Animating :after in css - css

Im trying to figure out why this simple code isn't working.
http://jsfiddle.net/yq1ro6n5/
#keyframes testing {
from: {font-size: 42px;}
to: {font-size: 64px;}
}
a:after {
content: "Hello!";
animation: testing 1s infinite;
}
-
<a></a>
Can anyone explain?

Remove : from the keyframe like this
#keyframes testing {
from {
font-size: 42px;
}
to {
font-size: 64px;
}
}
a {
}
#keyframes testing {
from {
font-size: 42px;
}
to {
font-size: 64px;
}
}
a:after {
content:"Hello!";
animation: testing 3s infinite;
}
<a></a>

Related

CSS - Number auto-increasing animation not work in Firefox and Safari

I am trying to implement an auto-increasing number animation by CSS following this article.
It works well in my application when opening in Chrome, but in Firefox and Safari, it always shows 0.
Do you have any idea about this problem? Here's the snippet:
#property --num {
syntax: "<integer>";
initial-value: 0;
inherits: false;
}
div {
animation: counter 5s infinite alternate ease-in-out;
counter-reset: num var(--num);
font: 800 40px system-ui;
padding: 2rem;
}
div::after {
content: counter(num);
}
#keyframes counter {
from {
--num: 0;
}
to {
--num: 100;
}
}
<div></div>
According to https://autoprefixer.github.io/ it should be like this:
/*
* Prefixed by https://autoprefixer.github.io
* PostCSS: v8.4.14,
* Autoprefixer: v10.4.7
* Browsers: last 4 versions
*/
#property --num {
syntax: "<integer>";
initial-value: 0;
inherits: false;
}
div {
-webkit-animation: counter 5s infinite alternate ease-in-out;
animation: counter 5s infinite alternate ease-in-out;
counter-reset: num var(--num);
font: 800 40px system-ui;
padding: 2rem;
}
div::after {
content: counter(num);
}
#-webkit-keyframes counter {
from {
--num: 0;
}
to {
--num: 100;
}
}
#keyframes counter {
from {
--num: 0;
}
to {
--num: 100;
}
}

How to make CSS animation to do vice versa after being completed?

The code below is a part of my code :
.myBox:hover::after {
animation-name: underline;
animation-duration: 350ms;
animation-fill-mode: forwards;
}
#keyframes underline {
from { width: 0; }
to { width: 100%; }
}
It works nicley, but I want to do it vice versa when animation completed, I mean when it finished then width should be 0 again, In fact for this part I want to do it when my element is not hovered. Which property can help me ?
You need to use alternate and run 2 iterations of the animation:
.box {
height:200px;
background:red;
animation: underline 500ms alternate 2 forwards;
}
#keyframes underline {
from { width: 0; }
to { width: 100%; }
}
<div class="box">
</div>
Or consider the use of transition if you want the effect on hover:
.box {
height: 200px;
background: red;
width: 0;
transition: 500ms;
}
body:hover .box {
width: 100%;
}
<div class="box">
</div>
You can specify multiple values for animations rather then from and to using percentage:
#keyframes underline {
0%, 100% { width: 0; }
50% { width: 100%; }
}
More detailed information can be found here.
.myBox:hover::after {
animation-name: underline infinite;
animation-duration: 350ms;
animation-fill-mode: forwards;
}
#keyframes underline {
from { width: 0; }
to { width: 100%; }
}
You infinite for this

Unexpected CSS Animation behaviour in Safari

I have the following HTML:
<p class="animate">X</p>
And this is my CSS:
.animate {
animation-duration: 0.75s;
animation-name: add-icon;
font-size: 8em;
}
#keyframes add-icon {
0% {
font-size: 18em;
}
25% {
font-size: 6em;
}
60% {
font-size: 13em;
}
100% {
font-size: 8em;
}
}
This is what I expect to see: (tested in Firefox, Chrome, Edge)
But this is how it actually behaves in Safari 11:
I tried to prefix my CSS with the Webkit prefixes but that doesn't change the result.
Here's a working demo of my problem.
Use rem instead of em
Actually em depends on the parent element and rem depends on the root element...so its good to use rem instead of em.
Read this article
Stack Snippet
.animate {
animation-duration: 0.75s;
animation-name: add-icon;
font-size: 8rem;
}
#keyframes add-icon {
0% {
font-size: 18rem;
}
25% {
font-size: 6rem;
}
60% {
font-size: 13rem;
}
100% {
font-size: 8rem;
}
}
<p class="animate">X</p>

How to prevent CSS animation on page load?

I have an animation, which is taking care of the fading in and out transition on button hover state.
The problem is that the default animation (-webkit-animation: off-state 1s;) is firing off on page load. How do I make it active only after first hover state?
I know how to achieve this using CSS transitions. I am looking for a solution using animation/keyframes.
HTML
<div class="button"></div>
CSS
.button { background: #000; width: 20px; height: 20px; -webkit-animation: off-state 1s; }
.button:hover { -webkit-animation: on-state 1s; }
#-webkit-keyframes on-state {
0% { height: 20px; }
100% { height: 100px; }
}
#-webkit-keyframes off-state {
0% { height: 100px; }
100% { height: 20px; }
}
Demo
As suggested by #Zeaklous, this can be done using JavaScript, e.g. using jQuery:
$('.button').one('mouseout', function () { $(this).addClass('alt-animation'); });
and moving the animation rule to .alt-animation class:
.button { background: #000; width: 20px; height: 20px; }
.button.alt-animation { -webkit-animation: off-state 1s; }
.button:hover { -webkit-animation: on-state 1s; }
Ideally, there should be CSS only alternative.

LESS CSS Pass mixin as a parameter to another mixin

Is there any way to pass one mixin or style's declaration to another mixin as an input parameter?
Let's take a look at an example with animation keyframes. Following is how we define keyframes in pure CSS:
#-moz-keyframes some-name
{
from { color: red; }
to { color: blue; }
}
#-webkit-keyframes some-name
{
from { color: red; }
to { color: blue; }
}
#keyframes some-name
{
from { color: red; }
to { color: blue; }
}
Idea is to simplify these declarations using mixins, so we can have something like following:
.keyframes(name, from, to)
{
// here we need somehow to reproduce structure
// that we have in an example above
}
// define one animation
.my-from() { color: red; }
.my-to() { color: blue; }
// the following won't work because you cannot pass mixin as a parameter
// in way I have here, so I am looking for a way to solve this problem
.keyframes('some-name', .my-from, .my-to);
// define another animation
.another-from() { font-size: 1em; }
.another-to() { font-size: 2em; }
.keyframes('another-name', .another-from, .another-to);
The system will have different modules that could be dynamically attached to application as well as removed. So, don't suggest me to use #import because it's not the case. Output CSS is dynamically compiled on-fly using information about modules and their own LESS styles as well as base LESS dependencies like mixins library and etc.
Note: it will work for me if you know a way to pass class definition instead of mixin. In an example above it would be .my-from instead of .my-from() and etc.
UPDATED for LESS 1.7.0+ (WAY Simpler)
We can do this far more directly now with the 1.7.0 update and the ability to create rulesets, and to use variables in setting #keyframes.
Now we really can pass a mixin through a parameter by a ruleset, or we can pass in the property stings themselves. So consider this:
LESS (using 1.7)
.keyframes(#name, #from, #to) {
#frames: {
from { #from(); }
to { #to(); }
};
#pre: -moz-keyframes;
#-moz-keyframes #name
{
#frames();
}
#-webkit-keyframes #name
{
#frames();
}
#keyframes #name
{
#frames();
}
}
.keyframes(testName, {color: red; .myMix(0);}, {color: blue; .myMix(1);});
.myMix(#value) {opacity: #value;}
Note that I am passing both a property setting and a mixin call, and my output is:
CSS Output
#-moz-keyframes testName {
from {
color: red;
opacity: 0;
}
to {
color: blue;
opacity: 1;
}
}
#-webkit-keyframes testName {
from {
color: red;
opacity: 0;
}
to {
color: blue;
opacity: 1;
}
}
#keyframes testName {
from {
color: red;
opacity: 0;
}
to {
color: blue;
opacity: 1;
}
}
Note how the rulesets are passed, in brackets {...}, and then called, via #from() and #to() (looking a lot like a mixin call). I'm using these passed rule sets to set another ruleset of #frames which is then itself called to fill the keyframes definitions.
More Generically
Here I pass a private mixin to another mixin and then call it from that other mixin:
LESS
.someMixin(#class; #expectedMixin) {
.#{class} {
#expectedMixin();
.myPrivateMix(0.6);
test: 1;
}
}
.someMixin(newClass; {.myClass;});
.myClass {
.myPrivateMix(#value) {opacity: #value;}
}
CSS Output
.newClass {
opacity: 0.6;
test: 1;
}
Kept the below for legacy info.
Updated (added LESS 1.4.0+ support)
Wow, this took some doing, but I think I have something you can work with. However, it does take some special defining of your mixins in your modules, specifically, using pattern matching. So...
First, Define Your Module Mixins
Note how the module mixins intended to be used in a specific future mixin are defined with the same mixin name, but with a different pattern name. This was key to making this work.
// define one animation in a module
.from(my-from){ color: red; }
.to(my-to) { color: blue; }
// define one animation in another module
.from(another-from){ font-size: 1em; }
.to(another-to) { font-size: 2em; }
If you also want individual mixin names in the modules, you should be able to do this:
// define one animation in a module
.my-from(){ color: red; }
.my-to() { color: blue; }
.from(my-from){ .my-from() }
.to(my-to) { .my-to() }
// define one animation in another module
.another-from(){ font-size: 1em; }
.another-to() { font-size: 2em; }
.from(another-from){ .another-from() }
.to(another-to) { .another-to() }
This should allow one to call either the straight mixin .my-from() or, to make it variably accessible within later mixins that access the singular .from() mixin group through the pattern matching.
Next, Define Your Mixin
For your #keyframes example, that was extremely difficult. In fact, a stack overflow answer was vital to helping me solve an issue with applying the #name, which was not applying under normal LESS rules because of it following the #keyframes definition. The solution to apply the #name looks nasty, but it works. It does have the, perhaps, unfortunate necessity of also defining a selector string to play the animation by (because it uses that string to help build the last } of the keyframes). This naming limitation would only be true of css strings that begin with # like #keyframes and probably #media.
Further, because we have a standard mixin name used in our module files, we can access that consistently within our new mixin, while at the same time passing a variable in to select the proper variation of that mixin through a pattern match. So we get:
LESS 1.3.3 or under
// define mixin in mixin file
.keyframes(#selector, #name, #from, #to) {
#newline: `"\n"`; // Newline
.setVendor(#pre, #post, #vendor) {
(~"#{pre}##{vendor}keyframes #{name} {#{newline}from") {
.from(#from);
}
to {
.to(#to);
}
.Local(){}
.Local() when (#post=1) {
(~"}#{newline}#{selector}") {
-moz-animation: #name;
-webkit-animation: #name;
-o-animation: #name;
-ms-animation: #name;
animation: #name;
}
}
.Local;
}
.setVendor("" , 0, "-moz-");
.setVendor(~"}#{newline}", 0, "-webkit-");
.setVendor(~"}#{newline}", 0, "-o-");
.setVendor(~"}#{newline}", 0, "-ms-");
.setVendor(~"}#{newline}", 1, "");
}
LESS 1.4.0+
.keyframes(#selector, #name, #from, #to) {
#newline: `"\n"`; // Newline
.setVendor(#pre, #post, #vendor) {
#frames: ~"#{pre}##{vendor}keyframes #{name} {#{newline}from";
#{frames} {
.from(#from);
}
to {
.to(#to);
}
.Local(){}
.Local() when (#post=1) {
#animationSector: ~"}#{newline}#{selector}";
#{animationSector} {
-moz-animation: #name;
-webkit-animation: #name;
-o-animation: #name;
-ms-animation: #name;
animation: #name;
}
}
.Local;
}
.setVendor("" , 0, "-moz-");
.setVendor(~"}#{newline}", 0, "-webkit-");
.setVendor(~"}#{newline}", 0, "-o-");
.setVendor(~"}#{newline}", 0, "-ms-");
.setVendor(~"}#{newline}", 1, "");
}
Now Call Your Mixin
You can give it your own name, and just pass the straight pattern (all are no dot [.] and no quotes) for the pattern matches on the module mixins, but don't forget that you also need a selector string (which is quoted) to get the mixin to work right:
.keyframes('.changeColor', some-name, my-from, my-to);
.keyframes('.changeFontSize', another-name, another-from, another-to);
Which Gives You the Desired Output
#-moz-keyframes some-name {
from {
color: red;
}
to {
color: blue;
}
}
#-webkit-keyframes some-name {
from {
color: red;
}
to {
color: blue;
}
}
#-o-keyframes some-name {
from {
color: red;
}
to {
color: blue;
}
}
#-ms-keyframes some-name {
from {
color: red;
}
to {
color: blue;
}
}
#keyframes some-name {
from {
color: red;
}
to {
color: blue;
}
}
.changeColor {
-moz-animation: some-name;
-webkit-animation: some-name;
-o-animation: some-name;
-ms-animation: some-name;
animation: some-name;
}
#-moz-keyframes another-name {
from {
font-size: 1em;
}
to {
font-size: 2em;
}
}
#-webkit-keyframes another-name {
from {
font-size: 1em;
}
to {
font-size: 2em;
}
}
#-o-keyframes another-name {
from {
font-size: 1em;
}
to {
font-size: 2em;
}
}
#-ms-keyframes another-name {
from {
font-size: 1em;
}
to {
font-size: 2em;
}
}
#keyframes another-name {
from {
font-size: 1em;
}
to {
font-size: 2em;
}
}
.changeFontSize {
-moz-animation: another-name
-webkit-animation: another-name;
-o-animation: another-name;
-ms-animation: another-name;
animation: another-name;
}
Simplification
I just simplified a little ScottS' way, separateing #keframes from -animation:
.keyframes(#name, #from, #to) {
#newline: `"\n"`;
.Local(#x){};
.Local(#x) when (#x="") {(~"}#{newline}/*"){a:a}/**/};
.setVendor(#pre, #vendor) {
(~"#{pre}##{vendor}keyframes #{name} {#{newline}from") {
.from(#from);
}
to {
.to(#to);
}
.Local(#vendor);
}
.setVendor("" , "-webkit-");
.setVendor(~"}#{newline}", "-moz-");
.setVendor(~"}#{newline}", "-o-");
.setVendor(~"}#{newline}", "");
}
.animation(...) {
-webkit-animation: #arguments;
-moz-animation: #arguments;
-o-animation: #arguments;
animation: #arguments;
}
use:
.from(a1-from){ width: 10px; }
.to(a1-to) { width: 20px; }
.keyframes(a1-animation, a1-from, a1-to);
.selector {
// some other css
.animation(a1-animation 1s infinite linear);
}
output:
#-webkit-keyframes a1-animation {
from {
width: 10px;
}
to {
width: 20px;
}
}
#-moz-keyframes a1-animation {
from {
width: 10px;
}
to {
width: 20px;
}
}
#-o-keyframes a1-animation {
from {
width: 10px;
}
to {
width: 20px;
}
}
#keyframes a1-animation {
from {
width: 10px;
}
to {
width: 20px;
}
}
/* {
a: a;
}
/**/
.selector {
// some other css
-webkit-animation: a1-animation 1s infinite linear;
-moz-animation: a1-animation 1s infinite linear;
-o-animation: a1-animation 1s infinite linear;
animation: a1-animation 1s infinite linear;
}
little problem:
So animation is now separated from #keyframes, but we got to pay the price. There is a nasty:
/* {
a: a;
}
/**/
but it shouldn't be a problem -> propably all of us push CSS files through any kinds of minifiers which cut comments out.
You can also use my solution to generate CSS keyframes: https://github.com/thybzi/keyframes
Features:
Cross-browser keyframes generation (Firefox 5+, Chrome 3+, Safari 4+, Opera 12+, IE 10+)
Up to 16 timepoints in each keyframes rule (and the number can be easily augmented, if needed)
Mixins, variables and functions can be used for styling timepoints
Keyframes are created separately from animation rules, so:
multiple animation rules can use the same keyframe with different values for timing, repeating, etc,
multiple animations can be used within same animation rule
animations can be applied (not created!) inside any parent selector
Lightweight and (almost) neat LESS code
Basic usage:
// Preparing styles for animation points
.keyframes-item(fadeIn, 0%) {
opacity: 0;
}
.keyframes-item(fadeIn, 100%) {
opacity: 1;
}
// Generating keyframes
.keyframes(fadeIn);
// Applying animation to fade-in block in 1.5 seconds
.myBlock {
.animation(fadeIn 1.5s);
}
Its not really how you would use mixins.
You should do something along the lines of:
.mixin-one { ... }
.mixin-two { ... }
.target-style {
.mixin-one;
.mixin-two;
font-family: 'Comic Sans MS';
color: magenta;
}

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