Cell Buffer

Termisu renders through a double-buffered grid:

• Back buffer receives writes via set_cell.
• Front buffer stores the last rendered frame.
• render emits only diffs.

Core Calls

termisu.set_cell(x, y, 'A', fg: Color.red, bg: Color.black, attr: Termisu::Attribute::Bold)
termisu.clear
termisu.render
termisu.sync

Use sync for full redraws (for example after large external changes), and render for normal frame updates.