Part of megapkg and available from http://code.google.com/p/megapkg/
Freetypeext is an extension that generates megaimage buffers using FreeType from TTF fonts. Other font types may work, but are untested. Antialias alpha blending is provided by using megaimage's blendobj subcommand.
License: 3 clause BSD (see the website)
Usage (assuming the user runs the install target):
$ tclsh8.5 % package require freetypeext 1.0 % freetype wrong # args: should be "freetype font size text RGBA-color widthvar heightvar ?char-width-listvar?" % freetype-measure wrong # args: should be "freetype-measure font size text widthvar heightvar" set buf [freetype /path/to/font.ttf 12 "Hello World" [list $r $g $b $a] width height]