FreeType 中函数 FT_Get_Kerning
- Backtrack(后迹) — This is the sequence of things that occur before the target in the rule.
This sequence can be composed of glyphs, classes or a mix of both. - Lookahead(前瞻) — This is the sequence of glyphs that occur after the target in the rule.
Like the backtrack, this sequence can be composed of glyphs, classes or a mix of both.
名词
FontCreator字库编辑工具，使用Ctrl-F8（OpenType设计工具）可以编辑TTF字库相关信息：
GSUB
The OpenType Layout Feature specification
describes eight types of substitution lookups in the glyph substitution table (GSUB).
The following table shows those currently supported by FontCreator:
- Single Substitute a single glyph by another single glyph (a -> b)
- Multiple Substitute a single glyph by other multiple glyphs (a -> xyz)
- Alternate Substitute a single glyph by one of multiple alternates (a -> x or y or z)
- Ligature Substitute multiple glyphs by a single ligature (f f i -> ffi)
- Context Substitute one or more glyphs in context
- Chaining Context Substitute context specific glyphs (3rd -> 3rd)
- Extension Substitution
- Reverse chaining context Applied in reverse order, replace single glyph in chaining context
GPOS
The OpenType Layout Feature specification
describes nine types of positioning lookups in the glyph positioning table (GPOS).
The following table shows those currently supported by FontCreator:
- Single adjustment Change the position of a single glyph (sub/superscript)
- Pair adjustment Mostly used to define kerning pairs
- Cursive attachment
- Mark to base attachment Attach a combining mark such as a diacritic to a base glyph
- Mark to ligature attachment Attach a combining mark to a ligature
- Mark to mark attachment Attach a combining mark to another mark
- Context Positioning Position one or more glyphs in context
- Chained Context Positioning Position one or more glyphs in chained context
- Extension Substitution
entries
字体 -> OpenType设计工具