FontData
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The FontData
interface of the Local Font Access API represents a single local font face.
Instance properties
FontData.family
Read only Experimental-
Returns the family of the font face.
FontData.fullName
Read only Experimental-
Returns the full name of the font face.
FontData.postscriptName
Read only Experimental-
Returns the PostScript name of the font face.
FontData.style
Read only Experimental-
Returns the style of the font face.
Instance methods
FontData.blob()
Read only Experimental-
Returns a
Promise
that fulfills with aBlob
containing the raw bytes of the underlying font file.
Examples
For a working live demo, see Font Select Demo.
Font enumeration
The following snippet will query for all available fonts, and log metadata. This could be used, for example, to populate a font-picker control.
js
async function logFontData() {
try {
const availableFonts = await window.queryLocalFonts();
for (const fontData of availableFonts) {
console.log(fontData.postscriptName);
console.log(fontData.fullName);
console.log(fontData.family);
console.log(fontData.style);
}
} catch (err) {
console.error(err.name, err.message);
}
}
Accessing low-level data
The blob()
method provides access to low-level SFNT data — this is a font file format that can contain other font formats, such as PostScript, TrueType, OpenType, or Web Open Font Format (WOFF).
js
async function computeOutlineFormat() {
try {
const availableFonts = await window.queryLocalFonts({
postscriptNames: ["ComicSansMS"],
});
for (const fontData of availableFonts) {
// `blob()` returns a Blob containing valid and complete
// SFNT-wrapped font data.
const sfnt = await fontData.blob();
// Slice out only the bytes we need: the first 4 bytes are the SFNT
// version info.
// Spec: https://docs.microsoft.com/en-us/typography/opentype/spec/otff#organization-of-an-opentype-font
const sfntVersion = await sfnt.slice(0, 4).text();
let outlineFormat = "UNKNOWN";
switch (sfntVersion) {
case "\x00\x01\x00\x00":
case "true":
case "typ1":
outlineFormat = "truetype";
break;
case "OTTO":
outlineFormat = "cff";
break;
}
console.log("Outline format:", outlineFormat);
}
} catch (err) {
console.error(err.name, err.message);
}
}
Specifications
Specification |
---|
Local Font Access # fontdata-interface |
Browser compatibility
BCD tables only load in the browser