I'm using Retina.js to swap out images on my site for retina screens. It's working fine however I have an issue when I am swapping images from an array. I have one image in the middle of the screen and every 3 seconds this changes to a different image stored in the array. Like so:
<script type = "text/javascript">
function displayNextImage() {
x = (x === images.length - 1) ? 0 : x + 1;
document.getElementById("img").src = images[x];
}
function displayPreviousImage() {
x = (x <= 0) ? images.length - 1 : x - 1;
document.getElementById("img").src = images[x];
}
function startTimer() {
setInterval(displayNextImage, 1600);
}
var images = [], x = -1;
images[0] = "smallslide2.png";
images[1] = "smallslide3.png";
images[2] = "smallslide4.png";
images[3] = "smallslide5.png";
images[4] = "smallslide1.png";
</script>
In my html I have:
<p class="centeredImage">
<img id ="img" src="smallslide1.png">
</p>
The first slide works and shows the retina image, I guess this because it's using the standard image detection i.e replacing image src = " ", for the rest of the images it doesn't work though. Is there a way to get it to work for the images in the array? Any pointers on this would be really appreciated. Thanks!
edit:
if (document.getElementById("img").src===smallslide1#2x.png){
images[0] = "smallslide2#2x.png";
images[1] = "smallslide3#2x.png";
images[2] = "smallslide4#2x.png";
images[3] = "smallslide5#2x.png";
images[4] = "smallslide1#2x.png";
}
else {
images[0] = "smallslide2.png";
images[1] = "smallslide3.png";
images[2] = "smallslide4.png";
images[3] = "smallslide5.png";
images[4] = "smallslide1.png";
}
Related
I am working on a slideshow/carousel for my website. I found this code online and would like to know how to add links to the images presented in the slideshow. I am open to any other suggestions for slideshows.
<!-- Showcase/Banner Image -->
<section id="banner">
<script>
var i = 0; // Start point
var images = [];
var time = 2500;
// Image List
images[0] = 'simpleslideshow/slide1.jpg';
images[1] = 'simpleslideshow/slide2.jpg';
images[2] = 'simpleslideshow/slide3.jpg';
images[3] = 'simpleslideshow/slide4.jpg';
// Change Image
function changeImg(){
document.slide.src = images[i];
if(i < images.length - 1){
i++;
} else {
i = 0;
}
setTimeout("changeImg()", time);
}
window.onload = changeImg;
I have this code:
<script type="text/javascript">
function displayNextImage() {
x = (x === images.length - 1) ? 0 : x + 1;
document.getElementById("img").src = images[x];
}
function displayPreviousImage() {
x = (x <= 0) ? images.length - 1 : x - 1;
document.getElementById("img").src = images[x];
}
function startTimer() { //this is started when the body is loaded
setInterval(displayNextImage, 10000);
}
var images = [], x = -1;
images[0] = "image0.jpg";
images[1] = "image1.jpg";
images[2] = "image2.jpg";
images[3] = "image3.jpg";
</script>
Basically every 10 seconds (defined by the setInterval) it changes to the next image, then cycles back to the first image again. What I need, is when it displays Image 0 it shows a caption bellow the image "This images was taken by etc.", but when it changes to the second image (Image1) it changes it to the caption for the second image and so on?
Preferably using Javascript or maybe JQuery if necessary (I'm better at JavaScript)
I know this could be done by editing the photo in Photoshop by adding some space on the bottom and adding some text that way, but I think it wouldn't look nice.
You can use your displayNextImage(), displayPreviousImage() functions to place prepared captions into a DIV element:
<script type="text/javascript">
function displayNextImage() {
x = (x === images.length - 1) ? 0 : x + 1;
document.getElementById("img").src = images[x];
document.getElementById("cap").innerHTML = captions[x];
}
function displayPreviousImage() {
x = (x <= 0) ? images.length - 1 : x - 1;
document.getElementById("img").src = images[x];
document.getElementById("cap").innerHTML = captions[x];
}
function startTimer() { //this is started when the body is loaded
setInterval(displayNextImage, 10000);
}
var images = [], captions = [], x = -1;
images[0] = "image0.jpg";
images[1] = "image1.jpg";
images[2] = "image2.jpg";
images[3] = "image3.jpg";
captions[0] = "foo";
captions[1] = "bar";
captions[2] = "foobar";
captions[3] = "foobarfoo";
</script>
In your HTML, add <div id="cap"></div>
I want to implement sliding images as soon as the website loads.
Here's my html code
<html>
<title>Wold of Guitars</title>
<body onload="images()">
</body>
</html>
And here's my javascript
var imgArray = new Array();
imgArray[0] = new Image();
imgArray[0].src = '../img/n/h1.jpg';
imgArray[1] = new Image();
imgArray[1].src = '../img/n/h2.jpg';
imgArray[2] = new Image();
imgArray[2].src = '../img/n/home.jpg';
imgArray[3] = new Image();
imgArray[3].src = '../img/n/h3.jpg';
imgArray[4] = new Image();
imgArray[4].src = '../img/n/h4.jpg';
x=-1;
function images()
{ x=x+1
if(x>4)
x=1
document.write("<li><img src='" + imgArray[x] + "' width="1350" height="630"/><span>" + imgArray[] + "</span></li>");
var t=setInterval("images()",3000);
}
Help will be appreciated.
Although you mentioned "sliding" your initial code looked liked you wanted to swap the images over time.
I admit you may struggle to find good resources on JavaScript for something so simple, which Is why I can relate to your question.
Ok so here's a quick & dirty but more modern-ish image changing slide requestAnimationFrame:
https://jsfiddle.net/julienetienne/95tqftnk/4/
The same principals apply for making images slide except you are pre-loading all images and shifting the position by the slide show width.
var speed = 3;
// Your image array
var images = [
'http://www.gettyimages.co.uk/gi-resources/images/Homepage/Category-Creative/UK/UK_Creative_462809583.jpg',
'http://www.hdwallpapersimages.com/wp-content/uploads/images/Child-Girl-with-Sunflowers-Images.jpg',
'http://www.gettyimages.co.uk/CMS/StaticContent/1391099215267_hero2.jpg'];
// Get the slideShow tag
var slideShow = document.getElementById('slide-show');
// Create the image tag //You could also just make one in HTML and get the tag
var img = document.createElement('img');
// Append the image to the slideshow container
slideShow.appendChild(img);
// Basic request animation polyfill
var rAF = window.requestAnimationFrame || window.webkitRequestAnimationFrame || window.mozRequestAnimationFrame || window.msRequestAnimationFrame || function (callback) {
return setTimeout(callback, 1000 / 60);
};
// declare var count outside of rAF loop
var count;
function changeImage(timeStamp) {
count = Math.floor(timeStamp / 1000 / speed);
while (count > images.length -1) {
count -= images.length;
}
img.src = images[count];
rAF(changeImage);
}
rAF(changeImage);
img {
width: 600px;
height auto;
}
<div id="slide-show"></div>
I created site with changing background images.
HTML:
<div id="templatemo_header">
</div>
CSS:
#templatemo_header {
background: url(images/templatemo_header.jpg) no-repeat;
}
And JS code which changes the BG image each 3 seconds
function displayImage(image) {
document.getElementById("templatemo_header").style.backgroundImage = image;
}
function displayNextImage() {
x = (x == images.length - 1) ? 0 : x + 1;
displayImage(images[x]);
}
function displayPreviousImage() {
x = (x <= 0) ? images.length - 1 : x - 1;
displayImage(images[x]);
}
function startTimer() {
setInterval(displayNextImage, 3000);
}
var images = [], x = -1;
images[0] = 'url("images/templatemo_header1.jpg")';
images[1] = 'url("images/templatemo_header2.jpg")';
images[2] = 'url("images/templatemo_header3.jpg")';
images[3] = 'url("images/templatemo_header.jpg")';
The problem is when each of BG images changed only first time, image dissapeares and after some moment new image appears.
I guess, it's because new BG image is downloaded.
Is it some way to force download the images immediately, say in function startTimer?
Thanks in advance.
There are a few ways to pre-load images using javascript here. By pre-loading the images you may have better luck when displaying them. In your case I would use Method 3 if possible, if not Method 2. As described in the article, you would use the window.onload event to kick off the downloading of the images once the page has loaded.
I would just setup your image array as follows:
window.onload = preLoadImages();
function preLoadImages(){
preLoadImage = new Image();
images[0] = "images/templatemo_header1.jpg";
images[1] = "images/templatemo_header2.jpg";
images[2] = "images/templatemo_header3.jpg";
images[3] = "images/templatemo_header.jpg";
for(i=0, i<=images.length, i++){
preLoadImage.src=images[i];
}
}
I've figured out the centering and resizing issues, but I still can't get onLoad to work properly. Anyone have any ideas? I thought onLoad was supposed to wait for the image to be loaded completely before firing the code. As this is right now, it resizes the img for the next img, and fades it in before it's loaded, so the previous image fades in again. Once the show has run through once, it works perfectly, so obviously it's not waiting for the image to load completely before firing imageLoad().
<div id="slideShow">
<div id="slideShowImg" style="display:none; margin-right:auto; margin-left:auto;">
</div>
<div id="slideShowThumbs">
</div>
<script type="text/javascript">
loadXMLDoc('http://www.thehoppr.com/hopspots/82/82.xml', function() {
var slideShow = document.getElementById('slideShow');
var items = [];
var nl = xmlhttp.responseXML.getElementsByTagName('image');
var i = 0;
var t;
var slideShowImg = document.getElementById('slideShowImg');
var slideShow = document.getElementById('slideShow');
var maxHeight = 300;
var maxWidth = 800;
var imgNode = new Image();
function image() {
var nli = nl.item(i);
var src = nli.getAttribute('src').toString();
var width = parseInt(nli.getAttribute('width').toString());
var height = parseInt(nli.getAttribute('height').toString());
imgNode.onLoad = imageLoad();
imgNode.src = src;
imgNode.height = height;
imgNode.width = width;
imgNode.setAttribute("style", "margin-right:auto; margin-left:auto; display:block;");
var ratio = maxHeight / maxWidth;
if (imgNode.height / imgNode.width > ratio) {
// height is the problem
if (imgNode.height > maxHeight) {
imgNode.width = Math.round(imgNode.width * (maxHeight / imgNode.height));
imgNode.height = maxHeight;
}
} else {
// width is the problem
if (imgNode.width > maxHeight) {
imgNode.height = Math.round(imgNode.height * (maxWidth / imgNode.width));
imgNode.width = maxWidth;
}
}
}
function imageLoad() {
slideShowImg.appendChild(imgNode);
Effect.Appear('slideShowImg', {
duration: 1
});
t = setTimeout(nextImage, 7000);
}
function nextImage() {
slideShowImg.setAttribute("style", "display:none");
if (i < nl.length - 1) {
i++;
image();
} else {
i = 0;
image();
}
}
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
//XML Loaded, create the slideshow
alert(xmlhttp.responseText);
image();
}
});
</script>
Here are some of my thoughts (it's all open discussion)...
Preloading - Since you're limited to downloading 2 resources in parallel per hostname, it may not make sense to preload everything up front. Since it's a slideshow, how about modifying image() to download the i + 1 image through an Image object that doesn't get appended to the DOM? It doesn't seem beneficial to prefetch i + 2 and beyond in a slideshow setting.
Centering the images - Regarding using the auto margin width for horizontal centering, I believe you'll have to explicitly set the image to display:block. Obviously that doesn't solve centering vertically. Are all the images the same size? Also, will the slideShowImg div have a defined height/width? If so, then some math can be applied to achieve the centering.
Hope this helps! :)
Ok so I fixed the issue with the onLoad, and I even added a little preloading to help the slideshow along as well. All I had to do was define the onload first, and then do everything else except define the src inside the onload's function. I then added a little nextImg preloading so there's little if no hiccup between images even if it's the first time the browser is loading them. Here's the final code for anyone who has similar onload issues and finds there way here:
<div id="slideShow">
<div id="slideShowImg" style="display:none; margin-right:auto; margin-left:auto;">
</div>
<div id="slideShowThumbs">
</div>
<script type="text/javascript">
loadXMLDoc('/82.xml', function() {
var slideShow = document.getElementById('slideShow');
var items = [];
var nl = xmlhttp.responseXML.getElementsByTagName('image');
var i = 0;
var t;
var slideShowImg = document.getElementById('slideShowImg');
var slideShow = document.getElementById('slideShow');
var maxHeight = 300;
var maxWidth = 800;
var curImg = new Image();
var nextImg = new Image();
function image() {
var cli = nl.item(i);
var src = cli.getAttribute('src').toString();
var width = parseInt(cli.getAttribute('width').toString());
var height = parseInt(cli.getAttribute('height').toString());
curImg.onload = function() {
curImg.height = height;
curImg.width = width;
curImg.setAttribute("style", "margin-right:auto; margin-left:auto; display:block;");
slideShowImg.appendChild(curImg);
var ratio = maxHeight / maxWidth;
if (curImg.height / curImg.width > ratio) {
// height is the problem
if (curImg.height > maxHeight) {
curImg.width = Math.round(curImg.width * (maxHeight / curImg.height));
curImg.height = maxHeight;
}
} else {
// width is the problem
if (curImg.width > maxHeight) {
curImg.height = Math.round(curImg.height * (maxWidth / curImg.width));
curImg.width = maxWidth;
}
}
}
curImg.src = src;
if (i < nl.length - 1) {
var nli = nl.item(i + 1);
var nsrc = nli.getAttribute('src').toString();
nextImg.src = nsrc;
}
Effect.Appear('slideShowImg', {
duration: 1
});
t = setTimeout(nextImage, 7000);
}
function imageLoad() {}
function nextImage() {
slideShowImg.removeChild(curImg);
slideShowImg.setAttribute("style", "display:none");
if (i < nl.length - 1) {
i++;
image();
} else {
i = 0;
image();
}
}
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
//XML Loaded, create the slideshow
alert(xmlhttp.responseText);
image();
}
});
</script>