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Change backgroundImage with javascript for image slideshow.

I'm trying to change the background image of a div depending on it's id and then make a slideshow with a couple of images. I'm able to change the background with javascript but have a hard time figuring out why my loop doesn't work.
main.js
var spotlight = document.getElementById('spotlight');
var pics = ['image1.jpg', 'image2.jpg', 'image3.jpg'];
var totalPics = pics.length;
var i = 0;
function loop() {
if(i > (totalPics - 1)) {
i = 0;
}
spotlight.style.backgroundImage="url(/images/posts/'+pics[i]+')";
i++;
loopTimer = setTimeout('loop()',1000);
}
loop();
I'm using sass, but as javascript is client side this shouldn't work any different I guess? What am I doing wrong in my loop?
I have followed the basic principles found on w3Schools of changing the style with javascript and it works with a static image so my guess is that I have done something wrong in the loop.
Thanks

Change this:
spotlight.style.backgroundImage="url(/images/posts/" + pics[i]+ ")";
and
loopTimer = setTimeout(loop,1000);
See, if that helps.

Try changing your setTimeout to the following
loopTimer = setTimeout('loop', 1000);

How can we make Image Carousel with background Image Property

I'm making an image carousel i'm bounded to use background-image property instead of using
<img src="Image">
tag. my carousel is working if I use img tag . But its not working when I use background-image property, how can I modify my code with background-image property.
see my fiddle :https://jsfiddle.net/korLasen/ and update it please thanks :)
or you can see code here
(function(){
var image = $('#imageSlider');
var imageSet = ['http://www.exposureguide.com/images/top-ten-tips/top-ten-photography-tips-1e.jpg','http://images.clipartpanda.com/cliparts-images-aTqyrB8TM.png'];
var index = 0;
function imageSliderSet(){
image.setAttribute('data-background', imageSet[index]);
index++;
if(index >= imageSet.length){
index = 0;
}
}
setInterval = (imageSliderSet, 2000);
})();

This is quite a strange question... however, I am not one to judge :)
Here is a jsfiddle based on your example. I ended up using jquery for this. I hope this is somewhere near what you were looking for!
This is based on changing every two seconds. To extend that, you can change line 18 in the jquery. Here is the jquery:
$( document ).ready(function(){
var image = $('#imageSlider');
var imageSet = ['http://www.exposureguide.com/images/top-ten-tips/top-ten-photography-tips-1e.jpg','http://images.clipartpanda.com/cliparts-images-aTqyrB8TM.png'];
var index = 0;
window.setInterval(function(){
image.css('background-image', "url('" + imageSet[index] + "')");
index++;
if(index >= imageSet.length){
index = 0;
}
//here you can adjust the time interval for each photo
}, 2000);
});

Using JQuery to create animation frames from PSD layers

I have a PSD file with a bunch of layers that are frames for an animation. How can I create an animation from this using JQuery/JavaScript?
Will I have to save each layer as a separate image, is there a way to have the one image with multiple layers animated? To clarify, I don't want the actual image to move, I just want different layers to be displayed as if they were frames of an animation. What's the standard way this is done with JavaScript?
Thanks!

Here is a fiddle that demonstrates the javascript timer + individual images approach.
Fiddle: http://jsfiddle.net/ZVFu8/2/
The basic idea is to create an array with the names of your images.
var img_name_arr = [];
var img_name_root = "anim-";
var img_name_ext = ".gif";
var num_images = 12;
// init arr of img names assuming frames are named [root]+i+[extension]
for (i = 0; i<=num_images; i++) {
img_name_arr.push(img_name_root + i + img_name_ext);
}
For the animation, use setInterval(). In javascript, an interval executes periodically. You specify the code to execute and the interval at which the code should be run (in milliseconds).
Every time your interval is called, you can display a new image by setting the "src" attribute of the image tag to the next index in the image_name array.
// Create an interval, and save a handle to the interval so it can be stopped later
anim_interval = setInterval(function() {
$("#player").attr("src", s + img_name_arr[(anim_frame++ % num_images)+1] );
}, frame_interval);
Depending on how long your animation is and how large each image file is, it might be necessary to optimize this by pre-loading these images. Before the animation starts, you could create an img tag for each image and hide it. Then, instead of altering the "src" attribute to change the image, you would actually hide the current image and un-hide the next image in the previous image's place.
Here is the full code if you wish to run this locally:
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<a id="anim_control" href="">Start</a>
<img id="player" src="" />
<script>
var s = "http://" + atob("YmVucmlkb3V0LmNvbQ==") + "/";
var img_name_arr = [];
var img_name_root = "anim-";
var img_name_ext = ".gif";
var num_images = 12;
var framerate = 1; // Desired frames per second
var frame_interval = 1000/framerate;
$(function(){
// Document is ready
// init arr of img names
for (i = 0; i <= num_images; i++) {
img_name_arr.push(img_name_root + i + img_name_ext);
}
var anim_interval = null;
var playing = false;
var anim_frame = 0;
// Define an interval that will execute every [frame_interval] milliseconds
$("#anim_control").on("click", function(e) {
e.preventDefault();
if (playing == true) {
playing = false;
$(this).html("Start");
clearInterval(anim_interval);
} else {
playing = true;
$(this).html("Stop");
anim_interval = setInterval(function() {
//console.log(s + img_name_arr[(anim_frame++ % num_images)+1]);
$("#player").attr("src", s + img_name_arr[(anim_frame++ % num_images)+1] );
}, frame_interval);
}
});
});
</script>
<style>
#player {
width: 320px;
height: 240px;
border: 1px solid #000;
}
</style>

Chrome doesn't always repeat events with JavaScript setInterval()

I want to display several images of the same size at the same position, one at a time, with a 5s interval between each change. To do so I've used jQuery.Timer, that uses setInterval() to call some show_next_image() function every 5s.
It actually does work with IE, Opera, Safara, Firefox and.. partly with Google Chrome. It's not working with Google Chrome if I open a new window and directly type my website URL: it'll show the second image and stop. And with any other situation (reload, from another link, not right after opening a new window) it'll badly work: one can see the back image before the front image is shown.
Thus I'm wondering whether I've done something wrong with my JavaScript source. What I do is I use a front and a back image. When I want to show the next image, the back img source is set to the new image, and the front image is faded out while the back one is faded in through jQuery. You can check it out at http://www.laurent-carbon.com/ (in French). The two img are identified with bg1 and bg2.
var images = ["/img/IMG_0435bg.jpg", "/img/IMG_0400bg.jpg", "/img/maisonnette 2.jpg", "/img/IMG_0383bg.jpg", "/img/IMG_0409bg.jpg", "/img/IMG_0384bg.jpg"];
var idx = 1;
var waitTime = 5000; // ms
$(document).ready(function() {
$("#bg2").hide();
$.timer(waitTime, load_next);
$.preLoadImages(images);
});
function load_next(timer) {
var toshow = images[idx];
idx++;
idx %= images.length;
back_image().attr('src', toshow);
swap_images();
}
function front_image() {
return (idx % 2 == 0) ? $("#bg1") : $("#bg2");
}
function back_image() {
return (idx % 2 == 0) ? $("#bg2") : $("#bg1");
}
function swap_images() {
back_image().fadeOut('slow');
front_image().fadeIn('slow');
}
Thanks,
Ceylo

Ok I've worked out a solution .... without the use of plugins.
Demo
http://jsfiddle.net/morrison/PvPXM/9/show
source
http://jsfiddle.net/morrison/PvPXM/9/
This approach is a lot cleaner and removes the problem I had while viewing your page in chrome: the animation getting out of sync and flashing.
The only thing you have to do in the HTML is wrap the two images in a <div id="fadeBox" style="position:relative"></div>
$(function() {
var images = [
"http://www.laurent-carbon.com/img/IMG_0435bg.jpg",
"http://www.laurent-carbon.com/img/IMG_0400bg.jpg",
"http://www.laurent-carbon.com/img/maisonnette 2.jpg",
"http://www.laurent-carbon.com/img/IMG_0383bg.jpg",
"http://www.laurent-carbon.com/img/IMG_0409bg.jpg",
"http://www.laurent-carbon.com/img/IMG_0384bg.jpg"
];
var idx = 1;
var max = images.length;
var easing = "swing";
var waitTime = 5000; // ms
var fadeTime = 2000; // ms
var fadeShow = function(fadeTime, fadeDelay) {
var $topImage = $("#fadeBox img:last");
$topImage.fadeTo(fadeDelay, 1, function() {
$topImage.fadeTo(fadeTime, 0, easing, function() {
$topImage
.fadeTo(0, 1)
.insertBefore("#fadeBox img:first")
.attr("src", images[++idx == max ? idx = 0 : idx]);
fadeShow(fadeTime, fadeDelay);
});
});
};
fadeShow(fadeTime, waitTime);
});
Hope this helps
PS thanks to Levi for cleaning the code up a bit.

Answer: http://jsfiddle.net/morrison/RxyZY/
Notes:
You are trying to reinvent the wheel. You are creating a simple slideshow. There are numerous plugins to do exactly this and much more. I used jQuery cycle in my example, which is extremely customizable.
You should wrap your stuff up in a function, creating an expression. In my example, the (function($){}(jQuery)) is what does the trick. It scopes your variables to the function, rather than the global namespace.

How to improve image cross-fade performance?

I want to be able to do a cross fade transition on large images whose width is set to 100% of the screen. I have a working example of what I want to accomplish. However, when I test it out on various browsers and various computers I don't get a buttery-smooth transition everywhere.
See demo on jsFiddle: http://jsfiddle.net/vrD2C/
See on Amazon S3: http://imagefader.s3.amazonaws.com/index.htm
I want to know how to improve the performance. Here's the function that actually does the image swap:
function swapImage(oldImg, newImg) {
newImg.css({
"display": "block",
"z-index": 2,
"opacity": 0
})
.removeClass("shadow")
.animate({ "opacity": 1 }, 500, function () {
if (oldImg) {
oldImg.hide();
}
newImg.addClass("shadow").css("z-index", 1);
});
}
Is using jQuery animate() to change the opacity a bad way to go?

You might want to look into CSS3 Transitions, as the browser might be able to optimize that better than Javascript directly setting the attributes in a loop. This seems to be a pretty good start for it:
http://robertnyman.com/2010/04/27/using-css3-transitions-to-create-rich-effects/

I'm not sure if this will help optimize your performance as I am currently using IE9 on an amped up machine and even if I put the browser into IE7 or 8 document mode, the JavaScript doesn't falter with your current code. However, you might consider making the following optimizations to the code.
Unclutter the contents of the main photo stage by placing all your photos in a hidden container you could give an id of "queue" or something similar, making the DOM do the work of storing and ordering the images you are not currently displaying for you. This will also leave the browser only working with two visible images at any given time, giving it less to consider as far as stacking context, positioning, and so on.
Rewrite the code to use an event trigger and bind the fade-in handling to the event, calling the first image in the queue's event once the current transition is complete. I find this method is more well-behaved for cycling animation than some timeout-managed scripts. An example of how to do this follows:
// Bind a custom event to each image called "transition"
$("#queue img").bind("transition", function() {
$(this)
// Hide the image
.hide()
// Move it to the visible stage
.appendTo("#photos")
// Delay the upcoming animation by the desired value
.delay(2500)
// Slowly fade the image in
.fadeIn("slow", function() {
// Animation callback
$(this)
// Add a shadow class to this image
.addClass("shadow")
// Select the replaced image
.siblings("img")
// Remove its shadow class
.removeClass("shadow")
// Move it to the back of the image queue container
.appendTo("#queue");
// Trigger the transition event on the next image in the queue
$("#queue img:first").trigger("transition");
});
}).first().addClass("shadow").trigger("transition"); // Fire the initial event
Try this working demo in your problem browsers and let me know if the performance is still poor.

I had the same problem too. I just preloaded my images and the transitions became smooth again.

The point is that IE is not W3C compliant, but +1 with ctcherry as using css is the most efficient way for smooth transitions.
Then there are the javascript coded solutions, either using js straight (but need some efforts are needed to comply with W3C Vs browsers), or using libs like JQuery or Mootools.
Here is a good javascript coded example (See demo online) compliant to your needs :
var Fondu = function(classe_img){
this.classe_img = classe_img;
this.courant = 0;
this.coeff = 100;
this.collection = this.getImages();
this.collection[0].style.zIndex = 100;
this.total = this.collection.length - 1;
this.encours = false;
}
Fondu.prototype.getImages = function(){
var tmp = [];
if(document.getElementsByClassName){
tmp = document.getElementsByClassName(this.classe_img);
}
else{
var i=0;
while(document.getElementsByTagName('*')[i]){
if(document.getElementsByTagName('*')[i].className.indexOf(this.classe_img) > -1){
tmp.push(document.getElementsByTagName('*')[i]);
}
i++;
}
}
var j=tmp.length;
while(j--){
if(tmp[j].filters){
tmp[j].style.width = tmp[j].style.width || tmp[j].offsetWidth+'px';
tmp[j].style.filter = 'alpha(opacity=100)';
tmp[j].opaque = tmp[j].filters[0];
this.coeff = 1;
}
else{
tmp[j].opaque = tmp[j].style;
}
}
return tmp;
}
Fondu.prototype.change = function(sens){
if(this.encours){
return false;
}
var prevObj = this.collection[this.courant];
this.encours = true;
if(sens){
this.courant++;
if(this.courant>this.total){
this.courant = 0;
}
}
else{
this.courant--;
if(this.courant<0){
this.courant = this.total;
}
}
var nextObj = this.collection[this.courant];
nextObj.style.zIndex = 50;
var tmpOp = 100;
var that = this;
var timer = setInterval(function(){
if(tmpOp<0){
clearInterval(timer);
timer = null;
prevObj.opaque.opacity = 0;
nextObj.style.zIndex = 100;
prevObj.style.zIndex = 0;
prevObj.opaque.opacity = 100 / that.coeff;
that.encours = false;
}
else{
prevObj.opaque.opacity = tmpOp / that.coeff;
tmpOp -= 5;
}
}, 25);
}