bufferSetContentType

Sets the type of buffer contents. Buffers are either empty, contain characters (before shaping), or contain glyphs (the result of shaping).

You rarely need to call this function, since a number of other functions transition the content type for you. Namely:

• A newly created buffer starts with content type harfbuzz.types.BufferContentType.Invalid. Calling harfbuzz.global.bufferReset, harfbuzz.global.bufferClearContents, as well as calling harfbuzz.global.bufferSetLength with an argument of zero all set the buffer content type to invalid as well.
• Calling harfbuzz.global.bufferAddUtf8, harfbuzz.global.bufferAddUtf16, harfbuzz.global.bufferAddUtf32, harfbuzz.global.bufferAddCodepoints and harfbuzz.global.bufferAddLatin1 expect that buffer is either empty and have a content type of invalid, or that buffer content type is harfbuzz.types.BufferContentType.Unicode, and they also set the content type to Unicode if they added anything to an empty buffer.
• Finally harfbuzz.global.shape and harfbuzz.global.shapeFull expect that the buffer is either empty and have content type of invalid, or that buffer content type is harfbuzz.types.BufferContentType.Unicode, and upon success they set the buffer content type to harfbuzz.types.BufferContentType.Glyphs.

The above transitions are designed such that one can use a buffer in a loop of "reset : add-text : shape" without needing to ever modify the content type manually.