Google AMP - 动画
Amp-animation 是一个 amp 组件,它定义了要在其他 amp 组件上使用的动画。本章将详细讨论它们。
要使用 amp-animation,我们需要添加以下脚本 −
<script async custom-element = "amp-animation"
src = "https://cdn.ampproject.org/v0/amp-animation-0.1.js">
</script>
动画的细节在 json 结构中定义。
amp-animation 的基本结构如下所示 −
<amp-animation layout = "nodisplay">
<script type = "application/json">
{
// Timing properties
...
"animations": [
{
// animation 1
},
...
{
// animation n
}
]
}
</script>
</amp-animation>
animation 动画组件由以下 − 选择器、变量、时间属性、关键帧等组成。
{
"selector": "#target-id",
// Variables
// Timing properties
// Subtargets
...
"keyframes": []
}
selector 选择器
在这里我们需要给出将使用动画的元素的类或 ID。
变量
它们是定义为在关键帧内使用的值。变量使用 var() 定义。
示例
{
"--delay": "0.5s",
"animations": [
{
"selector": "#target1",
"delay": "var(--delay)",
"--x": "150px",
"--y" : "200px",
"keyframes": {
"transform": "translate(var(--x), var(--y, 0px)"
}
}
]
}
此处 delay、x 和 y 是变量,变量的值在所示示例中定义。
时间属性
您可以在此处定义动画的持续时间和延迟。以下是支持的计时属性 −
| 属性 | 值 | 说明 |
|---|---|---|
| duration | 时间属性。值必须以毫秒为单位。 | 动画使用的持续时间。 |
| delay | 时间属性。值必须以毫秒为单位。 | 动画开始执行前的延迟 |
| endDelay | 时间属性。值必须以毫秒或秒为单位。 | 动画完成时应用的给定延迟。 |
| iterations | 值必须为数字。 | 动画必须重复的次数。 |
| iterationStart | 值必须为数字。 | 效果开始动画的时间偏移量。 |
| easing | 值为字符串 | 用于获取动画的缓动效果。一些缓动的示例有 linear 、ease、ease-in、ease-out 、ease-in-out 等 |
| direction | 值是一个字符串 | "normal"、"reverse"、"alternate"或"alternate-reverse"之一。 |
| fill | 值是一个字符串 | 值可以是"none"、"forwards"、"backwards"、"both"、"auto"。 |
Keyframes
Keyframes 关键帧可以通过多种方式定义,例如对象形式或数组形式。请考虑以下示例。
示例
"keyframes": {"transform": "translate(100px,200px)"}
示例
{
"keyframes": {
"opacity": [1, 0],
"transform": ["scale(1)", "scale(2)"]
}
}
示例
{
"keyframes": [
{"opacity": 1, "transform": "scale(1)"},
{"opacity": 0, "transform": "scale(2)"}
]
}
示例
{
"keyframes": [
{"easing": "ease-out", "opacity": 1, "transform": "scale(1)"},
{"opacity": 0, "transform": "scale(2)"}
]
}
使用 CSS 的关键帧
<style amp-custom>
div {
width: 100px;
height: 100px;
background-color: red;
position: relative;
margin: 0 auto;
transform:scale(3);
}
@keyframes example { 0% {transform:scale(3)}
75% {transform:scale(2)}
100% {transform:scale(1)}
}
</style>
<amp-animation layout = "nodisplay">
<script type = "application/json">
{
"duration": "4s",
"keyframes": "example"
}
</script>
</amp-animation>
有一些 CSS 属性可以在关键帧内使用。受支持的属性称为白名单属性。以下是可以在关键帧内使用的白名单属性 −
- opacity
- transform
- visibility
- 'offsetDistance'
注意 − 使用白名单属性以外的任何其他属性都会在控制台中抛出错误。
现在让我们通过一个简单的示例来了解,当在图像上应用动画时,该示例将旋转图像。在此示例中,我们使用 amp-animation 旋转图像。
示例
<!doctype html>
<html amp lang = "en">
<head>
<meta charset = "utf-8">
<script async src = "https://cdn.ampproject.org/v0.js"></script>
<title>Google AMP - Amp Video</title>
<link rel = "canonical" href = "http://example.ampproject.org/article-metadata.html">
<meta name = "viewport" content = "width = device-width, minimum-scale = 1,initial-scale = 1">
<style amp-boilerplate>
body{
-webkit-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;-moz-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;-ms
-amp-start 8s steps(1,end) 0s 1 normal both;animation:
-amp-start 8s steps(1,end) 0s 1 normal both
}
@-webkit-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-o-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}
</style>
<noscript>
<style amp-boilerplate>
body{
-webkit-animation:none;
-moz-animation:none;
-ms-animation:none;
animation:none
}
</style>
</noscript>
<script async custom-element = "amp-animation"
src =" https://cdn.ampproject.org/v0/amp-animation-0.1.js">
</script>
<style amp-custom>
amp-img {
border: 1px solid black;
border-radius: 4px;
padding: 5px;
}
</style>
</head>
<body>
<h3>Google AMP - Amp Animation Example</h3>
<amp-animation id = "anim1" layout = "nodisplay" trigger = "visibility">
<script type = "application/json">
{
"duration": "1s",
"fill": "both",
"direction": "alternate",
"animations": [
{
"selector": "#image1",
"easing": "cubic-bezier(0,0,.21,1)",
"keyframes": {
"transform": "rotate(20deg)"
}
}
]
}
</script>
</amp-animation>
<br/>
<br/>
<amp-img
id = "image1"
src = "images/christmas1.jpg"
width = 300
height = 250
layout = "responsive">
</amp-img>
<br/>
</body>
</html>
输出
上面使用的 amp-animation 细节在下面显示的代码中给出 −
<amp-animation id = "anim1" layout = "nodisplay" trigger = "visibility">
<script type = "application/json">
{
"duration": "1s",
"fill": "both",
"direction": "alternate",
"animations": [
{
"selector": "#image1",
"easing": "cubic-bezier(0,0,.21,1)",
"keyframes": {
"transform": "rotate(20deg)"
}
}
]
}
</script>
</amp-animation>
此处的选择器是应用旋转动画的图像的 id −
<amp-img id = "image1" src = "images/christmas1.jpg" width = 300 height = 250 layout = "responsive"> </amp-img>
使用 CSS 中的关键帧的示例
示例
<!doctype html>
<html amp lang = "en">
<head>
<meta charset = "utf-8">
<script async src = "https://cdn.ampproject.org/v0.js"></script>
<title>Google AMP - Amp Video</title>
<link rel = "canonical" href = "http://example.ampproject.org/article-metadata.html">
<meta name = "viewport" content = "width = device-width,minimum-scale = 1,initial-scale = 1">
<style amp-boilerplate>
body{
-webkit-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;-moz-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;-ms-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;animation:
-amp-start 8s steps(1,end) 0s 1 normal both
}
@-webkit-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-o-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}
</style>
<noscript>
<style amp-boilerplate>
body{
-webkit-animation:none;
-moz-animation:none;
-ms-animation:none;
animation:none
}
</style>
</noscript>
<script async custom-element = "amp-animation"
src = "https://cdn.ampproject.org/v0/amp-animation-0.1.js">
</script>
<style amp-custom>
div {
width: 100px;
height: 100px;
background-color: red;
position: relative;
margin: 0 auto;
transform:scale(3);
}
@keyframes example {
0% {transform:scale(3)}
75% {transform:scale(2)}
100% {transform:scale(1)}
}
</style>
</head>
<body>
<h3>Google AMP - Amp Animation Example</h3>
<amp-animation id = "anim1" layout = "nodisplay" trigger = "visibility">
<script type = "application/json">
{
"duration": "3s",
"fill": "both",
"direction": "alternate",
"animations": [{
"selector": "#image1",
"easing": "cubic-bezier(0,0,.21,1)",
"keyframes":"example"
}]
}
</script>
</amp-animation>
<br/>
<br/>
<div id = "image1"></div>
<br/>
</body>
</html>
输出
动画触发器
如果触发器 = "visibility",则默认应用动画。为了在事件上启动动画,我们必须删除触发器 = "visibility",并添加事件以启动动画,如下例所示 −
示例
<!doctype html>
<html amp lang = "en">
<head>
<meta charset = "utf-8">
<script async src = "https://cdn.ampproject.org/v0.js"></script>
<title>Google AMP - Amp Video</title>
<link rel = "canonical" href = "http://example.ampproject.org/article-metadata.html">
<meta name = "viewport" content = "width = device-width,
minimum-scale = 1,initial-scale = 1">
<style amp-boilerplate>
body{
-webkit-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;-moz-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;-ms-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;animation:
-amp-start 8s steps(1,end) 0s 1 normal both
}
@-webkit-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-o-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}
</style>
<noscript>
<style amp-boilerplate>
body{
-webkit-animation:none;
-moz-animation:none;
-ms-animation:none;
animation:none}
</style>
</noscript>
<script async custom-element = "amp-animation"
src = "https://cdn.ampproject.org/v0/amp-animation-0.1.js">
</script>
<style amp-custom>
div {
width: 100px;
height: 100px;
background-color: red;
position: relative;
margin: 0 auto;
transform:scale(2);
}
@keyframes example {
0% {transform:scale(2)}
75% {transform:scale(1)}
100% {transform:scale(0.5)}
}
button{
background-color: #ACAD5C;
color: white;
padding: 12px 20px;
border: none;
border-radius: 4px;
cursor: pointer;
float: left;
}
</style>
</head>
<body>
<h3>Google AMP - Amp Animation Example</h3>
<amp-animation id = "anim1" layout = "nodisplay">
<script type = "application/json">
{
"duration": "3s",
"fill": "both",
"direction": "alternate",
"animations": [{
"selector": "#image1",
"easing": "cubic-bezier(0,0,.21,1)",
"keyframes":"example"
}]
}
</script>
</amp-animation>
<button on = "tap:anim1.start">Start</button>
<br/>
<br/>
<div id = "image1"></div>
</body>
</html>
请注意,点击开始按钮时动画将开始。
输出
我们在 On 上使用名为 start 的操作来启动动画。同样,还支持其他操作,如下所示 −
- start
- pause
- restart
- resume
- togglePause
- seekTo
- reverse
- finish
- cancel
让我们看一个可以使用该操作的工作示例。
示例
<!doctype html>
<html amp lang = "en">
<head>
<meta charset = "utf-8">
<script async src = "https://cdn.ampproject.org/v0.js"></script>
<title>Google AMP - Amp Video</title>
<link rel = "canonical" href = "http://example.ampproject.org/article-metadata.html">
<meta name = "viewport" content = "width=device-width,minimum-scale = 1,initial-scale = 1">
<style amp-boilerplate>
body{
-webkit-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;-moz-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;-ms-animation:
-amp-start 8s steps(1,end) 0s 1 normal both;animation:
-amp-start 8s steps(1,end) 0s 1 normal both
}
@-webkit-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-moz-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-ms-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@-o-keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}@keyframes
-amp-start{from{visibility:hidden}to{visibility:visible}}
</style>
<noscript>
<style amp-boilerplate>
body{
-webkit-animation:none;
-moz-animation:none;
-ms-animation:none;
animation:none}
</style>
</noscript>
<script async custom-element = "amp-animation"
src = "https://cdn.ampproject.org/v0/amp-animation-0.1.js">
</script>
<style amp-custom>
#image1 {
width: 100px;
height: 100px;
background-color: red;
position: relative;
margin: 0 auto;
transform:scale(2);
}
@keyframes example {
0% {transform:scale(2)}
75% {transform:scale(1)}
100% {transform:scale(0.5)}
}
button1{
background-color: #ACAD5C;
color: white;
padding: 12px 20px;
border: none;
border-radius: 4px;
cursor: pointer;
float: left;
}
</style>
</head>
<body>
<h3>Google AMP - Amp Animation Example</h3>
<amp-animation id = "anim1" layout = "nodisplay">
<script type = "application/json">
{
"duration": "3s",
"fill": "both",
"direction": "alternate",
"animations": [{
"selector": "#image1",
"easing": "cubic-bezier(0,0,.21,1)",
"keyframes":"example"
}]
}
</script>
</amp-animation>
<button on = "tap:anim1.start">Start</button>
<button on = "tap:anim1.pause">Pause</button>
<button on = "tap:anim1.resume">Resume</button>
<button on = "tap:anim1.reverse">Reverse</button>
<button on = "tap:anim1.cancel">cancel</button>
<button on = "tap:anim1.finish">finish</button>
<button on = "tap:anim1.togglePause">togglePause</button>
<button on = "tap:anim1.seekTo(percent = 1.00)">seekTo(100%)</button>
<br/>
<br/>
<br/>
<br/>
<div id="image1"></div>
</body>
</html>
输出

