Cycling between 3 images (mobile Safari)
I have the following javascript. It works well when I am cycling between 2 images, but when I add a third it does not work correctly.
Here is my CSS:
img {
-webkit-transition-property: opacity;
-webkit-transition-duration: 2s;
position: absolute;
width: 320px;
height: auto;
}
img.fade-out {
opacity: 0;
}
img.fade-in {
opacity: 1;
}
Here is my javascript, which seems to work but seems laggy 开发者_StackOverflow社区and definately not an elegant solution.
</head><body style="color: black">
<img id="one" class="fade-out" src="Wallpaper.png"/>
<img id="two" class="fade-out" src="Wallpaper0.png"/>
<img id="three" class="fade-out" src="Wallpaper1.png"/>
<script>
var images = ['Wallpaper.png', 'Wallpaper0.png', 'Wallpaper1.png'];
var index = 0;
var fade_in = one;
var fade_out = two;
var fade_foo = three;
fade_in.src = images[0];
fade_out.src = images[images.length - 1];
var fade = function () {
fade_in.src = images[index];
index = (index + 1) % images.length;
fade_in.className = 'fade-out';
fade_out.className = 'fade-in';
fade_foo.className = 'fade-out';
var fade_tmp = fade_in;
fade_in = fade_out;
fade_out = fade_foo;
fade_foo = fade_tmp;
setTimeout(fade, 15000);
};
fade();
</body></html>
For one thing, you're not changing fade_out.src. Try something like this:
fade_in.src = images[0];
fade_out.src = images[1]; // let's use image next to current for fade-out
var fade = function () {
fade_in.src = images[index];
index = (index + 1) % images.length;
fade_out.src = images[index]; // put next to current image into fade-out
// Code below does something misterious.
// You first switch classes between two img's, then switch variables themselves
// Why?
//fade_in.className = 'fade-out';
//fade_out.className = 'fade-in';
//var fade_tmp = fade_in;
//fade_in = fade_out;
//fade_out = fade_tmp;
setTimeout(fade, 15000);
};
Can't tell more since I don't know what exactly you're doing.
It seems you're only displaying one image at a time, so you don't need two variables, one will do. You just need to fade out the current image and bring in a new image:
var index = -1, count = /* total number of images */;
var image = null;
function fade() {
if (image != null)
image.className = 'fade-out';
index = (index + 1) % count;
image = document.getElementById('image-' + index);
image.className = 'fade-in';
setTimeout(fade, 15000);
}
fade();
This assumes that you have set up all the images in HTML as follows:
<img id="image-0" class="fade-out" src="..." />
<img id="image-1" class="fade-out" src="..." />
<img id="image-2" class="fade-out" src="..." />
...
Note that you can achieve cross-fading only if you have several images preloaded, as in the above example. If you use only one image and change the source, the previous image will be lost when you try to fade in the new one.
you're not waiting for you transitions to finish before you swap the source. we just need to rearrange the order of things.
var fade = function() {
fade_in.className = 'fade-out';
fade_out.className = 'fade-in';
setTimeout(function() {
index = (index + 1) % images.length;
fade_in.src = images[index]; // should be completely invisible at this time
var fade_tmp = fade_in;
fade_in = fade_out;
fade_out = fade_tmp;
}, 2000); // 2 seconds, same as your transition time
setTimeout(fade, 15000);
};
setTimeout(fade, 15000);
here the only work that the fade method does is to change the classes, which initiates the transitions. we set a delay that matches your transition time to update the index and swap the image source.
edits: i guess i'm not making it clear what's going on and the assumptions i'm making. here's my complete html except for the provided css which is the same. i also fixed an issue with image order since the last example.
<body>
<img id="one" class="fade-out" /><img id="two" class="fade-out" />
<script>
var images = ['16jog8h.jpg', '20_11_2007_0044537001195507712_joe_baran.jpg', '400davesrig.jpg'];
var index = 0;
var fade_in = document.getElementById('one');
var fade_out = document.getElementById('two');
// fade_in.src = images[0];
fade_out.src = images[0];
var fade = function() {
fade_in.className = 'fade-out';
fade_out.className = 'fade-in';
setTimeout(function() {
index = (index + 1) % images.length;
fade_in.src = images[index];
var fade_tmp = fade_in;
fade_in = fade_out;
fade_out = fade_tmp;
}, 2000);
setTimeout(fade, 5000);
};
fade();
</script>
</body>
加载中,请稍侯......
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