Goal —
Smoothly animate a changing list of items.
Problem —
When an item enters the list, everything repositions smoothly. When an item leaves the list, everything snaps abruptly.
I've discovered that .drawer-move is applied when new items enter, but .drawer-move is not applied when items leave.
Docs: https://v2.vuejs.org/v2/guide/transitions.html#List-Move-Transitions
Template —
<transition-group class="utilities -animate" tag="section" name="drawer">
<div class="drawer" key="application-drawer">
<div class="heading">Select An Application</div>
</div>
<div class="drawer" v-if="selectCompanyVisible" key="company-drawer">
<div class="heading">Select A Company</div>
</div>
<div class="drawer" key="manage-drawer">
<div class="heading">Manage {{ user.id }}</div>
</div>
</transition-group>
CSS —
.drawer-enter-active,
.drawer-leave-active,
.drawer-move {
transition-property: opacity, transform;
transition-timing-function: cubic-bezier(0.5, 0, 0.5, 1);
transition-duration: .4s;
}
.drawer-enter,
.drawer-leave-to {
opacity: 0;
transform: translateX(3rem);
}
The -leave-active transition class must apply a position: absolute declaration, in order to take it out of the layout flow, so the siblings can move in to place around it.
https://forum.vuejs.org/t/transition-group-move-class-not-occuring-in-the-array/6381/4
This also could mean that you should declare positioning within the transition-group element. No one mentions this in the Vue team, but I don't find this applied automatically by the transition classes.
.drawer-leave-active {
position: absolute;
// optional, depends on your layout
left: 0;
width: 100%;
}
.utilities {
position: relative;
}
In React, I have a parent component and a child component. The parent shows an iframe, returning this jsx:
<div className={cx("col-md-6", classes.BWrapper)}>
<iframe className={classes.Iframe} width="100%" src="https://www.youtube.com/embed/OVoFzu-vH4o" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
</div>
Then the child component handles some asynchornous code and while doing that it changes the state to loading and showing a spinner
return (
<div className={globalStyles.Card}>
<div className={cx("card-header", globalStyles.CardHeader)}>
<ul className="nav nav-tabs card-header-tabs">
{formTypesJsx}
</ul>
</div>
<div className="card-body">
<div className="tab-content">
<div role="tabpanel" className="tab-panel" id="signup-form">
{this.props.loading && (<div><Backdrop show/><Spinner/></div>)}
I guess it's not ideal to show a spinner in the child component that is supposed to cover in gray the elements of the parent, but I set the spinner elements with z-index and it's working fine except the iframe window is still appearing on top of the spinner.
Spinner css:
.Center {
position: fixed;
left: 50%;
top: 50%;
transform: translate(-50%, -50%);
z-index: 200;
}
I tried different stuff including giving the spinner z-index: -1 , opacity: .99 and also tried to give the iframe an absolute positioning and a higher z-index than the spinner, and giving the spinner relative position
Is there something I'm missing? Why is only the iframe appearing on top of the spinner?
Thanks in advance
I just finnished of creating the basis for my chat... I just got around detecting the scroll positioning of the user and want to use this information to make a "Scroll down button" if the chat is not fully scrolled down and a message is recieved. I used position: sticky and that worked all well... But when i got around to testing it across web browsers it did not work very well seems to be very short term to go with it then. What kind of positioning can I use to achieve the same results cross platforms?
<div id = 'chatlogs'>
<div class='chatContainer self'>
<div class = 'imgContainer'>
<img src='displayProfilePicture.php?user_id=$id'>
</div>
<div class='content'>
<div class = 'message'>
". $extract['msg'] ."
</div>
</div>
The chatlogs is filled with multiple of the shown small "chat objects" and no i want for the popup to be placed at the bottom verticaly and center horizontaly in the chatlogs.
<span onclick = 'doScroll();' class = 'fa fa-arrow-down'></span>
</div>
position: sticky just works in chrome for now
To make the button fixed in the scroll you need to let him outside the content scrollable
<div class="scroll-wrapper">
<div class="scroll">
blah blah
</div>
<span onclick = 'doScroll();' class = 'fa fa-arrow-down'></span>
</div>
and with css you can use position absolute to let it fixed
.scroll-wrapper{
position: relative
}
.fa-arrow-down{
position: absolute;
left: 50%; // center horizontally
transform: translateX(-50%); // center horizontally
-webkit-transform: translateX(-50%);
-moz-transform: translateX(-50%);
-ms-transform: translateX(-50%);
bottom: 10px;
}
I'm dealing with an issue that shows up for people using Chrome 60.0.3112.90 where changing the disabled attribute of a button, hides it.
I've created a Minimal, Complete and Verifiable example where you can click the + button to toggle the disabled attribute.
https://jsfiddle.net/1wtj8a8a/3/
The element is still present in the DOM
The element doesn't have display: none set
If you zoom out and zoom in again (Ctrl and scroll) it shows again
If you add a margin or padding attribute to the wrap div, it appears again
Removing the overflow: hidden seems to solve the problem, but I'd rather not do it, because the text on the buttons will overlap (in my real setup). I've tried replacing it with overflow-x: hidden, but to no avail.
Question
Why does this happen?
What can I do instead of removing overflow: hidden?
I'm not entirely sure why this is happening, but I've run across randomly disappearing elements before (usually along with position: fixed) and using translateZ(0) on the element will cause the browser to repaint it, making sure it doesn't disappear.
angular.module('App',[])
.controller('MyCtrl', ['$scope', function ($scope) {
$scope.b = true;
}
])
div.wrap {
width: 50px;
}
button {
overflow: hidden;
transform: translateZ(0);
}
<link href="https://maxcdn.bootstrapcdn.com/twitter-bootstrap/2.0.4/css/bootstrap-combined.min.css" rel="stylesheet"/>
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.6.0/angular.min.js"></script>
<body ng-app="App">
<div ng-controller="MyCtrl" >
<div class="wrap">
<button class="btn btn-mini pull-left">A</button>
<button class="btn btn-mini pull-right" ng-disabled="b">B</button>
</div>
<button ng-click="b=!b">+</button>
</div>
</body>
I have a few images on my page. I'm finding that the page starts to render before the images have been loading (which is good), but that the visual effect is not great. Initially the user sees this:
--------hr--------
text
Then a few milliseconds later the page jumps to show this:
--------hr--------
[ ]
[ image ]
[ ]
text
Is there a simple way that I can show a grey background image of exactly the width and height that the image will occupy, until the image itself loads?
The complicating factor is that I don't know the height and width of the images in advance: they are responsive, and just set to width: 100% of the containing div. This is the HTML/CSS:
<div class="thumbnail">
<img src="myimage.jpeg" />
<div class="caption">caption</div>
</div>
img { width: 100% }
Here's a JSFiddle to illustrate the basic problem: http://jsfiddle.net/X8rTB/3/
I've looked into things like LazyLoad, but I can't help feeling there must be a simpler, non-JS answer. Or is the fact that I don't know the height of the image in advance an insurmountable problem? I do know the aspect ratio of the images.
Instead of referencing the image directly, stick it within a DIV, like the following:
<div class="placeholder">
<div class="myimage" style="background-image: url({somedynamicimageurl})"><img /></div>
</div>
Then in your CSS:
.placeholder {
width: 300;
height: 300;
background-repeat: no-repeat;
background-size: contain;
background-image: url('my_placeholder.png');
}
Keep in mind - the previous answers that recommend using a div background approach will change the semantic of your image by turning it from an img into a div background. This will result in things like no indexing of these images by a search crawler, delay in loading of these images by the browser (unless you explicitly preload them), etc.
A solution to this issue (while not using the div background approach) is to have a wrapper div to your image and add padding-top to it based on the aspect ratio of the image that you need to know in advance. The below code will work for an image with an aspect ratio of 2:1 (height is 50% of width).
<div style="width:100%;height:0; padding-top:50%;position:relative;">
<img src="<imgUrl>" style="position:absolute; top:0; left:0; width:100%;">
</div>
Of course - the major disadvantage of this approach is that you need to know the aspect ratio of the image in advance.
There is a really simple thing to check before you start looking into lazy-loading and other JavaScript. Make sure the JPEG images you are loading are saved with the 'progressive' option enabled!
This will cause them to load the image iteratively, starting with a placeholder that is low-resolution and faster to download, rather than waiting for the highest resolution data before rendering.
It's very simple...
This scenario allows to load a profile photo that defaults to a placeholder image.
You could load multi CSS background-image into an element. When an avatar photo fails, the placeholder image appears default of div.
If you're using a div element that loads via a CSS background-image, you could use this style:
#avatarImage {
background-image: url("place-holder-image.png"), url("avatar-image.png");
}
<div id="avatarImage"></div>
Feel free to copy this:
<script>
window.addEventListener("load", function () {
document.getElementById('image').style.backgroundColor = 'transparent';
});
</script>
<body>
<image src="example.example.example" alt="example" id="image" style="background-color:blue;">
</body>
I got this from here: Preloader keeps on loading and doesnt disappear when the content is loaded.
Apart from all solutions already mentioned, the last solution would be to hide the document until everything is loaded.
window.addEventListener('load', (e) => {
document.body.classList.add('loaded');
});
body {
opacity: 0;
}
body.loaded {
opacity: 1;
}
<div id="sidebar">
<img src="http://farm9.staticflickr.com/8075/8449869813_1e62a60f01_b.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-1.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-2.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-3.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-4.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-5.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-6.jpg" />
</div>
Or show some animation while everything is loading:
window.addEventListener('load', (e) => {
document.body.classList.add('loaded');
});
.loader {
border: 16px solid #f3f3f3;
border-radius: 50%;
border-top: 16px solid #3498db;
width: 70px;
height: 70px;
-webkit-animation: spin 2s linear infinite;
/* Safari */
animation: spin 2s linear infinite;
position: absolute;
left: calc(50% - 35px);
top: calc(50% - 35px);
}
#keyframes spin {
0% {
transform: rotate(0deg);
}
100% {
transform: rotate(360deg);
}
}
body :not(.loader) {
opacity: 0;
}
body .loader {
display: block;
}
body.loaded :not(.loader) {
opacity: 1;
}
body.loaded .loader {
display: none;
}
<div class="loader"></div>
<div id="sidebar">
<img src="http://farm9.staticflickr.com/8075/8449869813_1e62a60f01_b.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-1.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-2.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-3.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-4.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-5.jpg" />
<img src="https://www.nla.gov.au/sites/default/files/pic-6.jpg" />
</div>
The only thing I can think of, to minimize the jump effect on your text, is to set min-height to where the image will appear, I would say - set it to the "shorter" image you know of. This way the jump will be less evident and you won't need to use lazyLoad or so... However it doesn't completely fix your problem.
Here's one naive way of doing it,
img {
box-shadow: 0 0 10px 0 rgba(#000, 0.1);
}
You can manipulate the values, but it creates a very light border around the image that doesn't push the contents. Images can load at whatever time they want, and you get a good user experience.
Here is what I did with Tailwind CSS, but it's just CSS:
img {
#apply bg-no-repeat bg-center;
body.locale-en & {
background-image: url("data:image/svg+xml;utf8,<svg width='100' height='100' viewBox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'><text x='50%' y='50%' style='font-family: sans-serif; font-size: 12px;' dominant-baseline='middle' text-anchor='middle'>Loading…</text></svg>");
}
body.locale-fr & {
background-image: url("data:image/svg+xml;utf8,<svg width='100' height='100' viewBox='0 0 100 100' xmlns='http://www.w3.org/2000/svg'><text x='50%' y='50%' style='font-family: sans-serif; font-size: 12px;' dominant-baseline='middle' text-anchor='middle'>Chargement…</text></svg>");
}
}
You can find the width and height of the images in the developer tools console, for example in Chrome you can click the cursor icon in the developer tools console and when you hover on the page it will highlight all the properties of the elements in the page.
This will help you find the width and height of the images, because if you hover on top of your images it will give you the dimensions of the image and other more properties. You can also make an individual div for each image and make the div relative to the images width and height. You can do it like this:
The main div will contain the images and also the background-div which is below the image.
HTML:
<html>
<head>
<meta charset="utf-8">
</head>
<body>
<div class=".mainDiv">
<div class="below"></div>
<img src="https://imgix.bustle.com/uploads/image/2020/2/13/da1a1ca4-95ec-40ea-83c1-4f07fac8b9b7-eqb9xdwx0auhotc.jpg" width="500"/>
</div>
</body>
</html>
CSS:
.mainDiv {
position: relative;
}
.below {
position: absolute;
background: #96a0aa;
width: 500px;
height: 281px;
}
img {
position: absolute;
}
The result will be that .below will be below the image and so when the image has trouble loading the user will instead see the grey .below div. You cannot see the .below div because it is hidden below the image. The only time you will see this is when the loading of the image is delayed. And this will solve all your problems.
I have got a way. But you will need to use JavaScript for it.
The HTML:
img = document.getElementById("img")
text = document.getElementById("text")
document.addEventListener("DOMContentLoaded", () => {
img.src = "data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAOEAAADhCAMAAAAJbSJIAAAAA1BMVEWIiIhYZW6zAAAASElEQVR4nO3BgQAAAADDoPlTX+AIVQEAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAADwDcaiAAFXD1ujAAAAAElFTkSuQmCC";
text.innerHTML = "Loaded but image is not";
});
window.onload = function() {
img.src = "https://media.geeksforgeeks.org/wp-content/uploads/20190913002133/body-onload-console.png";
text.innerHTML = "Image is now loaded";
};
#img {
width: 400px;
height: 300px;
}
<hr>
<img id="img" src="https://media.geeksforgeeks.org/wp-content/uploads/20190913002133/body-onload-console.png">
<p>Here is the Image</p>
<p id="text">Not Loaded</p>