Develop Reference

jquery increase/decrease image contrast on scroll

This site I am developing is using HTML5, CSS3, Bootstrap 4, and Jquery. I would like to have a scroll effect on a full-screen background-image that is at the very top of my page (100vh hero banner type thing). I am trying to gradually increase the contrast (css filter: contrast(some%)) of an image as the user scrolls down (its fine if the image is completely unrecognizable by the time it leaves viewport).
I have some Jquery that somewhat does the effect I am looking for, however I would like the effect to be more gradual.
The main issue I am having is that when the user scrolls back to the top of the page the contrast value gets set to 0% leaving a completely grayed out image. What I would like is for the contrast to gradually decrease back to normal (100%) as the user scrolls back up all the way to the top of the page.
I have set up a very simplified codepen. I couldn't get a css background-image url value to reference an external link from codepen, so I am targeting the effect on a full screen image ().
Thanks!
Link to the Pen: [codepen-link][1]
[1]: http://codepen.io/wdzajicek/pen/MVovZE
See code below in snippet
$(document).ready(function (){
$(window).scroll(function(){
var pixelstop = $(window).scrollTop();
$(".myimage ").css("filter", "contrast(" + pixelstop + "%)");
});
});
.header {
height: 100vh;
}
.myimage {
position:absolute;
top: 0;
left: 0;
min-width: 100%;
width; 100%;
z-index: -1;
}
.jumbotron {
position: relative;
background-color: unset;
margin-top: 150px;
z-index: 999;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<header class="header text-center">
<img src="https://raw.githubusercontent.com/wdzajicek/portfolio/master/assets/img/header-bg.jpg" class="myimage" alt="">
</header>

There is the main problem in $(window).scrollTop(); it will return 0 value
that's why contrast value gets set to 0% leaving a completely grayed out image
var pixelstop = $(window).scrollTop();
replace the code with
var pixelstop = 100+100*$(window).scrollTop()/$(window).height();
don't just copy this code please understand thanks.

$(document).ready(function (){
$(window).scroll(function(){
var pixelstop = 100+100*$(window).scrollTop()/$(window).height();
console.log(pixelstop);
$(".myimage ").css("filter", "contrast(" + pixelstop + "%)");
});
});
.header {
height: 100vh;
}
.myimage {
position:absolute;
top: 0;
left: 0;
min-width: 100%;
width; 100%;
z-index: -1;
}
.jumbotron {
position: relative;
background-color: unset;
margin-top: 150px;
z-index: 999;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script>
<header class="header text-center">
<img src="https://raw.githubusercontent.com/wdzajicek/portfolio/master/assets/img/header-bg.jpg" class="myimage" alt="">
</header>
100 is default value of filter contrast not 0. that's why the background is grey out because it reaches zero.

Slider of images with undefined height

I'm trying to create a slider of images (previous/next) so the images slide to the left when I click "previous" and to the right when I click "next" with 0.5s of slowness, so it takes some animation. And when I reach the last image and click "next", I want images to "run backwards" to the first one, the same when I'm in the first one and click "previous", so it "run forward" until the last one.
I want the same behaviour this JSFiddle shows. (but I don't need the timer to move images automatically and don't need the "triggers" buttons, just "previous" and "next").
The problem here is that my images don't have fixed size. I define a width in percentage and can't define a height because I have responsive design, the image resizes as I resize the browser window.
The jQuery to previous/next actions is pretty easy, but I just can't find a way to add this animation when I remove/add the "active" class to my images (so they become visible or not).
I have already tried putting all images side by side and showing only the first one (setting container width equals to image width), so when I click "next" I just "move" the container to the left so it begins to display the next image, but it doesn't work because once I can't define the height of the images, they will appear underneath each other, not side by side.
JSFiddle
HTML
<div class="images">
<img class="active" src="1.jpg">
<img src="2.jpg">
<img src="3.jpg">
</div>
<div class="previous">previous</div>
<div class="next">next</div>
CSS
img {
width: 100px;
display: none;
float: left;
}
img.active {
display: block;
}
jQuery
$('.next').on('click', function() {
var active = $('img.active');
var next = active.next('img');
if (next.length) {
active.removeClass('active');
next.addClass('active');
} else {
active.removeClass('active');
$('.images img:first').addClass('active');
}
});

Well the problem is the height for sliding.
First you need to have an element which is the "picture frame" which hold all the other images. That's important.
For better imagination a picture:
Now you have several technics to show and hide images. One could be to set the opacity. When using transition: opacity .15s ease-in-out; The one Picture is fading out and the next on is fading in.
For the slideshow effect is given to the position of the visible image to its width to the left and the image previously purely new to his wide to the right and then to 0. Thus, moves the current picture on the left the frame out and the new comes out right in.
And here is the difficulty if the height is not the same. If the current image 300px high and the new 400px, so the image frame here would adjust his height immediately once the new image start to be visible.
The content below would start to jump with each slide.
Is that so desired???
If yes, I can make you an example how it works.

You can actually do this in Pure CSS!
You use an ID and a label (with a for attribute=for the targeted id)
That's basically it. All you have left is to style it! (Forked from Joshua Hibbert's Pen)
body {
background: #f7f4e2;
}
/* Slides */
.slider input {
display: none;
}
/* Buttons */
.slider label {
display: none;
cursor: pointer;
position: absolute;
top: 6em;
left: 50%;
transform: translateX(-50%);
color: #fff;
background: #000;
padding: 1.36em .5em;
opacity: .6;
font-size: 19px;
font-family: fantasy;
font-weight: bold;
transition: .25s;
}
.slider label:hover {
opacity: 1;
}
.previous {
margin-left: -188px;
}
.next {
margin-left: 188px;
}
#slide1:checked ~ .buttons .slide1 {
display: block;
}
#slide2:checked ~ .buttons .slide2 {
display: block;
}
#slide3:checked ~ .buttons .slide3 {
display: block;
}
#slide4:checked ~ .buttons .slide4 {
display: block;
}
/* Images */
.slider {
position: absolute;
top: 50%;
left: 50%;
width: 400px;
height: 300px;
margin-top: -150px;
margin-left: -200px;
white-space: nowrap;
padding: 0;
float: left;
transition: .25s;
overflow: hidden;
box-shadow: 0 0 0 3.12px #e8e8e8,
0 0 0 12.64px #eaebe4,
0 0 0 27.12px #000,
0 24px 3.824em 5.12px #000;
}
.slide {
width: 500em;
transition: .25s;
}
.slider img {
float: left;
width: 400px;
height: 300px;
}
#slide1:checked ~ .slide {
margin: 0;
}
#slide2:checked ~ .slide {
margin: 0 0 0 -400px;
}
#slide3:checked ~ .slide {
margin: 0 0 0 -800px;
}
#slide4:checked ~ .slide {
margin: 0 0 0 -1200px;
}
<div class="slider">
<input type="radio" name="slide" id="slide1" checked="true" />
<input type="radio" name="slide" id="slide2" />
<input type="radio" name="slide" id="slide3" />
<input type="radio" name="slide" id="slide4" />
<div class="buttons">
<!-- Slide 1 -->
<label for="slide4" class="slide1 previous"><</label>
<label for="slide2" class="slide1 next">></label>
<!-- Slide 2 -->
<label for="slide1" class="slide2 previous"><</label>
<label for="slide3" class="slide2 next">></label>
<!-- Slide 3 -->
<label for="slide2" class="slide3 previous"><</label>
<label for="slide4" class="slide3 next">></label>
<!-- Slide 4 -->
<label for="slide3" class="slide4 previous"><</label>
<label for="slide1" class="slide4 next">></label>
</div>
<div class="slide">
<img src="http://dribbble.s3.amazonaws.com/users/322/screenshots/872485/coldchase.jpg">
<img src="http://dribbble.s3.amazonaws.com/users/322/screenshots/980517/icehut_sm.jpg">
<img src="http://dribbble.s3.amazonaws.com/users/322/screenshots/943660/hq_sm.jpg">
<img src="http://dribbble.s3.amazonaws.com/users/322/screenshots/599584/home.jpg">
</div>
</div>
Although this method is the most compatible (except for old versions of IE) and depending on how you animate it this method can be more time consuming than a JS method, but can also be faster, it just depends on how you want the animations to go, or you could use a css library that does this for you.
Here are some css image sliders I recommend.
10 Amazing Pure CSS3 Image Sliders
http://bashooka.com/coding/pure-css3-image-sliders/
Pure CSS Image Slider Without Javascript #Codeconvey is a good solution for what you're looking for, but lots of CSS
http://codeconvey.com/pure-css-image-slider/
The downside to these along with what you're working on is that you can't touch to slide on a phone or tablet which is more common now a days with photo galleries.
I recommend checking out Fotorama it's amazing! :)

Perhaps not the ideal situation but at least it will give you an idea. you can use the animation function of jQuery and I also changed your code a bit. See demo here
Within your HTML I would say this:
<div id="images">
<div class="images-wrapper">
<img src="http://www.cutestpaw.com/wp-content/uploads/2016/02/In-the-spotlight.jpg">
<img src="http://www.cutestpaw.com/wp-content/uploads/2016/02/Bath-time-with-ducky.jpg">
<img src="http://www.cutestpaw.com/wp-content/uploads/2016/03/FB_IMG_1452981788903.jpg">
<img src="http://www.pictures-of-cats.org/images/Pixiebob-cat-list-of-cat-breeds-pictures-of-cats.jpg" />
</div>
</div>
<div class="previous">
previous
</div>
<div class="next">
next
</div>
and within your jQuery code you can animate the width:
$('.images-wrapper img:gt(0)').hide();
$('.next').click(function() {
$('.images-wrapper img:first-child').animate({width:'toggle'},350).next().fadeIn().end().appendTo('.images-wrapper');
});
$('.previous').click(function() {
$('.images-wrapper img:first-child').animate({width:'toggle'},350);
$('.images-wrapper img:last-child').prependTo('.images-wrapper').fadeOut();
$('.images-wrapper img:first-child').fadeIn();
});
With this implementation the whole process of changing and adding the active class to the image is removed and replaced by animation functions

Simplest solution (I think) is to force the items to be of the same size, by placing them in a div. You can even have the div show the image without the use of an img tag, by using the background-image CSS feature (see http://www.w3schools.com/css/css3_backgrounds.asp for more details).
The item CSS could look like:
.item {
background-size: contain;
background-position: center;
}
and in each item in the HTML:
<div class='item' style='background-image: url(img1.jpg)' />
<div class='item' style='background-image: url(img2.jpg)' />
<div class='item' style='background-image: url(img3.jpg)' />

I finally got there.
HERE is the fiddle with the solution I developed.
The main problem in the implementation of this image slider was that images, althought were all the same size, have dynamic width (defined in % on CSS) and dynamic height (not defined on CSS).
The solution was basically put an "fake" image (with opacity: 0) inside my container so the container get the actual size of images I will use in the slider; put a div to "hold" the real images with position: absolute and give it a width calculted by number of images * 100%; and for last, give each image in my slider a width of x%, based on number of images.
In the jQuery, I "move" the "images holder div" always by %, never by static values, once the width of everything can change if I resize the window.
If you start to slide the images to the left and right and then resize the window, you will see that it continues to work perfectly.

I have implemented using css3 animations. However this will require manipulating animation values in css every time a slide gets added or removed.
#keyframes slideAnim {
0% {
transform: translateX(0)
}
12.5% {
transform: translateX(0%);
}
25% {
transform: translateX(-25%);
}
37.5% {
transform: translateX(-25%)
}
50% {
transform: translateX(-50%)
}
62.5% {
transform: translateX(-50%)
}
75% {
transform: translateX(00%);
}
89.5% {
transform: translateX(00%)
}
100% {
transform: translateX(00%)
}
}
Here the animation values are set such that there is a pause between slide transitions. I have added a parent frame to show only one slide at a time.
Please refer this fiddle.

css show button over image

I am making a simple reactjs app where I need to put a button over image.
My html looks like:
<div className={"panel-body"}>
<img className={"img-responsive center-block"}
src={album.photos.data[0].source} />
{(this.state.isMouseInsideID === album.id) ? <button>Your Button</button> : null}
</div>
Its all fine except button is shown below the image.
But I want to show the button over the image or in the middle of the div
How can I make this work ?

make button position relative and use z-index: maybe it will be helpful for you.

If you want to center the button in a div, while there is a background image to the div. I would suggest, to assign a background image for the div, rather than inserting an image into the div. Check out the fiddle:
http://jsfiddle.net/49s505sa/1/
HTML:
<div id="wrapper">
<button type="button">Your Button</button>
</div>
CSS:
#wrapper {
width: 100%;
height: 400px;
border: 1px solid black;
background: url('http://placehold.it/350x150') /*assign image, for demo purposes */
}
button {
height: 20px;
position: relative;
margin: -20px -50px;
width: 100px;
top: 50%;
left: 50%;
}
So, inside the render method
var style = {
backgroundImage: 'url(' + album.photos.data[0].source+ ')'
}
<div className={"panel-body"} style={style}>
{(this.state.isMouseInsideID === album.id) ? <button>Your Button</button> : null}
</div>
In this way, we will dynamically assign images to particular divs. And wont have to worry too much about styling.
Hope that helps!

Use z-index properties
The z-index property in CSS controls the vertical stacking order of
elements that overlap. As in, which one appears as if it is physically
closer to you. z-index only effects elements that have a position
value other than static (the default).. Note: z-index only works on
positioned elements
(position:absolute, position:relative, or position:fixed).
img {
position: absolute;
left: 0px;
top: 0px;
z-index: 10;
}

Crossfade images with jQuery

Hi I'm trying to accomplish a crossfade effect for my banner images on my homepage. I'm doing this with jQuery and the fading effect is working fine.
This is my code:
<script>
function bannerImages(){
var $active = $('.banner-test .banner_one');
var $next = ($active.next().length > 0) ? $active.next() :
$('.banner-test img:first');
$next.css('z-index',2);//move the next image up the pile
$active.fadeOut(1500,function(){//fade out the top image
$active.css('z-index',1).show().removeClass('active');//reset the z-index and unhide the image
$next.css('z-index',3).addClass('active');//make the next image the top one
});
}
$(document).ready(function(){
// run every 7s
setInterval('cycleImages()', 7000);
})
</script>
As I said this is working fine however I've got one issue. In order for this to work I need to apply position:absolute to the .banner-test img class. Now I've also got another div within the .banner-test class to display some text on top of the banner image.
The code looks like this :
<div class="banner-test">
<img class="banner_one" src="../image.jpg" alt="" />
<img src="../image2.jpg" alt=""/>
<div id="text">
<p class="text1">Sample Text</p>
</div>
</div>
And the css for the #text :
#text {
position:absolute;
bottom:35px ;
left:10px;
width:70% ;
background-color:#104E8B;
font-size:1em;
color:white;
opacity:0.95;
filter:alpha(opacity=95); /* IE transparency */
}
.text1 {
padding:13px;
margin:0px;
}
.banner-test {
display: block;
position: relative;
}
So if I apply absolute positioning to the image it messes up the layout with the text (everything is pushed to the top of the page).
Can anybody think of a workaround for this?
EDIT
https://jsfiddle.net/ztrez888/1/embedded/result/ this is the fiddle - if position absolute is applied to the .banner-test img the text disappears

You said: (everything is pushed to the top of the page)
Its because your wrapper element .banner-test doesn't have a static height set. so when you apply a absolute position to the images in it .banner-test get shrink to height of the #text .text1.
Either set a height in the css:
.banner-test {
display: block;
position: relative;
height:200px; /* <--put the height of img */
}
or calculate it with jQuery:
$(document).ready(function(){
var arr = $('.banner-test img').map(function(){ // get the heights of imgs in array
return $(this).height();
}).get(),
h = Math.max.apply(Math, arr); // find out the greatest height in it.
$('.banner-test').css('height', h); // set the height here.
// run every 7s
setInterval('cycleImages()', 7000); // then cycle the images.
});
cycleImages() is been called in the setInterval and you have bannerImages() function on the page. I am assuming you have this cycleImages() function.
Updates:
#text {
position: absolute;
bottom: 30px;
left: 10px;
width: 100px;
background-color: #104E8B;
font-size: 1em;
color: white;
opacity: 0.95;
filter: alpha(opacity=95);
/* IE transparency */
z-index: 5; /* <----change these here*/
left: 10%;
top: 0;
}
Updated fiddle

JS: Resize div when an iframe was clicked?

I have an entire <iframe /> with a div as parent. That iframe came from different domain. How do you resize it bigger (add class in my case) the parent div when the iframe was click? and resize it back when a close button of the iframe is clicked?
I preferred if the button from iframe does the resize but apparently the div cannot be reached INSIDE the iframe, so I have to do it OUTSIDE the iframe.

I had the same problem and wrote a jquery plugin.
https://github.com/BergenSoft/iframeActivationListener
See example:
http://jsfiddle.net/56g7uLub/3/
How to use:
$(document).ready(function ()
{
$('iframe').iframeActivationListener();
$('iframe').on("activate", function(ev) {
$(ev.target).addClass("big");
});
});
This plugin don't use overlaying divs.
It checks if the mouse is on an inactive iframe and starts watching the activeElement of the document.
When it changes to another iframe, the custom event "activate" will be raised.
This is the best solution I found out.

You will have to create some kind of overlay to detect the initial focus event of the iframe. The close button can also be part of your website still if you show it based on class.
http://jsfiddle.net/cxtgn72g/4/
HTML
<div id="iframe">
<div id="overlay"></div>
<div id="close">X</div>
<iframe src="//www.youtube.com/embed/6PRq7CmiWhM?list=PLIOa6mDiSeismsV_7YFti-5XOGRzmofSZ"></iframe>
</div>
JS - Requires jQuery
$("#overlay").click(function() {
$("#iframe").addClass("big");
});
$("#close").click(function() {
$("#iframe").removeClass("big");
});
CSS
#iframe {
width : 500px;
height : 300px;
position : relative;
}
#iframe.big {
width : 600px;
height : 400px;
}
iframe {
width : 100%;
height : 100%;
border : none;
}
#overlay {
position : absolute;
left : 0;
top : 0;
width : 100%;
height : 100%;
}
#close {
display : none;
}
.big #close {
cursor : pointer;
display : block;
position : absolute;
right : 10px;
top : 10px;
content : "X";
background : red;
color : white;
border-radius : 25%;
padding : 8px;
}
.big #overlay {
display : none;
}

Try this:
document.getElementById("myIFrame").onclick = function(){
document.getElementById("myDiv").className = ""; //New Class Name
};
Good Luck!