I've been asked for advice regarding copyleft ("GPL-like") font
licensing.Without special exceptions, the GPL is not a suitable license for fonts because it is common practice to embed fonts (or subsets of fonts) into PDF documents (and other document formats). In this scenario, the GPL would require distribution of complete source code, which is impractical. This is true even if the outline font itself is the preferred form for making modifications because it defeats the purpose of subsetting. (The written offer option is not really feasible, either.) Maybe fonts could be licensed under the GPL plus the following exception? | As a special exception, if a document file embeds Type 1, TrueType, | OpenType or bitmap fonts derived from this source code, these fonts | do not by themselves cause the resulting document file to be covered | by the GNU General Public License. This exception does not however | invalidate any other reason why the document file might be covered | by the GNU General Public License. (This is modeled after the GNAT exception for the GPL.) This does not deal with artwork that contains outlines derived from the font (which was often used as a way around embedding, which is a pretty recent development). Perhaps today, embedding can be used in such cases, too?
