ensurePdfPageLoaded(thumbView).then(() => {
        this.renderingQueue.renderView(thumbView);
      });
      return true;
    }

    return false;
  }

}

exports.PDFThumbnailViewer = PDFThumbnailViewer;