-webkit-transform with two background layers? - css

I have an animation for a div with two semi-transparent backgrounds:
/* The animated background DIV. */
#-webkit-keyframes wind /*Keyframes*/
{
0%
{
background-position: 0px 0px, 0px 0px;
}
100%
{
background-position: 370px 370px, 424px 242px;
}
}
Have you noticed the comma? It's because I use
#animatedBkg
{
background-image: url('1.png'), url('2.png');
}
Both files contain alpha channel.
Now, I want to accelerate this code on iPhone. So, I've replaced CPU loader background-position with -webkit-transform: translate():
/* The animated background DIV. */
#-webkit-keyframes wind /*Keyframes*/
{
0%
{
-webkit-transform: translate(0px, 0px), translate(0px, 0px);
}
100%
{
-webkit-transform: translate(370px, 370px), translate(424px, 242px);
}
}
It doesn't work at all. But if I remove the comma, both bkg layers are moving synchronously (it seems only the first translate() works), but MUCH smoother. Actually, speed difference is so huge I just can't return to background-image.
Are there other options except making two divs: #animatedBkg1 and #animatedBkg2?
Regards,

Well, since translating is moving an object, and background-position is an object property, it looks like 2 divs are required. This means #animatedBkg1 and #animatedBkg2.

Related

Is there a way to prevent css keyframe percentages from fading into one another?

I am trying to create a super simple animation of a balloon using 4 different PNGs. I am using CSS to animate it by changing the background image at each keyframe. I don't want each keyframe to fade into the next but I can't use steps() since there is more than two images I'm trying to incorporate and to my understanding this only works with from and to. I have tried using jquery and looking into sprites to animate this instead but thought this would be simpler (for the sake of this being a very small aspect of my project), only it doesn't look quite right.
#balloon {
animation: balloon-float linear 2s infinite;
}
#keyframes balloon-float {
0% {
background-image: url(../img/balloon-1.png);
}
25% {
background-image: url(../img/balloon-2.png);
}
50% {
background-image: url(../img/balloon-3.png);
}
75% {
background-image: url(../img/balloon-4.png);
}
100% {
background-image: url(../img/balloon-1.png);
}
}
This is what I usually do in the CSS code embedded within my SVGs when I want something to "snap" instead of "glide" between values.
#balloon {
animation: balloon-float linear 2s infinite;
}
#keyframes balloon-float {
0%, 24.99%, 100%{
background-image: url(../img/balloon-1.png);
}
25%, 49.99%{
background-image: url(../img/balloon-2.png);
}
50%, 74.99%{
background-image: url(../img/balloon-3.png);
}
75%, 99.99%{
background-image: url(../img/balloon-4.png);
}
}

GPU Acceleration of animated and blurred content

Question: Why does my CPU register ~30% when blur is applied versus ~6% when no blur is applied to an animated object?
Details:
I have a set of randomly generated items on a page that have a CSS animation assigned (in a CSS file) and randomly generated values for width, height, and importantly, blur, applied inline.
CSS file styles looks like:
animation-name: rise;
animation-fill-mode: forwards;
animation-timing-function: linear;
animation-iteration-count: 1;
-webkit-backface-visibility: hidden;
-webkit-perspective: 1000;
-webkit-transform: translate3d(0,0,0);
transform: translateZ(0);
width, height and blur are applied inline via style attribute.
<div class="foo" style="width:99px;height:99px;
filter:blur(2px);
-webkit-filter:blur(2px) opacity(0.918866247870028);
-moz-filter:blur(2px) opacity(0.918866247870028);
-o-filter:blur(2px) opacity(0.918866247870028);
-ms-filter:blur(2px) opacity(0.918866247870028);"></div>
With the blur enabled my CPU usage is ~30%. When I disable the blur, CPU usage goes down to ~6%.
What's happening here? Is chrome only able to GPU accelerate when no blur is applied? If so, why?
Update 1:
The animation rise looks as follows:
#keyframes rise {
0% {
transform: translateY(0px);
}
100% {
transform: translateY(-1000px);
}
}
I don’t think the blur is actually causing your issues, it just seems to make it more noticeable than before. The problem is that the transform: translateY in your animation is overwriting the transform: translateZ(0) you’re using to force GPU acceleration.
This is a timeline recording for the the code you’re running right now, notice how there’s all this activity on the main and raster threads:
Now compare this to a recording where I applied will-change: transform to the .foo:
No activity on the main and raster whatsoever.
There’s two steps to applying this fix:
Apply will-change: transform to .foo. This will let the browser know you intend to change that property and have it render that element on the GPU to account for this.
No versions of Edge and IE support will-change at the moment. Therefore we’ll use transform: translate3d(0, -1000px, 0); in the animation to force GPU acceleration. Note this is a hack, so we’ll detect support for will-change and use transform: translateY in browsers that support it.
Final code:
#keyframes rise {
0% {
transform: translate3d(0, 0, 0);
}
100% {
transform: translate3d(0, 1000px, 0);
}
}
#supports (will-change: transform) {
#keyframes rise {
0% {
transform: translateY(0px);
}
100% {
transform: translateY(1000px);
}
}
}
div {
width: 100px;
height: 100px;
background: #f00;
animation: rise forwards 2s linear infinite;
will-change: transform;
}
See here for a working version: http://jsbin.com/mosuvikoto/edit?html,css,output
Don't blur it in inline styles. Put your blur in the style file.

animate flipping an element horizontally in IE11

I'm trying to animate an element back and forth, with a flip at each end. I'm using a CSS animation with scaleX(-1) at the end. It works fine in everything but IE, where it's shooting the element all the way off the page, then sliding it back into position.
#keyframes moveAndFlip {
48% {
transform: translateX(12vh) scaleX(1);
}
50% {
transform: translateX(12vh) scaleX(-1);
}
98% {
transform: translateX(0) scaleX(-1);
}
}
http://jsfiddle.net/pq9yqscy/2/
Is this a known issue in IE? Another way to tackle it?

CSS perspective with rotate & translate issue

I am attempting to make a type of CSS only slide transition from one content section to another. In order to do so in an interesting way, I use CSS's perspective and rotateX to in essence lay down the page content. I then am trying to slide the content out towards the bottom of the screen using translateY
Separately, both the translateY and the rotateX work perfectly, no matter what the perspective is. However, when combined, it only works with certain perspectives based on the window size and rotateY value
In this jsFiddle it works as I would like it to in the window sizes I have tried. The problem is that I would like the perspective value to be lower, around 250px, but I cannot do so without breaking the animation.
I tried using a higher rotateY degree instead of making the perspective lower but the same issue occurs
#keyframes slide {
0% { transform: perspective(450px); }
25% { transform: perspective(450px) rotateX(30deg); }
50%,100% { transform: perspective(450px) rotateX(30deg) translateY(100%); }
}
I have tested this on CSS Deck and jsFiddle both in FireFox and Chrome and it seems to be a consistent issue
Can anyone provide me with a reason why this is happening and offer a work around?
Try setting the perspective as a separate rule on a parent element (as opposed to being part of the transform in the animation).
.parent {
perspective: 250px;
}
#keyframes slide {
25% { transform: rotateX(30deg); }
50%, 100% { transform: rotateX(30deg) translateY(100%); }
}
Updated fiddle: http://jsfiddle.net/myajouri/DYpnU/
My reasoning:
The perspective does not change during the animation so there's no point in having it as part of the animation.
Since your elements occupy 100% of the parent's area, setting the perspective on the parent should produce the same result as setting it on the elements themselves (inside transform).
It seems to solve your problem (see fiddle above).
UPDATE: after more experimentation, I found that explicitly setting the translateY(0) initial value in the animation would solve the issue as well.
#keyframes slide {
0% { transform: perspective(150px); }
25% { transform: perspective(150px) rotateX(30deg) translateY(0); }
50%, 100% { transform: perspective(150px) rotateX(30deg) translateY(100%); }
}
Updated fiddle: http://jsfiddle.net/myajouri/YJS3v/
Only a slight improvement over myajouri answer.
At leats in Chrome, you can write
#-webkit-keyframes slide {
0% { -webkit-transform: perspective(50vh); }
10%,15% { -webkit-transform: perspective(50vh) rotateX(30deg) translateY(0%); }
50%,100% { -webkit-transform: perspective(50vh) rotateX(30deg) translateY(100%); }
}
Setting the perspective to the viewport height should make it more responsive that your current setting
demo
(Untested in other browsers)

-webkit-transform how can I change rotate() while preserving translate3d()?

What I am looking to do is change the translate3d transform of an element while a css3 animation is running on the element. When I try to do this, however, it seems that the animation resets the transform every time right before updating the animation such that the translation is always (0,0,0). I wish to have the animation running and still be able to translate it with javascript such as:
element.style.webkitTransform='translate3d(100px, 30px, 0px)';
I know it would be possible by using a second containing div to set the translation on while the inner div runs the animation, but I would like to be able to just use one div if possible. Do you know how to achieve this?
This is my css as it stands:
.class{
width:32px;
height:32px;
position:absolute;
background: transparent url('./img/sprite.png');
background-size:100%;
-webkit-transform: translate3d(48px, 176px, 0px);
-webkit-transition-property: -webkit-transform;
-webkit-transition-duration: 100ms;
-webkit-animation:spin .75s infinite linear;
}
#-webkit-keyframes spin {
0% { -webkit-transform:rotate(0deg); }
100% { -webkit-transform:rotate(360deg); }
}
You can concatenate several transformation functions with a space:
-webkit-transform: translate3d(48px, 176px, 0px) rotateY(30deg) rotateX(10deg);

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