resizeViewport
fun resizeViewport(columns: Int, rows: Int, oldScrollbackOffset: Int = 0): TerminalViewportResizeResult
Resizes the terminal and connector and captures the viewport anchor and history baseline under the same mutation lock. This keeps viewport resizes ordered with application-requested column switches.
Reflow may replace history storage and change its discarded-row counter. Consumers that retain scrollback position must adopt the complete result together, so later output is measured against the resized history.
Return
the resized viewport and history metadata from one synchronized state.
Parameters
columns
target terminal column width; must be positive.
rows
target terminal row height; must be positive.
oldScrollbackOffset
pre-resize whole-row offset, or zero for live output.