How to center image in the specific div according to current viewport position?

Question

I am trying create nice animation during loading content using ajax. I want to use display icon during reloading div with \"Content\", however I can\'t figured out is it possibl

Answer 1

This works best for me :)

function loadNewContent(){
 $(".loaderCont").removeClass("loading")
}

$(document).ready(function () {

 $("#hide_button").on("click", function () {
      $(this).closest(".bottom").toggleClass("left_hided");
      $(".loaderCont").toggleClass("left_hided2");
 });

 $("#filter1,#filter2,#filter3,#filter4").on("click", function() {
     $(".loaderCont").addClass("loading");
     setTimeout(loadNewContent, 2000);
 });
});

CSS:

.header {
    background-color: Green;
    width: 100%;
    margin-bottom: 20px;
     height: 100px;
}
.left {
    background-color: Red;
    float: left;
    width: 100px;
}
.left_hided .left{
    margin-left: -85px;
}
.right {
    background: Aqua url("http://i.imgur.com/ifyW4z8.png") 50% repeat-y;
    width: calc(100% - 140px);
    float: right;
}

.left_hided .right{
     width: calc(100% - 55px);
}

input{
    float:right;
}

.loaderCont {
    background-color: rgba(255, 0, 0, 0.6);
    height: 100%;
    width: calc(100% - 140px);
    position: fixed;
    right: 0;
    top: 0;
    z-index: -1;
}

.left_hided2 {
     width: calc(100% - 55px);
}

#loader {
    background: url(http://i.stack.imgur.com/FhHRx.gif) no-repeat center center;
    position: relative;
    top: calc(50% - 16px);
    left: calc(50% - 16px);
    display: block;
     height: 32px;
     width: 32px;
}

.loading {
    z-index: 9001;
}

JSFiddle: http://jsfiddle.net/ZRwzr/1/

Answer 2

You do not need to do so much of scripting to assign it a position. You can do it with simple css.

Just make the loader relative to its parent. Assign a height and width and do the following css part.

.loader{
    position: relative;
    top: -half of the height;
    left: -half of the width;
    margin-top: 50%;
    margin-left: 50%;
}

works with every device

Answer 3

.loading #img_loading {
    position: fixed;
    top: 50%;
    left: calc(50% + 55px);
    display: block;
}

The above will solve the half of the problem, you need to update the left dynamically with javascript.

Answer 4

use z-index example:-

 <div style="z-index:100;">loading image</div> 

Answer 5

For this to work to your requirements you will need to use JavaScript to determine where the loading image needs to be placed over the visible part using a fixed position div and then reposition it when the user resizes the window or scrolls the window so it is always in the desired position.

$(window).scroll(function() {
    scrolling();
});

$(window).resize(function() {
   scrolling(); 
});

scrolling();

function scrolling() {
    var windowHeight = $(window).height();
    var scrollTop = $(window).scrollTop();
    var offsetTop = $('#thediv')[0].offsetTop;
    var offsetHeight = $('#thediv')[0].offsetHeight;

    var offsetWidth = $('#thediv')[0].offsetWidth;

    var top = offsetTop - scrollTop;
    top = top < 0 ? 0 : top;

    var bottom = (scrollTop + windowHeight) - (offsetHeight + offsetTop);
    bottom = bottom < 0 ? 0 : bottom;

    $('.image').css('top', top);
    $('.image').css('bottom', bottom);
    $('.image').css('width', offsetWidth);
}

Please note that if you change the width of the div you will always need to call the scrolling() function so that it can recalculate the position.

I also added the loading image as a background image to the fixed div so that we can use CSS to centre it.

.image {
    position: fixed;
    text-align:center;
    background-image:url('http://i.stack.imgur.com/FhHRx.gif');
    background-repeat:no-repeat;
    background-position:center center;
    background-color:rgba(255,255,255,.4);
}

Here is the JSFiddle http://jsfiddle.net/QWB9x/89/