Font Decoration by Automatic Mesh Fitting 1 Cameron Browne   Canon Information Systems Research Australia (CISRA), Sydney, Australia Abstract: Glorious Fonts, a new graphically-based font type, allow interesting effects to be applied to existing character sets. The difficulties of automating this process are examined in the context of applying Celtic knotwork designs to plain text characters. An analysis of knotwork construction techniques shows how complete designs may be described by an expanded tile set. This paper also presents an algorithm for automatically fitting a flexible mesh to arbitrary character outlines, based on a semi- regular distribution of internal points and their Delaunay triangulation. This mesh is of particular interest as it is composed of well-formed quadrilateral elements, with few supporting triangular elements, upon which the knotwork design may be realised. 1 Introduction 1.1 Glorious Fonts Glorious Fonts are the native font type supported by OpenPage, a script-based graphics and image processing language developed at CISRA [17]. They draw on a rich supply of graphics capabilities to allow a variety of effects not available in traditional fonts. Glorious Fonts are parameterised, allowing the font designer to give the user a measure of control over the font's appearance at render time. With an overabundance of typefaces available today our attention has turned to the creation of decorated character sets derived from existing fonts, a task well suited to Glorious Fonts. One aspect of CISRA’s Glorious Font project is the development of an authoring tool that automatically applies parameterised effects to existing typefaces to produce aesthetically pleasing (and readable) results. This paper is the summary of one such effect. 1.2 Automatic Font Decoration Designing a complete font by hand is time consuming and prohibitively expensive. Automatic font generation is preferable although it is difficult to define the relevant parameters, provide a suitably expressive interface, and achieve artistically acceptable results. It is necessary to analyse the artist’s approach to the problem, and apply their innate aesthetic rules as much as possible. Figure 1 illustrates this process in the context of applying a style of artwork known as Celtic knotwork to the outline shape of a plain text character. Figure 1a illustrates a naive approach to this problem. The knotwork is applied to a low-resolution grid composed of square cells that roughly correspond to the character’s shape. This is the approach used by most knotwork generation 1 Colour figures can be dowloaded from the Web (http://diwww.epfl.ch/w3lsp/ridt98.html).