TrueType hinting takes the form of little programs attached to each glyph, and it is admittedly hard, in fact virtually impossible, to work out automatically which program instructions can remain, and which must change when a glyph is modified. However, it's a shame that you can't leave alone any glyphs you don't modify: these programs affect every glyph.

Failing the introduction of affordable native TrueType editing tools, if you're making TrueType fonts from scratch, or converting PostScript Type 1 fonts to TrueType, then the following programs are certainly worth a look. But be warned of the serious problem that arises when editing existing TrueTypes: total loss of all hints (followed by semi-automatic, almost always inferior, hint regeration); and of the not so serious problem: conversion of quadratic curves into cubics and back again, with probable loss of precision.

See also: Native TrueType tools

• FontLab 3.0
  by Yuri Yarmola and Vadim Suvorov of SoftUnion, St. Petersburg, Russia. This is an excellent program for creating and editing Type 1 fonts. Users often declare it to be the best on the PC. With version 3.0 comes native TrueType curve editing and hinting - something that no other mainstream editor offers. Also has superb capablities for multiple master Type 1 fonts. Runs on Windows 3.1 and above (a Mac version is on the cards for the future).

• MacroMedia Fontographer
  Written by Jim von Ehr and others at Altsys, before the company was taken over by MacroMedia. By far the most popular font design program for Mac and Windows, now in version 4.1. The program imports and exports Type 1 and TrueType fonts, but conversion between formats is less good than Type Designer. Macromedia has a Fontographer Support area of their site.

• Robofog
  This typehacktool just released by Petr van Blokland is a fully scriptable version of Fontographer 3.5 (Mac). You can now write programs in the Python language to control all aspects of font design - scripts for many tasks are available. It's licensed on a subscription basis.

• Letraset FontStudio
  Written by Ernie Brock, Harold Grey and others at Ares (long before it was taken over by Adobe), it is no longer marketed. FontStudio remains the choice of many professional type designers, such as Luc(as) de Groot [Thesis, Jesus Loves You, Move Me] of FontFabrik and Jonathan Barnbrook [Ma(n)son, Prozac, Exocet, Bastard] of Virus. According to Adobe's David Lemon, "most of Adobe's new designs are created in the old FontStudio". It is said that there's little likelihood of Adobe developing the program.

• URW Ikarus
  Ikarus was originally developed in 1973-74 at the Rudolf Weber company in Hamburg (now URW) by Peter Karow. This was the first time type had been digitized as outlines. The native curves of Ikarus are Hermite splines, having the important property that all the control points lie on the outline itself. (It must be disappointing to URW that designers have generally accepted off-curve Bézier handles.) Ikarus was written in FORTRAN and has been used by foundries on VAX and Sun workstations to store thousands of type designs.
    Now Ikarus is available for Mac, Windows and Unix workstations. Current versions can import and export Type 1 and TrueType (without substantial hinting power).
  

• DTP Type Designer
  by Manfred Albracht in Aachen, Germany, lets you "quickly and easily design professional-quality Type 1 and TrueType fonts". A complete Type 1 editor, it is commonly regarded as performing great Type 1 to TrueType conversions (equal best with the converter inside Windows NT 3.5), as it examines each Type 1 hint and recodes it as TrueType instructions. (Most programs have separate, automatic TrueType auto-hinters, the results of which are often unpredictable.) Runs on Windows 3.1.

• Ares FontMonger
  Although a budget program, FontMonger allows basic outline editing, import and export of Type 1 and TrueType (and several other scalable formats). Its autohinting isn't bad either. Adobe, which now owns Ares, no longer promotes FontMonger but it is still avaiable from some computer stores. Runs on Windows 3.1 and above.

• CorelDraw
  From version 3.0 onwards the Corel behemoth is occasionally used to create and edit TrueType and Type 1 fonts. But most people find it lacks too many features and move to a dedicated font editor if they are serious about type design. If you do try though, check out Laurie McCanna's tips: Designing Type with CorelDraw.

Other sites of interest

• Digital Type Design Tools
  Fontographer, Ikarus-M and FontStudio praised and damned in the Comp.fonts FAQ by Charles Bigelow and Clive Bruton.

• Digital tools for type design
  Nicholas Fabian reviews Metafont, Ikarus, Fontographer, FontStudio and FontLab.