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/*
* # Semantic - Visibility
* http://github.com/semantic-org/semantic-ui/
*
*
* Copyright 2014 Contributor
* Released under the MIT license
* http://opensource.org/licenses/MIT
*
*/
;(function ( $, window, document, undefined ) {
$.fn.visibility = function(parameters) {
var
$allModules = $(this),
moduleSelector = $allModules.selector || '',
time = new Date().getTime(),
performance = [],
query = arguments[0],
methodInvoked = (typeof query == 'string'),
queryArguments = [].slice.call(arguments, 1),
returnedValue
;
$allModules
.each(function() {
var
settings = $.extend(true, {}, $.fn.visibility.settings, parameters),
className = settings.className,
namespace = settings.namespace,
error = settings.error,
eventNamespace = '.' + namespace,
moduleNamespace = 'module-' + namespace,
$window = $(window),
$module = $(this),
$context = $(settings.context),
$container = $module.offsetParent(),
selector = $module.selector || '',
instance = $module.data(moduleNamespace),
requestAnimationFrame = window.requestAnimationFrame
|| window.mozRequestAnimationFrame
|| window.webkitRequestAnimationFrame
|| window.msRequestAnimationFrame
|| function(callback) { setTimeout(callback, 0); },
element = this,
module
;
module = {
initialize: function() {
module.verbose('Initializing visibility', settings);
module.setup.cache();
module.save.position();
if( module.should.trackChanges() ) {
module.bindEvents();
if(settings.type == 'image') {
module.setup.image();
}
if(settings.type == 'fixed') {
module.setup.fixed();
}
}
module.checkVisibility();
module.instantiate();
},
instantiate: function() {
module.verbose('Storing instance of module', module);
instance = module;
$module
.data(moduleNamespace, module)
;
},
destroy: function() {
module.verbose('Destroying previous module');
$module
.off(eventNamespace)
.removeData(moduleNamespace)
;
},
bindEvents: function() {
module.verbose('Binding visibility events to scroll and resize');
$window
.on('resize' + eventNamespace, module.event.refresh)
;
$context
.on('scroll' + eventNamespace, module.event.scroll)
;
},
event: {
refresh: function() {
requestAnimationFrame(module.refresh);
},
scroll: function() {
module.verbose('Scroll position changed');
if(settings.throttle) {
clearTimeout(module.timer);
module.timer = setTimeout(module.checkVisibility, settings.throttle);
}
else {
requestAnimationFrame(module.checkVisibility);
}
}
},
precache: function(images, callback) {
if (!(images instanceof Array)) {
images = [images];
}
var
imagesLength = images.length,
loadedCounter = 0,
cache = [],
cacheImage = document.createElement('img'),
handleLoad = function() {
loadedCounter++;
if (loadedCounter >= images.length) {
if ($.isFunction(callback)) {
callback();
}
}
}
;
while (imagesLength--) {
cacheImage = document.createElement('img');
cacheImage.onload = handleLoad;
cacheImage.onerror = handleLoad;
cacheImage.src = images[imagesLength];
cache.push(cacheImage);
}
},
should: {
trackChanges: function() {
if(methodInvoked && queryArguments.length > 0) {
module.debug('One time query, no need to bind events');
return false;
}
module.debug('Query is attaching callbacks, watching for changes with scroll');
return true;
}
},
setup: {
cache: function() {
module.cache = {
occurred : {},
screen : {},
element : {},
};
},
image: function() {
var
src = $module.data('src')
;
if(src) {
module.verbose('Lazy loading image', src);
// show when top visible
module.topVisible(function() {
module.precache(src, function() {
module.set.image(src);
settings.onTopVisible = false;
});
});
}
},
fixed: function() {
module.verbose('Setting up fixed on element pass');
$module
.visibility({
once: false,
continuous: false,
onTopPassed: function() {
$module
.addClass(className.fixed)
.css({
position: 'fixed',
top: settings.offset + 'px'
})
;
if(settings.animation && $.fn.transition !== undefined) {
$module.transition(settings.transition, settings.duration);
}
},
onTopPassedReverse: function() {
$module
.removeClass(className.fixed)
.css({
position: '',
top: ''
})
;
}
})
;
}
},
set: {
image: function(src) {
var
offScreen = (module.cache.screen.bottom < module.cache.element.top)
;
$module
.attr('src', src)
;
if(offScreen) {
module.verbose('Image outside browser, no show animation');
$module.show();
}
else {
if(settings.transition && $.fn.transition !== undefined) {
$module.transition(settings.transition, settings.duration);
}
else {
$module.fadeIn(settings.duration);
}
}
}
},
refresh: function() {
module.debug('Refreshing constants (element width/height)');
module.reset();
module.save.position();
module.checkVisibility();
settings.onRefresh.call(element);
},
reset: function() {
module.verbose('Reseting all cached values');
if( $.isPlainObject(module.cache) ) {
module.cache.screen = {};
module.cache.element = {};
}
},
checkVisibility: function() {
module.verbose('Checking visibility of element', module.cache.element);
module.save.calculations();
// percentage
module.passed();
// reverse (must be first)
module.passingReverse();
module.topVisibleReverse();
module.bottomVisibleReverse();
module.topPassedReverse();
module.bottomPassedReverse();
// one time
module.passing();
module.topVisible();
module.bottomVisible();
module.topPassed();
module.bottomPassed();
},
passed: function(amount, newCallback) {
var
calculations = module.get.elementCalculations(),
amountInPixels
;
// assign callback
if(amount !== undefined && newCallback !== undefined) {
settings.onPassed[amount] = newCallback;
}
else if(amount !== undefined) {
return (module.get.pixelsPassed(amount) > calculations.pixelsPassed);
}
else if(calculations.passing) {
$.each(settings.onPassed, function(amount, callback) {
if(calculations.bottomVisible || calculations.pixelsPassed > module.get.pixelsPassed(amount)) {
module.execute(callback, amount);
}
else if(!settings.once) {
module.remove.occurred(callback);
}
});
}
},
passing: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onPassing,
callbackName = 'passing'
;
if(newCallback) {
module.debug('Adding callback for passing', newCallback);
settings.onPassing = newCallback;
}
if(calculations.passing) {
module.execute(callback, callbackName);
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback !== undefined) {
return calculations.passing;
}
},
topVisible: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onTopVisible,
callbackName = 'topVisible'
;
if(newCallback) {
module.debug('Adding callback for top visible', newCallback);
settings.onTopVisible = newCallback;
}
if(calculations.topVisible) {
module.execute(callback, callbackName);
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback === undefined) {
return calculations.topVisible;
}
},
bottomVisible: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onBottomVisible,
callbackName = 'bottomVisible'
;
if(newCallback) {
module.debug('Adding callback for bottom visible', newCallback);
settings.onBottomVisible = newCallback;
}
if(calculations.bottomVisible) {
module.execute(callback, callbackName);
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback === undefined) {
return calculations.bottomVisible;
}
},
topPassed: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onTopPassed,
callbackName = 'topPassed'
;
if(newCallback) {
module.debug('Adding callback for top passed', newCallback);
settings.onTopPassed = newCallback;
}
if(calculations.topPassed) {
module.execute(callback, callbackName);
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback === undefined) {
return calculations.topPassed;
}
},
bottomPassed: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onBottomPassed,
callbackName = 'bottomPassed'
;
if(newCallback) {
module.debug('Adding callback for bottom passed', newCallback);
settings.onBottomPassed = newCallback;
}
if(calculations.bottomPassed) {
module.execute(callback, callbackName);
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback === undefined) {
return calculations.bottomPassed;
}
},
passingReverse: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onPassingReverse,
callbackName = 'passingReverse'
;
if(newCallback) {
module.debug('Adding callback for passing reverse', newCallback);
settings.onPassingReverse = newCallback;
}
if(!calculations.passing) {
if(module.get.occurred('passing')) {
module.execute(callback, callbackName);
}
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback !== undefined) {
return !calculations.passing;
}
},
topVisibleReverse: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onTopVisibleReverse,
callbackName = 'topVisibleReverse'
;
if(newCallback) {
module.debug('Adding callback for top visible reverse', newCallback);
settings.onTopVisibleReverse = newCallback;
}
if(!calculations.topVisible) {
if(module.get.occurred('topVisible')) {
module.execute(callback, callbackName);
}
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback === undefined) {
return !calculations.topVisible;
}
},
bottomVisibleReverse: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onBottomVisibleReverse,
callbackName = 'bottomVisibleReverse'
;
if(newCallback) {
module.debug('Adding callback for bottom visible reverse', newCallback);
settings.onBottomVisibleReverse = newCallback;
}
if(!calculations.bottomVisible) {
if(module.get.occurred('bottomVisible')) {
module.execute(callback, callbackName);
}
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback === undefined) {
return !calculations.bottomVisible;
}
},
topPassedReverse: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onTopPassedReverse,
callbackName = 'topPassedReverse'
;
if(newCallback) {
module.debug('Adding callback for top passed reverse', newCallback);
settings.onTopPassedReverse = newCallback;
}
if(!calculations.topPassed) {
if(module.get.occurred('topPassed')) {
module.execute(callback, callbackName);
}
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback === undefined) {
return !calculations.onTopPassed;
}
},
bottomPassedReverse: function(newCallback) {
var
calculations = module.get.elementCalculations(),
callback = newCallback || settings.onBottomPassedReverse,
callbackName = 'bottomPassedReverse'
;
if(newCallback) {
module.debug('Adding callback for bottom passed reverse', newCallback);
settings.onBottomPassedReverse = newCallback;
}
if(!calculations.bottomPassed) {
if(module.get.occurred('bottomPassed')) {
module.execute(callback, callbackName);
}
}
else if(!settings.once) {
module.remove.occurred(callbackName);
}
if(newCallback === undefined) {
return !calculations.bottomPassed;
}
},
execute: function(callback, callbackName) {
var
calculations = module.get.elementCalculations(),
screen = module.get.screenCalculations()
;
callback = callback || false;
if(callback) {
if(settings.continuous) {
module.debug('Callback being called continuously', callbackName, calculations);
callback.call(element, calculations, screen);
}
else if(!module.get.occurred(callbackName)) {
module.debug('Conditions met', callbackName, calculations);
callback.call(element, calculations, screen);
}
}
module.save.occurred(callbackName);
},
remove: {
occurred: function(callback) {
if(callback) {
if(module.cache.occurred[callback] !== undefined && module.cache.occurred[callback] === true) {
module.debug('Callback can now be called again', callback);
module.cache.occurred[callback] = false;
}
}
else {
module.cache.occurred = {};
}
}
},
save: {
calculations: function() {
module.verbose('Saving all calculations necessary to determine positioning');
module.save.scroll();
module.save.direction();
module.save.screenCalculations();
module.save.elementCalculations();
},
occurred: function(callback) {
if(callback) {
if(module.cache.occurred[callback] === undefined || (module.cache.occurred[callback] !== true)) {
module.verbose('Saving callback occurred', callback);
module.cache.occurred[callback] = true;
}
}
},
scroll: function() {
module.cache.scroll = $context.scrollTop() + settings.offset;
},
direction: function() {
var
scroll = module.get.scroll(),
lastScroll = module.get.lastScroll(),
direction
;
if(scroll > lastScroll && lastScroll) {
direction = 'down';
}
else if(scroll < lastScroll && lastScroll) {
direction = 'up';
}
else {
direction = 'static';
}
module.cache.direction = direction;
return module.cache.direction;
},
elementPosition: function() {
var
screen = module.get.screenSize()
;
module.verbose('Saving element position');
$.extend(module.cache.element, {
margin : {
top : parseInt($module.css('margin-top'), 10),
bottom : parseInt($module.css('margin-bottom'), 10)
},
fits : (element.height < screen.height),
offset : $module.offset(),
width : $module.outerWidth(),
height : $module.outerHeight()
});
return module.cache.element;
},
elementCalculations: function() {
var
screen = module.get.screenCalculations(),
element = module.get.elementPosition()
;
// offset
if(settings.includeMargin) {
$.extend(module.cache.element, {
top : element.offset.top - element.margin.top,
bottom : element.offset.top + element.height + element.margin.bottom
});
}
else {
$.extend(module.cache.element, {
top : element.offset.top,
bottom : element.offset.top + element.height
});
}
// visibility
$.extend(module.cache.element, {
topVisible : (screen.bottom >= element.top),
topPassed : (screen.top >= element.top),
bottomVisible : (screen.bottom >= element.bottom),
bottomPassed : (screen.top >= element.bottom),
pixelsPassed : 0,
percentagePassed : 0
});
// meta calculations
$.extend(module.cache.element, {
visible : (module.cache.element.topVisible || module.cache.element.bottomVisible),
passing : (module.cache.element.topPassed && !module.cache.element.bottomPassed),
hidden : (!module.cache.element.topVisible && !module.cache.element.bottomVisible)
});
if(module.cache.element.passing) {
module.cache.element.pixelsPassed = (screen.top - element.top);
module.cache.element.percentagePassed = (screen.top - element.top) / element.height;
}
module.verbose('Updated element calculations', module.cache.element);
},
screenCalculations: function() {
var
scroll = $context.scrollTop() + settings.offset
;
if(module.cache.scroll === undefined) {
module.cache.scroll = $context.scrollTop() + settings.offset;
}
module.save.direction();
$.extend(module.cache.screen, {
top : scroll,
bottom : scroll + module.cache.screen.height
});
return module.cache.screen;
},
screenSize: function() {
module.verbose('Saving window position');
module.cache.screen = {
height: $context.height()
};
},
position: function() {
module.save.screenSize();
module.save.elementPosition();
}
},
get: {
pixelsPassed: function(amount) {
var
element = module.get.elementCalculations()
;
if(amount.search('%') > -1) {
return ( element.height * (parseInt(amount, 10) / 100) );
}
return parseInt(amount, 10);
},
occurred: function(callback) {
return (module.cache.occurred !== undefined)
? module.cache.occurred[callback] || false
: false
;
},
direction: function() {
if(module.cache.direction === undefined) {
module.save.direction();
}
return module.cache.direction;
},
elementPosition: function() {
if(module.cache.element === undefined) {
module.save.elementPosition();
}
return module.cache.element;
},
elementCalculations: function() {
if(module.cache.element === undefined) {
module.save.elementCalculations();
}
return module.cache.element;
},
screenCalculations: function() {
if(module.cache.screen === undefined) {
module.save.screenCalculations();
}
return module.cache.screen;
},
screenSize: function() {
if(module.cache.screen === undefined) {
module.save.screenSize();
}
return module.cache.screen;
},
scroll: function() {
if(module.cache.scroll === undefined) {
module.save.scroll();
}
return module.cache.scroll;
},
lastScroll: function() {
if(module.cache.screen === undefined) {
module.debug('First scroll event, no last scroll could be found');
return false;
}
return module.cache.screen.top;
}
},
setting: function(name, value) {
if( $.isPlainObject(name) ) {
$.extend(true, settings, name);
}
else if(value !== undefined) {
settings[name] = value;
}
else {
return settings[name];
}
},
internal: function(name, value) {
if( $.isPlainObject(name) ) {
$.extend(true, module, name);
}
else if(value !== undefined) {
module[name] = value;
}
else {
return module[name];
}
},
debug: function() {
if(settings.debug) {
if(settings.performance) {
module.performance.log(arguments);
}
else {
module.debug = Function.prototype.bind.call(console.info, console, settings.name + ':');
module.debug.apply(console, arguments);
}
}
},
verbose: function() {
if(settings.verbose && settings.debug) {
if(settings.performance) {
module.performance.log(arguments);
}
else {
module.verbose = Function.prototype.bind.call(console.info, console, settings.name + ':');
module.verbose.apply(console, arguments);
}
}
},
error: function() {
module.error = Function.prototype.bind.call(console.error, console, settings.name + ':');
module.error.apply(console, arguments);
},
performance: {
log: function(message) {
var
currentTime,
executionTime,
previousTime
;
if(settings.performance) {
currentTime = new Date().getTime();
previousTime = time || currentTime;
executionTime = currentTime - previousTime;
time = currentTime;
performance.push({
'Name' : message[0],
'Arguments' : [].slice.call(message, 1) || '',
'Element' : element,
'Execution Time' : executionTime
});
}
clearTimeout(module.performance.timer);
module.performance.timer = setTimeout(module.performance.display, 100);
},
display: function() {
var
title = settings.name + ':',
totalTime = 0
;
time = false;
clearTimeout(module.performance.timer);
$.each(performance, function(index, data) {
totalTime += data['Execution Time'];
});
title += ' ' + totalTime + 'ms';
if(moduleSelector) {
title += ' \'' + moduleSelector + '\'';
}
if( (console.group !== undefined || console.table !== undefined) && performance.length > 0) {
console.groupCollapsed(title);
if(console.table) {
console.table(performance);
}
else {
$.each(performance, function(index, data) {
console.log(data['Name'] + ': ' + data['Execution Time']+'ms');
});
}
console.groupEnd();
}
performance = [];
}
},
invoke: function(query, passedArguments, context) {
var
object = instance,
maxDepth,
found,
response
;
passedArguments = passedArguments || queryArguments;
context = element || context;
if(typeof query == 'string' && object !== undefined) {
query = query.split(/[\. ]/);
maxDepth = query.length - 1;
$.each(query, function(depth, value) {
var camelCaseValue = (depth != maxDepth)
? value + query[depth + 1].charAt(0).toUpperCase() + query[depth + 1].slice(1)
: query
;
if( $.isPlainObject( object[camelCaseValue] ) && (depth != maxDepth) ) {
object = object[camelCaseValue];
}
else if( object[camelCaseValue] !== undefined ) {
found = object[camelCaseValue];
return false;
}
else if( $.isPlainObject( object[value] ) && (depth != maxDepth) ) {
object = object[value];
}
else if( object[value] !== undefined ) {
found = object[value];
return false;
}
else {
module.error(error.method, query);
return false;
}
});
}
if ( $.isFunction( found ) ) {
response = found.apply(context, passedArguments);
}
else if(found !== undefined) {
response = found;
}
if($.isArray(returnedValue)) {
returnedValue.push(response);
}
else if(returnedValue !== undefined) {
returnedValue = [returnedValue, response];
}
else if(response !== undefined) {
returnedValue = response;
}
return found;
}
};
if(methodInvoked) {
if(instance === undefined) {
module.initialize();
}
module.invoke(query);
}
else {
if(instance !== undefined) {
module.destroy();
}
module.initialize();
}
})
;
return (returnedValue !== undefined)
? returnedValue
: this
;
};
$.fn.visibility.settings = {
name : 'Visibility',
namespace : 'visibility',
className: {
fixed: 'fixed'
},
debug : false,
verbose : false,
performance : true,
offset : 0,
includeMargin : false,
context : window,
// visibility check delay in ms (defaults to animationFrame)
throttle : false,
// special visibility type (image, fixed)
type : false,
// image only animation settings
transition : false,
duration : 500,
// array of callbacks for percentage
onPassed : {},
// standard callbacks
onPassing : false,
onTopVisible : false,
onBottomVisible : false,
onTopPassed : false,
onBottomPassed : false,
// reverse callbacks
onPassingReverse : false,
onTopVisibleReverse : false,
onBottomVisibleReverse : false,
onTopPassedReverse : false,
onBottomPassedReverse : false,
once : true,
continuous : false,
// utility callbacks
onRefresh : function(){},
onScroll : function(){},
error : {
method : 'The method you called is not defined.'
}
};
})( jQuery, window , document );