freeCodeCamp/curriculum/challenges/english/01-responsive-web-design/applied-visual-design/change-animation-timing-with-keywords.english.md

id, title, challengeType, isHidden, videoUrl, forumTopicId

id	title	challengeType	isHidden	videoUrl	forumTopicId
587d78a8367417b2b2512ae7	Change Animation Timing with Keywords	0	false	https://scrimba.com/c/cJKvwCM	301045

Description

In CSS animations, the animation-timing-function property controls how quickly an animated element changes over the duration of the animation. If the animation is a car moving from point A to point B in a given time (your animation-duration), the animation-timing-function says how the car accelerates and decelerates over the course of the drive. There are a number of predefined keywords available for popular options. For example, the default value is ease, which starts slow, speeds up in the middle, and then slows down again in the end. Other options include ease-out, which is quick in the beginning then slows down, ease-in, which is slow in the beginning, then speeds up at the end, or linear, which applies a constant animation speed throughout.

Instructions

For the elements with id of ball1 and ball2, add an animation-timing-function property to each, and set #ball1 to linear, and #ball2 to ease-out. Notice the difference between how the elements move during the animation but end together, since they share the same animation-duration of 2 seconds.

Tests

tests:
  - text: The value of the <code>animation-timing-function</code> property for the element with the id <code>ball1</code> should be linear.
    testString: const ball1Animation = $('#ball1').css('animation-timing-function').replace(/\s/g, '');assert(ball1Animation == 'linear' || ball1Animation == 'cubic-bezier(0,0,1,1)');
  - text: The value of the <code>animation-timing-function</code> property for the element with the id <code>ball2</code> should be ease-out.
    testString: const ball2Animation = $('#ball2').css('animation-timing-function').replace(/\s/g, ''); assert(ball2Animation == 'ease-out' || ball2Animation == 'cubic-bezier(0,0,0.58,1)');

Challenge Seed

<style>

  .balls {
    border-radius: 50%;
    background: linear-gradient(
      35deg,
      #ccffff,
      #ffcccc
    );
    position: fixed;
    width: 50px;
    height: 50px;
    margin-top: 50px;
    animation-name: bounce;
    animation-duration: 2s;
    animation-iteration-count: infinite;
  }
  #ball1 {
    left:27%;

  }
  #ball2 {
    left:56%;

  }

  @keyframes bounce {
    0% {
      top: 0px;
    }
    100% {
      top: 249px;
    }
  }

</style>

<div class="balls" id="ball1"></div>
<div class="balls" id="ball2"></div>

Solution

<style>
  .balls {
    border-radius: 50%;
    background: linear-gradient(
      35deg,
      #ccffff,
      #ffcccc
    );
    position: fixed;
    width: 50px;
    height: 50px;
    margin-top: 50px;
    animation-name: bounce;
    animation-duration: 2s;
    animation-iteration-count: infinite;
  }
  #ball1 {
    left:27%;
    animation-timing-function: linear;
  }
  #ball2 {
    left:56%;
    animation-timing-function: ease-out;
  }

  @keyframes bounce {
    0% {
      top: 0px;
    }
    100% {
      top: 249px;
    }
  }
</style>
<div class="balls" id="ball1"></div>
<div class="balls" id="ball2"></div>