Some More Terms Used in Font Design
Font • A set of typestyles designed to work together.
Typeface • Classification of type into Serif, Sans-serif, Script, Black-letter, Decorative, Brush Script, etc.
Typestyle • Regular, Bold, Italic, Bold Italic, SMALL CAPITALS, Outline, etc.
Advance width
The width of a letter and its surrounding space; the space needed to set a line of text in a specific typeface. Some programs have tracking to adjust the typeface to make it set looser or tighter.
Bézier curve
Mathematical equations used to describe the shapes of characters in digital fonts. The Bézier curve was named after Pierre Bézier, a French computer scientist who developed the mathematical representation used to describe the curves. Type 1 fonts use cubic Bézier curves, whilst TrueType use a subset of the curves known as quadratic B-splines.
Character • A letter, symbol, or accent that is assigned a code-point so that it can be typed.
Code-point • A unique number assigned to a character.
Glyph • A graphical outline or letter form.
Contour • A closed curve of one or more that makes up a glyph.
Nodes • Points that define the curves that make a contour. Nodes may be on-curve or off-curve.
Composite Glyph • A glyph composed of two or more other glyphs. A base letter like a, for example, is often combined with an accent or diacritic like ¨ diaeresis) to form a composite glyph like ä (a diaeresis)
Composite Glyph Member • One of the glyphs used by a composite glyph or by several composite glyphs. Some composite glyph members may be characters in their own right, or they may simply be included in a font for composing composite glyphs.
Offset • The distance that a composite glyph member is offset vertically or horizontally when used in a composite glyph.
Diacritic • An accent
F-unit • The smallest unit used in font design. Many fonts are designed at 2,048 funits/em.
Em-square • The square within which most letters are designed to fit. Script letter forms or combining diacritical marks may overlap the em-square.
• The arm of the T overlaps the em-square to the right, and the bottom of the italic ƒ overlaps the em-square to the left.
• Four
nodes are selected — two
on-curve, and two
off-curve nodes.
• The blue grid is set at 1024
f-units so four small squares make one
em-square.
• The
composite glyph ä (a diaeresis, code-point 228) is composed of the
glyph of the
character a (code-point 97) and the
diacritic ¨ (diaeresis, code-point 168).
• The
right side-bearing of the italic ƒ is shown as a dotted line.
• The capital
T sits neatly on the
baseline, while the
descender of the italic ƒ descends almost to the
Win-Descent line.
• The space above the glyphs to the
Win-Ascent will be occupied by
diacritics of capital letters like Ä (A diaeresis, code-point 196).