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Amp font is an amp-component in amp which basically helps to trigger and monitor custom fonts to amp page. This chapter discusses amp-font in detail.
To work with amp-font, we need to add following javascript file −
<script async custom-element = "amp-font" src = "https://cdn.ampproject.org/v0/amp-font-0.1.js"> </script>
The amp-font component is used for controlling the time taken for font loading. It has a timeout attribute, which takes time in milliseconds.By default, it is 3000ms. The component allows to add/remove classes from document.documentElement or document.body depending upon whether the font required is loaded or got into an error state.
The format for amp-font tag is as shown below −
<amp-font layout = "nodisplay" font-family = "Roboto Italic" timeout = "2000" on-error-remove-class = "robotoitalic-loading" on-error-add-class = "robotoitalic-missing" on-load-remove-class = "robotoitalic-loading" on-load-add-class = "robotoitalic-loaded"> </amp-font>
A working example on how to use amp-font in amp pages is as shown here −
Example
<!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 Font</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>
<cript async custom-element = "amp-font"
src = "https://cdn.ampproject.org/v0/amp-font-0.1.js"
></script>
<style amp-custom>
@font-face {
font-family: ''This font is not available'';
font-style: normal;
font-weight: 300;
src: url(fonts/MissingFont.ttf) format(''truetype'');
}
.font-missing {
color:red;
font-size:25px;
}
</style>
</head>
<body>
<h1>Google AMP - Amp Font</h1>
<amp-font
layout = "nodisplay"
font-family = "Font Does Not exist"
timeout = "2000"
on-error-remove-class = "font-missing"
on-error-add-class = "font-error"
on-load-remove-class = "font-missing"
on-load-add-class = "font-loaded">
</amp-font>
<p class = "font-missing">
Example of amp-font component to show how
attributes on-error-remove-class,
on-error-add-class, on-load-remove-class
and on-load-add-class works when the font
file to be loaded does not exist.
</p>
</body>
</html>
Output
The output of the sample code given above is as shown below −
An example of amp-font when font file loads successfully is shown here −
Example
<!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 Font</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-font"
src = "https://cdn.ampproject.org/v0/amp-font-0.1.js">
</script>
<style amp-custom>
@font-face {
font-family: ''This font is not available'';
font-style: normal;
font-weight: 300;
src: url(fonts/MissingFont.ttf)
format(''truetype'');
}
@font-face {
font-family: ''Roboto Italic'';
font-style: normal;
font-weight: 300;
src:url(fonts/Roboto-Italic.ttf) format(''truetype'');
}
.font-missing {
color:red;
font-size:25px;
}
.robotoitalic-loading {
color: green;
}
.robotoitalic-loaded {
font-size:25px;
color: blue;
}
.robotoitalic-missing {
color: red;
}
.robotoitalic {
font-family: ''Roboto Italic'';
}
</style>
</head>
<body>
<h1>Google AMP - Amp Font</h1>
<amp-font
layout = "nodisplay"
font-family = "Font Does Not exist"
timeout = "2000"
on-error-remove-class = "font-missing"
on-error-add-class = "font-error"
on-load-remove-class = "font-missing"
on-load-add-class = "font-loaded">
</amp-font>
<p class="font-missing">
Example of amp-font component to show
how attributes on-error-remove-class,
on-error-add-class, on-load-remove-class
and on-load-add-class works when the
font file to be loaded does not exist.
</p>
<amp-font
layout = "nodisplay"
font-family = "Roboto Italic"
timeout = "2000"
on-error-remove-class = "robotoitalic-
loading"
on-error-add-class = "robotoitalic-missing"
on-load-remove-class = "robotoitalic-loading"
on-load-add-class = "robotoitalic-loaded">
</amp-font>
<p class = "robotoitalic">
Example of amp-font component to show how
attributes on-error-remove-class,
on-error-add-class, on-load-remove-class
and on-load-add-class works when the font
file exists and loads fine.
</p>
</body>
</html>
Output
The output of the sample code given above is as shown below −
The above example shows how to work with font attributes like font-family,timeout,on-error-remove-class,on-error-add-class,on-load-remove-class,on-load-add-class.The classes decide whether there is error or success in font loading.
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