pdf.js/web/toolbar.js

/* Copyright 2016 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.
 */
/* eslint no-var: error, prefer-const: error */

import {
  animationStarted,
  DEFAULT_SCALE,
  DEFAULT_SCALE_VALUE,
  MAX_SCALE,
  MIN_SCALE,
  noContextMenuHandler,
  NullL10n,
} from "./ui_utils";

const PAGE_NUMBER_LOADING_INDICATOR = "visiblePageIsLoading";
const SCALE_SELECT_CONTAINER_PADDING = 8;
const SCALE_SELECT_PADDING = 22;

/**
 * @typedef {Object} ToolbarOptions
 * @property {HTMLDivElement} container - Container for the secondary toolbar.
 * @property {HTMLSpanElement} numPages - Label that contains number of pages.
 * @property {HTMLInputElement} pageNumber - Control for display and user input
 *   of the current page number.
 * @property {HTMLSpanElement} scaleSelectContainer - Container where scale
 *   controls are placed. The width is adjusted on UI initialization.
 * @property {HTMLSelectElement} scaleSelect - Scale selection control.
 * @property {HTMLOptionElement} customScaleOption - The item used to display
 *   a non-predefined scale.
 * @property {HTMLButtonElement} previous - Button to go to the previous page.
 * @property {HTMLButtonElement} next - Button to go to the next page.
 * @property {HTMLButtonElement} zoomIn - Button to zoom in the pages.
 * @property {HTMLButtonElement} zoomOut - Button to zoom out the pages.
 * @property {HTMLButtonElement} viewFind - Button to open find bar.
 * @property {HTMLButtonElement} openFile - Button to open a new document.
 * @property {HTMLButtonElement} presentationModeButton - Button to switch to
 *   presentation mode.
 * @property {HTMLButtonElement} download - Button to download the document.
 * @property {HTMLAElement} viewBookmark - Element to link current url of
 *   the page view.
 */

class Toolbar {
  /**
   * @param {ToolbarOptions} options
   * @param {EventBus} eventBus
   * @param {IL10n} l10n - Localization service.
   */
  constructor(options, eventBus, l10n = NullL10n) {
    this.toolbar = options.container;
    this.eventBus = eventBus;
    this.l10n = l10n;
    this.buttons = [
      { element: options.previous, eventName: "previouspage" },
      { element: options.next, eventName: "nextpage" },
      { element: options.zoomIn, eventName: "zoomin" },
      { element: options.zoomOut, eventName: "zoomout" },
      { element: options.openFile, eventName: "openfile" },
      { element: options.print, eventName: "print" },
      {
        element: options.presentationModeButton,
        eventName: "presentationmode",
      },
      { element: options.download, eventName: "download" },
      { element: options.viewBookmark, eventName: null },
    ];
    this.items = {
      numPages: options.numPages,
      pageNumber: options.pageNumber,
      scaleSelectContainer: options.scaleSelectContainer,
      scaleSelect: options.scaleSelect,
      customScaleOption: options.customScaleOption,
      previous: options.previous,
      next: options.next,
      zoomIn: options.zoomIn,
      zoomOut: options.zoomOut,
    };

    this._wasLocalized = false;
    this.reset();

    // Bind the event listeners for click and various other actions.
    this._bindListeners();
  }

  setPageNumber(pageNumber, pageLabel) {
    this.pageNumber = pageNumber;
    this.pageLabel = pageLabel;
    this._updateUIState(false);
  }

  setPagesCount(pagesCount, hasPageLabels) {
    this.pagesCount = pagesCount;
    this.hasPageLabels = hasPageLabels;
    this._updateUIState(true);
  }

  setPageScale(pageScaleValue, pageScale) {
    this.pageScaleValue = (pageScaleValue || pageScale).toString();
    this.pageScale = pageScale;
    this._updateUIState(false);
  }

  reset() {
    this.pageNumber = 0;
    this.pageLabel = null;
    this.hasPageLabels = false;
    this.pagesCount = 0;
    this.pageScaleValue = DEFAULT_SCALE_VALUE;
    this.pageScale = DEFAULT_SCALE;
    this._updateUIState(true);
    this.updateLoadingIndicatorState();
  }

  _bindListeners() {
    const { pageNumber, scaleSelect } = this.items;
    const self = this;

    // The buttons within the toolbar.
    for (const { element, eventName } of this.buttons) {
      element.addEventListener("click", evt => {
        if (eventName !== null) {
          this.eventBus.dispatch(eventName, { source: this });
        }
      });
    }
    // The non-button elements within the toolbar.
    pageNumber.addEventListener("click", function() {
      this.select();
    });
    pageNumber.addEventListener("change", function() {
      self.eventBus.dispatch("pagenumberchanged", {
        source: self,
        value: this.value,
      });
    });

    scaleSelect.addEventListener("change", function() {
      if (this.value === "custom") {
        return;
      }
      self.eventBus.dispatch("scalechanged", {
        source: self,
        value: this.value,
      });
    });
    // Suppress context menus for some controls.
    scaleSelect.oncontextmenu = noContextMenuHandler;

    this.eventBus.on("localized", () => {
      this._wasLocalized = true;
      this._adjustScaleWidth();
      this._updateUIState(true);
    });
  }

  _updateUIState(resetNumPages = false) {
    if (!this._wasLocalized) {
      // Don't update the UI state until we localize the toolbar.
      return;
    }
    const { pageNumber, pagesCount, pageScaleValue, pageScale, items } = this;

    if (resetNumPages) {
      if (this.hasPageLabels) {
        items.pageNumber.type = "text";
      } else {
        items.pageNumber.type = "number";
        this.l10n
          .get("of_pages", { pagesCount }, "of {{pagesCount}}")
          .then(msg => {
            items.numPages.textContent = msg;
          });
      }
      items.pageNumber.max = pagesCount;
    }

    if (this.hasPageLabels) {
      items.pageNumber.value = this.pageLabel;
      this.l10n
        .get(
          "page_of_pages",
          { pageNumber, pagesCount },
          "({{pageNumber}} of {{pagesCount}})"
        )
        .then(msg => {
          items.numPages.textContent = msg;
        });
    } else {
      items.pageNumber.value = pageNumber;
    }

    items.previous.disabled = pageNumber <= 1;
    items.next.disabled = pageNumber >= pagesCount;

    items.zoomOut.disabled = pageScale <= MIN_SCALE;
    items.zoomIn.disabled = pageScale >= MAX_SCALE;

    const customScale = Math.round(pageScale * 10000) / 100;
    this.l10n
      .get("page_scale_percent", { scale: customScale }, "{{scale}}%")
      .then(msg => {
        let predefinedValueFound = false;
        for (const option of items.scaleSelect.options) {
          if (option.value !== pageScaleValue) {
            option.selected = false;
            continue;
          }
          option.selected = true;
          predefinedValueFound = true;
        }
        if (!predefinedValueFound) {
          items.customScaleOption.textContent = msg;
          items.customScaleOption.selected = true;
        }
      });
  }

  updateLoadingIndicatorState(loading = false) {
    const pageNumberInput = this.items.pageNumber;

    pageNumberInput.classList.toggle(PAGE_NUMBER_LOADING_INDICATOR, loading);
  }

  _adjustScaleWidth() {
    const container = this.items.scaleSelectContainer;
    const select = this.items.scaleSelect;

    animationStarted.then(function() {
      // Adjust the width of the zoom box to fit the content.
      // Note: If the window is narrow enough that the zoom box is not
      //       visible, we temporarily show it to be able to adjust its width.
      if (container.clientWidth === 0) {
        container.setAttribute("style", "display: inherit;");
      }
      if (container.clientWidth > 0) {
        select.setAttribute("style", "min-width: inherit;");
        const width = select.clientWidth + SCALE_SELECT_CONTAINER_PADDING;
        select.setAttribute(
          "style",
          `min-width: ${width + SCALE_SELECT_PADDING}px;`
        );
        container.setAttribute(
          "style",
          `min-width: ${width}px; max-width: ${width}px;`
        );
      }
    });
  }
}

export { Toolbar };