Release Notes > 12.0.1.0 > Updates in This Release > OpenType in Layout Developer > Introduction
  
Introduction
PTC Arbortext Layout Developer has supported OpenType fonts for many years, but only to use the font character shapes, kerning and ligature tables in the same way that TrueType fonts are supported. However, OpenType provides a great deal more information to the composition engine than just these parts. In addition, OpenType fonts can provide over 100 different tables of information which describes expected output behaviour in what are known as ‘Feature Tables’. The 12.0.0.0 release of Layout Developer is the first release which provides support for these Feature Tables.
OpenType Feature Tables are there to improve such things as language support (by telling the output engine how to position accents, for example) or to provide alternatives for standard characters, including small capital alternatives and old style numerals. In order to use these feature tables, Layout Developer must be able to access different glyphs inside the font rather than single character positions. Layout Developer must also understand how combinations of characters are expected to behave to ensure the correct contextual versions of the characters are output.
In this release we provide a means to turn on OpenType word shaping as well as the means to turn on and off individual Feature Tables.
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Turning on OpenType word shaping will cause word formatting to look different! Please do not expect line endings to be identical when using OpenType shaping compared to Layout Developer’s standard shaping. This is very important — Layout Developer uses a different process to derive the positions of each character when using OpenType shaping and consequently documents will format differently.
OpenType Feature Tables are organised according to a script and language based hierarchy. A default set of Feature Tables are applied, but should a script or language be activated, a different set of Feature Tables may be active by default. The scripts and languages supported by the font are unique to that font and therefore the Feature Tables supported by the font are also unique.
Arbortext Layout Developer provides tools to allow the user to activate the different scripts and languages as well as the individual Feature Tables.
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Using OpenType shaping is incompatible with custom kerning. If Layout Developer finds kerning commands within a word when OpenType is on, they will be ignored. Kerning commands come from a variety of different places in Layout Developer. Custom kerning tables will be ignored when OpenType shaping is turned on. If custom kerning is required, turn off OpenType shaping. This does not apply to letter and word spacing. If using the kerning commands in custom ligature tables to position characters over others, this will also be ignored. Yakumono also inserts kerning commands, and so these will be ignored too, but OpenType has half-width and punctuation feature tables designed for providing Yakumono support. The reason for ignoring kerning is that it is expected that the font being used will have adequate kerning information, and the codes placed within a word by Layout Developer’s kerning tools will disrupt the word shaping. Character replacement, such as character maps and ligatures will take place before the word is passed to the OpenType processor.
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Please also note that using OpenType shaping will not work with embedded fonts and my produce incorrect output if using pseudo fonts and characters are using different system fonts within the same word.