CSS animation: Dynamic effects beyond CSS transition

CSS animation is an advanced version of CSS transition. It supports infinite loops, uses keyframes to create complex effects, and can be paused during animation playback. This article will explore all aspects of CSS animation to help you easily master this powerful web design technology.

Create CSS animation: Keyframes and animation properties

To create a CSS animation, you first need to define a @keyframes rule that specifies the animation name and groups the keyframe rules. Then, apply the animation to the target element.

CSS animation can be controlled through a variety of attributes, including: animation-delay (animation delay), animation-duration (animation duration), animation-name (animation name), animation-timing-function (animation timing function), ??> (number of animation iterations), animation-iteration-count (animation direction), animation-direction (animation playback status), and animation-play-state (animation fill mode). animation-fill-mode

Animation control: Pause and loop

Use the

attribute to pause animation. Setting the animation-play-state property to animation-iteration-count can achieve infinite loops. infinite

Performance and accessibility: Use animation with caution

While CSS animation can enhance the user experience, it should be used with caution because it may pose a risk of accessibility, for example: patients with certain diseases may experience dizziness or nausea from the animation, while those with photosensitive epilepsy may have the potential to be used in people with photosensitive epilepsy. Epilepsy seizures caused by animation. In addition, the performance of animations is also affected by animation properties, and some properties may trigger reflow or redraw, resulting in performance degradation on low-performance devices.

Difference between animation and transition: Key differences

There are some key differences between CSS animations and their sister technology CSS transition:

• Elegant downgrade: Animation lacks an elegant downgrade mechanism. When the browser does not support it, the animation will be invalid and JavaScript is required as an alternative.
• Loop: Animation can be repeated, even repetitive indefinitely; while transitions are always limited.
• Keyframes: Animation uses keyframes to create more complex and detailed effects.
• Pause: Animation can be paused during playback cycle.

Browser compatibility: Mainstream browser support

The latest versions of all mainstream browsers support CSS animation. Firefox 15 and earlier require the

prefix; later does not. Internet Explorer 10 and 11, as well as all versions of Microsoft Edge, also supports prefixed animations. -moz-

Detection animation support: JavaScript method

CSS animation support can be detected in various ways. The first method is to test whether the window method of the CSSKeyframeRule object exists:

const hasAnimations = 'CSSKeyframeRule' in window;

If the browser supports @supports rules and CSS.supports() API, you can use the following methods:

const hasAnimations = CSS.supports('animation-duration: 2s');

Create the first animation: Keyframe rules and animation applications

First, define the animation using the @keyframes rule. @keyframesRules have two functions:

• Set the animation name
• Group keyframe rules

For example, create an animation called pulse:

@keyframes pulse {
    from {
        transform: scale(0.5);
        opacity: .8;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

Then, apply the animation to the element:

.pulse {
    animation: pulse 500ms;
}

Detailed explanation of animation attributes: carefully control animation effects

Although using animation shorthand attributes is simpler, sometimes using long format attributes is clearer. The following are the long format animation properties:

Properties	Description	Initial Value
animation-delay	Waiting time before animation execution	0s (Execute now)
animation-duration	Animation cycle duration	0s (no animation)
animation-name	屬性 描述 初始值 animation-delay 動畫執(zhí)行前的等待時間 0s (立即執(zhí)行) animation-duration 動畫周期持續(xù)時間 0s (無動畫) animation-name @keyframes規(guī)則的名稱 none animation-timing-function 計算起始狀態(tài)和結(jié)束狀態(tài)之間值的計算方式 ease animation-iteration-count 動畫重復(fù)次數(shù) 1 animation-direction 動畫是否反向播放 normal (不反向) animation-play-state 動畫是運行還是暫停 running animation-fill-mode 指定動畫未運行時應(yīng)用的屬性值 none The name of the rule	none
animation-timing-function	How to calculate the value between the start and end states	ease
animation-iteration-count	Number of animation repetitions	1
animation-direction	Is the animation played backward?	normal (not reverse)
animation-play-state	Is the animation running or pausing	running
animation-fill-mode	Specify the attribute value applied when the animation is not running	none

Loop animation: animation-iteration-count attribute

Setting the animation-iteration-count property to infinite can make the animation loop infinitely.

Animation direction: animation-direction attribute

The

animation-direction attribute accepts four values: normal, reverse, alternate, and alternate-reverse, which are used to control the playback direction of the animation.

Percent Keyframes: Create more complex animation sequences

More complex animation sequences can be created using percentage keyframes.

Animation fill mode: animation-fill-mode attribute

animation-fill-mode Attributes control the element style before and after the animation begins.

Pause animation: animation-play-state attribute

Use the animation-play-state attribute to pause and restore animations.

Detection of animation events: animationstart, animationend and animationitation events

You can use JavaScript to listen for animationstart, animationend and animationiteration events.

Performance optimization: Select the appropriate animation attributes

Some properties perform better than other properties. Avoid animations of properties that trigger reflow or redraw.

FAQ

The article also includes frequently asked questions about CSS animation, covering the differences between CSS animation and CSS transition, animation speed control, the role of @keyframes rules, layout animation, reverse playback animation, animation-fill-mode attributes, Pause animation, infinite loop animation, SVG element animation, and the differences between animation-delay and animation-end-delay.

By studying this article, you will be able to create more refined and complex CSS animation effects to improve the interactivity and user experience of the web page. Remember that when using animations, you always prioritize performance and accessibility.

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