TrueType is a digital Type Technology originaly developed by Sampo Kaasila of Apple, Ink, whose remit was to create a custom technology so as to avoid paying royalty fees to use font technologies developed by other parties, as well as to solve some technical limitations of Adobe’s PostScript based Type 1 font format. TrueType differs from Type 1 in that it uses quadratic as opposed to cubic bezier curves. TrueType excels at on-screen rendering due to the fact that it can support sophisticated hinting instructions. The technology was cross-licensed with a Microsoft replacement for PostScript called TrueImage, but today only TrueType survives. A few years later the format was extended to support Unicode and more complex linguistic and typographic behaviours such as automatic ligature substitution and Indic vowel rearrangement. However the new extensions, called AAT (Apple Advanced Typography), were not licensed to Microsoft, who then set about creating their own extensions to TrueType (along with Adobe), which they called OpenType. The two extensions are incompatible and whilst their feature sets overlap, there are many things that one can do which is impossible with the other.
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