Struct CellContent 

pub struct CellContent(/* private fields */);

Cell content: either a direct Unicode char or a reference to a grapheme cluster.

Encoding Scheme (4 bytes)

Bit 31 (type discriminator):
  0: Direct char (bits 0-20 contain Unicode scalar value, max U+10FFFF)
  1: GraphemeId reference (bits 0-30 contain slot + width)

This allows:

• 99% of cells (ASCII/BMP) to be stored without heap allocation
• Complex graphemes (emoji, ZWJ sequences) stored in pool

Special Values

• EMPTY (0x0): Empty cell, width 0
• CONTINUATION (0x1): Placeholder for wide character continuation

Implementations

impl CellContent

pub const EMPTY: Self

Empty cell content (no character).

pub const CONTINUATION: Self

Continuation marker for wide characters.

When a character has display width > 1, subsequent cells are filled with this marker to indicate they are part of the previous character.

Value is 0x7FFF_FFFF (max i32), which is outside valid Unicode scalar range (0..0x10FFFF) but fits in 31 bits (Direct Char mode).

pub const fn from_char(c: char) -> Self

Create content from a single Unicode character.

For characters with display width > 1, subsequent cells should be filled with CONTINUATION.

Tab Handling

The tab character \t is normalized to a space. This prevents cursor desynchronization, as the Presenter cannot predict terminal tab stops.

pub const fn from_grapheme(id: GraphemeId) -> Self

Create content from a grapheme ID (for multi-codepoint clusters).

The grapheme ID references an entry in the GraphemePool.

pub const fn is_grapheme(self) -> bool

Check if this content is a grapheme reference (vs direct char).

pub const fn is_continuation(self) -> bool

Check if this is a continuation cell (part of a wide character).

pub const fn is_empty(self) -> bool

Check if this cell is empty.

pub const fn is_default(self) -> bool

Check if this content is the default value.

This is equivalent to is_empty() and primarily exists for readability in tests.

pub fn as_char(self) -> Option<char>

Extract the character if this is a direct char (not a grapheme).

Returns None if this is empty, continuation, or a grapheme reference.

pub const fn grapheme_id(self) -> Option<GraphemeId>

Extract the grapheme ID if this is a grapheme reference.

Returns None if this is a direct char.

pub const fn width_hint(self) -> usize

Get the display width of this content.

• Empty: 0
• Continuation: 0
• Grapheme: width embedded in GraphemeId
• Char: requires external width lookup (returns 1 as default for ASCII)

Note: For accurate char width, use the unicode-display-width-based helpers in this crate. This method provides a fast path for known cases.

pub fn width(self) -> usize

Get the display width of this content with Unicode width semantics.

This is the accurate (but slower) width computation for direct chars.

pub const fn raw(self) -> u32

Raw u32 value.

Trait Implementations

impl Clone for CellContent

fn clone(&self) -> CellContent

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for CellContent

impl Debug for CellContent

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for CellContent

fn default() -> Self

Returns the “default value” for a type.

impl Eq for CellContent

impl Hash for CellContent

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for CellContent

fn eq(&self, other: &CellContent) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for CellContent