Extraction of Typographic Elements from Outline Representations of Fonts
Abstract
Digital typefaces for computer graphics and multimedia applications must be capable
of supporting operations such as font variations, transformations, deformations and
blending. A powerful implementation of such operations must rely on the inherent
typographic attributes of the typeface. However, even today's most advanced typeface
representations support only geometric outline representations and basic font variations.
In this paper we discuss high-level typeface representations which we term Parametric
Typographic Representations (PTRs). We present an algorithm for automatically extracting
typographic elements of typefaces from their outline representation, which is an essential
initial step in converting typefaces from outline representations to PTRs. The extracted
typographic elements include serifs, bars, stems, slants, bows, arcs, curve stems and curve
bars. Most notable is the treatment of serifs, which are represented by finite-automata. The
algorithm only needs to learn a serif type once, and is then capable of automatically
recognizing it in different typefaces.
We show an application of a PTR for automatic high-quality hinting of fonts, which is one of
the most important stages in digital font production. Our system was used to generate hints
for dozens of thousands of Kanji, Roman and Hebrew characters.