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July 15, 2014 21:24
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Balance yo' headlines (Require ready)
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/* | |
* Copyright (c) 2012 Adobe Systems Incorporated. All rights reserved. | |
* | |
* 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. * | |
*/ | |
/** | |
* jquery.balancetext.js | |
* | |
* Author: Randy Edmunds | |
*/ | |
/*jslint vars: true, plusplus: true, devel: true, browser: true, nomen: true, indent: 4, maxerr: 50 */ | |
/*global jQuery, $ */ | |
/* | |
* Copyright (c) 2007-2009 unscriptable.com and John M. Hann | |
* | |
* Permission is hereby granted, free of charge, to any person | |
* obtaining a copy of this software and associated documentation | |
* files (the “Softwareâ€), to deal in the Software without | |
* restriction, including without limitation the rights to use, | |
* copy, modify, merge, publish, distribute, sublicense, and/or sell | |
* copies of the Software, and to permit persons to whom the | |
* Software is furnished to do so, subject to the following | |
* conditions: | |
* | |
* The above copyright notice and this permission notice shall be | |
* included in all copies or substantial portions of the Software. | |
* | |
* THE SOFTWARE IS PROVIDED “AS ISâ€, WITHOUT WARRANTY OF ANY KIND, | |
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES | |
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND | |
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT | |
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, | |
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING | |
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR | |
* OTHER DEALINGS IN THE SOFTWARE. | |
* | |
* Except as contained in this notice, the name(s) of the above | |
* copyright holders (unscriptable.com and John M. Hann) shall not be | |
* used in advertising or otherwise to promote the sale, use or other | |
* dealings in this Software without prior written authorization. | |
* | |
* http://unscriptable.com/index.php/2009/03/20/debouncing-javascript-methods/ | |
* | |
*/ | |
require([ | |
'jquery/nyt' | |
], function(jQuery) { | |
var sr = "smartresize"; | |
"use strict"; | |
var debounce = function (func, threshold, execAsap) { | |
var timeout; | |
return function debounced() { | |
var obj = this, args = arguments; | |
function delayed() { | |
if (!execAsap) { | |
func.apply(obj, args); | |
} | |
timeout = null; | |
} | |
if (timeout) { | |
clearTimeout(timeout); | |
} else if (execAsap) { | |
func.apply(obj, args); | |
} | |
timeout = setTimeout(delayed, threshold || 100); | |
}; | |
}; | |
// smartresize | |
jQuery.fn[sr] = function (fn) { return fn ? this.bind('resize', debounce(fn)) : this.trigger(sr); }; | |
}); | |
require([ | |
'jquery/nyt' | |
], function($) { | |
"use strict"; | |
var style = document.documentElement.style, | |
hasTextWrap = (style.textWrap || style.WebkitTextWrap || style.MozTextWrap || style.MsTextWrap || style.OTextWrap); | |
function NextWS_params() { | |
this.reset(); | |
} | |
NextWS_params.prototype.reset = function () { | |
this.index = 0; | |
this.width = 0; | |
}; | |
/** | |
* Returns true iff c is an HTML space character. | |
*/ | |
var isWS = function (c) { | |
return Boolean(c.match(/^\s$/)); | |
}; | |
var removeTags = function ($el) { | |
$el.find('br[data-owner="balance-text"]').replaceWith(" "); | |
var $span = $el.find('span[data-owner="balance-text"]'); | |
if ($span.length > 0) { | |
var txt = ""; | |
$span.each(function () { | |
txt += $(this).text(); | |
$(this).remove(); | |
}); | |
$el.html(txt); | |
} | |
}; | |
/** | |
* Checks to see if we should justify the balanced text with the | |
* element based on the textAlign property in the computed CSS | |
* | |
* @param $el - $(element) | |
*/ | |
var isJustified = function ($el) { | |
style = $el.get(0).currentStyle || window.getComputedStyle($el.get(0), null); | |
return (style.textAlign === 'justify'); | |
}; | |
/** | |
* Add whitespace after words in text to justify the string to | |
* the specified size. | |
* | |
* @param txt - text string | |
* @param conWidth - container width | |
*/ | |
var justify = function ($el, txt, conWidth) { | |
txt = $.trim(txt); | |
var words = txt.split(' ').length; | |
txt = txt + ' '; | |
// if we don't have at least 2 words, no need to justify. | |
if (words < 2) { | |
return txt; | |
} | |
// Find width of text in the DOM | |
var tmp = $('<span></span>').html(txt); | |
$el.append(tmp); | |
var size = tmp.width(); | |
tmp.remove(); | |
// Figure out our word spacing and return the element | |
var wordSpacing = Math.floor((conWidth - size) / (words - 1)); | |
tmp.css('word-spacing', wordSpacing + 'px') | |
.attr('data-owner', 'balance-text'); | |
return $('<div></div>').append(tmp).html(); | |
}; | |
/** | |
* In the current simple implementation, an index i is a break | |
* opportunity in txt iff it is 0, txt.length, or the | |
* index of a non-whitespace char immediately preceded by a | |
* whitespace char. (Thus, it doesn't honour 'white-space' or | |
* any Unicode line-breaking classes.) | |
* | |
* @precondition 0 <= index && index <= txt.length | |
*/ | |
var isBreakOpportunity = function (txt, index) { | |
return ((index === 0) || (index === txt.length) || | |
(isWS(txt.charAt(index - 1)) && !isWS(txt.charAt(index)))); | |
}; | |
/** | |
* Finds the first break opportunity (@see isBreakOpportunity) | |
* in txt that's both after-or-equal-to index c in the direction dir | |
* and resulting in line width equal to or past clamp(desWidth, | |
* 0, conWidth) in direction dir. Sets ret.index and ret.width | |
* to the corresponding index and line width (from the start of | |
* txt to ret.index). | |
* | |
* @param $el - $(element) | |
* @param txt - text string | |
* @param conWidth - container width | |
* @param desWidth - desired width | |
* @param dir - direction (-1 or +1) | |
* @param c - char index (0 <= c && c <= txt.length) | |
* @param ret - return object; index and width of previous/next break | |
* | |
*/ | |
var findBreakOpportunity = function ($el, txt, conWidth, desWidth, dir, c, ret) { | |
var w; | |
for(;;) { | |
while (!isBreakOpportunity(txt, c)) { | |
c += dir; | |
} | |
$el.text(txt.substr(0, c)); | |
w = $el.width(); | |
if ((dir < 0) | |
? ((w <= desWidth) || (w <= 0) || (c === 0)) | |
: ((desWidth <= w) || (conWidth <= w) || (c === txt.length))) { | |
break; | |
} | |
c += dir; | |
} | |
ret.index = c; | |
ret.width = w; | |
}; | |
$.fn.balanceText = function () { | |
if (hasTextWrap) { | |
// browser supports text-wrap, so do nothing | |
return this; | |
} | |
return this.each(function () { | |
var $this = $(this); | |
// In a lower level language, this algorithm takes time | |
// comparable to normal text layout other than the fact | |
// that we do two passes instead of one, so we should | |
// be able to do without this limit. | |
var maxTextWidth = 5000; | |
removeTags($this); // strip balance-text tags | |
// save line-height if set via inline style | |
var oldLH = ''; | |
if ($this.attr('style') && | |
$this.attr('style').indexOf('line-height') >= 0) { | |
oldLH = $this.css('line-height'); | |
} | |
// remove line height before measuring container size | |
$this.css('line-height', 'normal'); | |
var containerWidth = $this.width(); | |
var containerHeight = $this.height(); | |
// save settings | |
var oldWS = $this.css('white-space'); | |
var oldFloat = $this.css('float'); | |
var oldDisplay = $this.css('display'); | |
var oldPosition = $this.css('position'); | |
// temporary settings | |
$this.css({ | |
'white-space': 'nowrap', | |
'float': 'none', | |
'display': 'inline', | |
'position': 'static' | |
}); | |
var nowrapWidth = $this.width(); | |
var nowrapHeight = $this.height(); | |
// An estimate of the average line width reduction due | |
// to trimming trailing space that we expect over all | |
// lines other than the last. | |
var guessSpaceWidth = ((oldWS === 'pre-wrap') ? 0 : nowrapHeight / 4); | |
if (containerWidth > 0 && // prevent divide by zero | |
nowrapWidth > containerWidth && // text is more than 1 line | |
nowrapWidth < maxTextWidth) { // text is less than arbitrary limit (make this a param?) | |
var remainingText = $this.text(); | |
var newText = ""; | |
var lineText = ""; | |
var shouldJustify = isJustified($this); | |
var totLines = Math.round(containerHeight / nowrapHeight); | |
var remLines = totLines; | |
// Determine where to break: | |
while (remLines > 1) { | |
var desiredWidth = Math.round((nowrapWidth + guessSpaceWidth) | |
/ remLines | |
- guessSpaceWidth); | |
// Guessed char index | |
var guessIndex = Math.round((remainingText.length + 1) / remLines) - 1; | |
var le = new NextWS_params(); | |
// Find a breaking space somewhere before (or equal to) desired width, | |
// not necessarily the closest to the desired width. | |
findBreakOpportunity($this, remainingText, containerWidth, desiredWidth, -1, guessIndex, le); | |
// Find first breaking char after (or equal to) desired width. | |
var ge = new NextWS_params(); | |
guessIndex = le.index; | |
findBreakOpportunity($this, remainingText, containerWidth, desiredWidth, +1, guessIndex, ge); | |
// Find first breaking char before (or equal to) desired width. | |
le.reset(); | |
guessIndex = ge.index; | |
findBreakOpportunity($this, remainingText, containerWidth, desiredWidth, -1, guessIndex, le); | |
// Find closest string to desired length | |
var splitIndex; | |
if (le.index === 0) { | |
splitIndex = ge.index; | |
} else if ((containerWidth < ge.width) || (le.index === ge.index)) { | |
splitIndex = le.index; | |
} else { | |
splitIndex = ((Math.abs(desiredWidth - le.width) < Math.abs(ge.width - desiredWidth)) | |
? le.index | |
: ge.index); | |
} | |
// Break string | |
lineText = remainingText.substr(0, splitIndex); | |
if (shouldJustify) { | |
newText += justify($this, lineText, containerWidth); | |
} else { | |
newText += lineText.replace(/\s+$/, ""); | |
newText += '<br data-owner="balance-text" />'; | |
} | |
remainingText = remainingText.substr(splitIndex); | |
// update counters | |
remLines--; | |
$this.text(remainingText); | |
nowrapWidth = $this.width(); | |
} | |
if (shouldJustify) { | |
$this.html(newText + justify($this, remainingText, containerWidth)); | |
} else { | |
$this.html(newText + remainingText); | |
} | |
} | |
// restore settings | |
$this.css({ | |
'position': oldPosition, | |
'display': oldDisplay, | |
'float': oldFloat, | |
'white-space': oldWS, | |
'line-height': oldLH | |
}); | |
}); | |
}; | |
// Call the balanceText plugin on the elements with "balance-text" class. When a browser | |
// has native support for the text-wrap property, the text balanceText plugin will let | |
// the browser handle it natively, otherwise it will apply its own text balancing code. | |
function applyBalanceText() { | |
$(".balance-text").balanceText(); | |
} | |
// Apply on DOM ready | |
$(window).ready(applyBalanceText); | |
// Reapply on resize | |
$(window).smartresize(applyBalanceText); | |
}); |
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