The FreeType library performs the rasterization operation in which each character is associated with a glyph index; this glyph index maps to the bitmap image. This information is more or less sufficient for simple scripts like English, which does not change its shape with the context. For example, based on the context, Arabic language has four different types of shape forms, where a character may change its shape depending on the own location or surrounding characters. With Unicode, there was a need for different languages to allow them to create complex transformations of glyphs, such as substitution, positioning, bi-directional text, context-sensitive shaping, and ligatures. Therefore, we need some special library that understands the context of the language and does the job of shaping for us; this is where Harfbuzz comes into the picture.

Harfbuzz is a text shaping engine that manages complex text; it performs the shaping job on the given Unicode...