85 lines
2.7 KiB
Markdown
85 lines
2.7 KiB
Markdown
---
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id: 587d78a9367417b2b2512aea
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title: Make Motion More Natural Using a Bezier Curve
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challengeType: 0
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videoUrl: ''
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localeTitle: 使用贝塞尔曲线使运动更自然
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---
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## Description
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<section id="description">这一挑战激发了一个元素来复制被玩杂耍的球的运动。先前的挑战涵盖了<code>linear</code>和<code>ease-out</code>三次贝塞尔曲线，但两者都没有准确描述杂耍运动。您需要为此自定义Bezier曲线。当<code>animation-iteration-count</code>设置为无限时， <code>animation-timing-function</code>在每个关键帧处自动循环。由于在动画持续时间的中间设置了关键帧规则（ <code>50%</code> ），因此在球的向上和向下移动时会产生两个相同的动画进度。下面的三次贝塞尔曲线模拟了一个杂耍运动： <code>cubic-bezier(0.3, 0.4, 0.5, 1.6);</code>请注意，y2的值大于1.虽然三次贝塞尔曲线映射在1乘1坐标系上，并且它只能接受0到1的x值，但y值可以设置为大于1的数字。这导致弹跳运动，非常适合模拟杂耍球。 </section>
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## Instructions
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<section id="instructions">将id为<code>green</code>的元素的<code>animation-timing-function</code>的值更改为<code>cubic-bezier</code>函数，x1，y1，x2，y2值分别设置为0.311,0.441,0.444,1.648。 </section>
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## Tests
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<section id='tests'>
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```yml
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tests:
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- text: 具有id <code>green</code>的元素的<code>animation-timing-function</code>属性的值应该是具有指定的x1，y1，x2，y2值的<code>cubic-bezier</code>函数。
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testString: 'assert($("#green").css("animation-timing-function") == "cubic-bezier(0.311, 0.441, 0.444, 1.649)", "The value of the <code>animation-timing-function</code> property for the element with the id <code>green</code> should be a <code>cubic-bezier</code> function with x1, y1, x2, y2 values as specified.'
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```
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</section>
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## Challenge Seed
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<section id='challengeSeed'>
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<div id='html-seed'>
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```html
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<style>
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.balls {
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border-radius: 50%;
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position: fixed;
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width: 50px;
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height: 50px;
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top: 60%;
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animation-name: jump;
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animation-duration: 2s;
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animation-iteration-count: infinite;
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}
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#red {
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background: red;
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left: 25%;
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animation-timing-function: linear;
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}
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#blue {
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background: blue;
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left: 50%;
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animation-timing-function: ease-out;
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}
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#green {
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background: green;
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left: 75%;
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animation-timing-function: cubic-bezier(0.69, 0.1, 1, 0.1);
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}
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@keyframes jump {
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50% {
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top: 10%;
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}
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}
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</style>
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<div class="balls" id="red"></div>
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<div class="balls" id="blue"></div>
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<div class="balls" id="green"></div>
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```
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</div>
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</section>
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## Solution
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<section id='solution'>
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```js
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// solution required
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```
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</section>
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