animation-timing-function

CSS animation-timing-function属性定义CSS动画在每一动画周期中执行的节奏。可能值为一或多个 <timing-function>。

对于关键帧动画来说，timing function作用于一个关键帧周期而非整个动画周期，即从关键帧开始开始，到关键帧结束结束。

定义于一个关键帧区块的缓动函数(animation timing function)应用到改关键帧；另外，若该关键帧没有定义缓动函数，则使用定义于整个动画的缓动函数。

/* Keyword values */
animation-timing-function: ease;
animation-timing-function: ease-in;
animation-timing-function: ease-out;
animation-timing-function: ease-in-out;
animation-timing-function: linear;
animation-timing-function: step-start;
animation-timing-function: step-end;

/* Function values */
animation-timing-function: cubic-bezier(0.1, 0.7, 1.0, 0.1);
animation-timing-function: steps(4, end);
animation-timing-function: frames(10);

/* Multiple animations */
animation-timing-function: ease, step-start, cubic-bezier(0.1, 0.7, 1.0, 0.1);

/* Global values */
animation-timing-function: inherit;
animation-timing-function: initial;
animation-timing-function: unset;

通常用animation简写定义整个动画属性更为方便。

<timingfunction>

每个 <timing-function>代表了应用于动画的timing function，定义于animation-property.

<timing-function>#
where 
<timing-function> = linear | <cubic-bezier-timing-function> | <step-timing-function>
where 
<cubic-bezier-timing-function> = ease | ease-in | ease-out | ease-in-out | cubic-bezier(<number <a href="/zh-CN/docs/CSS/Value_definition_syntax#Brackets" title="Brackets: enclose several entities, combinators, and multipliers to transform them as a single component">[0,1]>, <number>, <number <a href="/zh-CN/docs/CSS/Value_definition_syntax#Brackets" title="Brackets: enclose several entities, combinators, and multipliers to transform them as a single component">[0,1]>, <number>)
<step-timing-function> = step-start | step-end | steps(<integer>[, <step-position>]?)
where 
<step-position> = jump-start | jump-end | jump-none | jump-both | start | end

参见 CSS animations

• Using CSS animations
• AnimationEvent