We Keep Coding

Image move with mouse position - box issue?

I had originally taken some information from here and expanded on it: onextrapixel.com/examples/interactive-background/index4.html
I have instead incorporated the image to move with mouse position on the page, however there seems to be an issue with there being a top "box" that cuts off some of the hovered image. You can see it in action on a sample page here
My css:
.top-image {
background:url('http://i.imgur.com/wZRaMrB.png');
position:absolute ;
top:400px;
width:100%;
z-index:0;
height:100%;
background-repeat: no-repeat;
}
My js:
$(document).ready(function() {
var movementStrength = 25;
var height = movementStrength / $(window).height();
var width = movementStrength / $(window).width();
$("body").mousemove(function(e){
var pageX = e.pageX - ($(window).width() / 2);
var pageY = e.pageY - ($(window).height() / 2);
var newvalueX = width * pageX * -1 - 25;
var newvalueY = height * pageY * -1 - 50;
$('.top-image').css("background-position", newvalueX+"px "+newvalueY+"px");
});
});
I also hope to repeat this for the right side of the page.
After some suggesting in the comments here is the jsfiddle https://jsfiddle.net/yx1w8ysr/#&togetherjs=D4Q1xTfcaO

If you know the image's size beforehand, you can set the size of your div fixedly and don't need to use background-size:contain. Instead set it to some relative value (less than 100%) so that you have a padding around for the movement of the background image. However if you don't know the size of the image, you should use background-size:contain to ensure that your image sits right inside your div container. However with this approach we cannot control the size of the image anymore. That means you cannot use background-position to move the image around (because the size fits its parent, moving will cause the image be cut off).
So you need some another wrapper/container and move your inner div (.top-image) instead of changing the background-position.
Here is the detailed code:
var movementStrength = 25;
var w = $(window).width();
var h = $(window).height();
$(window).mousemove(function(e) {
var pageX = (e.pageX - w / 2) / w / 2;
var pageY = (e.pageY - h / 2) / h / 2;
var newvalueX = pageX * movementStrength;
var newvalueY = pageY * movementStrength;
$('.top-image').css({
left: newvalueX + 'px',
top: newvalueY + 'px'
});
});
.container {
padding: 25px;
width: 35%;
height: 35%;
position: absolute;
top: 400px;
}
.top-image {
background: url('http://i.imgur.com/wZRaMrB.png');
position: absolute;
background-size: contain;
width: 100%;
z-index: 0;
height: 100%;
background-repeat: no-repeat;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div class='container'>
<div class="top-image"></div>
</div>

Parallax - Offset element(s), tied to scroll

Banging my head trying to sort out the correct logic for adding simple parallax behavior.
I would like to have a number of elements on a page which start out with their top offset a certain distance (e.g. 300px). Then as you scroll down the page, once the top of the element is revealed it will slowly shift upwards (tied to scroll) until the top of element reaches middle of viewport at which time it's top offset is 0 and it remains in place.
I tried using third party script (Scroll Magic, Stellar, etc), but when I couldn't get it right now I'm trying custom code:
https://jsfiddle.net/louiswalch/5bxz8fku/1/
var $Window = $(window);
var offset_amount = 400;
var window_height = $Window.height();
var window_half = (window_height/2);
var sections = $('SECTION.reveal');
sections.each(function() {
var element = $(this);
// Make sure we always start with the right offset
element.css({top: offset_amount});
$Window.bind('scroll', function() {
var viewport_top = $Window.scrollTop();
var viewport_middle = viewport_top + (window_height/2)
var viewport_bottom = viewport_top + window_height;
var element_top = element.offset().top;
if (element_top > viewport_top && element_top <= viewport_bottom) {
var distance_to_middle = (element_top - viewport_middle);
var amount_to_middle = (distance_to_middle / window_half);
console.log(amount_to_middle);
if (amount_to_middle >= 0) {
element.css({top: (offset_amount * amount_to_middle)+ 'px'});
} else {
// ? Lock to end position ?
}
}
});
});

jsBin demo 1. (margin space effect on both enter and exit)
jsBin demo 2. (preserve 0 margin once touched)
Instead of targeting the section elements, (create and) target their first child elements,
otherwise you'll create a concurrency mess trying to get the top position but simultaneously modifying it.
Also, you cannot rely on fixed 300px margin (i.e: if window height is less than 500px, you're already missing 100px). That space can vary when the screen height is really small, so you also need to find the idealMarg value.
var $win = $(window),
$rev = $('.reveal'),
winH2 = 0,
winSt = 0;
function reveal() {
winSt = $win.scrollTop();
winH2 = $win.height()/2;
$rev.each(function(i, el){
var y = el.getBoundingClientRect().top,
toMiddleMax = Math.max(0, y-winH2),
idealMarg = Math.min(300, toMiddleMax),
margMin = Math.min(idealMarg, idealMarg * (toMiddleMax/winH2));
$(">div", this).css({transform: "translateY("+ margMin +"px)"});
});
}
$win.on({"load resize scroll" : reveal});
*{box-sizing:border-box; -webkit-box-sizing:border-box;}
html, body{height:100%; margin:0;}
section > div{
padding: 40px;
min-height: 100vh;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<section>
<div style="background-color:red">1</div>
</section>
<section class="reveal">
<div style="background-color: yellow">2</div>
</section>
<section class="reveal">
<div style="background-color: orange">3</div>
</section>
<section class="reveal">
<div style="background-color: pink">4</div>
</section>
I've used in HTML just a <div> logically, that has to be the one and only first child of a section parent.
You're welcome to tweak the above code to make it more performant.

Hey so here is my go at an awnser.
http://jsbin.com/wibiferili/edit?html,js,output
The jist of it is as follows.
JS
var $Window = $(window),
parallaxFactor = 2;
$('.parallaxblock').each(function(a,b){
var element = $(b);
element.css("top",element.data("pOffset") + "px");
$Window.bind('scroll', function() {
var pos =
// Base Offset
element.data("pOffset")
// parallaxFactor
- ($Window.scrollTop() / parallaxFactor);
pos = pos < 0 ? 0 : pos;
element.animate({"top": pos + "px"},10);
return;
});
});
Styles
body{
height: 4000px;
}
.parallaxblock{
position:fixed;
background:#999;
opacity:.5;
}
Example Usage
<div class="parallaxblock" data-p-offset=100>Im A Block</div>
<div class="parallaxblock" data-p-offset=200>Im Also Block</div>
<div class="parallaxblock" data-p-offset=1500>Im Another Block</div>
So by checking the offest its never lower then 0 we can lock it at the top of the screen once it reaches it.
I get the offset amount of the data tag on the div.
If you wanted to change the rate of scroll in different posistions you could change the parallax factor at a certain percentage of screen height.
Hope this helps.

Calculating child div top position - why does parent offsetHeight need to be subtracted?

I have created a magnifier in pure js. What I discovered in needing to translate the mouse position of a div relative to its parents is that in calculating the top for the overlaying magnifier div, the offsetTop works differently than the offsetLeft. After adjusting for what should be the top, I need to subtract the whole container div's offsetHeight.
The line in the code in question is this:
magnifier.style.top = yPosition - container.offsetHeight + "px";
Why do I need to subtract container.offsetHeight?
I know I've read something regarding this, but can't find it.
Disclaimers This code is working. I am asking so I (and those following) can understand how the box model works.
I know there are jQuery alternatives that are more cross browser reliable. I like to code it myself so that I can learn how it all works. If you see something which is not compatible for a modern browser, feel free to comment.
Lastly, For anyone using this, I removed code from this example to adjust for transforms. For example, if the wrapper has a transform: translate(-50%, 0); to center the wrapper horizontally, you will need to add the resulting amount of the translation (which translates to the wrapper's left position) back into the calculation.
I have created a jsfiddle here. I left more comments in the Fiddle as to methodology if anyone is interested.
<!DOCTYPE html>
<html>
<head>
<script type="text/javascript" src="../css/ms.js"></script>
<style type="text/css">
/********************/
body {
background-color: #FFF;
margin-left: 30px;
margin-top: 10px;
}
.wrapper {
position: absolute;
left: 100px;
}
#container {
width: 527px;
height: 450px;
border: 5px black solid;
overflow: hidden;
background-color: #F2F2F2;
cursor: pointer;
}
#image {
width: 527px;
height: 450px;
}
#magnifier {
width: 250px;
height: 250px;
overflow:hidden;
position:relative;
z-index: 1000;
border: solid 1px;
}
#magnifier img {
position: absolute;
}
</style>
</head>
<body>
<div class="wrapper" id="wrapper">
<div id="container">
<img id="image" src="../docs/grade-2/jpg/g2-bb-saints-francis.jpg">
<div id="magnifier" class="magnifier">
<img id="imagecopy">
</div>
<br>
</div>
<input type="button" value="Zoom" onClick="initmagnifier('magnifier', 'image', 'imagecopy');"><br>
</div>
<script>
function initmagnifier(magnifier, image, imagecopy){
var magnifier = document.getElementById("magnifier");
var container = document.getElementById("container");
var wrapper = document.getElementById("wrapper");
var img = document.getElementById(image);
var imgcopy = document.getElementById(imagecopy);
var zoom = 2;
container.addEventListener("mousemove",
function(e){
movemagnifier(e, img, imgcopy, magnifier, container, wrapper, zoom)
}, false);
var src = img.src;
imgcopy.src = src;
var src2 = imgcopy.src;
imgcopy.height = img.height * zoom;
imgcopy.width = img.width * zoom ;
}
function movemagnifier(e, img, imgcopy, magnifier, container, wrapper, zoom) {
// to get the left & top of the magnifier
// position needs to be adjusted for WRAPPER & CONTAINER top and left
// gets the top and left of the container
var containerPosition = getPosition(e.currentTarget);
// adjust out the CONTAINER's top / left
// Then takes 1/2 the hight of the MAGNIFIER and subtracts it from the MOUSE position to center MAGNIFIER around the MOUSE cursor
var xPosition = e.clientX - containerPosition.x - (magnifier.clientWidth / 2);
var yPosition = e.clientY - containerPosition.y - (magnifier.clientHeight / 2);
magnifier.style.left = xPosition + "px";
magnifier.style.top = yPosition - container.offsetHeight + "px";
// Adjust for zoom
// adjust the MAGNIFIER's top/left at an equal pace to the zoom amount
var yTravel = (e.clientY - containerPosition.y ) * (zoom - 1);
var yimgPosition = -(yPosition - container.clientTop + yTravel);
imgcopy.style.top = yimgPosition + "px";
var xTravel = (e.clientX - containerPosition.x) * (zoom - 1); // * 1.5
var ximgPosition = -(xPosition + xTravel);
imgcopy.style.left = ximgPosition + "px";
console.log('****');
console.log(e.clientY); // MOUSE POSTION
console.log(containerPosition.y);
console.log(wrapper.offsetTop);
console.log(wrapper.clientHeight);
console.log(container.offsetTop);
console.log(container.clientHeight);
console.log(yPosition);
console.log(container.offsetHeight);
console.log(magnifier.style.top);
}
function getPosition(element) {
var xPosition = 0;
var yPosition = 0;
// element is the CONTAINER
// This calculates the postion of the element (CONTAINER) TOP & LEFT relative to ALL parents
while (element) {
// if transform: translate in place for x and y,
// add it back as it skews the offsetLeft offsetTop values by the translate amount
xPosition += ((element.offsetLeft) - element.scrollLeft);
yPosition += ((element.offsetTop) - element.scrollTop);
element = element.offsetParent;
}
return { x: xPosition, y: yPosition };
}
</script>
</body>
</html>

It took me longer than I care to admit, but I have found the reason. In your fiddle you position the #magnifier-element relative, which means you have to move it from its 'natural' position, which is below the image inside the container.
So with every move you have to compensate for this, by pulling the #magnifier to the top/left position of the container, the left position already matches, but the 'natural' top position of the #magnifier is the full height of the container, as you calculate from the top/left position of the #container, you need to subtract the #container height.
A simple fix is to add position: relative to the #container and change position: relative on the #magnifier to position: absolute.
This will give you the expected coordinate system for the #magnifier as top: 0; left: 0 for the absolute positioned element is the top left corner of the its relative parent (the first positioned parent element, in this case #container).
a working example without the need to to subtract container.offsetHeight.
While I'm at it, you may want to look into the Element.getBoundingClientRect function, as you can get all information you need to determine the position in a single call.

Custom scroll bar flows out of screen

I'm trying to make my own scroll bar, and so far it's working fine, for this small exception.
When I reach the bottom of the page, the bar handle goes under the viewport.
Gif of what's happening:
I know it has to do with the CSS, but I'm unsure on how to set it correctly. Foundation's .off-canvas-content has a class added named .full-height, and the height property is added so that the scroll bar won't be tied to that element.
The scroll bar markup is added to div.content, which is where all the remaining content will be.
I'm trying to get the handle bar to stop at the bottom of the container, when the user has scrolled all the way of the bottom of the document, but haven't found a way to do this correctly.
CSS:
.scroll-container {
position: fixed;
right: 50px;
top: 0;
height: 100%;
width: 7.5px;
background-color: rgba(55,55,55,.3);
}
.scroll-bar {
position: relative;
top: 0;
height: 20%;
width: 100%;
background-color: #6A1B9A;
}
.full-height {
height: 100vh;
min-height: 100vh;
}
.content {
float: left;
width: 100%;
height: 100%;
display: block;
padding: 10px 20px;
overflow-y: scroll;
}
JS:
(function($) {
$.fn.scroller = function() {
var self = this,
scrollBarDrag = false,
docHeight = $(document).height();
var scrollContainer = document.createElement('div'),
scrollBar = document.createElement('div');
scrollContainer.className = 'scroll-container';
scrollBar.className = 'scroll-bar';
scrollContainer.appendChild(scrollBar);
self[0].appendChild(scrollContainer);
self.on('scroll', function() {
var top = $(this).scrollTop();
setScrollBarTop(top);
});
function setScrollBarTop (top) {
scrollBar.style.top = top + 'px';
}
};
})(jQuery);
I tried using plugins for this, but they don't simulate the scroll bar as intended (missing mouse wheel click and drag to scroll), so I decided to make my own, lightweight version of it. Any suggestions about using plugins, albeit appreciated, will be disregarded and not accepted as an answer.
With absolute positioning:

I think you forgot to account for the scrollbar's height. Lets say the scrollbar is 100px tall and your page is 500px tall, you are only able to move the scrollbar by 400px, not all 500.
Find out the difference between your scrollbar height and the document height, find the ratio of how they compare, and apply that to your new scrollbar position.
havent tested it, but something like;
var heightToWorkWith = docHeight - scrollBarHeight;
var ratio = heightToWorkWith / docHeight;
function setScrollBarTop (top) {
scrollBar.style.top = (top * ratio) + 'px';
}

Have found a solution regarding this, was quite a bit of trial and error, but managed to find it in the end. Hope it can be of use to some of you.
Edited it to a more revised version.
self.on('scroll', function() {
elHeight = self.height();
docHeight = $(document).height();
var sTop = self[0].scrollTop;
var sHeight = self[0].scrollHeight;
var sBHeight = $(scrollBar).height();
var ratio = (elHeight - $(scrollBar).height()) / elHeight;
var currentPosY = (sTop / (sHeight - docHeight)) * 100;
scrollBar.style.top = (currentPosY * ratio) + '%';
});

You can get scroll ratio by doing this:
(thumbHeight / containerHeight) + 1
containerHeight is not the scroll area height, but the actual overflow: hidden container.
When you get the scrollTop value just multiply it with your ratio. Like this:
thumbPosition.top = el.scrollTop * ratio + 'px';

Setting <div> size to be the same as window?

I'm trying to use jQuery to set the height of a div so that it takes up the entire window + the height of a header (so that you can scroll the header off the page) but no more than that. I would think the height of the div would be the height of the window + the height of the header I'm trying to hide.
When I set the div to window height, however, it creates overflow. Here's the rough code:
var $body = $("#body"),
$container = $("#container"),
$window = $(window),
$content = $("#mainContent"),
$header = $("#header"),
bodyHeight = window.innerHeight + $header.height();
$body.css("height", window.innerHeight);
$container.css("height", bodyHeight);
div {
display: block;
width: 100%;
margin: 0;
}
#body {
overflow-y: scroll;
}
#container {
overflow-y: hidden;
}
#header {
overflow: hidden;
}
#navbar {
height: 10px;
background-color: brown;
}
#mainContent {
height: 200px;
overflow-y: scroll;
}
#contentP {
height: 400px
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<div id="body">
<div id="container">
<div id="header">
<h1>Header</h1>
</div>
<div id="navbar">
</div>
<div id="mainContent">
<p id="contentP">This is content</p>
</div>
</div>
</div>
Why is there overflow if the div is sized to fit in the window?
EDIT: So far, answers haven't helped. This is the site I'm working on. It's joomla. I want the nav bar to lock at the top of the screen.
$(document).ready(function() {
//Declare some variables
var $window = $(window),
$body = $(".body"),
$mainContent = $("#maincontent"),
headerGap = parseFloat($("#headerimg").css("margin-top")),
headerHeight = headerGap + $("#header").height() + parseFloat($("#navbar").css("margin-top")),
navbarHeight = $("#navbar").height(),
footerHeight = $("#footer").height();
//set the height of the body and the maincontent
resizePage();
//Set the listeners for resizing and scrolling
$window.resize(resizePage);
$window.scroll(scrollHandler);
//When you scroll, see if the navbar is at the top. Set maincontent overflow
//to scroll when the navbar is at the top of the window. Set it to hidden otherwise
function scrollHandler() {
if ($window.scrollTop() < headerHeight - 1) {
$mainContent.css("overflow", "hidden");
} else {
$mainContent.css("overflow", "auto");
}
}
//Set the body and the mainContent to be the correct sizes when the window size is changed. In theory, the body should be:
// windowHeight + headerHeight
// maincontent should be:
// windowHeight - (headerHeight + navbarHeight + footerHeight)
// But that doesn't quite work out.
function resizePage() {
//Deal with the changing CSS due to media queries
if ($(window).width() > 768) {
headerGap = parseFloat($("#headerimg").css("margin-top"));
headerHeight = headerGap + $("#header").height() + parseFloat($("#navbar").css("margin-top")) - 1;
$(".nav.menu.nav-pills").css("width", "92.5%");
}
else {
headerHeight = $("#header").height();
$(".nav.menu.nav-pills").css("width", $window.width());
}
//The header and navbar height change at certain sizes, so grab them again to be safe.
navbarHeight = $("#navbar").height();
footerHeight = $("#footer").height();
var windowHeight = $window.height(),
contentHeight = windowHeight - (footerHeight + navbarHeight);
//if we account for headerHeight too, maincontent is too big
resizeContent(contentHeight);
resizeBody(windowHeight);
}
//The body should take up the whole height of the window, plus the header
//and margin heights at the top. This way, you scroll to the navbar.
// But it doesn't work this way.
// -7 and -27 are from eyeballing it.
function resizeBody(windowHeight) {
if($window.width() > 728) {
$body.css("height", windowHeight - 7);
}
else {
$body.css("height", windowHeight - 27);
}
}
// The content should go from the bottom of the navbar to the bottom of the footer.
//
function resizeContent(contentHeight) {
$mainContent.css("top", (headerHeight + navbarHeight));
$mainContent.css("bottom", (0 - headerHeight));
//For the background slideshow on the Furniture page
// Again, + 5 was eyeballed
$("div.moduletable").css("height", contentHeight + 5);
if ( (contentHeight + 5) < ($(window).width()) /2 ) {
$(".wk-slideshow img").css("width", "100%");
$(".wk-slideshow img").css("height", "auto");
}
else {
$(".wk-slideshow img").css("height", contentHeight + 5);
$(".wk-slideshow img").css("width", "auto");
}
}
});
It works for a lot of sizes, but one you get to small resolutions it falls apart.
EDIT 2: I was able to get the effect I was going for by adding another div. I set the body to be the height of the window and the new div to be the size of the body + the height of the header. The body has "overflow-y: scroll". The container would have "overflow-y: hidden" (See updated snippet). This doesn't totally answer my question, but at least it helps?

I've taken a look at your code and altered it. Try this and see if this is what you're looking for.
In my example i'm looking for the element by getElementById and then I set it's style.height to window.innerHeight - 10px without taking the 10px it wouldn't show the border fully on the page. So you just remove 10px's. The example has been tested on different screen sizes.
Javascript example:
function autoResizeDiv() {
document.getElementById('body').style.height = window.innerHeight - 10 + 'px';
console.log(window.innerHeight - 10 + 'px');
}
window.onresize = autoResizeDiv;
autoResizeDiv();
#body {
display: block;
border: 5px solid black;
}
body {
overflow: hidden;
margin: 0;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<div id="body">
</div>

The following worked for me:
$(".body").height($(window).height());

I figured out the biggest problem. I was using some absolutely positioned elements without giving a parent any other position. This made things show up wonky when I was trying to size other things. I also needed to have an extra div as a container for all the content on the page that would be the height of the window + the height of the header.
Thanks to everyone who answered, it helped!