imageviewer_terrydr/src/js/utilities.js

A simple jQuery image viewing plugin.

  function isString(s) {
    return typeof s === 'string';
  }

  function isNumber(n) {
    return typeof n === 'number' && !isNaN(n);
  }

  function isUndefined(u) {
    return typeof u === 'undefined';
  }

  function toArray(obj, offset) {
    var args = [];

    if (isNumber(offset)) { // It's necessary for IE8
      args.push(offset);
    }

    return args.slice.apply(obj, args);
  }

  // Custom proxy to avoid jQuery's guid
  function proxy(fn, context) {
    var args = toArray(arguments, 2);

    return function () {
      return fn.apply(context, args.concat(toArray(arguments)));
    };
  }

  function getTransform(options) {
    var transforms = [];
    var rotate = options.rotate;
    var scaleX = options.scaleX;
    var scaleY = options.scaleY;

    // Scale should come first before rotate
    if (isNumber(scaleX) && isNumber(scaleY)) {
      transforms.push('scale(' + scaleX + ',' + scaleY + ')');
    }

    if (isNumber(rotate)) {
      transforms.push('rotate(' + rotate + 'deg)');
    }

    return transforms.length ? transforms.join(' ') : 'none';
  }

  // Force reflow to enable CSS3 transition
  function forceReflow(element) {
    return element.offsetWidth;
  }

  // e.g.: http://domain.com/path/to/picture.jpg?size=1280×960 -> picture.jpg
  function getImageName(url) {
    return isString(url) ? url.replace(/^.*\//, '').replace(/[\?&#].*$/, '') : '';
  }

  function getImageSize(image, callback) {
    var newImage;

    // Modern browsers
    if (image.naturalWidth) {
      return callback(image.naturalWidth, image.naturalHeight);
    }

    // IE8: Don't use `new Image()` here
    newImage = document.createElement('img');

    newImage.onload = function () {
      callback(this.width, this.height);
    };

    newImage.src = image.src;
  }

  function getTouchesCenter(touches) {
    var length = touches.length;
    var pageX = 0;
    var pageY = 0;

    if (length) {
      $.each(touches, function (i, touch) {
        pageX += touch.pageX;
        pageY += touch.pageY;
      });

      pageX /= length;
      pageY /= length;
    }

    return {
      pageX: pageX,
      pageY: pageY
    };
  }

  function getResponsiveClass(option) {
    switch (option) {
      case 2:
        return CLASS_HIDE_XS_DOWN;

      case 3:
        return CLASS_HIDE_SM_DOWN;

      case 4:
        return CLASS_HIDE_MD_DOWN;
    }
  }