lib/web/ui_utils.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2020 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.isValidRotation = isValidRotation;
exports.isValidScrollMode = isValidScrollMode;
exports.isValidSpreadMode = isValidSpreadMode;
exports.isPortraitOrientation = isPortraitOrientation;
exports.clamp = clamp;
exports.getPDFFileNameFromURL = getPDFFileNameFromURL;
exports.noContextMenuHandler = noContextMenuHandler;
exports.parseQueryString = parseQueryString;
exports.backtrackBeforeAllVisibleElements = backtrackBeforeAllVisibleElements;
exports.getVisibleElements = getVisibleElements;
exports.roundToDivide = roundToDivide;
exports.getPageSizeInches = getPageSizeInches;
exports.approximateFraction = approximateFraction;
exports.getOutputScale = getOutputScale;
exports.scrollIntoView = scrollIntoView;
exports.watchScroll = watchScroll;
exports.binarySearchFirstItem = binarySearchFirstItem;
exports.normalizeWheelEventDirection = normalizeWheelEventDirection;
exports.normalizeWheelEventDelta = normalizeWheelEventDelta;
exports.waitOnEventOrTimeout = waitOnEventOrTimeout;
exports.moveToEndOfArray = moveToEndOfArray;
exports.WaitOnType = exports.animationStarted = exports.ProgressBar = exports.EventBus = exports.NullL10n = exports.SpreadMode = exports.ScrollMode = exports.TextLayerMode = exports.RendererType = exports.PresentationModeState = exports.VERTICAL_PADDING = exports.SCROLLBAR_PADDING = exports.MAX_AUTO_SCALE = exports.UNKNOWN_SCALE = exports.MAX_SCALE = exports.MIN_SCALE = exports.DEFAULT_SCALE = exports.DEFAULT_SCALE_VALUE = exports.CSS_UNITS = exports.AutoPrintRegExp = void 0;
const CSS_UNITS = 96.0 / 72.0;
exports.CSS_UNITS = CSS_UNITS;
const DEFAULT_SCALE_VALUE = "auto";
exports.DEFAULT_SCALE_VALUE = DEFAULT_SCALE_VALUE;
const DEFAULT_SCALE = 1.0;
exports.DEFAULT_SCALE = DEFAULT_SCALE;
const MIN_SCALE = 0.1;
exports.MIN_SCALE = MIN_SCALE;
const MAX_SCALE = 10.0;
exports.MAX_SCALE = MAX_SCALE;
const UNKNOWN_SCALE = 0;
exports.UNKNOWN_SCALE = UNKNOWN_SCALE;
const MAX_AUTO_SCALE = 1.25;
exports.MAX_AUTO_SCALE = MAX_AUTO_SCALE;
const SCROLLBAR_PADDING = 40;
exports.SCROLLBAR_PADDING = SCROLLBAR_PADDING;
const VERTICAL_PADDING = 5;
exports.VERTICAL_PADDING = VERTICAL_PADDING;
const PresentationModeState = {
  UNKNOWN: 0,
  NORMAL: 1,
  CHANGING: 2,
  FULLSCREEN: 3
};
exports.PresentationModeState = PresentationModeState;
const RendererType = {
  CANVAS: "canvas",
  SVG: "svg"
};
exports.RendererType = RendererType;
const TextLayerMode = {
  DISABLE: 0,
  ENABLE: 1,
  ENABLE_ENHANCE: 2
};
exports.TextLayerMode = TextLayerMode;
const ScrollMode = {
  UNKNOWN: -1,
  VERTICAL: 0,
  HORIZONTAL: 1,
  WRAPPED: 2
};
exports.ScrollMode = ScrollMode;
const SpreadMode = {
  UNKNOWN: -1,
  NONE: 0,
  ODD: 1,
  EVEN: 2
};
exports.SpreadMode = SpreadMode;
const AutoPrintRegExp = /\bprint\s*\(/;
exports.AutoPrintRegExp = AutoPrintRegExp;

function formatL10nValue(text, args) {
  if (!args) {
    return text;
  }

  return text.replace(/\{\{\s*(\w+)\s*\}\}/g, (all, name) => {
    return name in args ? args[name] : "{{" + name + "}}";
  });
}

const NullL10n = {
  async getLanguage() {
    return "en-us";
  },

  async getDirection() {
    return "ltr";
  },

  async get(property, args, fallback) {
    return formatL10nValue(fallback, args);
  },

  async translate(element) {}

};
exports.NullL10n = NullL10n;

function getOutputScale(ctx) {
  const devicePixelRatio = window.devicePixelRatio || 1;
  const backingStoreRatio = ctx.webkitBackingStorePixelRatio || ctx.mozBackingStorePixelRatio || ctx.msBackingStorePixelRatio || ctx.oBackingStorePixelRatio || ctx.backingStorePixelRatio || 1;
  const pixelRatio = devicePixelRatio / backingStoreRatio;
  return {
    sx: pixelRatio,
    sy: pixelRatio,
    scaled: pixelRatio !== 1
  };
}

function scrollIntoView(element, spot, skipOverflowHiddenElements = false) {
  let parent = element.offsetParent;

  if (!parent) {
    console.error("offsetParent is not set -- cannot scroll");
    return;
  }

  let offsetY = element.offsetTop + element.clientTop;
  let offsetX = element.offsetLeft + element.clientLeft;

  while (parent.clientHeight === parent.scrollHeight && parent.clientWidth === parent.scrollWidth || skipOverflowHiddenElements && getComputedStyle(parent).overflow === "hidden") {
    if (parent.dataset._scaleY) {
      offsetY /= parent.dataset._scaleY;
      offsetX /= parent.dataset._scaleX;
    }

    offsetY += parent.offsetTop;
    offsetX += parent.offsetLeft;
    parent = parent.offsetParent;

    if (!parent) {
      return;
    }
  }

  if (spot) {
    if (spot.top !== undefined) {
      offsetY += spot.top;
    }

    if (spot.left !== undefined) {
      offsetX += spot.left;
      parent.scrollLeft = offsetX;
    }
  }

  parent.scrollTop = offsetY;
}

function watchScroll(viewAreaElement, callback) {
  const debounceScroll = function (evt) {
    if (rAF) {
      return;
    }

    rAF = window.requestAnimationFrame(function viewAreaElementScrolled() {
      rAF = null;
      const currentX = viewAreaElement.scrollLeft;
      const lastX = state.lastX;

      if (currentX !== lastX) {
        state.right = currentX > lastX;
      }

      state.lastX = currentX;
      const currentY = viewAreaElement.scrollTop;
      const lastY = state.lastY;

      if (currentY !== lastY) {
        state.down = currentY > lastY;
      }

      state.lastY = currentY;
      callback(state);
    });
  };

  const state = {
    right: true,
    down: true,
    lastX: viewAreaElement.scrollLeft,
    lastY: viewAreaElement.scrollTop,
    _eventHandler: debounceScroll
  };
  let rAF = null;
  viewAreaElement.addEventListener("scroll", debounceScroll, true);
  return state;
}

function parseQueryString(query) {
  const parts = query.split("&");
  const params = Object.create(null);

  for (let i = 0, ii = parts.length; i < ii; ++i) {
    const param = parts[i].split("=");
    const key = param[0].toLowerCase();
    const value = param.length > 1 ? param[1] : null;
    params[decodeURIComponent(key)] = decodeURIComponent(value);
  }

  return params;
}

function binarySearchFirstItem(items, condition) {
  let minIndex = 0;
  let maxIndex = items.length - 1;

  if (maxIndex < 0 || !condition(items[maxIndex])) {
    return items.length;
  }

  if (condition(items[minIndex])) {
    return minIndex;
  }

  while (minIndex < maxIndex) {
    const currentIndex = minIndex + maxIndex >> 1;
    const currentItem = items[currentIndex];

    if (condition(currentItem)) {
      maxIndex = currentIndex;
    } else {
      minIndex = currentIndex + 1;
    }
  }

  return minIndex;
}

function approximateFraction(x) {
  if (Math.floor(x) === x) {
    return [x, 1];
  }

  const xinv = 1 / x;
  const limit = 8;

  if (xinv > limit) {
    return [1, limit];
  } else if (Math.floor(xinv) === xinv) {
    return [1, xinv];
  }

  const x_ = x > 1 ? xinv : x;
  let a = 0,
      b = 1,
      c = 1,
      d = 1;

  while (true) {
    const p = a + c,
          q = b + d;

    if (q > limit) {
      break;
    }

    if (x_ <= p / q) {
      c = p;
      d = q;
    } else {
      a = p;
      b = q;
    }
  }

  let result;

  if (x_ - a / b < c / d - x_) {
    result = x_ === x ? [a, b] : [b, a];
  } else {
    result = x_ === x ? [c, d] : [d, c];
  }

  return result;
}

function roundToDivide(x, div) {
  const r = x % div;
  return r === 0 ? x : Math.round(x - r + div);
}

function getPageSizeInches({
  view,
  userUnit,
  rotate
}) {
  const [x1, y1, x2, y2] = view;
  const changeOrientation = rotate % 180 !== 0;
  const width = (x2 - x1) / 72 * userUnit;
  const height = (y2 - y1) / 72 * userUnit;
  return {
    width: changeOrientation ? height : width,
    height: changeOrientation ? width : height
  };
}

function backtrackBeforeAllVisibleElements(index, views, top) {
  if (index < 2) {
    return index;
  }

  let elt = views[index].div;
  let pageTop = elt.offsetTop + elt.clientTop;

  if (pageTop >= top) {
    elt = views[index - 1].div;
    pageTop = elt.offsetTop + elt.clientTop;
  }

  for (let i = index - 2; i >= 0; --i) {
    elt = views[i].div;

    if (elt.offsetTop + elt.clientTop + elt.clientHeight <= pageTop) {
      break;
    }

    index = i;
  }

  return index;
}

function getVisibleElements(scrollEl, views, sortByVisibility = false, horizontal = false) {
  const top = scrollEl.scrollTop,
        bottom = top + scrollEl.clientHeight;
  const left = scrollEl.scrollLeft,
        right = left + scrollEl.clientWidth;

  function isElementBottomAfterViewTop(view) {
    const element = view.div;
    const elementBottom = element.offsetTop + element.clientTop + element.clientHeight;
    return elementBottom > top;
  }

  function isElementRightAfterViewLeft(view) {
    const element = view.div;
    const elementRight = element.offsetLeft + element.clientLeft + element.clientWidth;
    return elementRight > left;
  }

  const visible = [],
        numViews = views.length;
  let firstVisibleElementInd = numViews === 0 ? 0 : binarySearchFirstItem(views, horizontal ? isElementRightAfterViewLeft : isElementBottomAfterViewTop);

  if (firstVisibleElementInd > 0 && firstVisibleElementInd < numViews && !horizontal) {
    firstVisibleElementInd = backtrackBeforeAllVisibleElements(firstVisibleElementInd, views, top);
  }

  let lastEdge = horizontal ? right : -1;

  for (let i = firstVisibleElementInd; i < numViews; i++) {
    const view = views[i],
          element = view.div;
    const currentWidth = element.offsetLeft + element.clientLeft;
    const currentHeight = element.offsetTop + element.clientTop;
    const viewWidth = element.clientWidth,
          viewHeight = element.clientHeight;
    const viewRight = currentWidth + viewWidth;
    const viewBottom = currentHeight + viewHeight;

    if (lastEdge === -1) {
      if (viewBottom >= bottom) {
        lastEdge = viewBottom;
      }
    } else if ((horizontal ? currentWidth : currentHeight) > lastEdge) {
      break;
    }

    if (viewBottom <= top || currentHeight >= bottom || viewRight <= left || currentWidth >= right) {
      continue;
    }

    const hiddenHeight = Math.max(0, top - currentHeight) + Math.max(0, viewBottom - bottom);
    const hiddenWidth = Math.max(0, left - currentWidth) + Math.max(0, viewRight - right);
    const percent = (viewHeight - hiddenHeight) * (viewWidth - hiddenWidth) * 100 / viewHeight / viewWidth | 0;
    visible.push({
      id: view.id,
      x: currentWidth,
      y: currentHeight,
      view,
      percent
    });
  }

  const first = visible[0],
        last = visible[visible.length - 1];

  if (sortByVisibility) {
    visible.sort(function (a, b) {
      const pc = a.percent - b.percent;

      if (Math.abs(pc) > 0.001) {
        return -pc;
      }

      return a.id - b.id;
    });
  }

  return {
    first,
    last,
    views: visible
  };
}

function noContextMenuHandler(evt) {
  evt.preventDefault();
}

function isDataSchema(url) {
  let i = 0;
  const ii = url.length;

  while (i < ii && url[i].trim() === "") {
    i++;
  }

  return url.substring(i, i + 5).toLowerCase() === "data:";
}

function getPDFFileNameFromURL(url, defaultFilename = "document.pdf") {
  if (typeof url !== "string") {
    return defaultFilename;
  }

  if (isDataSchema(url)) {
    console.warn("getPDFFileNameFromURL: " + 'ignoring "data:" URL for performance reasons.');
    return defaultFilename;
  }

  const reURI = /^(?:(?:[^:]+:)?\/\/[^\/]+)?([^?#]*)(\?[^#]*)?(#.*)?$/;
  const reFilename = /[^\/?#=]+\.pdf\b(?!.*\.pdf\b)/i;
  const splitURI = reURI.exec(url);
  let suggestedFilename = reFilename.exec(splitURI[1]) || reFilename.exec(splitURI[2]) || reFilename.exec(splitURI[3]);

  if (suggestedFilename) {
    suggestedFilename = suggestedFilename[0];

    if (suggestedFilename.includes("%")) {
      try {
        suggestedFilename = reFilename.exec(decodeURIComponent(suggestedFilename))[0];
      } catch (ex) {}
    }
  }

  return suggestedFilename || defaultFilename;
}

function normalizeWheelEventDirection(evt) {
  let delta = Math.sqrt(evt.deltaX * evt.deltaX + evt.deltaY * evt.deltaY);
  const angle = Math.atan2(evt.deltaY, evt.deltaX);

  if (-0.25 * Math.PI < angle && angle < 0.75 * Math.PI) {
    delta = -delta;
  }

  return delta;
}

function normalizeWheelEventDelta(evt) {
  let delta = normalizeWheelEventDirection(evt);
  const MOUSE_DOM_DELTA_PIXEL_MODE = 0;
  const MOUSE_DOM_DELTA_LINE_MODE = 1;
  const MOUSE_PIXELS_PER_LINE = 30;
  const MOUSE_LINES_PER_PAGE = 30;

  if (evt.deltaMode === MOUSE_DOM_DELTA_PIXEL_MODE) {
    delta /= MOUSE_PIXELS_PER_LINE * MOUSE_LINES_PER_PAGE;
  } else if (evt.deltaMode === MOUSE_DOM_DELTA_LINE_MODE) {
    delta /= MOUSE_LINES_PER_PAGE;
  }

  return delta;
}

function isValidRotation(angle) {
  return Number.isInteger(angle) && angle % 90 === 0;
}

function isValidScrollMode(mode) {
  return Number.isInteger(mode) && Object.values(ScrollMode).includes(mode) && mode !== ScrollMode.UNKNOWN;
}

function isValidSpreadMode(mode) {
  return Number.isInteger(mode) && Object.values(SpreadMode).includes(mode) && mode !== SpreadMode.UNKNOWN;
}

function isPortraitOrientation(size) {
  return size.width <= size.height;
}

const WaitOnType = {
  EVENT: "event",
  TIMEOUT: "timeout"
};
exports.WaitOnType = WaitOnType;

function waitOnEventOrTimeout({
  target,
  name,
  delay = 0
}) {
  return new Promise(function (resolve, reject) {
    if (typeof target !== "object" || !(name && typeof name === "string") || !(Number.isInteger(delay) && delay >= 0)) {
      throw new Error("waitOnEventOrTimeout - invalid parameters.");
    }

    function handler(type) {
      if (target instanceof EventBus) {
        target._off(name, eventHandler);
      } else {
        target.removeEventListener(name, eventHandler);
      }

      if (timeout) {
        clearTimeout(timeout);
      }

      resolve(type);
    }

    const eventHandler = handler.bind(null, WaitOnType.EVENT);

    if (target instanceof EventBus) {
      target._on(name, eventHandler);
    } else {
      target.addEventListener(name, eventHandler);
    }

    const timeoutHandler = handler.bind(null, WaitOnType.TIMEOUT);
    const timeout = setTimeout(timeoutHandler, delay);
  });
}

const animationStarted = new Promise(function (resolve) {
  window.requestAnimationFrame(resolve);
});
exports.animationStarted = animationStarted;

function dispatchDOMEvent(eventName, args = null) {
  throw new Error("Not implemented: dispatchDOMEvent");
}

class EventBus {
  constructor(options) {
    this._listeners = Object.create(null);
  }

  on(eventName, listener) {
    this._on(eventName, listener, {
      external: true
    });
  }

  off(eventName, listener) {
    this._off(eventName, listener, {
      external: true
    });
  }

  dispatch(eventName) {
    const eventListeners = this._listeners[eventName];

    if (!eventListeners || eventListeners.length === 0) {
      return;
    }

    const args = Array.prototype.slice.call(arguments, 1);
    let externalListeners;
    eventListeners.slice(0).forEach(function ({
      listener,
      external
    }) {
      if (external) {
        if (!externalListeners) {
          externalListeners = [];
        }

        externalListeners.push(listener);
        return;
      }

      listener.apply(null, args);
    });

    if (externalListeners) {
      externalListeners.forEach(function (listener) {
        listener.apply(null, args);
      });
      externalListeners = null;
    }
  }

  _on(eventName, listener, options = null) {
    let eventListeners = this._listeners[eventName];

    if (!eventListeners) {
      this._listeners[eventName] = eventListeners = [];
    }

    eventListeners.push({
      listener,
      external: (options && options.external) === true
    });
  }

  _off(eventName, listener, options = null) {
    const eventListeners = this._listeners[eventName];

    if (!eventListeners) {
      return;
    }

    for (let i = 0, ii = eventListeners.length; i < ii; i++) {
      if (eventListeners[i].listener === listener) {
        eventListeners.splice(i, 1);
        return;
      }
    }
  }

}

exports.EventBus = EventBus;

function clamp(v, min, max) {
  return Math.min(Math.max(v, min), max);
}

class ProgressBar {
  constructor(id, {
    height,
    width,
    units
  } = {}) {
    this.visible = true;
    this.div = document.querySelector(id + " .progress");
    this.bar = this.div.parentNode;
    this.height = height || 100;
    this.width = width || 100;
    this.units = units || "%";
    this.div.style.height = this.height + this.units;
    this.percent = 0;
  }

  _updateBar() {
    if (this._indeterminate) {
      this.div.classList.add("indeterminate");
      this.div.style.width = this.width + this.units;
      return;
    }

    this.div.classList.remove("indeterminate");
    const progressSize = this.width * this._percent / 100;
    this.div.style.width = progressSize + this.units;
  }

  get percent() {
    return this._percent;
  }

  set percent(val) {
    this._indeterminate = isNaN(val);
    this._percent = clamp(val, 0, 100);

    this._updateBar();
  }

  setWidth(viewer) {
    if (!viewer) {
      return;
    }

    const container = viewer.parentNode;
    const scrollbarWidth = container.offsetWidth - viewer.offsetWidth;

    if (scrollbarWidth > 0) {
      this.bar.style.width = `calc(100% - ${scrollbarWidth}px)`;
    }
  }

  hide() {
    if (!this.visible) {
      return;
    }

    this.visible = false;
    this.bar.classList.add("hidden");
    document.body.classList.remove("loadingInProgress");
  }

  show() {
    if (this.visible) {
      return;
    }

    this.visible = true;
    document.body.classList.add("loadingInProgress");
    this.bar.classList.remove("hidden");
  }

}

exports.ProgressBar = ProgressBar;

function moveToEndOfArray(arr, condition) {
  const moved = [],
        len = arr.length;
  let write = 0;

  for (let read = 0; read < len; ++read) {
    if (condition(arr[read])) {
      moved.push(arr[read]);
    } else {
      arr[write] = arr[read];
      ++write;
    }
  }

  for (let read = 0; write < len; ++read, ++write) {
    arr[write] = moved[read];
  }
}