struct Termisu::Cell

• Termisu::Cell
• Struct
• Value
• Object

Overview

Cell represents a single character cell in the terminal buffer.

Cell contains:

• grapheme: The Unicode grapheme cluster (single grapheme for leading cells)
• width: Display column width (0, 1, or 2)
• continuation: True for trailing cell of a wide grapheme
• fg: Foreground color (supports ANSI-8, ANSI-256, and RGB)
• bg: Background color (supports ANSI-8, ANSI-256, and RGB)
• attr: Text attributes (bold, underline, etc.)

Grapheme and Continuation Cells

Wide characters (CJK, emoji) occupy 2 columns. The Cell model represents this:

• Leading cell: continuation = false, width = 2, #grapheme contains the full grapheme
• Trailing cell: continuation = true, width = 0, #grapheme is empty

Example:

# Leading cell for "中" (width auto-calculated as 2)
lead = Termisu::Cell.new("中")
lead.grapheme      # => "中"
lead.width         # => 2
lead.continuation? # => false

# Trailing continuation cell
trail = Termisu::Cell.continuation
trail.grapheme      # => ""
trail.width         # => 0
trail.continuation? # => true

Compatibility (Public API)

The #grapheme property provides backward-compatible access:

cell = Termisu::Cell.new("ABC")
cell.grapheme # => "A" (first grapheme of input-String is stored)

continuation = Termisu::Cell.continuation
continuation.grapheme # => "" (empty for continuation cells)

Defined in:

Constant Summary

CONTINUATION_KEY = Cell.new(continuation: true).key

Key of the canonical continuation cell, so Buffer's key planes can write continuation cells without materializing a Cell.

DEFAULT_KEY = Cell.new.key

Key of the canonical default cell, resolved lazily so default_state? stays a single integer compare.

KEY_STYLE_MASK = (1_u128 << 84) - 1

Style portion of a key (attr + fg + bg, bits 0..83). Cells with equal masked keys render with identical styling (see injectivity notes on #key).

Constructors

• .new(grapheme : String = " ", continuation : Bool = false, fg : Color = Color.white, bg : Color = Color.default, attr : Attribute = Attribute::None)

  Creates a new Cell with the specified grapheme and colors.

Class Method Summary

• .continuation

  Continuation cells represent the trailing column occupied by a wide character.

• .default

  default empty cell (space with default colors, width 1, not continuation).

Instance Method Summary

• #attr : Attribute
• #attr=(attr : Attribute)
• #bg : Color
• #bg=(bg : Color)
• #continuation? : Bool
• #default_state? : Bool

  Returns true when this cell is the canonical default blank cell.

• #fg : Color
• #fg=(fg : Color)

  Style setters splice only their own key field instead of re-running compute_key, which would re-derive the grapheme id and take the process-global intern mutex for non-ASCII cells.

• #grapheme : String
• #grapheme=(grapheme : String)
• #key : UInt128

  Packed identity key: equal keys <=> equal cells (memberwise equality).

• #width : UInt8

Constructor Detail

Class Method Detail

trail = Termisu::Cell.continuation
trail.continuation? # => true
trail.width         # => 0
trail.grapheme      # => ""

Instance Method Detail