Standard Music Font Layout (SMuFL)

Version 1.5 (draft)

Latest editor's draft:

• https://w3c.github.io/smufl/latest

Editor:

• Daniel Spreadbury, Steinberg

Participate:

• GitHub w3c/smufl
• File a bug
• Commit history

Abstract

SMuFL is a specification that provides a standard way of mapping the thousands of musical symbols required by conventional music notation into the Private Use Area in Unicode’s Basic Multilingual Plane for a single (format-independent) font.

The goal of SMuFL is to establish a new standard glyph mapping for musical symbols that is optimised for modern font formats and that can be adopted by a variety of software vendors and font designers, for the benefit of all users of music notation software.

Status of this document

This specification was published by the W3C Music Notation Community Group. It is not a W3C Standard nor is it on the W3C Standards Track. Please note that under the W3C Community Contributor License Agreement (CLA) other conditions apply. Learn more about W3C Community and Business Groups.

If you wish to make comments regarding this document, please send them to public-music-notation-contrib@w3.org (subscribe, archives).

Preamble

This section contains important information about the copyright and license of SMuFL.

Acknowledgements

This document reproduces glyphs from the Bravura font, copyright © Steinberg Media Technologies GmbH. Bravura is released under the SIL Open Font License and can be downloaded from GitHub.

This document also reproduces some glyphs from the Unicode 11.0 code chart for the Musical Symbols range. These glyphs are the copyright of their respective copyright holders, listed on the Unicode Consortium web site.

License

SMuFL is free to use, and is licensed under the terms of the W3C Community Final Specification Agreement (FSA).

Copyright © 2022 the Contributors to the Standard Music Font Layout Specification, published by the W3C Music Notation Community Group under the W3C Community Contributor License Agreement (CLA). A human-readable summary is available.

Version history

Version 1.40 (2021-03-15):

• Added new font metadata values for font design size, barline separation, H-bar thickness, and preferred text fonts to accompany music fonts (#95, #102, #124, #131)
• Added clarification for registration of glyphs in the Rests range (#100)
• Added fingeringQLower (U+ED8E) and fingeringSLower (U+ED8F) glyphs in the Fingering supplement range
• Added figbassTripleFlat (U+ECC1) and figbassTripleSharp (U+ECC2) in the Figured bass supplement range
• Added headless notes (U+E204–U+E20A) to Beamed groups of notes range (#77)
• Added glyphs to new Scale degrees range (U+EF00–U+EF07) (#64)
• Added glyphs in new Note name noteheads supplement range (U+EEE0–U+EEFF) (#82)
• Added mensuralWhiteSemibrevis (U+E962) to Medieval and Renaissance individual notes range
• Added guitarString10, guitarString11, guitarString12, guitarString13 (U+E84A–U+E84D) to Guitar range (#81)
• Added glyphs in Medieval and Renaissance prolations supplement (U+EE90–U+EE94) (#88)
• Added Cowell's noteheads for irrational durations (U+EEA1–U+EEB5) to Noteheads supplement range (#93)
• Added noteheadNancarrowSine (U+EEA0) in Noteheads supplement range (#92)
• Added arpeggiato (U+E63C) to Plucked techniques range (#97)
• Added caesuraSingleStroke (U+E4D7) to the Holds and pauses range (#108)
• Added Alois Hába's set of accidentals for 24-EDO quarter-tones (U+EE63–U+EE69) to the Other accidentals supplement range (#109)
• Added Chop (percussive bowing) notation range (U+EE80–U+EE8F) (#115)
• Added swissRudimentsNoteheadBlackFlam (U+EE70), swissRudimentsNoteheadHalfFlam (U+EE71), swissRudimentsNoteheadBlackDouble (U+EE72), swissRudimentsNoteheadHalfDouble (U+EE73) to the new Techniques noteheads range (#118)
• Changed registration of fretboardFilledCircle (U+E858), fretboardX (U+E859) and fretboardO (U+E85A) so that they are centred vertically and horizontally around the origin (#117)
• Added ups and downs accidentals (U+EE60–U+EE63) to new Other accidentals supplement range (#124)
• Added recommended stylistic alternates for U+E4A0 and U+E4A1, Rossini accent above and below (#134)
• Added Extended Helmholtz-Ellis accidentals (just intonation) supplement range (U+EE50–U+EE5F); revised appearance of accidentalCombiningLower31Schisma (U+E2EC) and accidentalCombiningRaise31Schisma (U+E2ED) (#126)
• Added glyphs to the Olympian Sagittal extension (extreme precision) accidental diacritics (U+E3F4–U+E3F7) and Magrathean Sagittal extension (insane precision) accidental diacritics (U+E3F8–U+E41F) ranges of Sagittal accidentals (#156)
• Added clarification to the Beamed groups of notes, Metronome marks and Standard accidentals for chord symbols ranges that these glyphs should all follow the guidelines for text-based applications, even in fonts primarily intended for use with scoring applications (#178)

Version 1.30 (2019-01-14):

• This specification is now published under the terms of the W3C Community Final Specification Agreement (FSA) (#38)
• Added dynamicCombinedSeparatorSlash (U+E549)
• Added keyboardPedalParensLeft (U+E676) and keyboardPedalParensRight (U+E677)
• Added new Chord symbol accidentals range (U+ED60-U+ED66)
• Added new glyphs to the Fingering range, with digits between 6 and 9, parentheses, brackets, and middle dot separator
• Added new Kahnotation range, with thanks to Matthew Dougherty, Sam Katz and Sam Weber (U+EDA0–U+EDF1) (#58)
• Added new German organ tablature range, with thanks to John McKean (U+EE00–U+EE3F) (#72)
• Added new Clefs supplement range, including new universal Indian drum notation clef (U+ED70)
• Added new Fingering supplement range, with italic fingering digits, parentheses and brackets (U+ED80-U+ED8D)
• Added more separators for brass fingering (U+ED2D–U+ED2E) to Fingering range
• Added pictBeaterMalletDown (U+E7EC), pictBeaterBrassMalletsRight (U+E7ED), pictBeaterBrassMalletsLeft (U+E7EE), pictTriangleBeaterPlain (U+E7EF) to Beaters pictograms range (#73, #66)
• Added vocalHalbGesungen (semi-sprechgesang) to Vocal techniques range (U+E64B) (#68)
• Added separate glyphs for upper dot, lower dot and central slash (U+E503–U+E505) to Bar repeats range, to allow construction of bar repeats for arbitrary number of bars (#62)
• Added lyricsTextRepeat glyph (U+E555) to Lyrics range (#61)
• Added one-handed roll (U+E233) and double lateral roll (U+E234) for mallet percussion, popularised by Leigh Howard Stevens, to Tremolos range (#56)
• Clarified legerLineExtension engraving default scales according to notehead size (#70)
• Clarified that bounding box cut-out coordinates are relative to the glyph origin, i.e. its bottom left-hand corner (#90)
• Added recommended optional glyphs for tuplet digits in lighter weight to the Tuplets range
• Added recommended optional glyphs for optical variants for some chord symbols glyphs, e.g. +/- for augmented/diminished chord quality for the Chord symbols range
• Added recommended optional glyphs for optical variants for chord symbol accidentals shown at smaller sizes for the new Chord symbol accidentals range
• Added recommended optional glyphs for oversized versions of the Slash notehead range
• Added recommended optional glyphs for new large, narrow bold serif time signatures in Time signatures and Time signatures supplement ranges
• Expanded range of recommended optional glyphs for large, narrow sans serif time signatures to complete Time signatures and Time signatures supplement ranges

Version 1.20 (2016-04-25):

• Added double whole note slash notehead (U+E10A) (#19).
• Added double-slashed black and white round noteheads, often used to denote striking piano strings (U+E11C, U+E11D) (#22).
• Added irregular tremolo mark, used by Stockhausen (U+E232) (#48)
• Added square brackets for editorial accidentals (U+E26C, U+E26D) (#10)
• Added equal-tempered quarter-tone flat and quarter-tone sharp, combining glyphs to raise and lower by a 53-limit comma, and tilde and equals characters to indicate enharmonic equivalence, to the Extended Helmholtz-Ellis accidentals (just intonation) range (U+E2F5-U+E2FB) (#24)
• Added quarter-tone sharp and flat accidentals, used by Ferneyhough (U+E48E, U+E48F) (#23)
• Added parentheses and brackets for hairpins (U+E542–U+E545) (#42)
• Added hyphen, colon, and space separators for use in combined dynamics, e.g. p-mp (U+E546–U+E548) (#43)
• Added brass valve trill to Brass techniques range (U+E5EF) (#25)
• Added wind mouthpiece pop and rim only to Wind techniques range (U+E60A, U+E60B) (#25)
• Added bow behind bridge on one, two, three, or four strings to String techniques range (U+E627–U+E62A) (#26)
• Added nasal voice (#27), tongue click, finger click, and tongue and finger click (as used by Stockhausen) to Vocal techniques range (U+E648–U+E64A) (#49)
• Added L and reversed-L hooks used instead of Ped. to start and stop sustain pedal indications to Keyboard techniques range (U+E672, U+E673) (#17)
• Added pedal-to-heel and heel-to-pedal transitions to Keyboard techniques range (U+E674, U+E675) (#28)
• Added damp low strings, damp with both hands, damp below, damp above, metallic sounds on a single string, isolated sounds, and snare drum techniques as used by Salzedo to 'Harp techniques' range (U+E697–U+E69D) (#29)
• Added clockwise variant of scrape around rim to 'Percussion playing technique pictograms' range (U+E80E) (#30)
• Added full barré and half-barré to Guitar range (U+E848, U+E849), plus recommended stylistic alternate with horizontal fraction slash for half-barré (#14)
• Added unconducted/free passages to Conductor symbols range (U+E89A) (#31)
• Added upper case F, I, K, L, and lower case i, k, l, glyphs to existing Function theory symbols range (U+EA99–U+EA9F), plus a new Function theory symbols supplement range including upper case M and N, and lower case m and r (U+ED00–U+ED03) (#32)
• Added "cut 3" to Time signatures supplement range (U+EC86) (#16)
• Added diminished 7 to new Figured bass supplement range (U+ECC0) (#9)
• Added new Shape note noteheads supplement range containing double whole note versions of all of the different notehead shapes in the existing 'Shape note noteheads' range (U+ECD0–U+ECDD) (#18)
• Added turned time signature digits, common time and cut common time (U+ECE0–U+ECEB) (#21)
• Added reversed time signature digits, common time and cut common time (U+ECF0–U+ECFB) (#21)
• Added new Fingering range, containing digits bold 0–5 suitable for keyboard fingering, and a variety of symbols used in guitar fingering (U+ED10–U+ED23) (#34)
• Added new Arabic accidentals range (U+ED30–U+ED38) (#44)
• Added new Articulation supplement range containing so-called "soft accent", plus combinations with staccato and tenuto (U+ED40–U+ED47) (#35)
• Added new Stockhausen accidentals (24-EDO) range (U+ED50–U+ED5E) (#51)
• Added stylistic alternates for cClef and cClefChange in the style of 20th century French publishers (#11)
• Added stylistic alternates for 15/22 octave markings using 16/24, as used by some 20th century French publishers (#20)
• Added stylistic alternates for wiggleArpeggiatoUpSwash and wiggleArpeggiatoDownSwash based on Couperin's L'Art de Toucher Le Clavecin (#33)
• Changed the appearance of clefBridge (U+E078) to match the design used by Lachenmann in ...zwei Gefühle... and added a stylistic alternate with the previous design (#8)
• Changed specification for font metadata locations on Linux to match the recommendations of the XDG Base Directory Specification (#39).
• Converted license for SMuFL specification from MIT License to W3C Community Contributor License Agreement (CLA) Deed (#37).
• Fixed the appearance of figBassRaised5 to have a forward slash rather than a backward slash, the correct appearance for a diminished fifth (U+EA5A) (#9)

Version 1.19 (2015-08-07):

• Corrected implementation notes to clarify how brace glyphs should be handled by consuming applications: rather than scaling them only in the vertical dimension to fit the height of the staves being braced, they should be scaled proportionally.

Version 1.18 (2015-05-18):

• Added specification of locations for font-specific metadata to be installed on Windows, OS X, and Linux, to aid consuming applications in the identification of SMuFL-compliant fonts.

• Added recommendation that characters in ranges that will typically be drawn using runs of text (e.g. time signature digits, octave line labels, figured bass, and function theory symbols) should have appropriate non-zero side bearings.

• Reworked the triangular clefs in the Clefs range between U+E06F and U+E072 to match the descriptions given of their use by Schäffer in Karkoschka’s book. This involved changing the names and descriptions of these glyphs as follows: U+E06F was cClefTriangular, now schaefferClef; U+E070 was fClefTriangular, now schaefferPreviousClef; U+E071 was cClefTriangularToFClef, now schaefferGClefToFClef; U+E072 was fClefTriangularToCClef, now schaefferFClefToGClef.

• Added z-style quarter (crotchet) rest to the Rests range.

Version 1.17 (2015-04-29):

• Added specification of new optionalGlyphs structure for font-specific metadata to provide information about non-core glyphs included in fonts.

• Added specification of the name of the glyph for which the glyph in a stylistic set is an alternate to the sets structure in font-specific metadata.

• Added new implementation notes concerning noteWholeEmpty, noteHalfEmpty, and noteBlackEmpty in the Note name noteheads range.

• Added new Metronome marks range, with stem up and stem down notes intended to be proportioned for setting in line with characters from a regular text font; specifically, it is recommended that stems are shortened by 0.75 spaces from their default length.

• Clarified role of Individual notes range, which is that notes in this range are intended for drawing on a stave, and as such should have the default stem length (3.5 spaces minimum).

• Added baseline and superscript italic a, b, m, and v characters to the Octaves supplement range, to allow the creation of arbitrary octave line markers beyond those included in the Octaves range.

• Added marcato-tenuto above/below composites to the Articulation range.

• Added alternative “raised 6” character to the Figured bass range.

Version 1.12 (2015-01-07):

• Added specification of new noteheadOrigin anchor points for the glyphsWithAnchors structure to help with the correct alignment of noteheads that have left-hand side bearings with those that do not.

• Added specification of new opticalCenter anchor points for the glyphsWithAnchors structure to help with the correct balancing of glyphs that should be centered on noteheads and stems (e.g. dynamics)

• Added new Time signatures supplement range, with square brackets for the whole time signature and numerator only, the slash separator sometimes used for interchangeable time signatures, and new timeSig2Cut glyph, used by Bach and other composers of that period as an alternative to the normal cut common (alla breve) symbol.

• Added new Octaves supplement range, with loco text (octaveLoco). Revised the existing Octaves range, correcting the recommended appearance of the ottava bassa, quindicesima bassa, and ventiduesima bassa glyphs, and adding new glyphs for commonly-used but incorrect abbreviations for these glyphs.

• Added missing stem down noteheads for smnSharp and smnSharpWhite in the Simplified Music Notation range.

• Added Salzedo’s symbols for ascending and descending Aeolian chords to the Harp techniques range.

• Added short, medium, and long smooth lifts to the Brass techniques range.

• Added Hauptrhythmus and Choralmelodie, as used by Alban Berg, to the Analytics range.

Version 1.0 (2014-06-16):

• Now that SMuFL has reached 1.0, the code points and glyph names for all current glyphs will not change in future revisions.

• Added specification for new splitStemUpSE, splitStemUpSW, splitStemDownNW and splitStemDownNE anchors in font-specific metadata to define stem connection points for altered unisons.

• Added punctum deminutum (chantPunctumDeminutum) glyph to Medieval and Renaissance plainchant single-note forms range.

Version 0.99 (2014-06-02):

• Modified the specification of the glyphsWithBBoxes structure in the font-specific JSON metadata such that the glyph’s name is the primary key, rather than the value of a name key, which makes it easier to consume this data.

• Added an optional description key to the sets structure in the font-specific JSON metadata, to contain a human-readable description of a stylistic set.

• Added a new fourth value to the type key for the sets structure, for large time signature digits intended for drawing outside the staff.

• Added specification of new graceNoteSlashSW, graceNoteSlashNE, graceNoteSlashNW and graceNoteSlashSE anchor points for the glyphsWithAnchors structure to help with the correct positioning of slashes on stem up and stem down flags of unbeamed grace notes.

• Added specification of new repeatOffset anchor point for the glyphsWithAnchors structure to help with the correct registration of tessellating glyphs.

• Added clarifications in the glyph registration guidelines for fonts intended for use in scoring applications that parentheses glyphs may have negative side bearings to improve default kerning of these glyphs with the symbols they are intended to bracket; likewise, tessellating glyphs (such as the wiggle that follows the  symbol) may have negative side bearings to produce correct tessellation when set in a single run of text.

• Added 8 and 15 digits scaled correctly for positioning on G and F clefs.

• Added recommended stylistic alternates for common time, cut time and + intended for use as large time signatures printed above the staff.

• Added a set of noteheads enclosed in large circles, used by some drummers.

• Added an ornate X notehead contained within an ellipse.

• Added Couperin’s pincé and tremblement appuyé ornaments.

• Redesigned the thumb position string technique glyph to more closely resemble a zero digit, and added a turned version.

• Added a zero-width rectangle intended to enclose single percussion beaters inside a box.

• Added strum direction arrows for guitar, and a stylistic alternate for the golpe glyph as used by Antonis Vounelakos.

• Added an additional raised 7 digit for figured bass.

• Added left- and right-pointing arrows for use in metric modulations.

• Added recommended ligatures for combining Johnston accidentals with standard sharp and flat accidentals.

• Removed the ranges of glyphs for wind instrument fingering charts.

Version 0.9 (2014-04-17):

• Expanded the specification of font-specific metadata to include new structures to describe stylistic alternates, stylistic sets and ligatures present in fonts for applications that cannot access advanced font features.

• Defined new values for the “glyphs” structure in font-specific metadata to describe cut-outs from the four corners of a glyph’s bounding box, in order to allow better kerning or interlocking of glyphs in some circumstances, e.g. when stacking accidentals; also renamed this structure to “glyphsWithAnchors” to clarify its purpose.

• Defined specification for new ranges.json file, which provides information about the ranges of glyphs described in this specification in a machine-readable fashion.

• Added initial glyph registration and font metrics guidelines for fonts intended for use in text-based applications.

• Added new range for Kodály solfège hand signs.

• Added new range for Peter Hayes George’s Simplified Music Notation.

• Added narrow and wide versions of the sine wave, square wave and sawtooth wavy lines in the Multi-segment lines range.

• Added wide versions of the black and white diamond noteheads, as used in some handbells music.

• Added turned (i.e. inverted) versions of up bow and down bow marks.

• Added oriscus liquescens to the Medieval and Renaissance plainchant single-note forms range, and moved punctum auctum inclinatum and punctum auctum diminutum to this range.

• Added strophicus liquescens (for intervals of a second up to a fifth) to the Medieval and Renaissance plainchant multiple-note forms range.

• Added oblique ligature forms for mensural notes describing intervals of a second up to a fifth for black, void, black and void, and white noteheads to a new Medieval and Renaissance oblique forms range.

• Added single glyph for right and left repeat barlines to the Repeats range, and a recommended stylistic alternate using thick-thick rather than thin-thick-thin barlines.

• Added reversed versions of brackets to denote play with right/left hand in the Keyboard techniques range, to allow the demarcation of the end of a passage to be played with the other hand.

• Added more recommended stylistic alternates for display on smaller staff sizes: time signature digits; G, C and F clef; black, half, whole and double whole noteheads; standard articulations; dynamics letter forms.

• Added recommended ligatures for standard noteheads and accidentals in parentheses.

• Added open arrowheads and arrows.

• Added Kievan half note on space, and Kievan beam.

• Added new percussion pictograms from the books by Sevsay and Peinkofer/Tannigel, plus new combining glyphs for stems showing the “crush” rudiment, “dead” notes, and to instruct the performer to turn the instrument.

• Added five further mensural proportion signs, from Apel’s book.

• Added 12 new pre-composed trills and mordents, based on Bach’s ornamentation chart and ornaments found in the Emmentaler font.

• Added restHBarMiddle glyph, for text-based applications to construct H-bar multirests of variable width.

• Added noteheadWholeFilled and noteheadHalfFilled, for modern transcriptions of coloration in Medieval and Renaissance music.

• Consolidated breath marks into a single range, and added a new upbow-like breath mark (as used in music from Russia).

• Added range of glyphs for lyrics, including three lengths of elision undertie, and baseline hyphen (as used in music from Russia).

• Added a wider slash notehead, for whole note (semibreve) duration.

• Added more shape note noteheads to support the 7-shape conventions of Joseph Funk and William Walker.

• Added maxima rest, and double whole (breve) rest with leger lines above and below.

• Added curved caesura.

• Added separate glyphs for the ‘e’, ‘d’ and dot in keyboard pedal marks, plus a curved hyphen to be used along with the ‘P’ to show start/end pedal in some editions.

• Added new mensural C clef, plus variations of the Petrucci C clef for different staff positions.

• Added different custos for different staff positions.

• Added stylistic alternates for the Medieval and Renaissance “soft b” flat accidental.

• Added dedicated glyphs for C, G, and F clef changes, plus new combining clef change character to produce other clef change glyphs by way of glyph substitution.

• Added one- and two-third tones sharp and flat accidentals as used by Brian Ferneyhough.

• Added “just air” open diamond notehead as used by Brian Ferneyhough.

• Added white and wide white diamond noteheads.

• Added a range of glyphs for denoting accel./rit. beam lines above the staff.

• Added normal, wide and narrow leger line glyphs.

Version 0.85 (2014-03-09):

• Updated glyph registration guidelines for articulations, such that articulations above the note should be positioned sitting on the baseline, and articulations below the note should be positioned hanging from the baseline.

• Quite a few changes to canonical glyph names, especially for accidentals, with the aim of making the names clarify the actual interval represented by each accidental (where that is unambiguous) in terms of fractions of a tone.

• Added whole and half rests with leger lines, i.e. as if displayed outside the staff.

• Added clef for diatonic accordion.

• Added recommended stylistic alternates for C and F clef forms used in 18th century French music, and for an F clef form used in 19th century music across Europe.

• Added recommended ligature for G clef with ligated 8 above.

• Added half-brackets for keyboard notation to show notes that should be played by the other hand.

• Moved staff divide arrows from the Miscellaneous symbols range to the (now renamed) Staff brackets and dividers range.

• Moved the percussion swish arrow from the Miscellaneous symbols range to the Percussion playing techniques pictograms range.

• Moved all the glyphs from the Quartertone accidentals (24-EDO) range to the (now renamed) Other accidentals range, eliminating the former range and moving the latter to the very end of all of the ranges of accidentals.

• Further revisions to the plainchant ranges, including adding reversed virga, smaller version of punctum inclinatum, moving the punctum mora to the plainchant articulations range, and eliminating the precomposed podatus and clivis glyphs in favour of individual components that provide the means to construct these easily for any interval. Also added strophicus, strophicus auctus, punctum inclinatum auctum to the single-note forms range.

• Added new range for Kievan square notation, as used for liturgical chant in the Russian Orthodox Church.

• Added new glyphs for tabling one handbell and tabling a pair of handbells.

• Added alternative pedal heel glyph and pedal heel or toe glyph to Keyboard techniques range.

• Added recommended stylistic alternates for braces designed for use across different sizes of gaps, designed to be scaled uniformly rather than simply stretched vertically.

• Added many new electronic music pictograms, including speaker configurations, more transport controls, additional hardware devices, and so on.

• Added guitar fade in, fade out and swell glyphs.

• Added the glyphs used in the Corpus Monodicum project to the Medieval and Renaissance plainchant in CMN range.

• Added notes on the currently-defined classes in the JSON metadata file to the Notes for implementers section.

Version 0.8 (2014-02-03):

• Based on community feedback, added clarification that code points for glyphs may change until SMuFL reaches version 1.0, after which point existing code points will become immutable.

• Glyphs in SMuFL encoded in the primary range of U+E000–U+F3FF are no longer considered “mandatory”, but rather they are “recommended”: in order to be considered SMuFL-compliant, a font need not implement every recommended glyph, just as a text font need not implement every Unicode code point in order to be considered Unicode-compliant. Fonts need only implement those glyphs that are appropriate for their intended use at the correct SMuFL code points in order to be considered SMuFL-compliant.

• Changed guidelines for metrics of text-like glyphs (e.g. dynamics, D.C./D.S. markings in repeats) in fonts intended for use in scoring applications, such that it is recommended that the x-height of such glyphs is around 1 staff space (0.25 em).

• Added Ivan Wyschnegradsky’s system of 72-EDO accidentals.

• Added Bosanquet’s comma up/down.

• Dispersed the glyphs formerly in the Sagittal-compatible accidentals range to other ranges, and revised the canonical glyph names for Sagittal accidentals that describe specific ratios in order to make those ratios clearer.

• Added slashed sharp/flat accidentals used by John Tavener in his Byzantine-inspired choral works.

• Added left/right parentheses for accidentals.

• Added new ranges for Renaissance lute tablature, covering French/English, Italian/Spanish and German conventions.

• Added new ranges for fingering charts for flute, oboe, clarinet, bassoon, saxophone and recorder, as used in educational materials such as instructional or method books.

• Added Britten’s curlew sign for a pause of an indeterminate length.

• Added push/pull signs for accordion.

• Added separate noteheads for white mensural notation.

• Added inverted signum congruentiae.

• Added combined tenuto-accent articulation.

• Added quasi-random wiggly lines (wiggleRandom1, wiggleRandom2, wiggleRandom3, wiggleRandom4) to multi-segment lines range.

• Added flipped and large versions of constant circular motion (wiggleCircularConstantFlipped, wiggleCircularConstantLarge, wiggleCircularConstantFlippedLarge) to multi-segment lines range.

• Added combining top/middle/bottom segments for black and white rectangular note clusters.

• Added 2, 3, 4 and 6-dot divisi indicators for measured tremolos (tremoloDivisiDots2, tremoloDivisiDots3, etc.) to tremolos range.

• Added clavichord bebung glyphs for 2, 3, and 4 finger movements (keyboardBebung2DotsAbove, keyboardBebung3DotsBelow, etc.) to the keyboard techniques range.

• Added double-height parentheses and brackets (csymParensLeftTall, csymParensRightTall, csymBracketLeftTall, csymBracketRightTall) to the chord symbols range.

• Added recommendation for stylistic alternates for time signature digits 0–9 suitable for use as large time signatures shown above/between staves (timeSig0Large through timeSig9Large).

• Added sfzp (sforzato-piano) dynamic and ligature.

• Added Penderecki’s quarter-flat and Bussotti’s three-quarter sharp accidentals.

• Added six further accordion coupler diagrams for right-hand three-rank accordions, and accordion ricochet glyphs.

Version 0.7 (2013-11-27):

• Introduced canonical names for every recommended glyph, which are intended to be immutable. Code points, on the other hand, may change as required to accommodate insertions or deletions of glyphs.

• New Notes for implementers section with expanded guidelines for glyph registration, with changes for precomposed stems and stem decorations (which should now be centered around x=0) and flags (which should be positioned vertically relative to the end of a stem of normal length at y=0).

• Added specification for JSON metadata files for SMuFL and for SMuFL-compliant fonts, developed in conjunction with Joe Berkovitz.

• Significantly expanded the repertoire of glyphs for Medieval and Renaissance notation, with new ranges for clefs, accidentals and ligatures, plus considerable reworking of the notes and prolations ranges, expansion of the repertoire of glyphs for plainchant notation (with new ranges for staves, divisions, clefs and articulations, and a wider range of neumes).

• Added range for Daseian notation, as found in the ninth century treatises Musica enchiriadis and Scolica enchiriadis.

• Added new range of control characters for adjusting the staff position of staff-relative glyphs, intended for fonts designed for text-based applications.

• Added narrow and wide staff line glyphs, intended for fonts designed for text-based applications.

• Added C clef ottava bassa, and recommended stylistic alternate for G clef ottava bassa with parentheses around the 8.

• Added control characters for time signature digits to allow digits to be stacked vertically, intended for fonts designed for text-based applications.

• Added square double whole note (breve) notehead.

• Added new combining harp string noise for stem glyph, and corresponding precomposed stem glyph.

• Added four further quarter-tone accidental symbols to “other microtonal accidentals” group.

• Added some percussion playing technique symbols from Dante Agostini’s method books.

• Added a golpe (tap the pick guard) glyph from Claude Worm’s flamenco guitar method book.

• Added short and long fermata glyphs as used by Henze.

• Added combining glyphs for accordion couplers, allowing the creation of any coupler diagram not explicitly encoded.

• Added “pf” dynamic.

Version 0.6 (2013-07-29):

• Added opening parenthesis and closing parenthesis for noteheads, circled slash notehead, heavy X and heavy X with hat noteheads, as used in Dante Agostini’s drum method.

• Added muted slash noteheads.

• Added “si” note name noteheads for French solfège, and H sharp note name noteheads for German.

• Added combining rim shot stem.

• Added “sharp sharp” accidental for compatibility with MusicXML.

• Added extended Stein-Zimmermann accidentals with arrows.

• Added one-third-tone sharp and two-third-tones sharp accidentals as used by Xenakis.

• Significant revision to the ornaments range, including splitting into separate ranges (common ornaments, other baroque ornaments, combining strokes for trills/mordents, precomposed trills/mordents). A small number of glyphs from previous versions of SMuFL have been removed to make way for symbols drawn from Frederick Neumann’s authoritative book on baroque ornamentation.

• Added left hand pizzicato.

• Added recommended stylistic alternates for Bartok pizzicato above/below.

• Added recommended stylistic alternates for ‘Ped.’ and ‘Sost.’ that do not include terminal dots.

• Added choke cymbal glyph from Weinberg.

• Added open, half-open and closed wah/volume pedals, left- and right-hand tapping glyphs for guitar.

• Added new range for arrows and arrowheads, including moving the up/down/right/left arrows from the vocal techniques into this new range.

Version 0.5 (2013-07-08):

• Many existing code points have been changed, as a result of hundreds of new glyphs being added, plus a number of new ranges.

• Added long and very long system dividers for very large scores.

• Added heavy, double heavy and dotted barlines.

• Added square coda and small repeat signs for repeats within bars.

• Added recommended stylistic alternates for segno and coda for the appearance preferred by Japanese publishers.

• Added quindicesima bassa G clef and F clef, G clef combined with C clef, G clefs designed to be ligated with numbers below and above to show the transposition of an instrument, plus recommended ligatures for G and F clefs with numbers above and below; also added G, C and F clefs with arrows up and down, which may be used either as alternatives for octave clefs or to represent the extremes of register on an instrument, and semi-pitched percussion clefs, plus a bridge clef.

• Removed “tall” versions of 6- and 4-string tab clefs, and instead made them recommended stylistic alternates, together with versions that use letterforms with serifs.

• Added +, -, X (multiply), comma, parentheses glyphs for time signatures, plus basic fractions, and Penderecki-style open time signature.

• Added specific noteheads for double whole note and whole note to the noteheads range rather than relying on the glyphs in the pre-composed notes range.

• Added shaped noteheads for specific note values (double whole note, whole note, half note, and quarter note and shorter); also added large up- and down-pointing triangles for highest/lowest notes played by an instrument.

• Added large slashed circular noteheads as used by Stockhausen for notating gong/tam-tam hits.

• Added combining glyphs for note clusters of specific note values.

• Added noteheads with solfège and chromatic note names embedded within them, as seen in “EZ-Play” educational scores.

• Added specific range of noteheads for sacred harp shape note singing.

• Added pre-composed 1024th notes, tails and rest.

• Added range for typing simple beamed groups of notes in text-based applications, designed to be used in conjunction with pre-composed notes, and allowing beamed groups with rhythmic values between 8th notes and 64th notes, plus ties and triplets.

• Added combining stems for multiphonics, damp, sussurando, Saunders vibrato pulse accent.

• Added four- and five-stroke tremolos plus Wieniawski-style unmeasured tremolo glyphs.

• Added stylistic alternates for flags: straight flags; and shorter stem-up flags to avoid collisions with augmentation dots.

• Separated accidentals into several discrete ranges based around the various accidental systems, including 12-EDO, 24-EDO, the system of up- and down-pointing arrows favoured by Gould, Stein-Zimmermann (also known as Tartini-Couper), Sims (also known as Maneri-Sims, due to the adoption of Ezra Sims’ accidentals by Joe Maneri of the Boston Microtonal Society), Ben Johnston, Marc Sabat and Wolfgang von Schweinitz’s Extended Helmholtz-Ellis Just Intonation Pitch Notation.

• Added George Secor and Dave Keenan’s Sagittal system of accidentals.

• Added accidentals used in Turkish folk music.

• Added Persian accidentals.

• Added staccatissimo wedge and stroke glyphs.

• Added very short and very long fermatas, plus short caesura.

• Added left and right halves of multirest H-bars and old-style quarter rest as seen in e.g. Novello editions.

• Added ventiduesima (three octaves, “22”) glyphs to octaves range.

• Added precomposed glyphs for common dynamics and niente circle for hairpins.

• Added schleifer (long mordent) and Haydn ornament.

• Added additional brass techniques, including short, medium and long versions of lift, doit, lip fall, smooth fall, rough fall, plus jazz turn.

• Added range of glyphs for embouchure tightness, reed position, multiphonics, and stylistic alternates for double- and triple-tonguing with no slurs.

• Added further overpressure glyphs, plus jété, fouetté, Rebecca Saunders’s “vibrato pulse” accent, thumb position and indeterminate bow direction to string techniques range.

• Added plectrum pictogram and combining damp glyph for note stems to plucked techniques range.

• Added arrows for breathing and intonation, plus combining sussurando glyph for note stems, to vocal techniques range.

• Added pedal pictograms, sostenuto pedal symbols, and half-pedal marks to keyboard techniques range.

• Added pictograms for metal rod and tuning key to harp techniques range.

• Added Smith Brindle’s pictograms for tuned percussion instruments.

• Added pictogram for Indian table, plus stylistic alternate for tambourine as used by Stockhausen.

• Added pictogram for football rattle, plus Smith Brindle’s pictogram for castanets as a stylistic alternate.

• Added pictogram for handbell, plus stylistic alternates for cow bell (from Berio) and sleigh bell (from Smith Brindle).

• Added pictogram for Chinese cymbal.

• Added pictogram for tam-tam with beater from Smith Brindle.

• Added pictogram for maracas, rainstick, plus stylistic alternate for maraca from Smith Brindle.

• Added pictogram for megaphone.

• Added soft and hard glockenspiel beaters, superball beaters, wound beaters with hard and soft cores, plus soft, medium and hard gum beaters.

• Added pluck lift to handbells range.

• Added “Theme” indicators to analytics range.

• Added minor (minus sign) glyph to chord symbols range.

• Added mensural proportion glyphs.

• Added combining raise and lower glyphs to figured bass range.

• Added repetition, angle brackets, and prefix + and ring glyphs to Function theory range.

• Added new range for multi-segment lines, including moving all of the various “wiggle” glyphs (for trill, glissando, arpeggiando, vibrato, etc.) plus the 11 ornament strokes from the Unicode Musical Symbols range into this range, and adding further glyphs for variable speed trills, alternate arpeggiato ending glyphs, wavy lines, squaretooth and sawtooth lines, group glissando, circular motion, and variable speed and intensity of vibrato.

• Added new range of pictograms for electronic music, including microphone, loudspeaker, transport controls, volume level and MIDI controller level.

• Added new “do not copy” glyphs, eyeglasses and choral divide arrows glyphs to the miscellaneous symbols range.

• Adjusted the registration of many glyphs (e.g. noteheads, accidentals, time signatures, flags, rests) in Bravura in line with the interim guidelines for metrics and registration for SMuFL-compliant fonts intended for use with scoring applications.

Version 0.4 (2013-05-16):

• Added range for Arel-Ezgi-Uzdilek (AEU) accidentals for Turkish maqam music.

• Added equals sign and open time signature glyphs.

Version 0.3 (2013-03-11):

• Moved combining flags glyphs to accommodate glyphs for 256th note stem up, 256th note stem down, 512th note stem up and 512th note stem down.

Version 0.2 (2013-02-08)

• Added tick barline.

• Changed names of time signature, tuplet and figured bass digit glyphs to ensure that they are unique.

• Add upside-down and reversed G, F and C clefs for cancrizans and inverted canons.

• Added Time signature + and Time signature fraction slash glyphs.

• Added Black diamond notehead, White diamond notehead, Half-filled diamond notehead, Black circled notehead, White circled notehead glyphs.

• Added 256th and 512th note glyphs.

• All symbols shown on combining stems now also exist as separate symbols.

• Added reversed sharp, natural, double flat and inverted flat and double flat glyphs for cancrizans and inverted canons.

• Added trill wiggle segment, glissando wiggle segment and arpeggiato wiggle segment glyphs.

• Added string Half-harmonic, Overpressure down bow and Overpressure up bow glyphs.

• Added Breath mark glyph.

• Added angled beater pictograms for xylophone, timpani and yarn beaters.

• Added alternative glyph for Half-open, per Weinberg.

• Added Scrape from rim to center and Scrape around rim glyphs.

• Added Start of stimme glyph.

• Added colon for tuplet ratios.

• Added stem down versions of mensural notes, and signum congruentia and custos glyphs.

• Added three additional mensuration signs.

• Added Riemann Function theory glyphs.

Version 0.1 (2013-01-31)

• Initial version.

About SMuFL

This section provides useful background information about what SMuFL is, why it was developed, and what problems it solves.

A brief history of music fonts

Computer software has been displaying musical symbols of various kinds since the 1960s, but the first font for musical symbols did not arrive until 1985, when Cleo Huggins designed Sonata for Adobe.¹

Sonata mapped the musical symbols onto keys on the standard QWERTY keyboard, using some simple mnemonics (the treble G clef, for example, was mapped onto the & key, and the sharp sign onto #). Most music fonts developed since then, including Steve Peha’s Petrucci (the first music font for Finale, dating from 1988²) and Jonathan Finn’s Opus (the first music font for Sibelius, dating from 1993), have followed Sonata’s layout.

However, since Sonata includes fewer than 200 glyphs, and even conventional music notation³ requires many more symbols than that, individual vendors have devised their own mappings for glyphs beyond Sonata’s initial set.

By 2013, for example, the Opus font family that is still Sibelius’s default font set contains no fewer than 18 fonts with more than 600 glyphs between them.

In 1998, Perry Roland of the University of Virginia drafted a proposal for a new range of musical symbols to be incorporated into the Unicode Standard⁴. This range of 220 characters was duly accepted into the Unicode Standard, and those symbols are found at code points U+1D100–U+1D1FF⁵. However, its repertoire of 220 symbols does not extend dramatically beyond the scope of the original 1985 version of Sonata, though it does add some symbols for mensural and Gregorian notation.

To date the only commercially available music font that uses the Unicode mapping is Adobe Sonata Std, and its repertoire is incomplete.

How SMuFL is organized

The aim of the Standard Music Font Layout (SMuFL) is to provide the basis for music font mapping for the age of Unicode and OpenType fonts.

SMuFL uses the standard Private Use Area in the Basic Multilingual Plane (starting at code point U+E000), and currently includes just over 2440 recommended characters, plus several hundred further optional but recommended glyphs, primarily ligatures (i.e. two or more symbols drawn as a single glyph) and stylistic alternates (i.e. a different appearance for the same character with equivalent meaning). SMuFL is a superset of the Unicode Musical Symbols range, and it is recommended that common characters are included both at code points in SMuFL and in the Unicode Musical Symbols range. In the tables of glyphs in this document, where glyphs are shared between SMuFL and the Unicode Musical Symbols range, the Unicode Musical Symbols code point is shown following the SMuFL code point.

The groupings of characters within SMuFL are based on the groupings defined by Perry Roland in the Unicode Musical Symbols range, but with finer granularity. There are currently 118 groups of characters, proceeding roughly in order from least to most idiomatic, i.e. specific to particular instruments, types of music, or historical periods. The grouping has no significance other than acting as an attempt to provide an overview of the included characters.

Room for future expansion has generally been left in each group, so code points are not contiguous. The code point of each character in SMuFL 1.0 is intended to be immutable, and likewise every character has a canonical name, also intended to be immutable.

Recommended characters and optional glyphs

One of the aims of SMuFL is to make it as simple as possible for developers both of fonts and of scoring software to implement support for a wide range of musical symbols. Although modern font technologies such as OpenType enable a great deal of sophistication in automatic substitution features¹, applications that wish to use SMuFL-compliant fonts are not obliged to support advanced OpenType features.

The basic requirements for the use of SMuFL-compliant fonts are the ability to access glyphs by their Unicode code point, to measure glyphs, and to scale them (e.g. by drawing the font at different point sizes). If applications are able to access OpenType features such as stylistic sets and ligatures, then additional functionality may be enabled.

However, all glyphs that can be accessed via OpenType features are also accessible via an explicit code point. For example, a stylistic alternate for the sharp accidental designed to have a clearer appearance when reproduced at a small size can be accessed as a stylistic alternate for accidentalSharp, but also by way of its explicit code point, which will be in the range U+F400–U+F8FF.

Because optional glyphs for ligatures, stylistic alternates, etc. are not required, and different font developers may choose to provide different sets (e.g. several different appearances of tab clefs, or different sets of glyphs whose designs are optimized for drawing at different optical sizes), SMuFL does not make any specific recommendations for how these glyphs should be assigned explicit code points, except that they must be within the range U+F400–U+F8FF, which is reserved for this purpose and for any other private use required by font or application developers.

In summary, recommended characters are encoded from U+E000, with a nominal upper limit of U+F3FF (a total of 5120 possible characters), while optional glyphs (ligatures, stylistic alternates, etc.) are encoded from U+F400, with a nominal upper limit of U+F8FF (a total of 1280 possible glyphs).

In order for a font to be considered SMuFL-compliant, it should implement as many of the recommended characters as are appropriate for the intended use of the font, at the specified code points. Fonts need not implement every recommended character, and need not implement any optional glyphs, in order to be considered SMuFL-compliant.

Implementations

The reference font for SMuFL is Bravura, which can be downloaded from GitHub. Bravura is provided in OpenType, WOFF, WOFF2 and SVG formats, and is released under the SIL Open Font License. The example glyphs in this specification are all taken from Bravura.

Other SMuFL-compliant fonts are available under a variety of licenses. A list of such fonts can be found here.

Support for SMuFL-compliant fonts has been implemented by a variety of applications. A list of applications that support SMuFL can be found here.

Sources for symbols

In addition to surveying the music fonts supplied with existing major scoring applications, the following texts were consulted as sources for musical symbols:

• Abbās (al-), Ḥabīb Ẓāhir, et حبيب ظاهر Ḥabīb Dhāhir العباس. نظرياتالموسيقى العربية Nadhariyyāt al-Mūsīqā al-ʿArabiyya. Vol. Theorie Musique Arabe. (Baghdad – Irak) بغداد – العراق: وزارة الثقافةوالٳعلام، دائرة الفنون الموسيقية، معهد الدراسات النغمية العراقى (Wizārat a-th-Thaqāfa wa-l Iʿlām, Dāʾirat al-Funūn al-Mūsīqiyya, Maʿhad a-d-Dirāsāt a-n-Naghmiyya al-ʿIrāqiyy), 1986.

• Agostini, Dante. Methode de Batterie. France: Carisch Musicom, 2009.

• Apel, Willi. The Notation of Polyphonic Music 900–1600, Fourth Edition. Cambridge, MA, USA: The Medieval Academy of America, 1953.

• Bach, J.S. (ed. Palmer, Willard). J.S. Bach: Inventions and Sinfonias, 2nd Edition. Van Nuys, CA, USA: Alfred Publishing Co., 1991.

• Balestrieri, Donald. Registers of the Standard Stradella Keyboard Accordion. USA: Accord Magazine, 1979.¹

• Couperin, François. L'Art de Toucher Le Clavecin. France, 1716.

• Davis, Roger E. The Organists’ Manual. New York: W. W. Norton, 1985.

• Deyoe, Nicholas. *Lachenmann for the Conductor: Understanding, Learning, and Rehearsing Helmut Lachenmann’s "...zwei Gefühle..." Musik mit Leonardo. UC San Diego, CA, USA: 2008.

• Doty, David B. The Just Intonation Primer. San Francisco, USA: The Just Intonation Network, 1993.

• Dougherty, Matthew & Katz, Sam & Weber, Sam. Proposal to encode Kahnotation, 2016.

• Draugsvoll, Geir & Højsgaard, Erik (translated Borregaard, Andreas). Handbook on Accordion Notation. Copenhagen: The Royal Danish Academy of Music in Copenhagen, 2001.²

• Drobner, Mieczysław. Instrumentoznawstwo i akustyka (Musical Instruments and Acoustics). Cracow: PWM Edition, 1960 (7th Edition, 2008).

• Gould, Elaine. Behind Bars. London: Faber Music, 2011.

• Inglefield, Ruth & Neill, Lou Anne. Writing for the Pedal Harp: Standardized Manual for Composers and Harpists. University of California Press, 1985.

• Karkoschka, Erhard (tr. Koenig, Ruth). Notation in New Music. Universal Edition, 1972.

• McCarty, Frank. Notational Standards for Percussion: A Report on the Ghent Conference (from The Instrumentalist, xxix). Northfield, IL: The Instrumentalist Publishing Co., 1975.

• McKean, John. Proposal for the encoding of German organ tablature. 2017.

• Neumann, Frederick. Ornamentation in Baroque and Post-Baroque Music. Princeton, NJ: Princeton University Press, 1978.

• Peinkofer, Karl & Tannigel, Fritz: Handbuch des Schlagzeugs. Praxis und Technik. Mainz: Schott, 1981.

• Poulton, Diana. A Tutor for the Renaissance Lute. London, UK: Schott, 1991.

• Read, Gardner. Twentieth-Century Microtonal Notation. USA: Praeger, 1990.

• Richardson, Andrew Paul. Selected solo marimba music of Raymond Hieble: a guide for teaching and performance. Oklahoma: University of Oklahoma, 2013.

• Roland, Perry. Proposal for Encoding Western Music Symbols in ISO/IEC 10646. Virginia: University of Virginia, 1998.

• Sabat, Marc. The Extended Helmholtz-Ellis JI Pitch Notation. Plainsound Music Edition, 2005.

• Salzedo, Carlos. Modern Study of the Harp. London: G. Schirmer, 1921.

• Secor, George & Keenan, David. Sagittal – A Microtonal Notation System. Xenharmonikôn, An Informal Journal of Experimental Music, Volume 18, 2006. www.sagittal.org, 2004.

• Sevsay, Ertugrul: Handbuch der Instrumentationspraxis. Kassel: Bärenreiter, 2005

• Simmons, Nikita. A Primer of Kievan Square-Note (Quadratic or Synodal) Notation. www.synaxis.info, 2004.

• Smith Brindle, Reginald. Contemporary Percussion. New York: Oxford University Press, 1991.

• Stiller, Andrew. Handbook of Instrumentation. Philadelphia: Kallisti Music Press, 1994.

• Stone, Kurt. Music Notation in the Twentieth Century: A Practical Guidebook. New York: W.W. Norton, 1980.

• Vounelakos, Antonis. Die Konzepte der Flamenco-Gitarrentranskription. Vienna: Universität Wien, 2009.

• Weinberg, Norman. Guide to Standardized Drumset Notation. Lawton: Percussive Arts Society, Inc., 1998.

• “Ornaments”, Grove Music Online, ed. L. Macy (accessed January 24 2013)

• AGEHR Handbell and Handchime Notation Booklet, 8th ed. Dayton: Lorenz, 2010.³

Other contributors

Grateful thanks are also extended to the following, all of whom have contributed their time and expertise to identifying further sources of glyphs for inclusion in SMuFL: Mark Adler, Stephen Begley, Michael Scott Cuthbert, Matthew Dougherty, Ben Finn, Maurizio Gavioli, Michael Good, Mark Johnson, James Ingram, Sam Katz, Dave Keenan, Phil Knights, Matthew Maslanka, John McKean, Jean-Christoph Michel, Alexander Plötz, Grzegorz Rolek, Ahmed Tahar, Sam Weber, Emil Wojtacki, Notengrafik Berlin.

Thanks also to Joe Berkovitz for his contribution towards the guidelines for font metrics and glyph registration for fonts intended for use with scoring applications, and the initial design of the font metadata JSON files.

Missing symbols?

If you know of any commonly used symbols that are not included in SMuFL, please either create a new issue at GitHub or post your suggestions to the public-music-notation-contrib mailing list.

Specification

This section provides guidelines and recommendations for metrics, glyph registration and font metadata, and is intended for font designers who want to design SMuFL-compliant fonts, and for software developers who want to build applications that can consume SMuFL-compliant fonts.

Metadata for SMuFL glyphs and ranges

To aid software developers in implementing SMuFL-compliant fonts, three support files in JSON format are available. For more information about the JSON format, see www.json.org.

glyphnames.json

glyphnames.json maps code points to canonical glyph names, which by convention use lower camel case, a convenient format for most programming languages. Here is an excerpt of this file:

{
...
  "barlineDashed": {
    "alternateCodepoint": "U+1D104",
    "codepoint": "U+E036",
    "description": "Dashed barline"
  },
  "barlineDotted": {
    "codepoint": "U+E037"
    "description": "Dotted barline"
  },
  "barlineDouble": {
    "alternateCodepoint": "U+1D101",
    "codepoint": "U+E031"
    "description": "Double barline"
  },
  "barlineFinal": {
    "alternateCodepoint": "U+1D102",
    "codepoint": "U+E032"
    "description": "Final barline"
  },
    "barlineHeavy": {
    "codepoint": "U+E034"
    "description": "Heavy barline"
  },
...
}

The file is keyed using the glyph names, with the SMuFL code point provided as the value for the "codepoint" key, and the Unicode Musical Symbols range code point (if applicable) provided as the value for the "alternateCodepoint" key. The "description" key contains the glyph’s description, as it appears in this specification.

classes.json

classes.json groups glyphs together into classes, so that software developers can handle similar glyphs (e.g. noteheads, clefs, flags, etc.) in a similar fashion. Here is an excerpt of this file:

{
...
  "clefs": [
    "gClef",
    "gClef15mb",
    "gClef8vb",
    "gClef8va",
    "gClef15ma",
    "gClef8vbOld",
    "gClef8vbCclef",
    ...
  ],
  "noteheads": [
    "noteheadDoubleWhole",
    "noteheadWhole",
    "noteheadHalf",
    "noteheadBlack",
    "noteheadNull",
    ...
  ],
  "flags": [
    "flag8thUp",
    "flag8thDown",
    "flag16thUp",
    "flag16thDown",
    "flag32ndUp",
    "flag32ndDown",
    ...
  ],
...
}

Glyphs are listed within their classes using the names specified in glyphnames.json. Not all glyphs are contained within classes, and the same glyph can appear in multiple classes.

The classes defined at present are as follows:

ranges.json

ranges.json provides information about the way glyphs are presented in discrete ranges in this specification. Here is an excerpt of this file:

{
  ...
  "analytics": {
    "description": "Analytics",
    "glyphs": [
      "analyticsHauptstimme",
      "analyticsNebenstimme",
      "analyticsStartStimme",
      "analyticsEndStimme",
      "analyticsTheme",
      "analyticsThemeRetrograde",
      "analyticsThemeRetrogradeInversion",
      "analyticsThemeInversion",
      "analyticsTheme1",
      "analyticsInversion1"
    ],
    "range_end": "U+E86F",
    "range_start": "U+E860"
  }
  ...
}

This file uses a unique identifier for each range as the primary key, and within each structure the “description” specifies the human-readable range name (as it appears in this specification), “glyphs” is an array listing the canonical names of the glyphs contained within the range, and the “range_start” and “range_end” key/value pairs specify the first and last code point allocated to this range respectively.

The current versions of glyphnames.json, classes.json and ranges.json are available for download at GitHub.

It is further recommended that SMuFL-compliant fonts also contain font-specific metadata JSON files, which are described below.

Designing for scoring applications and text-based applications

In addition to providing a standard approach to how musical symbols should be assigned to Unicode code points, SMuFL also aims to provide two sets of guidelines for the metrics and glyph registration, addressing the two most common use cases for fonts that contain musical symbols, i.e. use within dedicated scoring applications, and use within text-based applications (such as a word processors, desktop publishers, web pages, etc.).

Since it is helpful for scoring applications that all symbols in a font be scaled relative to each other as if drawn on a staff of a particular size, and conversely it is helpful for musical symbols to be drawn in-line with text to be scaled relative to the letterforms with which the musical symbols are paired, in general a single font cannot address these two use cases: the required metrics and relative scaling of glyphs are incompatible¹.

Therefore, it is recommended that font developers make clear whether a given font is intended for use by scoring applications or by text-based applications by appending “Text” to the name of the font intended for text-based applications; for example, “Bravura” is intended for use by scoring applications, and “Bravura Text” is intended for use by text-based applications (or indeed for mixing musical symbols with free text within a scoring application).

Metrics and glyph registration for scoring applications

The following guidelines are provided for fonts intended for use in scoring applications:

• Dividing the em in four provides an analogue for a five-line staff: if a font uses 1000 upm (design units per em), as is conventional for a PostScript font, one staff space is equal to 250 design units; if a font uses 2048 upm, as is conventional for a TrueType font, one staff space is equal to 512 design units.

• The origin (bottom left corner of the em square, i.e. x = 0 and y = 0 in font design space) therefore represents the middle of the bottom staff line of a nominal five-line staff, and y = 1 em represents the middle of the top staff line of that same five-line staff.

• All glyphs should be drawn at a scale consistent with the key measurement that one staff space = 0.25 em.

• Unless otherwise stated, all glyphs shall be horizontally registered so that their leftmost point coincides with x = 0.

• Unless otherwise stated, all glyphs shall have zero-width side bearings, i.e. no blank space to the left or right of the glyph.

• Glyphs that apply to a staff as a whole (e.g. barlines) shall be registered such that the font baseline lies at the nominal vertical position of the bottom line of a five-line staff. If the glyph is specific to a staff other than a regular five-line staff, then for registration purposes that staff’s vertical center shall be exactly aligned with the vertical center of a five-line staff.

• Glyphs for movable notations that apply to some vertical staff position (e.g. noteheads, accidentals) shall be registered such that the font baseline lies exactly at that position. For example, a typical notehead or accidental glyph is registered such that it is vertically centered on the baseline.

• Clefs should be positioned such that the pitch the clef refers to is on the baseline (e.g. the F clef is placed such that the upper dot is above and the lower dot below the baseline). If a clef does not refer specifically to a pitch, its y=0 should coincide with the center staff line on a five-line staff, or the visual center for staves with more or fewer than five lines (e.g. tablature staves).

• Noteheads should be positioned as if on the bottom line of the staff (except for complete clusters representing intervals of a second or third, which should be positioned as if in the bottom space of the staff).

• Pre-composed stems should be positioned as if they are pointing upwards and attached to a notehead on the bottom line of the staff. The center of the stem should be at x=0.

• Combining glyphs that are designed to be superimposed on stems (stem decorations) should be registered such that the point that should sit in the center of the stem (i.e. typically the visual center of the symbol) should be at x=0 and y=0.

• Accidentals should be positioned as if they apply to a notehead on the bottom line of the staff.

• Articulations to be positioned above a note or chord should be positioned such that they sit on the baseline (y=0), while articulations to be positioned below a note or chord should be positioned such that they hang from the baseline.

• Pre-composed notes should be positioned as if on the bottom line of the staff.

• Flags are positioned such that y=0 corresponds to the end of a stem of normal length, and such that x=0 corresponds to the left-hand side of the stem.

• Rests are relative to an imaginary staff position, typographically speaking (usually the center line of a five-line staff in which the rest assumes its default position). The font baseline should represent this staff position, with the exception of the whole note (semibreve) rest, which should hang from the font baseline.

• Bracket ends are positioned such that the point at which they connect to the top or bottom of a vertical bracket is at y=0.

• Letters for dynamics (and for D.C./D.S. in the repeats range) should be scaled such that the caps height is around 0.5 em, and the x-height is around 0.25 em. Letters for dynamics should also have non-zero side bearings to achieve good default spacing when set in a single run.

• Digits for time signatures should be scaled such that each digit is two staff spaces tall, i.e. 0.5 em, and vertically centered on the baseline. Although some glyphs in the time signatures range (such as the large + sign, common and cut time glyphs, etc.) apply to the whole staff, these should likewise be vertically centered on the baseline. Time signature digits should also have non-zero side bearings to achieve good default spacing when set in a single run.

• Parentheses (for accidentals, time signatures, figured bass, etc.) may have non-zero side bearings, in order to achieve good default spacing when set in a single run with the glyphs they are intended to bracket.

• Figured bass digits and function theory symbols should have non-zero side bearings to achieve good default spacing when set in a single run.

• Tessellating glyphs (such as wavy lines, or the component parts of complex trills and mordents) should have negative side bearings, in order to achieve correct tessellation when set in a single run.

Many of these guidelines are based on the conventions established by Adobe’s Sonata font and carried through by most other fonts designed for use in scoring applications, for the sake of making it as easy as possible for font and application developers to transition their existing fonts and software to supporting SMuFL-compliant fonts.

Metadata for SMuFL-compliant fonts

To help software developers integrate SMuFL-compliant fonts, it is recommended that font designers provide a font-specific metadata file, in JSON format, in the distribution package for their fonts.

The metadata file allows the designer to provide information that cannot easily (or in some cases at all) be encoded within or retrieved from the font software itself, including recommendations for how to draw the elements of music notation not provided directly by the font itself (such as staff lines, barlines, hairpins, etc.) in a manner complementary to the design of the font, and important glyph-specific metrics, such as the precise coordinates at which a stem should connect to a notehead.

Glyph names may be supplied either using their Unicode code point or their canonical glyph name (as defined in the glyphnames.json file – see above). Measurements are specified in staff spaces, using floating point numbers to any desired level of precision.

The following key/value pairs are mandatory:

All other key/value pairs are optional.

The following key/value pairs may be used, if desired, to specify the useful range of sizes for which the font is designed:

These values are based on features in the OpenType font specification to specify design size and size range; initially these were encoded in the size feature in the GPOS table, but has been superseded by the STAT table, which defines sizes for families with optical size variants.

engravingDefaults

The "engravingDefaults" structure contains key/value pairs defining recommended defaults for line widths etc., as follows, with all measurements expressed in staff spaces:

Below is a dummy "engravingDefaults" structure, with some of the values filled in:

{
  ...
  "engravingDefaults": {
    "textFontFamily" : [ "Academico", "Century Schoolbook", "serif" ],
    "staffLineThickness": 0.1,
    "stemThickness": 0.1,
    "beamThickness": 0.5,
    "beamSpacing": 0.25,
    "legerLineThickness": 0.2,
    "legerLineExtension": 0.2,
    ...
  },
  ...
}

glyphAdvanceWidths

The optional "glyphAdvanceWidths" structure describes the advance width of each glyph. The advance width is defined as the width of a glyph as measured from its origin to the origin of the next glyph on the line. In text fonts for many languages, glyphs normally have positive left and right side-bearings, i.e. space to either side of the glyph, so that a string of glyphs will show the expected letter spacing. The advance width includes these side-bearing values. If a glyph's path protrudes beyond the width defined for the glyph in the font, however, these protrusions to the left or the right – which can be termed negative side-bearings – are not included in the advance width.

In SMuFL fonts, glyphs typically have zero left and right side-bearings, and some glyphs may have negative side-bearings. For example, stemSulPonticello has a very narrow width, and large negative side-bearings to accommodate the sul ponticello sign that is centered on the stem.

Values in the "glyphAdvanceWidths" structure are expressed as a single value in staff spaces, to any required degree of precision.

Below is an excerpt from a dummy font metadata file for Bravura, with a section of the "glyphAdvanceWidths" structure filled in:

{
...
  "glyphAdvanceWidths":
  {
    "analyticsNebenstimme": 2.836,
    "figbass9": 0.944,
    "pictBeaterSoftBassDrumDown": 1.28,
    "wiggleCircularEnd": 0.648,
  ...
  }
}

For each glyph, the "glyphAdvanceWidths" structure provides the glyph’s name and its advance width.

glyphsWithAnchors

The "glyphsWithAnchors" structure contains a structure for each glyph for which metadata is supplied, with the canonical glyph name as the key. Each glyph may define any of the following key/value pairs:

Below is an excerpt of a dummy font metadata file for the Bravura font, with some of the "glyphsWithAnchors" structure filled in:

{
  ...
  "glyphsWithAnchors": {
    "noteheadBlack": {
      "stemDownNW": [
        0.0,
        -0.184
      ],
      "stemUpSE": [
        1.328,
        0.184
      ]
    },
    ...
  },
  ...
}

glyphsWithAlternates

The "glyphsWithAlternates" structure contains a list of the glyphs in the font for which stylistic alternates are provided, together with their name and code point. Applications that cannot access advanced font features like OpenType stylistic alternates can instead determine the presence of an alternate for a given glyph, and its code point, using this data.

Below is an excerpt from a dummy font metadata file for Bravura, with a section of the "glyphsWithAlternates" structure filled in:

{
  ...
  "glyphsWithAlternates": {
    "flag8thUp": {
      "alternates": [
        {
          "codepoint": "U+F410",
          "name": "flag8thUpStraight",
        },
        {
          "codepoint": "U+F411",
          "name": "flag8thUpShort"
        }
      ]
    },
    "gClef": {
      "alternates": [
        {
          "codepoint": "U+F470",
          "name": "gClefSmall"
        }
      ]
    },
  ...
}

For each recommended glyph for which one or more alternates is provided, the "alternates" structure provides an array containing the name and code point of each alternate. Font designers are encouraged to use a consistent naming scheme for alternates.

glyphBBoxes

The optional "glyphBBoxes" structure contains information about the actual bounding box for each glyph.¹ The glyph bounding box is defined as the smallest rectangle that encloses every part of the glyph’s path, and is described as a pair of coordinates for the bottom-left (or southwest) and top-right (or northeast) corners of the rectangle, expressed staff spaces to any required degree of precision, relative to the glyph origin.

Below is an excerpt from a dummy font metadata file for Bravura, with a section of the "glyphBBoxes" structure filled in:

{
...
  "glyphBBoxes":
  {
    "brace": {
      "bBoxNE": [
        0.328,
        3.988
      ],
      "bBoxSW": [
        0.008,
        0.0
      ]
    },
    "braceFlat": {
      "bBoxNE": [
        0.36,
        4.084
      ],
      "bBoxSW": [
        0.0,
        0.004
      ]
    },
  ...
  }
}

For each glyph, the "glyphBBoxes" structure provides the glyph’s name and the coordinates of the opposite corners of the bounding rectangle (keys bBoxSW and bBoxNE).

ligatures

The "ligatures" structure contains a list of ligatures defined in the font. Applications that cannot access advanced font features like OpenType ligatures can instead determine the presence of a ligature that joins together a number of recommended glyphs, and its code point, using this data.

Below is an excerpt from a dummy font metadata file for Bravura, with a section of the "ligatures" structure filled in:

{
  ...
  "ligatures": {
    "accidentalDoubleFlatParens": {
      "codepoint": "U+F530",
      "componentGlyphs": [
        "accidentalParensLeft",
        "accidentalDoubleFlat",
        "accidentalParensRight"
      ]
    },
    ...
  }
...
}

The structure uses the name of the ligature as its key, and the values include its code point, and its component glyphs. The component glyphs should be listed in an array called "componentGlyphs", in the same order as they are listed in e.g. the liga OpenType table.

sets

The "sets" structure contains a list of stylistic sets defined in the font. Applications that cannot access advanced font features like OpenType stylistic sets can instead determine the presence of sets in a font, the purpose of each set, and the name and code point of each glyph in each set, using this data.

The purpose of each set is specified by the "type" key, which can have any of the following values:

The current list of values for "type" are based on the sets present in Bravura. If you are a font designer and wish to add other sets to your own font, please propose a new value and description for the "type" key to the SMuFL community so that it can be discussed and subsequently added to the above list in a future revision.

Below is an excerpt from a dummy font metadata file for Bravura, with a section of the "sets" structure filled in:

{
...
  "sets": {
    "ss01": {
      "type": "opticalVariantsSmall",
      "description": "Smaller optical size for small staves",
      "glyphs": [
        {
          "codepoint": "U+F428",
          "name": "accidentalFlatSmall",
          "alternateFor": "accidentalFlat"
        },
        {
          "codepoint": "U+F429",
          "name": "accidentalNaturalSmall",
          "alternateFor": "accidentalNatural"
        },
        {
          "codepoint": "U+F42A",
          "name": "accidentalSharpSmall",
          "alternateFor": "accidentalSharp"
        },
        ...
      ],
    },
    "ss02": {
      "type": "FlagsShort",
      "description": "Short flags (to avoid augmentation dots)",
      "glyphs": [
        {
          "codepoint": "U+F411",
          "name": "flag8thUpShort",
          "alternateFor": "flag8thUp"
        },
        {
          "codepoint": "U+F414",
          "name": "flag16thUpShort",
          "alternateFor": "flag16thUp"
        },
        ...
      ],
    },
  ...
  }
...
}

The structure uses the name of the set as its key, and the values include the code point and name of the alternate glyph, together with the name of the character for which this is an alternate ("alternateFor").

optionalGlyphs

The "optionalGlyphs" structure contains a list of all the optional glyphs (those in the range of code points U+F400–U+FFFF) contained within the font. Applications that cannot use advanced OpenType features can use this structure to identify the presence of stylistic alternates (though the "glyphsWithAlternates" and "sets" structures also specify the original glyphs for each alternate by name).

However, a font designer may choose to include some characters in his font that are neither recommended characters in the core SMuFL ranges nor alternates for any of those characters, i.e. completely private to the particular font. This structure provides a direct way for a consuming application to identify the name, code point, and optional class (or classes) for each optional glyph in the font.

Below is an excerpt from a dummy font metadata file for Bravura, with a section of the "optionalGlyphs" structure filled in:

{
  ...
  "optionalGlyphs": {
    "accdnPushAlt": {
      "classes": [],
      "codepoint": "U+F45B"
    },
    "accidentalDoubleFlatJoinedStems": {
      "classes": [
        "accidentals",
        "accidentalsSagittalMixed",
        "accidentalsStandard",
        "combiningStaffPositions"
      ],
      "codepoint": "U+F4A1"
    },
    "accidentalDoubleFlatParens": {
      "codepoint": "U+F566"
    },
    ...
  },
  ...
}

The structure uses the name of each optional glyph as the key, and the values include the code point and an optional list of classes to which the glyph belongs. (The class names should be taken from the classes.json SMuFL metadata file where possible, though font designers can define new classes as required.)

Example of glyph registration for notes with flags

The figure below shows how font-specific metadata may be used in conjunction with the conventions of glyph registration to construct two notes: an up-stem 16th note (semiquaver), and a down-stem 32nd (demisemiquaver).

• The horizontal grey lines denote staff lines, for scale.

• The light blue boxes show glyph bounding boxes, with the left-hand side of the box corresponding to x=0, while the horizontal lines bisecting the blue boxes show the origin for each glyph, i.e. y=0.

• The red boxes show the locations of the glyph attachment points, as specified in the font metadata JSON file.

• The shaded area on the down-stem note shows the amount by which a stem of standard length (i.e. the unfilled portion of the stem) should be extended in order to ensure good on-screen appearance at all zoom levels.

Note that the stemUpSE attachment point corresponds to the bottom right-hand (or south-east) corner of the stem, while stemDownNW corresponds to the top left-hand (or north-west) corner of the stem. Likewise, for correct alignment, the flag glyphs must always be aligned precisely to the left-hand side of the stem, with the glyph origin positioned vertically at the end of the normal stem length.

Bounding box cut-outs

The four points cutOutNE, cutOutSE, cutOutSW and cutOutNW describe rectangular cut-outs from the four corners of a glyph’s rectangular bounding box. The bounding box is the box with the smallest area that encloses every part of the path of a glyph.

Because a glyph may not occupy every part of its bounding box, it can be useful to have an extra level of detail about the shape of the glyph, but at a coarser level than directly examining the path of the glyph to determine which areas of the bounding box are occupied and which are empty.

For example, when stacking accidentals to the left of a chord, accidentals are arranged into columns, where accidentals belonging to notes separated by a wide interval (normally a seventh or more) are aligned in the same column, i.e. at the same horizontal position. Successive columns of accidentals are laid out from right to left to the left of a chord, and depending on the accidentals that are present, it may be possible to interlock or kern those columns. The figure below shows a simple example:

In the first chord above, the two columns of accidentals (numbered 0 and

1. are positioned almost as close as the bounding boxes of the accidentals (shown in light blue) in each column will allow. In the second chord, column 1 is allowed to interlock with column 0 because the cut-outs in the bounding boxes of the two accidentals (shown as dashed red lines) are removed: the bounding boxes of the accidentals can overlap, provided it is only the cut-outs that overlap.

Font designers can specify four cut-outs to the bounding box, one in each corner, as illustrated in the figure below:

Each cut-out is specified as a pair of X,Y coordinates (in spaces), describing the innermost corner of a nominal rectangle that intersects the bounding box. For example, cutOutNE specifies the bottom left corner of a rectangle that intersects the top right corner of the bounding box of the glyph. The coordinates of each cut-out are all specified relative to the origin of the glyph, i.e. its bottom left-hand corner.

Repeat offsets

The repeatOffset point is defined for glyphs that are designed to tessellate, such as the wiggly line that follows the  symbol, or any of the glyphs in the Multi-segment lines range.

These glyphs are registered such that they may have negative side bearings on either or both the left- and right-hand sides. When entered in a run of text, the advance width produces the correct tessellation. However, in some situations it may not be possible to use a run of text to draw such a line, or the API in use may not provide easy access to the advance width of a glyph (e.g. when using the HTML canvas element).

In these situations, correct tessellation can be achieved by positioning the origin of subsequent glyphs in a tessellating line at the horizontal position defined by the repeatOffset point for a given glyph.

Here, for example, is an illustration of the glyph wiggleTrill:

The vertical dashed lines show the left- and right-hand side bearings for this glyph. The repeatOffset anchor’s coordinates are at the x position of the right-hand side bearing and y = 0. Positioning another trillWiggle glyph at the position of the repeatOffset anchor produces correct tessellation, like this:

Aligning noteheads horizontally

The noteheadOrigin point is defined for noteheads with non-zero left-hand side bearings, such as the double whole (breve) notehead that has two vertical lines at either side of the oval notehead itself, as illustrated in the figure below:

• The horizontal grey lines denote staff lines, for scale.

• The light blue boxes show glyph bounding boxes, with the left-hand side of the box corresponding to x=0.

• The vertical dashed grey lines denote the left-hand edge of the rhythmic position, i.e. the position against which the notehead is aligned.

• The red box shows the location of the noteheadOrigin point, as specified in the font metadata JSON file.

The left-hand example shows the alignment that will be produced simply by positioning notehead glyphs using the left-hand edges of their bounding boxes. The right-hand example shows the superior alignment that can be produced by offsetting the double whole (breve) note leftwards by the distance between x=0 and the noteheadOrigin point.

Aligning dynamics with noteheads and stems

The opticalCenter point is defined for glyphs that are normally centered on a notehead or stem, such as dynamics. There are a number of possible approaches to centering a dynamic, which are illustrated in the figure below:

• The horizontal grey lines denote staff lines, for scale.

• The light blue boxes show glyph bounding boxes.

• The intersecting vertical and horizontal dashed light blue lines show the glyph origin relative to its bounding box.

• The vertical dashed grey lines denote the center of the notehead, the point against which the dynamics should be aligned.

• The vertical dashed red line shows the position of the opticalCenter point, as specified in the font metadata JSON file.

The figure shows that centering the dynamic by determining the bounding rectangle and using half its width is least satisfactory, while using half the advance width is an acceptable default in the absence of a specific optical center position determined by the font designer.

The opticalCenter point can be set by the font designer to provide a very specific balancing point, relative to e.g. the bowl of the italic  or the curve at the top of the italic .

Metrics and glyph registration for text-based applications

The following guidelines are provided for fonts intended for use in text-based applications, such as word processors, desktop publishers and other text editors.

Upper case letters in a text font do not typically occupy the whole height of the em square: instead, they typically occupy around 75–80% of the height of the em square, with the key metrics for ascender and caps height both falling within this range. In order for the line spacing of a font containing music characters to be equivalent to that of a text font, its key metrics must match, i.e. the ascender, caps height and descender must be very similar. Glyphs with unusually large ascenders and descenders (such as notes of short duration with multiple flags) should not be scaled individually in order to fit within the ascender height, as they will not then fit with the other glyphs at the same point size; however, the behavior of glyphs that extend beyond the font’s ascender and descender metrics is highly variable between different applications.

Leading on from the premise that a SMuFL-compliant font for text-based applications should use metrics compatible with regular text fonts, specific guidelines are as follows:

• Dividing 80% of the height of the em in four provides an analogue for a five-line staff. If a font uses 1000 upm (design units per em), as is conventional for a PostScript font, the height of a five-line staff is 800 design units, or 0.8 em; therefore, one staff space height is 200 design units, or 0.2 em. If a font uses 2048 upm, as is conventional for a TrueType font, the height of a five-line staff is 1640 design units, and one staff space is 410 design units.

• The origin (bottom left corner of the em square, i.e. x = 0 and y = 0 in font design space) therefore represents the middle of the bottom staff line of a nominal five-line staff, and y = 0.8 em represents the middle of the top staff line of that same five-line staff.

• Unless otherwise stated, all glyphs should be drawn at a scale consistent with the key measurement that one staff space = 0.2 em.

• Unless otherwise stated, all glyphs shall be horizontally registered so that their leftmost point coincides with x = 0.

• Unless otherwise stated, all glyphs shall have zero-width side bearings, i.e. no blank space to the left or right of the glyph.

• Staff line and leger line glyphs should have an advance width of zero, so that other glyphs can be drawn on top of them easily.

• Time signature digits should also have an advance width of zero, so that they can be positioned above each other (using the timeSigCombNumerator and timeSigCombDenominator ligatures).

• Clefs should be positioned such that they are aligned with the five-line staff glyphs (e.g. staff5lines) at their most usual staff position: G clefs (in the class clefsG) should be positioned such that the bottom loop is aligned with the bottom staff line (0.2 em higher than the position in a SMuFL-compliant font for a scoring application); F clefs (in the class clefsF) should be positioned such that the second-highest staff line passes between the two dots (0.6 em higher than in a font for a scoring application); and C clefs (in the class clefsC) should be positioned such that the middle staff line passes through the middle of the clef (0.4 em higher than in a font for a scoring application).¹

• Glyphs that can appear at different staff positions, e.g. noteheads, notes, accidentals, etc. (in class combiningStaffPositions), should be positioned such that they are centered around the middle staff line of the five-line staff glyphs (i.e. centered vertically around y = 0.4 em).

• To enable the positioning of glyphs at different staff positions, fonts should support the combination of combining staff position control characters and glyphs in the class combiningStaffPositions using a glyph substitution feature such as OpenType ligatures. This allows the end user to position e.g. a black notehead on the second-highest staff line by using a ligature of staffPosRaise2 and noteheadBlack.

• Letters for dynamics and numbers for octave lines should be scaled such that the x-height is around 0.5 em, consistent with other typical text fonts.

• Ornaments symbols should be scaled such that e.g. the  symbol is around 0.5 em in height (e.g. a scale factor of 150% compared to fonts intended for use in scoring applications).

• Keyboard pedal marks should be scaled such that e.g. the  symbol is around 0.75 em in height (e.g. a scale factor of 130% compared to fonts intended for use in scoring applications).

• Percussion pictograms should be scaled such that they are around 0.75 em in height.

• Figured bass digits should be scaled such that e.g.  is around 0.5 em in height (e.g. a scale factor of 185% compared to fonts intended for use in scoring applications).

• Composite note glyphs for setting in-line with characters from other text fonts (e.g. those in the Metronome marks range) should be positioned such that they sit on the font baseline (in contrast to notes intended for drawing on a staff, e.g. those in the Individual notes range).

Font-specific metadata locations

SMuFL-compliant applications running on desktop operating systems such as Windows, macOS, or Linux need to be able to determine whether a given font installed on the system is itself SMuFL-compliant.

There is no simple way to encode this information in the font itself¹, so instead applications should identify SMuFL-compliant fonts by the presence of the font-specific JSON metadata file in a known location.

System-wide location

It is recommended that, if possible, the font metadata is installed in a system-wide location that allows access by all users on the system:

• Windows: %COMMONPROGRAMFILES%/SMuFL/Fonts/fontname/fontname.json

• macOS: /Library/Application Support/SMuFL/Fonts/fontname/fontname.json

• Linux: $XDG_DATA_DIRS/SMuFL/Fonts/fontname/fontname.json

On Windows, the %COMMONPROGRAMFILES% environment variable expands to C:\Program Files\Common Files, or its localised equivalent.

On Linux, $XDG_DATA_DIRS is an environment variable defined by the XDG Base Directory Specification.

It is typically necessary to require administrator privileges to install files into these locations. However, it is also recommended that, if possible, fonts themselves should also be installed in system-wide locations, so if the metadata is installed by the same installer as the fonts, no additional privileges will typically be required.

User-specific location

If it is impossible or inappropriate to install the font metadata in a system-wide location, use a user-specific location instead:

• Windows: %LOCALAPPDATA%/SMuFL/Fonts/fontname/fontname.json

• macOS: ~/Library/Application Support/SMuFL/Fonts/fontname/fontname.json

• Linux: $XDG_DATA_HOME/SMuFL/Fonts/fontname/fontname.json

On Windows, %LOCALAPPDATA% expands to C:\Users\username\AppData\Local.

On Linux, $XDG_DATA_HOME is an environment variable for user-specific configuration files, defined by the XDG Base Directory Specification.

On macOS, ~ is a shortcut to the current user's home folder, e.g. /Users/username/.

It is not typically necessary to require administrator privileges to install files into these locations. However, files installed in these locations will not be accessible to any other user account on the system.

Private fonts

If a font is not designed to be used outside of a particular, specific application, then of course it is not mandatory for it to be installed in a system-wide location, nor for its metadata to be installed in these publicly accessible locations: a private font intended for use within the confines of a single application may choose to install its metadata in any convenient private location.

Precedence rules

Because font-specific metadata may be installed in either (or both) a user-level location or a system-level location, applications should give metadata found in the user-level location precedence over metadata found in the system-level location.

Glyph tables

Staff brackets and dividers (U+E000–U+E00F)

Recommended stylistic alternates

Implementation notes

The brace glyph should have a height of 1em, i.e. the height of a single five-line stave, and should be scaled proportionally (i.e. in both dimensions, not only in the vertical dimension) in a scoring application to the appropriate height of the two or more staves it encompasses.

Font designers may choose to include a number of alternative brace glyphs designed to accommodate larger distances, to avoid the standard brace glyph becoming too wide and bold at larger sizes. (Bravura, for example, includes four stylistic alternates for brace, designed to encompass numbers of staves from one up to 10 or more.)

bracket is a complete bracket of a fixed height useful for displaying brackets in text-based documents or applications.

To display a bracket of variable height in a scoring application, use bracketTop and bracketBottom as the top and bottom terminals of a bracket drawn using a stroked line or filled rectangle of the appropriate width.

Staves (U+E010–U+E02F)

Implementation notes

Scoring programs should draw their own staff lines using primitives, not use the glyphs in this range. Narrow and wide versions are provided for use in fonts intended for use in text-based applications. These glyphs should be zero-width in such fonts.

Barlines (U+E030–U+E03F)

Implementation notes

Scoring programs should draw their own barlines using primitives, not use the glyphs in this range.

Repeats (U+E040–U+E04F)

Recommended stylistic alternates

Implementation notes

Scoring programs should draw their own repeat barlines using primitives to draw the thick and thin lines and repeatDots to draw the dots, not use the precomposed glyphs repeatLeft or repeatRight.

dalSegno and daCapo are provided for compatibility with the Unicode Musical Symbols range. Scoring applications should allow the user to specify the appearance of the da capo and dal segno instructions using any regular text font.

Clefs (U+E050–U+E07F)

Recommended stylistic alternates

Recommended ligatures

Supplementary Groups

Clefs supplement

Implementation notes

Scoring applications may choose to create e.g. ottava alta and ottava bassa versions of the G clef and F clef by combining gClef and fClef with clef8 and clef15 rather than using the precomposed glyphs.

The basic G clef, F clef and C clef symbols can be positioned at different vertical positions relative to the staff as required (e.g. the C clef can be positioned to create an alto or tenor clef).

Clef changes are normally drawn at two-thirds the size of clefs at the beginning of the system¹, but different publishers and engravers may prefer to use a different size. Dedicated glyphs for drawing a clef change are provided for the three most commonly-used clefs (gClefChange, cClefChange, and fClefChange), together with a combining control character (clefChangeCombining) that font designers may use to produce smaller versions of less commonly-used clefs by way of glyph substitution (such as OpenType ligatures). Scoring applications may choose to use these dedicated clef change glyphs if they do not provide the end user with control over the size of clef changes. Otherwise, scoring applications should draw clef changes by using the regular clef glyphs at a smaller point size, either fixed at two-thirds the size of normal clefs, or at a size of the end user’s choosing.

Time signatures (U+E080–U+E09F)

Recommended stylistic alternates

Recommended ligatures

Supplementary Groups

Time signatures supplement

Implementation notes

timeSigCombNumerator and timeSigCombDenominator are control characters designed to be combined with the time signature digits (by way of glyph substitution, such as OpenType ligatures) to shift them vertically into position suitable for drawing as the numerator and denominator of a time signature. These control characters are intended for fonts to be used in text-based applications, since scoring applications should position the numerator and denominator of time signatures independently.

Noteheads (U+E0A0–U+E0FF)

Recommended stylistic alternates

Recommended ligatures

Supplementary Groups

Noteheads supplement

Implementation notes

These noteheads should be combined with stems and flags as necessary to create complete notes. In text-based applications, per the Unicode Musical Symbols documentation:

Scoring applications should draw stems using primitives, rather than using stem (i.e. U+1D165 as shown in the above image¹), so that they can be drawn to the correct length.

See also the implementation notes for flags.

Slash noteheads (U+E100–U+E10F)

Recommended stylistic alternates

Implementation notes

See the implementation notes for noteheads.

Round and square noteheads (U+E110–U+E11F)

Note clusters (U+E120–U+E14F)

Implementation notes

Scoring applications should draw simple note clusters (e.g. noteheadClusterSquareWhite, noteheadClusterRoundBlack) directly using primitives rather than using these glyphs, so that the clusters can be drawn spanning the correct interval.

The combining glyphs for note clusters are designed to allow the creation of clusters of any interval larger than a third, with a scoring application inserting the appropriate number of “middle” segments between a single instance of the “top” and “bottom” segments:

The left-hand cluster is a stack (top to bottom) of 1 x noteheadClusterHalfTop, 3 x noteheadClusterHalfMiddle, 1 x noteheadClusterHalfBottom; the right-hand cluster is 1 x noteheadDiamondClusterBlackTop, 2 x noteheadDiamondClusterBlackMiddle, 1 x noteheadDiamondClusterBlackBottom.

Clusters for intervals of a second or a third are created using a single glyph, e.g. noteheadClusterQuarter2nd. These glyphs are registered such that the lowest pitch in the cluster is centered around y = 0, so to draw correctly, the glyph should be positioned on the staff position corresponding to the lowest note in the cluster.

See also the implementation notes for noteheads.

Note name noteheads (U+E150–U+E1AF)

Supplementary Groups

Note name noteheads supplement

Implementation notes

These noteheads are designed for use by scoring applications to render music where the names of notes are shown inside noteheads. For practical use, scoring applications should provide a means of automatically substituting regular noteheads for the appropriate note name notehead glyph according to the pitch of each note.

For maximum legibility, stave lines and ledger lines should not be drawn through the letterforms in these noteheads. Applications should either draw segments of stave lines and ledger lines to the left and right of the extent of each notehead positioned on a line, or draw noteEmptyWhole, noteEmptyHalf and noteEmptyBlack as appropriate in white (or the paper color) on top of the stave or ledger line but behind the note name notehead.

See also the implementation notes for Noteheads.

Shape note noteheads (U+E1B0–U+E1CF)

Supplementary Groups

Shape note noteheads supplement

Implementation notes

A number of different shape note traditions remain in common use in the shape note community. SMuFL encodes the noteheads required for four such systems: one four-shape system; and three seven-shape systems (Walker, Funk, and Aikin). All three seven-shape systems also use the four shapes of the four-shape system, each introducing three additional shapes.

The four-shape system, used in books such as William Walker’s Southern Harmony (1835), uses a form of solmization where the syllables fa, so, la, fa, so, la, mi are assigned to the seven notes of an ascending major scale. Each syllable has its own note shape:

Joseph Funk devised his seven-shape system, building upon the existing four-shape system, for his book Harmonia Sacra (1851), adding to the four-shape system by adding the syllables do, re and ti (sometimes si), so the ascending major scale would use the syllables do, re, mi, fa, so, la, ti. The note shapes for each syllable are as follows:

In addition to being the composer of Southern Harmony, William Walker also later devised his own seven-shape system for the book Christian Harmony (1867), using the same solmization as Funk. The note shapes for each syllable are as follows:

Perhaps the most commonly-used seven-shape system, however, is that devised by Jesse B. Aikin, though his system is sometimes incorrectly referred to as the “Aiken” system due to an error made by the musicologist George Pullen Jackson. Aikin introduced his system in The Christian Minstrel (1846), and after his shapes were adopted by the influential Ruebush & Kieffer Publishing Company in the late 19th century they have become increasingly widely used. Again using the same solmization as both Funk and Walker, the note shapes for each syllable are as follows:

For practical use, scoring applications should provide a means of automatically substituting regular noteheads for the appropriate shape note notehead glyph according to the pitch of each note.

See also the implementation notes for noteheads.

Individual notes (U+E1D0–U+E1EF)

Recommended stylistic alternates

Implementation notes

Precomposed notes in this range may be used for placing notes on a staff. In fonts intended for text-based applications, these characters may be set up as ligatures with the control characters in the Combining staff positions range to allow them to be moved up and down to different positions on a staff (e.g. using characters from the Staves range).

However, scoring applications should draw all notes by combining notehead glyphs — e.g. noteheadBlack for quarter notes (crotchets) and shorter notes, noteheadHalf for half notes (minims) — with stems drawn using primitives.

It is recommended that the characters in this range should have full-length stems, i.e. a minimum length of 3.5 spaces.

Characters suitable for mixing with characters from a regular text font, e.g. as part of a metronome mark, tempo equations, l’istesso tempo marking, etc., are found in the Metronome marks range (where it is recommended that stems should be shortened to provide a more pleasing balance between the note and the surrounding text characters).

Beamed groups of notes (U+E1F0–U+E20F)

Implementation notes

This range is intended for mixing music symbols with text. Its metrics and glyph registrations should follow the guidelines for fonts intended for text-based applications, even in fonts that are themselves primarily intended for use in scoring applications.

These glyphs may be used for displaying complex metric modulations and l’istesso tempo directions in conjunction with the precomposed note glyphs in the Individual notes range.

Kerning pairs for every combination of these glyphs should be included such that the fractional beams overlap slightly with the stems of notes and other beams; this helps provide a consistent appearance in a variety of rendering contexts and at different zoom levels. Special attention should be given to the kerning pairs including textAugmentationDot, which should be kerned rightwards away from notes and leftwards so that it lies underneath glyphs showing the middle of beams (e.g. textCont8thBeamShortStem); and to the pairs involving the tuplet brackets (e.g. textTupletBracketStartShortStem), which should be kerned leftwards such that they are correctly aligned when entered after a note character.

By way of example:

Example	Uses glyphs
	textBlackNoteShortStem, textCont8thBeamShortStem, textBlackNoteFrac8thShortStem, textCont16thBeamShortStem, textBlackNoteFrac16thShortStem
	textBlackNoteShortStem, textCont8thBeamShortStem, textBlackNoteFrac8thShortStem, space, =, space, textBlackNoteShortStem, textTupletBracketStartLongStem, textTuplet3LongStem, note8thUp, textTupletBracketEndLongStem
	textBlackNoteShortStem, textCont8thBeamShortStem, textAugmentationDot, textCont8thBeamShortStem, textBlackNoteFrac16thShortStem

Stems (U+E210–U+E21F)

Implementation notes

The glyphs shown here may be combined with noteheads to produce precomposed glyphs with a fixed stem length.

Scoring applications should produce this effect by imposing the required symbol on a stem drawn using a primitive line, rather than using these precomposed stem glyphs:

• Sprechgesang (vocalSprechgesang)

• Swish (pictSwish)

• Penderecki unmeasured tremolo (pendereckiTremolo)

• Sul ponticello (stringsBowBehindBridge)

• Bow on bridge (stringsBowOnBridge)

• Bow on tailpiece (stringsBowOnTailpiece)

• Buzz roll (buzzRoll)

• Damp (pluckedDampOnStem)

• Vibrato pulse accent (stringsVibratoPulse)

• Multiphonics (windMultiphonicsBlackStem, windMultiphonicsWhiteStem, windMultiphonicsBlackWhiteStem )

• Sussurando (vocalsSussurando)

• Rim shot (pictRimShotOnStem)

• Harp string noise (harpStringNoiseStem)

Tremolos (U+E220–U+E23F)