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@pdfa-lab/fontkit / Font

Interface: Font<TDirectory> ​

Defined in: src/font.ts:70

Baseline interface representing an unvalidated SFNT-based layout. Every table property is considered nullable by default. As a consequence, many properties are possibly undefined. You can avoid that by upcasting the font object with ["asOpenTypeFont"] to an OpenTypeFont, which guarantees the presence of the 8 core tables, and 0-2 outline tables.

This interface is mostly useless for application programming. You can normally just use TrueTypeFont as a type instead!

Extended by ​

Type Parameters ​

Type ParameterDefault type
TDirectory extends SFNTDirectorySFNTDirectory

Properties ​

avar ​

avar: avar | null

Defined in: src/font.ts:324

Axis Variations Table. Modifies normalised coordinates across axes in variable fonts.

BASE ​

BASE: BASE | null

Defined in: src/font.ts:235

Baseline Data Table. Sets alignment values dynamically shifting script baselines.

bsln ​

bsln: bsln | null

Defined in: src/font.ts:330

Baseline Table. Provides baseline shift measurements for multi-script alignment.

CBLC ​

CBLC: EBLC | null

Defined in: src/font.ts:211

Colour Bitmap Data Table. Variant containing colour bitmap raw data blocks.

cff ​

cff: CFF1Font | null

Defined in: src/font.ts:183

PostScript Compact Font Format (CFF) Outline Table version 1.

CFF ​

**CFF **: CFF1Font | null

Defined in: src/font.ts:188

Alternate PostScript Compact Font Format alias mapping.

CFF2 ​

CFF2: CFF2Font | null

Defined in: src/font.ts:193

PostScript Compact Font Format (CFF) Outline Table version 2.

characterSet ​

characterSet: number[] | undefined

Defined in: src/font.ts:468

An array of all of the unicode code points supported by the font.

cmap ​

cmap: cmap | null

Defined in: src/font.ts:106

Character to Glyph Index Mapping Table. Maps characters to internal glyph indices.

COLR ​

COLR: COLR | null

Defined in: src/font.ts:223

Colour Table. Outlines layering configurations for multi-coloured vector icon layouts.

copyright: string | null

Defined in: src/font.ts:394

The font's copyright information, or null if not present.

CPAL ​

CPAL: CPAL | null

Defined in: src/font.ts:229

Colour Palette Table. Maps index arrays declaring hex colours utilised by COLR elements.

cvt ​

**cvt **: cvt | null

Defined in: src/font.ts:172

Control Value Table. Stores indexed control values used by TrueType instructions to maintain consistency when hinting glyphs.

defaultLanguage ​

readonly defaultLanguage: string | null

Defined in: src/font.ts:607

The default language for strings to get from the font with getName().

See ​

directory ​

directory: TDirectory

Defined in: src/font.ts:577

The structural binary wrapper tracking offset blocks and table pointers.

DSIG ​

DSIG: DSIG | null

Defined in: src/font.ts:271

Digital Signature Table. Encapsulates cryptographic signatures validating binary authenticity.

EBLC ​

EBLC: EBLC | null

Defined in: src/font.ts:205

Embedded Bitmap Data Table. Stores bitmap images for specific point sizes.

familyName ​

familyName: string | null

Defined in: src/font.ts:384

The font's family name, e.g. "Helvetica", or null if not present.

feat ​

feat: feat | null

Defined in: src/font.ts:336

Feature Name Table. Maps AAT feature selectors to localised string references.

fpgm ​

fpgm: fpgm | null

Defined in: src/font.ts:154

Font Program Table. Contains low-level hints executing instruction sets across grid points.

fullName ​

fullName: string | null

Defined in: src/font.ts:379

The font's full name, e.g. "Helvetica Bold", or null if not present.

fvar ​

fvar: fvar | null

Defined in: src/font.ts:342

Font Variations Table. Declares design axes and instance configurations in variable fonts.

gasp ​

gasp: gasp | null

Defined in: src/font.ts:277

Grid-fitting and Scan-conversion Procedure Table. Optimises text raster rendering constraints.

GDEF ​

GDEF: GDEF | null

Defined in: src/font.ts:241

Glyph Definition Table. Categorises glyph types (e.g., base, ligature, mark) for layout alignment.

glyf ​

glyf: glyph | null

Defined in: src/font.ts:178

Glyph Data Table. Describes TrueType glyph outlines, including contour coordinates, composite glyph components, and hinting instructions.

GPOS ​

GPOS: GPOS | null

Defined in: src/font.ts:247

Glyph Positioning Table. Provides precise metric adjustments handling kerning and attachment marks.

GSUB ​

GSUB: GSUB | null

Defined in: src/font.ts:253

Glyph Substitution Table. Supplies glyph substitutions for contextual alternates, ligatures, and script-specific rendering.

gvar ​

gvar: gvar | null

Defined in: src/font.ts:348

Glyph Variations Table. Controls structural outline distortion transformations for variable glyphs.

hdmx ​

hdmx: hdmx | null

Defined in: src/font.ts:283

Horizontal Device Metrics Table. Preserves explicit pixel width mappings optimising spacing.

head: head | null

Defined in: src/font.ts:112

Font Header Table. Tracks global typographic metrics, scale grid bounds, and metadata.

hhea ​

hhea: hhea | null

Defined in: src/font.ts:118

Horizontal Header Table. Stores global metric parameters for horizontal glyph layouts.

hmtx ​

hmtx: hmtx | null

Defined in: src/font.ts:124

Horizontal Metrics Table. Contains advance widths and left side bearings for all glyphs.

HVAR ​

HVAR: HVAR | null

Defined in: src/font.ts:265

Horizontal Variation Metrics Table. Adjusts advance metrics across design spaces in variable fonts.

JSTF ​

JSTF: JSTF | null

Defined in: src/font.ts:259

Justification Table. Provides options for justification adjustments in complex scripts.

just ​

just: just | null

Defined in: src/font.ts:354

Justification Table (just). Provides layout rules for line justification, glyph width deltas, and post-compensation actions in AAT typography.

kern ​

kern: kern | null

Defined in: src/font.ts:288

Kerning Table. Contains traditional pairwise spacing adjustments.

layoutEngine ​

layoutEngine: LayoutEngine

Defined in: src/font.ts:498

The shaping engine matching text scripts to font tables.

loca ​

loca: loca | null

Defined in: src/font.ts:160

Index to Location Table. Maps local offsets for binary data streams resolving glyph outlines.

LTSH ​

LTSH: LTSH | null

Defined in: src/font.ts:294

Linear Threshold Table. Sets pixel-per-em limits where scaling instructions degrade.

maxp ​

maxp: maxp | null

Defined in: src/font.ts:130

Maximum Profile Table. Explicitly defines memory boundaries and total glyph count constraints.

morx ​

morx: morx | null

Defined in: src/font.ts:360

Extended Glyph Metamorphosis Table. Powers state-machine transformations substituting AAT items.

name ​

name: name | null

Defined in: src/font.ts:136

Naming Table. Contains multilingual string records for copyrights, families, and system IDs.

opbd ​

opbd: opbd | null

Defined in: src/font.ts:366

Optical Bounds Table. Sets bounding limits to align glyphs based on visual centre points.

OS/2 ​

OS/2: OS2 | null

Defined in: src/font.ts:142

OS/2 and Windows Metrics Table. Contains subsystem configurations, weights, and unicode ranges.

PCLT ​

PCLT: PCLT | null

Defined in: src/font.ts:300

PCL 5 Table. Contains metrics and command parameters for HP LaserJet compatibility.

post ​

post: post | null

Defined in: src/font.ts:148

PostScript Table. Encapsulates printer operational bounds and memory-tracking metrics.

postscriptName ​

postscriptName: string | Uint8Array<ArrayBufferLike> | null

Defined in: src/font.ts:374

The unique PostScript name for this font or null if not present.

Some broken fonts have PostScript names that cannot be decoded into a string. They are exposed as Uint8Array.

prep ​

prep: prep | null

Defined in: src/font.ts:166

Control Value Program Table. Provides global instructions establishing variable outline alignment.

sbix ​

sbix: sbix | null

Defined in: src/font.ts:217

Standard Bitmap Graphics Table. Embeds raster configurations (PNG/JPEG) directly within glyph IDs.

stream ​

stream: DecodeStream

Defined in: src/font.ts:582

The raw input stream reading binary payload slices.

subfamilyName ​

subfamilyName: string | null

Defined in: src/font.ts:389

The font's sub-family, e.g. "Bold", or null if not present.

variationProcessor ​

variationProcessor: GlyphVariationProcessor | null

Defined in: src/font.ts:595

The processor responsible for calculating delta adjustments to glyph outlines along design variation axes. This is initialised when variation coordinates are applied, and is null for static fonts.

VDMX ​

VDMX: VDMX | null

Defined in: src/font.ts:306

Vertical Device Metrics Table. Preserves explicit vertical pixel height mappings.

version ​

version: string | null

Defined in: src/font.ts:399

The font's version number or null if not present.

vhea ​

vhea: vhea | null

Defined in: src/font.ts:312

Vertical Header Table. Stores global metric parameters for vertical text directions.

vmtx ​

vmtx: vmtx | null

Defined in: src/font.ts:318

Vertical Metrics Table. Contains advance heights and top side bearings for vertical layouts.

VORG ​

VORG: VORG | null

Defined in: src/font.ts:199

Vertical Origin Table. Specifies vertical coordinate origins for dynamic metrics scaling.

Accessors ​

ascent ​

Get Signature ​

get ascent(): number | undefined

Defined in: src/font.ts:404

The font’s ascender.

Returns ​

number | undefined

availableFeatures ​

Get Signature ​

get availableFeatures(): keyof Features[]

Defined in: src/font.ts:534

An array of all OpenType feature tags supported by the font.

Returns ​

keyof Features[]

bbox ​

Get Signature ​

get bbox(): Readonly<BoundingBox> | undefined

Defined in: src/font.ts:463

Deprecated ​

Use boundingBox instead!

Returns ​

Readonly<BoundingBox> | undefined

boundingBox ​

Get Signature ​

get boundingBox(): Readonly<BoundingBox> | undefined

Defined in: src/font.ts:458

The font’s bounding box, i.e. the box that encloses all glyphs in the font.

Returns ​

Readonly<BoundingBox> | undefined

capHeight ​

Get Signature ​

get capHeight(): number | undefined

Defined in: src/font.ts:436

The height of capital letters above the baseline. See here for more details.

Returns ​

number | undefined

descent ​

Get Signature ​

get descent(): number | undefined

Defined in: src/font.ts:409

The font’s descender.

Returns ​

number | undefined

italicAngle ​

Get Signature ​

get italicAngle(): number | undefined

Defined in: src/font.ts:430

If this is an italic font, the angle the cursor should be drawn at to match the font design.

Returns ​

number | undefined

lineGap ​

Get Signature ​

get lineGap(): number | undefined

Defined in: src/font.ts:414

The line gap, i.e. amount of space that should be included between lines.

Returns ​

number | undefined

numGlyphs ​

Get Signature ​

get numGlyphs(): number | undefined

Defined in: src/font.ts:447

The total count of glyph indexes present in the font mapping.

Returns ​

number | undefined

underlinePosition ​

Get Signature ​

get underlinePosition(): number | undefined

Defined in: src/font.ts:419

The offset from the normal underline position that should be used.

Returns ​

number | undefined

underlineThickness ​

Get Signature ​

get underlineThickness(): number | undefined

Defined in: src/font.ts:424

The weight of the underline that should be used.

Returns ​

number | undefined

unitsPerEm ​

Get Signature ​

get unitsPerEm(): number

Defined in: src/font.ts:453

The size of the font's internal coordinate grid in units per em. Defaults to 1000, if all other attempts to calculate the value fail.

Returns ​

number

xHeight ​

Get Signature ​

get xHeight(): number

Defined in: src/font.ts:442

The height of lowercase letters in the font. See here for more details.

Returns ​

number

Methods ​

asAATFont() ​

asAATFont(): AATFont | null

Defined in: src/font.ts:93

Attempts to view this font as an AATFont.

Returns ​

AATFont | null

the font with narrowed to an @{link AATFont} or `null if a required table is missing

asOpenTypeFont() ​

asOpenTypeFont(): OpenTypeFont | null

Defined in: src/font.ts:86

Attempts to view this font instance as a strict OpenType font layout. Returns null, if a structurally required table is missing.

See OpenTypeFont for usage instructions!

Returns ​

OpenTypeFont | null

the font with narrowed to an @{link OpenTypeFont} or `null if a required table is missing

asTrueTypeSubsetFont() ​

asTrueTypeSubsetFont(): TrueTypeSubsetFont | null

Defined in: src/font.ts:100

Attempts to view this font as an TrueTypeSubsetFont font.

Returns ​

TrueTypeSubsetFont | null

the font with narrowed to a @{link TrueTypeSubsetFont} or `null if a required table is missing

codePointsForGlyph() ​

codePointsForGlyph(gid): number[]

Defined in: src/font.ts:529

Returns an array of alternative unicode mapping arrays tied to a specific glyph ID.

Parameters ​

ParameterType
gidnumber

Returns ​

number[]

createSubset() ​

createSubset(): Subset

Defined in: src/font.ts:572

Creates an empty layout subset utilising this font structure as its baseline data map.

Returns ​

Subset

getAvailableFeatures() ​

getAvailableFeatures(script, language?): keyof Features[]

Defined in: src/font.ts:540

An array of all OpenType feature tags supported by the font for a given script and language.

Parameters ​

ParameterType
script"Caucasian_Albanian" | "Arabic" | "Imperial_Aramaic" | "Armenian" | "Avestan" | "Balinese" | "Bamum" | "Bassa_Vah" | "Batak" | "Bengali" | "Bopomofo" | "Brahmi" | "Braille" | "Buginese" | "Buhid" | "Chakma" | "Canadian_Aboriginal" | "Carian" | "Cham" | "Cherokee" | "Coptic" | "Cypriot" | "Cyrillic" | "Devanagari" | "Deseret" | "Duployan" | "Egyptian_Hieroglyphs" | "Elbasan" | "Ethiopic" | "Georgian" | "Glagolitic" | "Gothic" | "Grantha" | "Greek" | "Gujarati" | "Gurmukhi" | "Hangul" | "Han" | "Hanunoo" | "Hebrew" | "Hiragana" | "Pahawh_Hmong" | "Katakana_Or_Hiragana" | "Old_Italic" | "Javanese" | "Kayah_Li" | "Katakana" | "Kharoshthi" | "Khmer" | "Khojki" | "Kannada" | "Kaithi" | "Tai_Tham" | "Lao" | "Latin" | "Lepcha" | "Limbu" | "Linear_A" | "Linear_B" | "Lisu" | "Lycian" | "Lydian" | "Mahajani" | "Mandaic" | "Manichaean" | "Mende_Kikakui" | "Meroitic_Cursive" | "Meroitic_Hieroglyphs" | "Malayalam" | "Modi" | "Mongolian" | "Mro" | "Meetei_Mayek" | "Myanmar" | "Old_North_Arabian" | "Nabataean" | "Nko" | "Ogham" | "Ol_Chiki" | "Old_Turkic" | "Oriya" | "Osmanya" | "Palmyrene" | "Pau_Cin_Hau" | "Old_Permic" | "Phags_Pa" | "Inscriptional_Pahlavi" | "Psalter_Pahlavi" | "Phoenician" | "Miao" | "Inscriptional_Parthian" | "Rejang" | "Runic" | "Samaritan" | "Old_South_Arabian" | "Saurashtra" | "Shavian" | "Sharada" | "Siddham" | "Khudawadi" | "Sinhala" | "Sora_Sompeng" | "Sundanese" | "Syloti_Nagri" | "Syriac" | "Tagbanwa" | "Takri" | "Tai_Le" | "New_Tai_Lue" | "Tamil" | "Tai_Viet" | "Telugu" | "Tifinagh" | "Tagalog" | "Thaana" | "Thai" | "Tibetan" | "Tirhuta" | "Ugaritic" | "Vai" | "Warang_Citi" | "Old_Persian" | "Cuneiform" | "Yi" | "Inherited" | "Common" | "Unknown"
language?string

Returns ​

keyof Features[]

getGlyfTableStream() ​

getGlyfTableStream(): DecodeStream | null

Defined in: src/font.ts:588

Extracts a raw readable segment slice targeting vector outline definitions.

Returns ​

DecodeStream | null

getGlyph() ​

getGlyph(glyph, characters?): Glyph | null

Defined in: src/font.ts:554

Returns a glyph object for the given glyph id. You can pass the array of code points this glyph represents for your use later, and it will be stored in the glyph object.

Parameters ​

ParameterTypeDescription
glyphnumberthe glyph id
characters?readonly number[]an array of code points this glyph represents

Returns ​

Glyph | null

the corresponding glyph

glyphForCodePoint() ​

glyphForCodePoint(codePoint): Glyph | null

Defined in: src/font.ts:485

Maps a single unicode code point to a Glyph object. Does not perform any advanced substitutions.

Parameters ​

ParameterTypeDescription
codePointnumberthe unicode code point

Returns ​

Glyph | null

the corresponding glyph

glyphsForString() ​

glyphsForString(str): Glyph[]

Defined in: src/font.ts:494

Returns an array of Glyph objects for the given string. This is only a static one-to-one mapping from characters to glyphs.

Parameters ​

ParameterTypeDescription
strstringthe string to encode

Returns ​

Glyph[]

the corresponding glyphs

hasGlyphForCodePoint() ​

hasGlyphForCodePoint(codePoint): boolean

Defined in: src/font.ts:476

Returns whether there is a glyph in the font for the given unicode code point.

Parameters ​

ParameterTypeDescription
codePointnumberthe unicode code point

Returns ​

boolean

true if a glyph is available for the code point, false otherwise

hasTable() ​

hasTable<K>(tag): boolean

Defined in: src/font.ts:76

Tests whether a certain table is present in the font file.

Type Parameters ​

Type ParameterDefault type
K extends stringstring

Parameters ​

ParameterTypeDescription
tag"name" | "head" | "kern" | "opbd" | "loca" | "hmtx" | "cmap" | "hhea" | "maxp" | "OS/2" | "post" | "fpgm" | "prep" | "cvt " | "glyf" | "CFF " | "CFF2" | "VORG" | "EBLC" | "CBLC" | "sbix" | "COLR" | "CPAL" | "BASE" | "GDEF" | "GPOS" | "GSUB" | "JSTF" | "HVAR" | "DSIG" | "gasp" | "hdmx" | "LTSH" | "PCLT" | "VDMX" | "vhea" | "vmtx" | "avar" | "bsln" | "feat" | "fvar" | "gvar" | "just" | "morx" | Kthe table name like cmap, OS/2, or hmtx

Returns ​

boolean

layout() ​

layout(str, userFeatures?, script?, language?, direction?): GlyphRun

Defined in: src/font.ts:511

Returns a GlyphRun object, which includes an array of Glyphs and GlyphPositions for the given string.

Parameters ​

ParameterTypeDescription
strstringthe string to encode
userFeatures?Features | keyof Features[]an array of OpenType feature tags to be applied in addition to the default set.
script?OpenTypeTagthe script of the string
language?stringthe language of the string
direction?BidiDirectionthe writing direction for the string

Returns ​

GlyphRun

the rendered string as a GlyphRun

safeGetGlyph() ​

safeGetGlyph(glyph, characters?): Glyph

Defined in: src/font.ts:563

Like getGlyph but falls back to the fallback glyph .notdef if the glyph cannot be resolved, because of missing tables.

Parameters ​

ParameterTypeDescription
glyphnumberthe glyph id
characters?readonly number[]an optional sequence of codepoints

Returns ​

Glyph

setDefaultLanguage() ​

setDefaultLanguage(lang): void

Defined in: src/font.ts:614

Set the default language.

Parameters ​

ParameterType
langstring | null

Returns ​

void

See ​

defaultLanguage

stringsForGlyph() ​

stringsForGlyph(gid): string[]

Defined in: src/font.ts:523

Returns an array of strings that map to the given glyph id.

Parameters ​

ParameterTypeDescription
gidnumberthe glyph id

Returns ​

string[]