app/assets/javascripts/trunk8.js
/**!
* trunk8 v1.3.2
* https://github.com/rviscomi/trunk8
*
* Copyright 2012 Rick Viscomi
* Released under the MIT License.
*
* Date: October 21, 2012
*/
(function ($) {
var methods,
utils,
SIDES = {
/* cen...ter */
center: 'center',
/* ...left */
left: 'left',
/* right... */
right: 'right'
},
WIDTH = {
auto: 'auto'
};
function trunk8(element) {
this.$element = $(element);
this.original_text = this.$element.html();
this.settings = $.extend({}, $.fn.trunk8.defaults);
}
trunk8.prototype.updateSettings = function (options) {
this.settings = $.extend(this.settings, options);
};
function truncate() {
var data = this.data('trunk8'),
settings = data.settings,
width = settings.width,
side = settings.side,
fill = settings.fill,
line_height = utils.getLineHeight(this) * settings.lines,
str = data.original_text,
length = str.length,
max_bite = '',
lower, upper,
bite_size,
bite;
/* Reset the field to the original string. */
this.html(str);
if (width === WIDTH.auto) {
/* Assuming there is no "overflow: hidden". */
if (this.height() <= line_height) {
/* Text is already at the optimal trunkage. */
return;
}
/* Binary search technique for finding the optimal trunkage. */
/* Find the maximum bite without overflowing. */
lower = 0;
upper = length - 1;
while (lower <= upper) {
bite_size = lower + ((upper - lower) >> 1);
bite = utils.eatStr(str, side, length - bite_size, fill);
this.html(bite);
/* Check for overflow. */
if (this.height() > line_height) {
upper = bite_size - 1;
}
else {
lower = bite_size + 1;
/* Save the bigger bite. */
max_bite = (max_bite.length > bite.length) ? max_bite : bite;
}
}
/* Reset the content to eliminate possible existing scroll bars. */
this.html('');
/* Display the biggest bite. */
this.html(max_bite);
if (settings.tooltip) {
this.attr('title', str);
}
}
else if (!isNaN(width)) {
bite_size = length - width;
bite = utils.eatStr(str, side, bite_size, fill);
this.html(bite);
if (settings.tooltip) {
this.attr('title', str);
}
}
else {
$.error('Invalid width "' + width + '".');
}
}
methods = {
init: function (options) {
return this.each(function () {
var $this = $(this),
data = $this.data('trunk8');
if (!data) {
$this.data('trunk8', (data = new trunk8(this)));
}
data.updateSettings(options);
truncate.call($this);
});
},
/** Updates the text value of the elements while maintaining truncation. */
update: function (new_string) {
return this.each(function () {
var $this = $(this);
/* Update text. */
if (new_string) {
$this.data('trunk8').original_text = new_string;
}
/* Truncate accordingly. */
truncate.call($this);
});
},
revert: function () {
return this.each(function () {
/* Get original text. */
var text = $(this).data('trunk8').original_text;
/* Revert element to original text. */
$(this).html(text);
});
},
/** Returns this instance's settings object. NOT CHAINABLE. */
getSettings: function () {
return this.get(0).data('trunk8').settings;
}
};
utils = {
/** Replaces [bite_size] [side]-most chars in [str] with [fill]. */
eatStr: function (str, side, bite_size, fill) {
var length = str.length,
key = utils.eatStr.generateKey.apply(null, arguments),
half_length,
half_bite_size;
/* If the result is already in the cache, return it. */
if (utils.eatStr.cache[key]) {
return utils.eatStr.cache[key];
}
/* Common error handling. */
if ((typeof str !== 'string') || (length === 0)) {
$.error('Invalid source string "' + str + '".');
}
if ((bite_size < 0) || (bite_size > length)) {
$.error('Invalid bite size "' + bite_size + '".');
}
else if (bite_size === 0) {
/* No bite should show no truncation. */
return str;
}
if (typeof (fill + '') !== 'string') {
$.error('Fill unable to be converted to a string.');
}
/* Compute the result, store it in the cache, and return it. */
switch (side) {
case SIDES.right:
/* str... */
return utils.eatStr.cache[key] =
$.trim(str.substr(0, length - bite_size)) + fill;
case SIDES.left:
/* ...str */
return utils.eatStr.cache[key] =
fill + $.trim(str.substr(bite_size));
case SIDES.center:
/* Bit-shift to the right by one === Math.floor(x / 2) */
half_length = length >> 1; // halve the length
half_bite_size = bite_size >> 1; // halve the bite_size
/* st...r */
return utils.eatStr.cache[key] =
$.trim(utils.eatStr(str.substr(0, length - half_length), SIDES.right, bite_size - half_bite_size, '')) +
fill +
$.trim(utils.eatStr(str.substr(length - half_length), SIDES.left, half_bite_size, ''));
default:
$.error('Invalid side "' + side + '".');
}
},
getLineHeight: function (elem) {
var $elem = $(elem),
floats = $elem.css('float'),
position = $elem.css('position'),
html = $elem.html(),
wrapper_id = 'line-height-test',
line_height;
if (floats !== 'none') {
$elem.css('float', 'none');
}
if (position === 'absolute') {
$elem.css('position', 'static');
}
/* Set the content to a small single character and wrap. */
$elem.html('i').wrap('<div id="' + wrapper_id + '" />');
/* Calculate the line height by measuring the wrapper.*/
line_height = $('#' + wrapper_id).innerHeight();
/* Remove the wrapper and reset the style/content. */
$elem.html(html).css({
'float': floats,
'position': position
}).unwrap();
return line_height;
}
};
utils.eatStr.cache = {};
utils.eatStr.generateKey = function () {
return Array.prototype.join.call(arguments, '');
};
$.fn.trunk8 = function (method) {
if (methods[method]) {
return methods[method].apply(this, Array.prototype.slice.call(arguments, 1));
}
else if (typeof method === 'object' || !method) {
return methods.init.apply(this, arguments);
}
else {
$.error('Method ' + method + ' does not exist on jQuery.trunk8');
}
};
/* Default trunk8 settings. */
$.fn.trunk8.defaults = {
fill: '…',
lines: 1,
side: SIDES.right,
tooltip: true,
width: WIDTH.auto
};
})(jQuery);