Discuss how to write and implement CSS animations

CSS animation refers to the technology of using CSS to achieve animation effects in web pages. Compared with traditional JavaScript animation, CSS animation has the advantages of easy operation, high efficiency, smoothness, and easy maintenance, so it is widely used in modern web design.

CSS animation can make web pages more lively and interesting, giving users a better visual experience. Here, we will discuss how to write and implement CSS animations.

1. Use keyframe animation

Keyframe animation is the most basic animation method in CSS. The so-called keyframe refers to important time points or key points in the animation. In keyframe animation, we usually need to use the @keyframes rule to define the keyframes of the animation. By defining the transition effect between keyframes, we can achieve a coherent presentation of the animation effect.

Sample code:

div{
  width: 100px;
  height: 100px;
  background-color: red;
  animation: myanimation 2s ease-in-out infinite;
}

@keyframes myanimation{
  0% {transform: rotate(0deg);}
  50% {transform: rotate(180deg);}
  100% {transform: rotate(360deg);}
}

In this example, we define a div element and apply the myanimation animation to the element through the animation attribute superior. @keyframesRules are used to define key frames of animation.

myanimationThe key frames of the animation include three key frames: 0%, 50%, and 100%. Among them, 0% is the starting state of the animation, defining the element without any changes; 50% is the intermediate state, defining the element to rotate 180 degrees; 100% is the end state, defining the element to rotate 360 ​​degrees.

The transform attribute here is used to change the transformation effect of the element. Because the state of each keyframe is calculated by linear interpolation, the state of the element automatically transitions between keyframes. Finally, we apply the animation effect to the element and make the animation smoother by specifying the animation time of 2s and the easing function of ease-in-out.

2. Use CSS transition

CSS transition refers to the animation of specifying certain attributes of an element. When it changes, the browser automatically transitions the element from the old state to the new state. Transitions are often used to create a smooth transition effect when clicking a button changes the state of some elements. By specifying the transition attribute of the element and setting the duration, time function and delay time of the transition effect, the application of transition animation can be realized.

Sample code:

.btn:hover{
  background-color: red;
  color: #fff;
  transition: all 0.3s ease-in-out;
}

In this example, we set up a button that changes the button background color to red and the text color to white when the mouse hovers over it . At the same time, we use the transition attribute to change the transition effect of the all attribute (that is, all possible attributes) to a time of 0.3 seconds, ease-in-out easing function.

When we hover over the button, CSS will automatically and smoothly transition the background color and text color from the old state to the new state within 0.3 seconds, giving users a smoother and more natural effect.

3. Apply CSS animation library

In actual development, we can also choose to use a professional CSS animation library to help us achieve complex animation effects more easily. Common CSS animation libraries include Animate.css, Hover.css, Magic.css, etc. These libraries provide a rich set of preset animation effects. You only need to simply import the library file and add the corresponding CSS class to the element. achieve results.

For example, when using the Animate.css library, we only need to introduce the library file into the HTML file and add the corresponding class name to the element to achieve the corresponding animation effect, for example:

<link rel="stylesheet" href="animate.css">

<div class="animated bounce">我会弹跳效果</div>

Here, we introduce the Animate.css library file, add a div element, and add the animated bounce class to it. This will give the element a dynamic bouncing effect when entering and leaving the page, giving users a more lively and interesting experience.

In this way, you can get rich and colorful animation effects, make the web page more vivid and interesting, and enhance the user experience.

In short, CSS animation is an essential tool for creating vivid and interesting web pages. After mastering the basic animation principles, we can flexibly apply keyframe animation, transition, CSS animation library and other technologies according to our needs to achieve diverse and personalized animation effects.

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