goodnesskay / LARAVEL-PDF-VIEWER

laraview/ui_utils.js

/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* Copyright 2012 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';

var CSS_UNITS = 96.0 / 72.0;
var DEFAULT_SCALE = 'auto';
var UNKNOWN_SCALE = 0;
var MAX_AUTO_SCALE = 1.25;
var SCROLLBAR_PADDING = 40;
var VERTICAL_PADDING = 5;

// optimised CSS custom property getter/setter
var CustomStyle = (function CustomStyleClosure() {

  // As noted on: http://www.zachstronaut.com/posts/2009/02/17/
  //              animate-css-transforms-firefox-webkit.html
  // in some versions of IE9 it is critical that ms appear in this list
  // before Moz
  var prefixes = ['ms', 'Moz', 'Webkit', 'O'];
  var _cache = {};

  function CustomStyle() {}

  CustomStyle.getProp = function get(propName, element) {
    // check cache only when no element is given
    if (arguments.length === 1 && typeof _cache[propName] === 'string') {
      return _cache[propName];
    }

    element = element || document.documentElement;
    var style = element.style, prefixed, uPropName;

    // test standard property first
    if (typeof style[propName] === 'string') {
      return (_cache[propName] = propName);
    }

    // capitalize
    uPropName = propName.charAt(0).toUpperCase() + propName.slice(1);

    // test vendor specific properties
    for (var i = 0, l = prefixes.length; i < l; i++) {
      prefixed = prefixes[i] + uPropName;
      if (typeof style[prefixed] === 'string') {
        return (_cache[propName] = prefixed);
      }
    }

    //if all fails then set to undefined
    return (_cache[propName] = 'undefined');
  };

  CustomStyle.setProp = function set(propName, element, str) {
    var prop = this.getProp(propName);
    if (prop !== 'undefined') {
      element.style[prop] = str;
    }
  };

  return CustomStyle;
})();

function getFileName(url) {
  var anchor = url.indexOf('#');
  var query = url.indexOf('?');
  var end = Math.min(
    anchor > 0 ? anchor : url.length,
    query > 0 ? query : url.length);
  return url.substring(url.lastIndexOf('/', end) + 1, end);
}

/**
 * Returns scale factor for the canvas. It makes sense for the HiDPI displays.
 * @return {Object} The object with horizontal (sx) and vertical (sy)
                    scales. The scaled property is set to false if scaling is
                    not required, true otherwise.
 */
function getOutputScale(ctx) {
  var devicePixelRatio = window.devicePixelRatio || 1;
  var backingStoreRatio = ctx.webkitBackingStorePixelRatio ||
                          ctx.mozBackingStorePixelRatio ||
                          ctx.msBackingStorePixelRatio ||
                          ctx.oBackingStorePixelRatio ||
                          ctx.backingStorePixelRatio || 1;
  var pixelRatio = devicePixelRatio / backingStoreRatio;
  return {
    sx: pixelRatio,
    sy: pixelRatio,
    scaled: pixelRatio !== 1
  };
}

/**
 * Scrolls specified element into view of its parent.
 * element {Object} The element to be visible.
 * spot {Object} An object with optional top and left properties,
 *               specifying the offset from the top left edge.
 */
function scrollIntoView(element, spot) {
  // Assuming offsetParent is available (it's not available when viewer is in
  // hidden iframe or object). We have to scroll: if the offsetParent is not set
  // producing the error. See also animationStartedClosure.
  var parent = element.offsetParent;
  var offsetY = element.offsetTop + element.clientTop;
  var offsetX = element.offsetLeft + element.clientLeft;
  if (!parent) {
    console.error('offsetParent is not set -- cannot scroll');
    return;
  }
  while (parent.clientHeight === parent.scrollHeight) {
    if (parent.dataset._scaleY) {
      offsetY /= parent.dataset._scaleY;
      offsetX /= parent.dataset._scaleX;
    }
    offsetY += parent.offsetTop;
    offsetX += parent.offsetLeft;
    parent = parent.offsetParent;
    if (!parent) {
      return; // no need to scroll
    }
  }
  if (spot) {
    if (spot.top !== undefined) {
      offsetY += spot.top;
    }
    if (spot.left !== undefined) {
      offsetX += spot.left;
      parent.scrollLeft = offsetX;
    }
  }
  parent.scrollTop = offsetY;
}

/**
 * Helper function to start monitoring the scroll event and converting them into
 * PDF.js friendly one: with scroll debounce and scroll direction.
 */
function watchScroll(viewAreaElement, callback) {
  var debounceScroll = function debounceScroll(evt) {

The parameter evt is not used and could be removed.

The variable debounceScroll already seems to be declared on line 153. Consider using another variable name or omitting the var keyword.

    if (rAF) {
      return;
    }
    // schedule an invocation of scroll for next animation frame.
    rAF = window.requestAnimationFrame(function viewAreaElementScrolled() {
      rAF = null;

      var currentY = viewAreaElement.scrollTop;
      var lastY = state.lastY;
      if (currentY !== lastY) {
        state.down = currentY > lastY;
      }
      state.lastY = currentY;
      callback(state);
    });
  };

  var state = {
    down: true,
    lastY: viewAreaElement.scrollTop,
    _eventHandler: debounceScroll
  };

  var rAF = null;
  viewAreaElement.addEventListener('scroll', debounceScroll, true);
  return state;
}

/**
 * Use binary search to find the index of the first item in a given array which
 * passes a given condition. The items are expected to be sorted in the sense
 * that if the condition is true for one item in the array, then it is also true
 * for all following items.
 *
 * @returns {Number} Index of the first array element to pass the test,
 *                   or |items.length| if no such element exists.
 */
function binarySearchFirstItem(items, condition) {
  var minIndex = 0;
  var maxIndex = items.length - 1;

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

  while (minIndex < maxIndex) {
    var currentIndex = (minIndex + maxIndex) >> 1;
    var currentItem = items[currentIndex];
    if (condition(currentItem)) {
      maxIndex = currentIndex;
    } else {
      minIndex = currentIndex + 1;
    }
  }
  return minIndex; /* === maxIndex */
}

/**
 * Generic helper to find out what elements are visible within a scroll pane.
 */
function getVisibleElements(scrollEl, views, sortByVisibility) {
  var top = scrollEl.scrollTop, bottom = top + scrollEl.clientHeight;
  var left = scrollEl.scrollLeft, right = left + scrollEl.clientWidth;

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

  var visible = [], view, element;
  var currentHeight, viewHeight, hiddenHeight, percentHeight;
  var currentWidth, viewWidth;
  var firstVisibleElementInd = (views.length === 0) ? 0 :
    binarySearchFirstItem(views, isElementBottomBelowViewTop);

  for (var i = firstVisibleElementInd, ii = views.length; i < ii; i++) {
    view = views[i];
    element = view.div;
    currentHeight = element.offsetTop + element.clientTop;
    viewHeight = element.clientHeight;

    if (currentHeight > bottom) {
      break;
    }

    currentWidth = element.offsetLeft + element.clientLeft;
    viewWidth = element.clientWidth;
    if (currentWidth + viewWidth < left || currentWidth > right) {
      continue;
    }
    hiddenHeight = Math.max(0, top - currentHeight) +
      Math.max(0, currentHeight + viewHeight - bottom);
    percentHeight = ((viewHeight - hiddenHeight) * 100 / viewHeight) | 0;

    visible.push({
      id: view.id,
      x: currentWidth,
      y: currentHeight,
      view: view,
      percent: percentHeight
    });
  }

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

  if (sortByVisibility) {
    visible.sort(function(a, b) {
      var pc = a.percent - b.percent;
      if (Math.abs(pc) > 0.001) {
        return -pc;
      }
      return a.id - b.id; // ensure stability
    });
  }
  return {first: first, last: last, views: visible};
}

/**
 * Event handler to suppress context menu.
 */
function noContextMenuHandler(e) {
  e.preventDefault();
}

/**
 * Returns the filename or guessed filename from the url (see issue 3455).
 * url {String} The original PDF location.
 * @return {String} Guessed PDF file name.
 */
function getPDFFileNameFromURL(url) {
  var reURI = /^(?:([^:]+:)?\/\/[^\/]+)?([^?#]*)(\?[^#]*)?(#.*)?$/;
  //            SCHEME      HOST         1.PATH  2.QUERY   3.REF
  // Pattern to get last matching NAME.pdf
  var reFilename = /[^\/?#=]+\.pdf\b(?!.*\.pdf\b)/i;
  var splitURI = reURI.exec(url);
  var suggestedFilename = reFilename.exec(splitURI[1]) ||
                           reFilename.exec(splitURI[2]) ||
                           reFilename.exec(splitURI[3]);
  if (suggestedFilename) {
    suggestedFilename = suggestedFilename[0];
    if (suggestedFilename.indexOf('%') !== -1) {
      // URL-encoded %2Fpath%2Fto%2Ffile.pdf should be file.pdf
      try {
        suggestedFilename =
          reFilename.exec(decodeURIComponent(suggestedFilename))[0];
      } catch(e) { // Possible (extremely rare) errors:
        // URIError "Malformed URI", e.g. for "%AA.pdf"
        // TypeError "null has no properties", e.g. for "%2F.pdf"
      }
    }
  }
  return suggestedFilename || 'document.pdf';
}

var ProgressBar = (function ProgressBarClosure() {

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

  function ProgressBar(id, opts) {
    this.visible = true;

    // Fetch the sub-elements for later.
    this.div = document.querySelector(id + ' .progress');

    // Get the loading bar element, so it can be resized to fit the viewer.
    this.bar = this.div.parentNode;

    // Get options, with sensible defaults.
    this.height = opts.height || 100;
    this.width = opts.width || 100;
    this.units = opts.units || '%';

    // Initialize heights.
    this.div.style.height = this.height + this.units;
    this.percent = 0;
  }

  ProgressBar.prototype = {

    updateBar: function ProgressBar_updateBar() {
      if (this._indeterminate) {
        this.div.classList.add('indeterminate');
        this.div.style.width = this.width + this.units;
        return;
      }

      this.div.classList.remove('indeterminate');
      var 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: function ProgressBar_setWidth(viewer) {
      if (viewer) {
        var container = viewer.parentNode;
        var scrollbarWidth = container.offsetWidth - viewer.offsetWidth;
        if (scrollbarWidth > 0) {
          this.bar.setAttribute('style', 'width: calc(100% - ' +
                                         scrollbarWidth + 'px);');
        }
      }
    },

    hide: function ProgressBar_hide() {
      if (!this.visible) {
        return;
      }
      this.visible = false;
      this.bar.classList.add('hidden');
      document.body.classList.remove('loadingInProgress');
    },

    show: function ProgressBar_show() {
      if (this.visible) {
        return;
      }
      this.visible = true;
      document.body.classList.add('loadingInProgress');
      this.bar.classList.remove('hidden');
    }
  };

  return ProgressBar;
})();