Font engineering¶

Spacing, kerning, masters, hinting, and the structure of a font.

Use the entry for the relevant application. Draft terms require confirmation before publication.

advance height¶

Applies to: fontlab. Translatable: yes.

The distance the text position advances vertically after a glyph. It is the vertical counterpart of advance width, not the height of the visible outline.

Write: Use advance height when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

advance width¶

Also written: advance, width. Applies to: fontlab, fontographer, transtype. Translatable: yes. Fallback original term: glyph box width.

Advance width is the horizontal distance allocated to a glyph before layout adjustments, measured in font units. In an OpenType font, the base values are stored in the hmtx table. Kerning and other positioning operations can adjust advances during layout without rewriting those base values. Advance width differs from the visible outline width; a space can have an advance without an outline.

Write: You set the advance width in the Metrics panel.

Not: Kerning never changes glyph advances during layout.

Shared noun. Name the application.

The short label width names this metric only in a spacing context. Geometric width, bounding-box width, width class and the width axis are separate senses; use the contextual localized label.

See also: sidebearing, metrics, kerning, UPM

alignment zone¶

Also written: blue zone, zone. Applies to: fontlab. Translatable: yes. Fallback original term: height band for snapping.

An alignment zone is a region around a common vertical alignment, such as the baseline or cap height, used in PostScript hinting. It can include the overshoot of rounded letters. A rasterizer uses zone information when fitting outlines to a pixel grid. Keep this mechanism distinct from design measurements and from the control-value and instruction mechanisms used in TrueType hinting.

Write: You declare the x-height zone so the o and the x snap together.

Not: All font formats use PostScript alignment zones for hinting.

See also: hinting, autohinting, overshoot, x-height

anchor¶

Applies to: fontlab, fontographer. Translatable: yes. Fallback original term: attachment point.

An anchor is a named attachment point in a glyph that says where a mark belongs. A base letter carries a top anchor, and the accent carries a matching one, so the accent lands in the same relation on every letter that uses it. You place anchors in the Anchors and Pins panel, and FontLab uses them both to build composites and to generate mark attachment lookups in GPOS, which is what positions marks in text the font never composed itself.

Write: You place the top anchor, and FontLab attaches the accent to it.

Not: Anchors are used so that marks can be positioned correctly.

See also: mark attachment, component, composite glyph, GPOS

anti-aliasing¶

Also written: antialiasing. Applies to: fontlab, transtype. Translatable: yes. Fallback original term: edge smoothing.

Anti-aliasing paints partly covered pixels in intermediate shades so a rendered outline looks smooth. FontLab's preview can show anti-aliased, monochrome or subpixel rendering so you can check how hints behave under each. Write the hyphenated form.

Write: Switch off anti-aliasing to see the monochrome bitmap.

Not: Disable antialiasing functionality to view the monochrome result.

See also: rendering, hint

autohinting¶

Applies to: fontlab. Translatable: yes. Fallback original term: automatic screen fitting.

Autohinting generates hints for a font from its outlines and its declared stems and zones, in one pass over the glyphs. It is a starting point rather than a finish: it hints the regular cases well and leaves the awkward glyphs for you. You run it after the alignment zones and standard stem widths are correct in Font Info, because it reads them. Then you check the glyphs that matter at text sizes and correct by hand what the pass got wrong.

Write: You set the zones in Font Info, then run autohinting.

Not: Autohinting will take care of the hinting for you.

See also: hinting, alignment zone, stem link, CVT table

axis¶

Also written: design axis. Applies to: fontlab, fontographer. Translatable: yes.

An axis is one dimension of font variation, such as weight, width or optical size. In an OpenType variable font, each axis has a four-character tag and a minimum, default and maximum value. Registered tags, such as wght, have defined meanings. Preserve tag spelling and case, and check the axis registry when assigning a custom tag.

Write: You declare the weight axis, then place each master on it.

Not: Every axis tag consists of four lowercase letters.

See also: design space, master, instance, variable font

axis map¶

Also written: axis mapping, avar. Applies to: fontlab. Translatable: yes. Fallback original term: axis value mapping.

An axis map converts user coordinates on an axis, such as weight 400, to the design coordinates of the masters. It is stored in the avar table and lets a slider feel even when masters are not.

Write: Edit the axis map so Medium sits halfway.

Not: The axis map lists the masters.

See also: axis, design space, instance

bottom sidebearing¶

Applies to: fontlab. Translatable: yes.

The space below the glyph outline within its vertical advance. This value participates in vertical text spacing rather than horizontal spacing.

Write: Use bottom sidebearing when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

component¶

Applies to: fontlab, fontographer. Translatable: yes.

A component is a reference to another glyph placed inside this one, so that aacute holds the a and the acute rather than copies of their outlines. Change the source glyph and every glyph that references it follows. You build composites from components, position them with anchors, and keep them as references through to export, where a TrueType flavoured font stores them in the glyf table. In FontLab a component is one kind of element reference.

Write: You place the acute as a component, and it follows the source glyph.

Not: Components are placed so that composite glyphs can be built.

See also: composite glyph, element, element reference, anchor

composite glyph¶

Also written: composite. Applies to: fontlab, fontographer. Translatable: yes. Fallback original term: assembled glyph.

A composite glyph is built from references to other glyphs rather than from its own outlines: an accented letter, a currency symbol with a bar, a stacked fraction. You assemble it from components and anchor them to the base, so a change to the base or to the mark reaches every composite that uses it. Composites keep a large accented character set consistent and small. A composite that has been decomposed is no longer one, and no longer follows its sources.

Write: You build aacute as a composite glyph from the a and the acute.

Not: Composite glyphs are built out of components by the user.

See also: component, anchor, element reference, glyph

conversion profile¶

Applies to: transtype. Translatable: yes. Fallback original term: export settings set.

A conversion profile is the saved set of choices TransType applies to a conversion: the output format, the naming scheme, the filters, and the options that go with them. You build a profile once for a job you repeat, then run it over a new set of sources without repeating the decisions. It matters because a family converted with two different sets of options ships as two families that do not quite match, which shows up in a font menu rather than in a test.

Write: You save the conversion profile and run it over the next family.

Not: Conversion profiles are saved so settings can be reused.

CVT table¶

Also written: cvt, control value table. Applies to: fontlab. Translatable: yes.

The CVT table holds the control values that TrueType hinting instructions refer to: the stem widths, heights, and other measurements a font wants held constant across glyphs. An instruction cites a CVT entry rather than a raw number, so one change to the table reaches every glyph that cites it. You work with it through the TrueType Hinting panel. It ships in the font, alongside the instructions themselves and the prep and fpgm programs that set the machine up.

Write: The instruction reads its stem width from the CVT table.

Not: Stem widths are read from the cvt by the instructions.

See also: hinting, stem link, TTF, autohinting

design space¶

Applies to: fontlab. Translatable: yes. Fallback original term: variation range.

A design space describes the positions defined by a font project's variation axes. Masters provide source data at specified locations; instances represent results at selected locations. User coordinates and internal design coordinates may be connected by a mapping, or may have the same values. State which coordinate system a number belongs to when the distinction affects a procedure.

Write: You move through the design space in the Variations panel.

Not: User coordinates and design coordinates always have different values.

See also: axis, master, instance, interpolation

device correction¶

Also written: delta, size correction. Applies to: fontlab. Translatable: yes. Fallback original term: per-size pixel correction.

A device correction adjusts a kerning or positioning value by whole pixels at one pixel size, to fix rounding at that size only. Stored in GPOS device tables; rarely needed on modern rasterizers.

Write: Add a device correction at 12 ppm.

Not: Device corrections change the design size.

See also: kerning pair, PPM, hinting

dimensions¶

Applies to: fontlab. Translatable: yes.

The font or family vertical values, such as ascender, descender, capital height, x-height and line gap. Distinguish these values from glyph spacing and canvas measurements.

Write: Use dimensions when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

element¶

Applies to: fontlab. Translatable: yes.

An element is FontLab's container for a piece of drawing inside a glyph: one or more contours, an image, or a reference to another element. A glyph holds elements, and an element holds contours, which is the layer of structure that makes a serif or a stem reusable across a family. You work with elements in the Elements panel and with the Element tool. The word is FontLab's own; other editors call the nearest thing a path group or a component.

Write: You select the element and reuse it in the other glyphs.

Not: Elements can be reused for the building of other glyphs.

See also: element reference, component, contour, glyph

element reference¶

Applies to: fontlab. Translatable: yes. Fallback original term: shared drawing link.

An element reference is a placed copy of an element that still points at the original. Edit the original and every reference updates. You use references to share a serif, a stem, or a whole letter across a family, and you decompose a reference only when a glyph genuinely needs to diverge. A component is the familiar case of an element reference: one glyph placed inside another. Keep references intact through the design phase, since decomposing early throws away the link that makes a late change cheap.

Write: You keep the serif as an element reference so one edit reaches every glyph.

Not: Every compact reference label must repeat the word element.

See also: element, component, composite glyph, glyph

family dimensions¶

Applies to: fontlab. Translatable: yes.

The vertical values used to establish line layout for a font family. Platform-specific ascender, descender and line-gap fields belong to this group.

Write: Use family dimensions when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

Flex¶

Also written: flex hint. Applies to: fontlab. Translatable: yes.

Flex is a PostScript hint that flattens a shallow curve, such as a cup serif, to a straight line at small sizes. FontLab marks glyphs that carry it. Keep the name.

Write: The Flex column shows which glyphs carry the hint.

Not: Flex makes the curve flexible.

See also: hinting, ghost hint

font dimensions¶

Applies to: fontlab. Translatable: yes.

The design dimensions of a font master, including ascender, descender, capital height and x-height. These values describe the vertical proportions of the design.

Write: Use font dimensions when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

font target¶

Also written: target. Applies to: transtype. Translatable: yes. Fallback original term: export target.

A font target is what TransType produces from a source: the output font, with its format, its names, and the filters applied on the way. Sources go in on one side and targets come out on the other, and one source can produce several targets. You set the target options before you convert, and you name the target in a procedure step so a reader knows which side of the conversion a setting belongs to.

Write: You set the format on the target, and TransType converts the source into it.

Not: The target gets converted from the source by the app.

See also: TransType 5, conversion profile, OTF, TTC

font unit¶

Also written: units. Applies to: fontlab, fontographer, transtype. Translatable: yes.

A font unit is the coordinate step of a font's design grid. UPM says how many of them make one em, so a 700 unit stem in a 1000 UPM font is 70 percent of the em. Metrics, kerning values and node coordinates are all stated in font units.

Write: Enter the sidebearing in font units.

Not: Enter the sidebearing in pixels.

See also: UPM, em, advance width

fractional coordinates¶

Also written: decimal coordinates. Applies to: fontlab. Translatable: yes. Fallback original term: non-integer coordinates.

Fractional coordinates are node positions with decimal places, kept for curve fidelity while you draw. Font formats store integers, so FontLab rounds on export or when you turn on Round coordinates for the font.

Write: Keep fractional coordinates until the final export.

Not: Fractional coordinates are stored in the TTF.

See also: node, font unit, UPM

friendly glyph name¶

Also written: readable name. Applies to: fontlab. Translatable: yes. Fallback original term: readable glyph name.

A friendly glyph name is the readable name FontLab shows for editing, such as Aacute, as opposed to the production name written into the exported font, such as uni00C1. FontLab can keep both and convert on export.

Write: Search by friendly glyph name.

Not: The friendly name is the Unicode value.

ghost hint¶

Also written: one sided hint. Applies to: fontlab. Translatable: yes. Fallback original term: edge-only fitting instruction.

A ghost hint is a PostScript hint with a special width that marks one edge, such as the top of a round letter, when there is no stem to hint. It aligns that edge to an alignment zone.

Write: Add a ghost hint at the overshoot.

Not: A ghost hint hides the stem.

See also: hinting, alignment zone, standard stem

hint¶

Also written: hints. Applies to: fontlab, transtype. Translatable: yes. Fallback original term: screen fitting instruction.

A hint is a stored instruction that tells a rasterizer how to align a stem or a zone to the pixel grid at small sizes. PostScript hints describe stems and zones; TrueType hints are instructions. FontLab draws hints in the Glyph window and generates them with autohinting. The word stays English in every language.

Write: Add a vertical hint to the stem.

Not: Apply a hinting directive to the vertical stem region.

See also: hinting, autohinting, hint zone, ghost hint, Flex

hint zone¶

Applies to: fontlab. Translatable: yes. Fallback original term: hinting height band.

A hint zone is a horizontal band, such as the baseline or the x-height, inside which a rasterizer snaps overshoots to the same pixel row. FontLab stores zones in Font Info and shows them in the Glyph window. An alignment zone is the PostScript name for the same thing; hint zone is the general term.

Write: Set a hint zone at the x-height.

Not: Configure an alignment region corresponding to the x-height.

See also: hint, alignment zone, overshoot

hinting¶

Applies to: fontlab, fontographer. Translatable: yes. Fallback original term: screen fitting.

Hinting is the extra information a font carries so that its outlines land predictably on a pixel grid at small sizes. PostScript hinting declares stems and alignment zones and leaves the rasterizer to interpret them. TrueType hinting gives instructions that move points explicitly, with the control values in the CVT table. You work on PostScript hints in the glyph and in Font Info, and on TrueType hints with the TrueType Hinting tool and panel. Autohinting produces a starting point you then correct.

Write: You hint the stems, and the rasterizer snaps them to the pixel grid.

Not: Stems are snapped to the grid by the hinting that is applied.

See also: autohinting, alignment zone, stem link, CVT table

instance¶

Applies to: fontlab. Translatable: yes. Fallback original term: generated design.

An instance is a particular result at a location in a font's variation space. A named instance, such as Semibold, gives a selected location a name that applications can present. Other locations need not have names. In FontLab, configured instances can be exported as static fonts or included as named instances in a variable font.

Write: You define the Semibold instance, and FontLab interpolates it from the masters.

Not: Every possible instance must have a style name.

See also: master, axis, design space, variable font

interpolation¶

Applies to: fontlab, fontographer. Translatable: yes.

Interpolation calculates values between source values. In font design, it can calculate outlines, metrics and other data from masters at specified design-space locations. Outline interpolation requires corresponding contour and point structures. Structural compatibility makes the calculation possible, but does not guarantee a good drawing: inspect intermediate results as well as the masters. Extrapolation calculates beyond the source range.

Write: FontLab interpolates the Medium weight from the Light and Bold masters.

Not: Compatible masters guarantee good outlines at every intermediate position.

kern exception¶

Applies to: fontlab. Translatable: yes. Fallback original term: pair spacing exception.

A kern exception is a pair value that overrides what the classes would otherwise apply. One member of a class rarely behaves like the rest, and the exception says so without breaking the class apart. You create one in the Kerning panel by kerning the single pair while its classes stay in place. Keep exceptions few: a class with many exceptions is the wrong class, and the cheaper fix is to split it rather than to list every disagreement.

Write: You add a kern exception for the one pair that the class gets wrong.

Not: Exceptions can be created for pairs that are not being handled correctly.

See also: kerning class, kerning pair, kerning, GPOS

kerning¶

Applies to: fontlab, fontographer, transtype. Translatable: yes. Fallback original term: pair spacing correction.

Kerning adjusts the spacing of particular glyph combinations beyond their normal advances. A pair such as AV may need a different gap from the one produced by its unadjusted metrics. OpenType fonts commonly store horizontal kerning in GPOS lookups associated with the kern feature; some formats and workflows use a separate kern table. Name the mechanism when it matters to export or compatibility.

Write: This export stores kerning in GPOS lookups for the kern feature.

Not: Every font format stores kerning in GPOS.

See also: kerning pair, kerning class, visual kerning, GPOS

kerning class¶

Also written: class kerning. Applies to: fontlab, transtype. Translatable: yes. Fallback original term: pair spacing group.

A kerning class groups glyphs that need the same kerning. You put every glyph that behaves alike on one side into one class, then kern the class once instead of kerning each pair inside it. FontLab applies the class value to every member pair and keeps single pairs as exceptions where a member needs its own value. Classes matter because a text face carries thousands of readable pairs, and a hand kerned list of that size is unmaintainable. FontLab writes the result into GPOS as class based positioning.

Write: A kerning class groups glyphs that kern alike.

Not: A kerning class is a way of grouping glyphs together for the purpose of kerning.

See also: kerning, kerning pair, kern exception, GPOS

kerning pair¶

Applies to: fontlab, fontographer. Translatable: yes. Fallback original term: spacing-corrected pair.

A kerning pair associates two glyphs, or two kerning classes, with a spacing adjustment. In horizontal kerning, a negative value normally reduces the gap and a positive value increases it. An individual glyph pair may provide an exception to class kerning, but it can also exist without a class rule. Check pairs in representative text as well as in isolation.

Write: You nudge the pair until the gap matches the pairs around it.

Not: Every individual kerning pair overrides an existing class rule.

See also: kerning, kerning class, kern exception, GPOS

left sidebearing¶

Applies to: fontlab. Translatable: yes.

The horizontal space between the glyph origin and the left edge of its outline. It contributes to the glyph advance width and its spacing.

Write: Use left sidebearing when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

Lib¶

Also written: font lib, master lib. Applies to: fontlab. Translatable: yes.

Lib is the custom metadata dictionary of a font or a master, mirroring the UFO lib and stored in VFJ. Scripts and tools keep their own keys there.

Write: Store the build settings in the font Lib.

Not: Lib is the font's library folder.

See also: UFO, VFJ, master

line gap¶

Also written: linegap. Applies to: fontlab, transtype. Translatable: yes.

The line gap is extra vertical space between lines that a font recommends beyond ascender and descender. hhea and OS/2 each store one.

Write: Set the line gap to zero for web use.

Not: The line gap is the x-height.

See also: ascender, descender, OS/2 table

line height¶

Applies to: fontlab. Translatable: yes.

The distance between successive text baselines. It includes the relevant ascender, descender and line-gap contributions; line gap alone is only the additional space.

Write: Use line height when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

link metrics¶

Also written: metrics link, metrics expression. Applies to: fontlab. Translatable: yes. Fallback original term: tie spacing to another glyph.

Link metrics ties a glyph's sidebearing or advance width to another glyph or to an expression, so the value follows its source. FontLab shows linked metrics with the expression and updates them when the source changes.

Write: Link the right sidebearing of d to b.

Not: Link metrics copies the value once.

See also: sidebearing, advance width, metrics

linked metrics¶

Applies to: fontlab. Translatable: yes.

Glyph spacing values linked to another glyph or to an expression. Updating the source or expression changes the dependent advance width or sidebearings.

Write: Use linked metrics when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

mark attachment¶

Applies to: fontlab. Translatable: yes. Fallback original term: combining mark positioning.

Mark attachment positions a combining mark relative to a base glyph, a ligature component or another mark. OpenType GPOS lookups describe the anchor relationships, and the shaping engine applies the positioning during layout. FontLab can generate attachment code from suitable anchors. Check the relevant generation settings and test combinations, including stacked marks, rather than assuming that every anchor automatically becomes a lookup.

Write: Check the generated mark attachment lookups with stacked accents.

Not: Mark attachment can position a mark only against a base glyph.

See also: anchor, GPOS, lookup, composite glyph

master¶

Applies to: fontlab, fontographer. Translatable: yes. Fallback original term: source design.

A master provides source outlines and other font data at a specified location in a design space. Masters can describe weight, width or other variations, including intermediate locations. FontLab uses corresponding data from masters to calculate instances. For outline interpolation, check contour and point compatibility in each affected glyph; the word master alone does not guarantee that every glyph is present or compatible.

Write: You draw the Bold master, and FontLab interpolates the weights between.

Not: Masters can represent only the lightest and boldest weights.

See also: instance, axis, interpolation, master compatibility

master compatibility¶

Applies to: fontlab. Translatable: yes. Fallback original term: matching master structure.

Master compatibility is the condition every glyph must meet before it can interpolate: the same number of contours in the same order, with the same number of nodes and the same start point in each. FontLab reports incompatible glyphs and gives you Matchmaker to repair them by matching contours and start points between masters. Fix compatibility before you tune shapes, because a repair that reorders nodes moves every curve that depends on them.

Write: You open Matchmaker and match the contours between masters.

Not: Compatibility issues will be fixed by Matchmaker automatically.

See also: master, interpolation, Matchmaker, extremum

metrics¶

Applies to: fontlab, fontographer, transtype. Translatable: yes.

Metrics are the measurements that place a glyph in a line: its advance width and its two sidebearings. Vertical metrics are a separate set, the font wide values for ascender, descender, and line gap. You work on horizontal metrics in the Metrics panel and with the Metrics tool, and on vertical metrics in Font Info. Say which set you mean whenever a page discusses both, because a reader who applies a horizontal instruction to the vertical fields breaks line spacing everywhere the font is used.

Write: You edit the horizontal metrics in the Metrics panel.

Not: Metrics are edited in the metrics panel by the user.

See also: advance width, sidebearing, ascender, kerning

metrics expression¶

Applies to: fontlab. Translatable: yes.

An expression that calculates a glyph advance width or sidebearing from other values. It describes a spacing relationship rather than a canvas measurement.

Write: Use metrics expression when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

metrics key¶

Applies to: fontlab. Translatable: yes.

A glyph reference or expression used to derive a spacing value. The referenced value determines an advance width or sidebearing.

Write: Use metrics key when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

pin¶

Applies to: fontlab. Translatable: yes.

Draft

Draft. The house usage of this name is not settled. Confirm the intended product and version before using it.

A pin is a named point inside an element. Use pins to position elements with expressions and to attach elements to each other. An anchor is a named point in a glyph layer, used for component placement and mark attachment. Create either with the Guides tool and edit it in the Anchors and Pins panel.

Write: Add a pin to position the element.

Not: Add a glyph anchor inside the element.

See also: anchor, element, component

PPM¶

Also written: ppem, pixels per em. Applies to: fontlab. Translatable: yes. Fallback original term: pixels per type body.

PPM, pixels per em, is the size at which a rasterizer renders a font: how many pixels one em occupies. TrueType hints, device corrections and bitmap strikes are specified per PPM. In explanatory prose expand it; in hinting fields the short form is usual.

Write: Check the stems at 12 PPM.

Not: PPM is the print resolution.

See also: UPM, hinting, device correction

production glyph name¶

Also written: production name. Applies to: fontlab. Translatable: yes. Fallback original term: shipping glyph name.

A production glyph name is the name written into the exported font, chosen for compatibility with tools and the Adobe Glyph List, such as uni00C1 rather than Aacute.

Write: Export with production glyph names.

Not: Production names appear in the Glyph window.

rendering¶

Also written: rasterization. Applies to: fontlab, transtype. Translatable: yes. Fallback original term: drawing on screen.

Rendering is the conversion of an outline into pixels on a screen or a printer. The rasterizer of the operating system or of FontLab's preview reads the outline, applies the hints and paints the result. FontLab previews rendering at chosen pixel sizes so you can judge hints. Rasterization names the same step from the pixel side.

Write: Preview the rendering at 12 ppm.

Not: The font renders its glyphs at 12 ppm.

See also: hint, PPM, anti-aliasing

required glyphs¶

Applies to: fontlab. Translatable: yes. Fallback original term: mandatory glyphs.

Required glyphs are the ones the OpenType specification and common tools expect at the start of a font: .notdef, NULL or uni0000, CR or uni000D and space. FontLab can add them on export.

Write: Add the required glyphs before export.

Not: Required glyphs are the basic Latin letters.

See also: glyph name, conversion profile

right sidebearing¶

Applies to: fontlab. Translatable: yes.

The horizontal space between the right edge of a glyph outline and the end of its advance width. It contributes to spacing.

Write: Use right sidebearing when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

sidebearing¶

Also written: LSB, RSB, side bearing. Applies to: fontlab, fontographer. Translatable: yes. Fallback original term: side space.

A sidebearing is the space between a glyph's outline and the edge of its advance width: the left sidebearing before the shape, the right sidebearing after it. Together with the advance width it sets how the glyph spaces against every other glyph, which is the work that carries a text face further than kerning does. You edit sidebearings in the Metrics panel or with the Metrics tool, one glyph at a time or across a selection, and you check them in a word rather than in isolation.

Write: You widen the left sidebearing of the n in the Metrics panel.

Not: Side bearings can be adjusted so spacing gets improved.

See also: advance width, metrics, kerning, tracking

size¶

Applies to: fontlab. Translatable: yes.

The size of an object or the chosen size of displayed text. Name a specific width or height when only one direction is intended.

Write: Use size when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

spacing¶

Applies to: fontlab. Translatable: yes.

The adjustment of glyph advance widths and sidebearings to establish the space between letters. Kerning makes additional adjustments to particular pairs.

Write: Use spacing when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

standard stem¶

Also written: StdHW, StdVW, stem width. Applies to: fontlab. Translatable: yes. Fallback original term: reference stem width.

Standard stems are the representative horizontal and vertical stem widths declared in a font for hinting. The rasterizer snaps stems near those widths to the same pixel count, so like stems stay alike at small sizes.

Write: Measure the standard stems from n and H.

Not: A standard stem width is the font weight class.

See also: stem, hinting, alignment zone

stem link¶

Also written: stem hint. Applies to: fontlab, vexy-vextra. Translatable: yes. Fallback original term: stem tie.

A stem link ties two edges of a stroke together as a stem, so hinting can hold their distance as the size changes. A vertical link governs a horizontal measurement and a horizontal link governs a vertical one. You add links in the glyph, either by hand or from an autohinting pass, and you keep them consistent with the standard stem widths declared in Font Info. Vextra reuses the term for the paired edges it detects in artwork that is not type.

Write: You add a stem link across the upright of the H.

Not: Stem links get added to the stems by the hinting process.

See also: hinting, autohinting, stem, CVT table

styling group name¶

Also written: SGN, styling link value, SLV, styling link name, SLN. Applies to: transtype. Translatable: yes.

The styling group name, SGN, ties together the styles an application reaches through its bold and italic buttons, and the styling link value and styling link name say which slot each style takes in that group. The mechanism is older than typographic family names and narrower: four slots, no more. You set these fields in TransType when a family has to behave correctly in applications that still drive style selection from those buttons.

Write: You set the styling group name so the bold button reaches the Bold style.

Not: Styling groups are set up so bold and italic will work.

subsetting¶

Also written: subset. Applies to: fontlab, transtype. Translatable: yes. Fallback original term: cutting down a font.

Subsetting exports only part of a font, such as the glyphs a page uses or one codepage, to make a smaller file. The OS/2 embedding bits can forbid it.

Write: Subset the web font to Latin.

Not: Subsetting compresses the outlines.

See also: WOFF2, OS/2 table, Unicode codepoint

top sidebearing¶

Applies to: fontlab. Translatable: yes.

The space above the glyph outline within its vertical advance. This value participates in vertical text spacing rather than horizontal spacing.

Write: Use top sidebearing when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

tracking¶

Applies to: fontlab, transtype. Translatable: yes. Fallback original term: uniform letter spacing.

Tracking changes the spacing across a run of text, rather than correcting particular pairs as kerning does. Layout applications apply it to text. TransType's Tracking filter changes spacing in the font data itself. That changes the font's starting metrics; a layout application can still apply additional tracking to text set in the resulting font.

Write: Apply the Tracking filter to change the font's spacing.

Not: A layout app cannot add tracking after TransType changes the font's metrics.

See also: kerning, sidebearing, metrics, TransType 5

TrueType instruction¶

Also written: instruction. Applies to: fontlab, transtype. Translatable: yes. Fallback original term: pixel fitting instruction.

A TrueType instruction is one step of the program a TrueType font runs to fit an outline to the pixel grid. Instructions are the TrueType form of hints. FontLab writes them from visual TrueType hints and can keep the ones a font already has. Say instruction for the code and hint for what the reader draws.

Write: Keep the existing TrueType instructions when converting.

Not: Preserve the pre-existing TrueType instruction set during conversion.

See also: hint, hinting

typographic family name¶

Also written: TFN, typographic style name, TSN. Applies to: transtype, fontlab. Translatable: yes.

The typographic family name, TFN, is the name that groups every style of a family under one entry, and the typographic style name, TSN, is what distinguishes a style inside it. They sit beside the older four style family and style names that legacy applications read. You set them in TransType and in Font Info, and you keep them consistent across a family, because an app that reads these fields builds its font menu from them.

Write: You set the typographic family name once and vary only the style name.

Not: TFN and TSN get set so the family will group correctly.

update metrics¶

Applies to: fontlab. Translatable: yes.

Recalculate glyph spacing values from their links or expressions. This command updates the advance widths and sidebearings that depend on those relationships.

Write: Use update metrics when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

variable font¶

Applies to: fontlab, fontographer. Translatable: yes.

A variable font contains data for design variation along one or more axes. Applications select axis values and calculate the corresponding outlines and other variable data. Named instances identify selected locations, but users are not limited to those locations when the application exposes axis controls. A variable font's supported range depends on its data; it need not contain every style in the family.

Write: You export the family as a variable font with a weight axis.

Not: Every variable font contains all the family's styles.

See also: axis, master, instance, design space

variation location¶

Also written: location. Applies to: fontlab. Translatable: yes. Fallback original term: position in the variation range.

A variation location is a point in the design space, given as one value per axis. Masters and instances each have one, and the Variations panel slider shows the current one.

Write: Add an instance at location weight 500.

Not: The location is the glyph position.

See also: design space, axis, instance, master

vertical advance¶

Also written: advance height. Applies to: fontlab. Translatable: yes. Fallback original term: glyph box height.

The vertical advance is the distance a glyph advances in vertical text, the counterpart of advance width for East Asian layout. Stored in vmtx.

Write: Set the vertical advance to the em height.

Not: The vertical advance is the ascender.

See also: advance width, metrics

vertical metrics¶

Applies to: fontlab. Translatable: yes.

The font-wide vertical values used for line layout, including ascender, descender and line gap. FontLab groups these as dimensions, distinct from glyph spacing metrics.

Write: Use vertical metrics when describing this specific concept.

Not: Use one name for glyph spacing, font dimensions and canvas measurements.

See also: metrics

visual kerning¶

Applies to: fontlab. Translatable: yes. Fallback original term: shape-measured spacing correction.

Visual kerning is kerning that FontLab proposes by measuring the shapes, so that a font gets a usable first pass without a person typing thousands of values. You run it over a selection, then review what it produced, because a measurement of two outlines does not know about the words a reader will meet. Treat the result as a draft: keep the pairs it got right, correct the ones it did not, and kern the difficult pairs by eye in real words.

Write: You run visual kerning, then review every pair it proposes.

Not: Visual kerning will kern the whole font for you automatically.

See also: kerning, kerning pair, kerning class, FontLab 8

weight axis¶

Also written: wght, weight. Applies to: fontlab. Translatable: yes. Fallback original term: thickness axis.

The weight axis, tag wght, varies stroke thickness from light to bold. In a variable font it is the most common axis; its master locations use the usWeightClass scale, such as 400 for Regular and 700 for Bold.

Write: Add a weight axis with masters at 300 and 700.

Not: Weight, stroke thickness and stem thickness are interchangeable UI labels.

See also: axis, width axis, master, instance

weight class¶

Also written: usWeightClass. Applies to: fontlab, transtype. Translatable: yes.

The weight class is the OS/2 value from 100 to 900 that tells applications how heavy a style is, with 400 for Regular and 700 for Bold. Style linking and menus rely on it.

Write: Set the weight class to 600 for Semibold.

Not: The weight class is a measurement of stroke thickness.

See also: width class, weight axis, OS/2 table

width axis¶

Also written: wdth, width. Applies to: fontlab. Translatable: yes. Fallback original term: narrow-to-wide axis.

The width axis, tag wdth, varies letter proportions from condensed to extended. It is distinct from advance width, which is the spacing of one glyph, and from the geometric width of a shape. Its scale is a percentage of normal width.

Write: Add a width axis from 75 to 125.

Not: Increase the width axis of the glyph box.

See also: axis, weight axis, advance width

width class¶

Also written: usWidthClass. Applies to: fontlab, transtype. Translatable: yes.

The width class is the OS/2 value from 1, ultra condensed, to 9, ultra expanded, that tells applications how wide a style is. It is a classification, not the width axis value and not the advance width.

Write: Set the width class to 3 for Condensed.

Not: The width class sets the glyph widths.

See also: weight class, width axis, OS/2 table