Parallax 'background-image/position/attachment' jQuery animation is jittery - javascript

Here's the breakdown...
wrapper (position:relative; overflow:hidden; )
section-container (position:absolute)
multiple child sections
I attach a mousewheel event listener and animate (with easing) the 'top' position of 'section-container'. As this position changes, the 'background-position' of each section moves vertically based on the position of 'section-container's 'top' property (continually updated through a setTimeout()).
All of that works as it should, except as the 'background-position' changes, the image has a bit of a jitter. This doesn't happen if the 'background-attachment' is set to 'fixed'... but I don't want that.
Can anyone explain this, with a possible fix? I continually refer to the https://victoriabeckham.landrover.com/ site and can't figure out what they're doing differently to get theirs operating so efficiently.

You can check this out, i believe its where they do most of the animating:
https://victoriabeckham.landrover.com/js/ScrollAnimator.js?v=471
I would have to say they have some kind of framework that they are using to accomplish this.
EDIT: Sorry didn't see the new answer above mine, seems like a good starting point.
-Ken

If you inspect this website carefully, you will able to use it like landrover site.
You need to use: scrollTo plugin and parallax plugin
And document jQuery should be like this:
$(document).ready(function(){
$('#nav').localScroll(800);
//.parallax(xPosition, speedFactor, outerHeight) options:
//xPosition - Horizontal position of the element
//inertia - speed to move relative to vertical scroll. Example: 0.1 is one tenth the speed of scrolling, 2 is twice the speed of scrolling
//outerHeight (true/false) - Whether or not jQuery should use it's outerHeight option to determine when a section is in the viewport
$('#intro').parallax("50%", 0.1);
$('#second').parallax("50%", 0.1);
$('.bg').parallax("50%", 0.4);
$('#third').parallax("50%", 0.3);
});

Ok. So I figured out my issue was when trying to animate() the 'section-container' on the 'top' property. I was using a "+=" to allow it to increment from its current position. Not a good idea when using 'mousewheel' events. I changed it to a hard-set variable that is continually incremented/decremented.

Related

Transform element based on scroll position without using scroll events (Css only if possible)

I currently have a full screen hero image slideshow on the homepage of a site. I have an javascript effect which gets the scroll position and divides it by 1.5 then sets the image transformY position causing a parallex effect.
Here is the code I currently have:
$(window).on("load scroll resize", function () {
$("form:not(.blive_PageEdit) .hero-img .blive_Control img").css({ "margin-top": $(window).scrollTop() / 1.5 });
});
This works as I want, but I have noticed that performance is a major issue expecially on browsers which support asynchronous scrolling which causes a juddering effect.
What I want to know is if there is a better way to implement this? What would be perfect would be to have something like the following but I don't think this is possible with just CSS:
img {
transformY(calc(scrollTop / 1.5));
}
I have also looked at IntersectionObserver, but I am unsure this would achieve what I want to do.
Any thoughts would be helpful. Thanks

Get element position relative to screen. (Or alternative solution)

I am aware this had been asked before, but no answer actually did the trick as far as I tested them.
Basically what I need is to change some element styles as soon as it "hits" the top border of the screen while scrolling down. This element is a 'Back to Top' button that will be sitting in a section and start following the user when they scroll pass said section.
I am not asking about CSS properties, I am asking about some JS property or method that allow me to know this. IE:
$('#back').distanceFromTopOfTheScreen() // This value will decrease as I scroll down
I know there are other soultions, but the client has asked for this behavior.
Any idea?
You can :
distance = $('#eleId')[0].getBoundingClientRect().top;
For more about getBoundingClientRect() look at the MDN Documentation
Note: This value change when you're scrolling, it gives you the distance between the top border of the element and the top of the Page
Sometimes JQuery make's everything more confusing than Native Javascript, even forgothing the very basics functions:
window.onscroll = function() { fixPosition()};
function fixPosition() {
var Yplus = 4; //number of lines in every scroll
document.getElementById('element').style.top = document.body.scrollTop + Yplus ;
}
This will allows you to move an "element" static on the window following the scroll.

scrolling effect

I'm trying to do something like this.
http://www.mini.jp/event_campaign/big-point/
What I can't figure out is how to make the animation happen based on the scroll when the scroll hits a specific position. I have similar blocks of content that I only want to animate parts of it based on the scroll and when the block is within the browsers view area when scrolling.
I understand using the scroll event to get the scrollTop position I'm more concerned with how everything else would work.
$(window).bind('scroll',function(e){
var scrolledY = $(window).scrollTop();
});
Anyone can help explain some of this.
Thanks
Just like what MiniGod said in the comment, look in to the source code (animate.js), and you can see that they have recorded all the "scenes" and all other things like alpha and pos for everything.
// scene 1
{
scene:"#scene1",
name:".car",
runStatus:[
{p:10,pos:true,x:275,y:240,alpha:true,opacity:1,scale:true,orgSize:[475,270],scaleSize:1},
{p:180,pos:true,x:275,y:200,alpha:true,opacity:1,scale:true,orgSize:[475,270],scaleSize:1},
{p:270,pos:true,x:275,y:140,alpha:true,opacity:1,scale:true,orgSize:[475,270],scaleSize:1},
{p:500,pos:true,x:275,y:-300,alpha:true,opacity:0,scale:true,orgSize:[475,270],scaleSize:1}
]
}

How to solve element flicker while scrolling with parallax effect in JavaScript?

I am trying to re-create website with parallax effect using JavaScript. That means that I have two or more layers, that are moving different speeds while scrolling.
In my case I'm moving only one layer, the other one remains static:
layer 1 = website text;
layer 2 = element background;
for this I'm using simple source code (with jQuery 1.6.4):
var docwindow = $(window);
function newpos(pos, adjust, ratio){
return ((pos - adjust) * ratio) + "px";
}
function move(){
var pos = docwindow.scrollTop();
element.css({'top' : newpos(pos, 0, 0.5)});
}
$(window).scroll(function(){
move();
});
The Problem:
- All calculations are done right and the effect "works" as expected. But there is some performance glitch under some browsers (Chrome MAC/Windows, Opera MAC, IE, paradoxically not Safari).
What do I see during scrolling?
- While scrolling the background moves in one direction together with scroll, but it seems to occasionally jump few pixels back and then forth, which creates very disturbing effect (not fluid).
Solutions that I tried:
- adding a timer to limit scroll events
- using .animate() method with short duration instead of .css() method.
I've also observed, that the animation is smooth when using .scrollTo method (scrollTo jQuery plugin). So I suspect that there is something wrong with firing scroll events (too fast).
Have you observed the same behavior?
Do you know, how to fix it?
Can you post a better solution?
Thanks for all responses
EDIT #1:
Here you can find jsfiddle demonstration (with timer): http://jsfiddle.net/4h9Ye/1/
I think you should be using scrollTop() instead and change the background position to fixed. The problem is that setting it to absolute will make it move by default when you scroll up or down.
The flicker occurs because the position is updated as part of the default browser scroll and updated again as part of your script. This will render both positions instead of just the one you want. With fixed, the background will never move unless you tell it so.
I've created a demo for you at http://jsfiddle.net/4h9Ye/2/ .

tween back to auto-height with xuijs

I'm having problems to create a equivalent slideDown for xuijs.
The slideUp (hide) is easily done with
x$('elm').tween({height:'0'});
but there seem to be no way to revert back to original height using tween.
$x('elm').setStyle('height','auto !important');
works fine but no animation of course,
x$('elm').tween({height:'auto !important'});
does not work. (setting height to fixed value does however, but that's not an option).
Kind of stuck here, document.getElementById('target_box').clientHeight doesn't help either once the height is set to 0 by tween or setStyle. Only solution I can think of is storing the heights in an array before initial global collapse of divs.
thankful for any help.
(the divs affected uses overflow: hidden)
regards,
//t
If you're using html5 Why not store the height as a data- attribute before you call tween?
x$.extend({
'slideUp' : function(){
this = this[0];
x$(this).attr('data-h',this.clientHeight);
x$(this).tween({height:'0'});
},
'slideDown' : function(){
this = this[0];
x$(this).tween({height:x$(this).attr('data-h');});
}
});
this code is untested, but it's worth a shot.
Not sure if you have solved this but I got a solution. Pretty sure there are better ways but this seemed to do the trick.
emile.js and xui animation needing double click?
uses emile instead of tween but sure you could change it if you want however emile.js is in xui.

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