readCluster

Copies all codepoints of the grapheme cluster at col into dest and returns the number of codepoints written.

The copy itself does not allocate. The caller owns capacity and may reuse dest while it remains large enough. Use getClusterLength to discover required capacity before copying, under the same uninterrupted serialization; core-owned lines retain at most 32 codepoints per cluster. Alternatively, use io.github.ketraterm.render.api.TerminalRenderFrame.copyLine with a io.github.ketraterm.render.api.TerminalRenderClusterDataSink. Its callback supplies the full length and a borrowed primitive range to copy before returning. Keep the owning terminal serialized for either read path. An insufficient destination is rejected by core-owned lines before any elements are changed.

Returns 0 for non-cluster cells; callers should check isCluster first or treat a return value of 0 as "use getCodepoint instead".

Parameters

Throws