N.B. An asterisk before a word means it has its own entry in the glossary.
The original codename for TrueType, internal to Apple, preceding *RoyalT. According to an insider, its derivation was down to the fact that a bass (fish) is scale-able... Some TrueType editing programs still refer to "Bass files".
- 'bdat' table (see also: 'EBDT' table)
Embedded bitmap data table (Apple only).
This TrueType table contains any bitmap *strikes for the font. These are used for *glyphs that would be very complicated to *hint, or simply to re-use old *bitmap fonts in new environments. See Apple's spec for the format in detail.
N.B. The Microsoft table specifications 'EBDT' and 'EBLC' are identical to Apple's 'bdat' and 'bloc'.
- Bézier curve
The standard Bézier curve, used throughout PostScript and in many standard computer drawing packages, is a parametric *cubic (or third order) curve defined by its two end-points and two control-points, which in general are not on the curve. As well as other characteristics, the control-points define the tangents of the curve as it leaves the two end-points. A Bézier curve always remains inside a polygon drawn around all of its points (the "convex hull").
The curves of TrueType are a *quadratic (second order) version of Bézier curves, having two end-points but only one off-curve control-point. The single off-curve point then defines both tangent vectors, while the curve remains within the triangular convex hull.
The curve formulation was conceived by Pierre Bézier of the Renault car company in the late 1960s for representing 3D car body forms.
See the TrueType Outlines page.
A simple digital representation of an image as a 2-dimensional array of bits. Strictly a bitmap is always monochrome, such that each pixel is represented by a single data bit. The less common terms raster, bytemap and pixmap refer to shaded or coloured images, but "bitmap" is routinely used for these too.
On computer systems using *outline fonts, temporary bitmap characters are created on-the-fly by the *rasterizer, then stored in a *cache.
A bitmap font at a particular *ppem is called a *strike.
- 'bloc' table (see also: 'EBLC' table)
Embedded bitmap location table (Apple only).
This TrueType table describes the information contained in the *'bdat' table. See Apple's spec for the format in detail.
TrueType Typography |