Glyph Construction

Glyph Construction is a simple, human-readable, powerful language for describing how shapes are constructed.

Glyph Construction can be used to create new glyphs from components. It is specially useful for creating accented glyphs.

Collections of Glyph Construction rules can be saved as *.glyphConstruction files, and can be shared between fonts.

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Assigning a construction to a glyph

Build <destGlyphName> out of one or more components.

<destGlyphName> = <glyphName> + <glyphName>
Aacute = A + acute

Optionally, a suffix can be provided. If a glyph with the given suffix does not exist in the font, the suffix is ignored.

Aacute = A + acute.cap

Comments

A line starting with (or anything after) a # is a comment and will not be used during execution.

# this is a comment
Aacute = A + acute
Agrave = A + grave # this is a note

Notes

A comment # at the end of a glyph construction is a note.

<destGlyphName> = <glyphName> + <glyphName> # <note>
Aacute = A + acute # this is a note

Unicodes

<destGlyphName> = <glyphName> + <glyphName> | <unicode>
Aacute = A + acute | 00C1

Mark Color

<destGlyphName> = <glyphName> + <glyphName> ! <rgba>
Aacute = A + acute ! 1, 0, 0, 1

Metrics

Width

<destGlyphName> = <glyphName> + <glyphName> ^ <width>
Aacute = A + acute ^ 400

Left and Right Margins

<destGlyphName> = <glyphName> + <glyphName> ^ <leftmargin>, <rightMargin>
Aacute = A + acute ^ 30, 30

Width and margin values can also be defined using basic maths and references to width, leftMargin or rightMargin of other glyphs.

# width is equal to twice the width of A
Aacute = A + acute ^ A * 2

# left margin is equal to one third of the left margin of A
# right margin is equal to twice the right margin of B
Aacute = A + acute ^ A / 3, B * 2

Decompose glyph

Add * before a glyph construcntion rule to explicityly tell the constructor to decompose the final result.

*agrave = a + grave

Ignore existing glyphs

Add ? before a glyph construction rule to ignore this glyph if it already exists in the font.

?Aacute = A + acute

Positioning

The Glyph Construction language offers different ways to position the added components in relation to the current glyph.

By Numbers

Aacute = A + acute@100
Aacute = A + acute@100,100

By Percentages

Aacute = A + acute@50%,50%

By Reference

A reference could be (in this order):

• double anchor (with the _<anchorName> notation)
• a single anchor name
• a local guide name
• a global guide name
• a font dimension attribute: descender, xHeight, capHeight, ascender
• a calculated reference position: top, bottom, left, right, innerLeft, innerRight, center, origin, width

Aacute = A + acute@center,top

By Transformation Matrix

@ followed by a transformation matrix: 6 values xx, xy, yx, yy, x, y

Aacute = A + acute@1, 0, 0, 1, 100, 100

Change the current glyph

The current glyph is always the last component added.

For example, Aacute = A + acute will:

• add component with name A (there is no current glyph)
• add component with name acute (the current glyph is A)
• force the current glyph with @<glyphName>:<pos>

Ocircumflexdotaccent =  O + circumflex@center,top + dotaccent@O:center,bottom

Flipping

~ followed by a position will flip a component:

# flip horizontal
Aacute = A + acute@~center,top

# flip vertical
Aacute = A + acute@center,~top

# flip both horizontal and vertical
Aacute = A + acute@~center,~top

Stacking Vertically

Aringacute = A + ring@center,top + acute@center,top

Positioning formulas

Aringacute = A + ring@center,`top+10` + acute@center,`top-10`

Stacking Horizontally

ffi = f & f & i

Apply kerning while stacking horizontally

Start a sub-glyphConstruction with a backslash to indicate kerning should be applied while stacking horizotally.

A_V = A &\ V

Variables

Glyph Construction supports variables, which can be defined once at the top of the document and used multiple times.

$name = something # declaration
{name} # usage

$myColorMark = 1, 0, 0, 1 # declaration
agrave = a + grave@center,top ! {myColorMark} # usage