Struct TextInputState 

pub struct TextInputState { /* private fields */ }

A String value, a byte cursor into it, and a horizontal scroll offset.

The state a single-line editable text field needs, mirroring ListState’s split between “what’s selected/typed” and “how it’s drawn”.

Holds no reference to any widget: the same TextInputState can be reused across frames (and across a resized field) the way ListState is reused across a resized list.

cursor is a byte index into value, not a char or display-column index, and every mutating method here maintains the invariant that it always lands on a char boundary: insert/ insert_str/backspace/delete never split a multi-byte character, and move_left/ move_right step by whole chars. Display-column math (where the caret actually draws, and how far the field has scrolled) is a separate concern handled by ensure_visible and the TextInput widget itself, via retroglyph_core::text::width_usize: a byte or char count is the wrong unit once the value contains a double-width character.

Handles typed characters (Event::Key(KeyCode::Char(c))) and pasted text (Event::Paste) only, not IME/text composition or multi-line editing.

Cursor movement and deletion step by Unicode char (codepoint), not by grapheme cluster: a base character plus a combining mark is two chars, so backspace there removes only the mark and move_left stops between the two. A field over text with combining marks or emoji-ZWJ sequences will show per-codepoint, not per-glyph, editing.

Implementations

impl TextInputState

pub const fn new() -> Self

An empty field: empty value, cursor at 0, scroll at 0.

pub fn value(&self) -> &str

The current text content.

pub fn set_value(&mut self, s: impl Into<String>)

Replace the entire content and move the cursor to its end. Resets the scroll offset to zero. Call ensure_visible afterward if the new value should scroll to keep the cursor (still at the end) in view.

Sets the cursor to value.len(), a trivially-valid char boundary, so this skips the debug-only boundary guard the other mutators carry.

pub const fn cursor(&self) -> usize

The cursor’s byte offset into value. Always on a char boundary.

pub const fn scroll(&self) -> u16

The current horizontal scroll offset, in display columns from the start of value. See ensure_visible.

pub fn insert(&mut self, c: char)

Insert c at the cursor and move the cursor past it.

pub fn insert_str(&mut self, s: &str)

Insert s at the cursor and move the cursor past it, e.g. from an Event::Paste.

pub fn backspace(&mut self)

Delete the character before the cursor, if any, and move the cursor onto its place.

pub fn delete(&mut self)

Delete the character at the cursor, if any. The cursor itself does not move.

pub fn move_left(&mut self)

Move the cursor one character left, if not already at the start.

pub fn move_right(&mut self)

Move the cursor one character right, if not already at the end.

pub const fn move_home(&mut self)

Move the cursor to the start of the value.

Sets the cursor to 0, a trivially-valid char boundary, so this skips the debug-only boundary guard the other mutators carry.

pub const fn move_end(&mut self)

Move the cursor to the end of the value.

Sets the cursor to value.len(), a trivially-valid char boundary, so this skips the debug-only boundary guard the other mutators carry.

pub fn handle_event(&mut self, event: &Event) -> bool

Apply one input event: typed characters, Backspace/Delete, Left/Right/Home/End, and pasted text. Returns whether the event was consumed (so a caller can decide whether to fall through to its own key handling, e.g. Enter/Escape/Tab, none of which this consumes).

Key releases and auto-repeats other than presses are ignored except that auto-repeat presses are treated the same as a press (matches FocusRing/ Shortcuts’s own is_down gating). Event has no IME/composition variant to begin with; see the scope note above.

pub fn ensure_visible(&mut self, width: u16)

Nudge the scroll offset by the minimum amount needed to keep the cursor within a width-column window, the way ListState::ensure_visible keeps a selection in view.

A no-op if width is zero or the cursor is already visible. Call this once per frame before rendering (with the actual, current field width, since that can change on resize) rather than only after an edit: it’s cheap and idempotent.

Trait Implementations

impl Clone for TextInputState

fn clone(&self) -> TextInputState

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for TextInputState

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

Formats the value using the given formatter.

impl Default for TextInputState

fn default() -> TextInputState

Returns the “default value” for a type.

impl PartialEq for TextInputState

fn eq(&self, other: &TextInputState) -> 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 Eq for TextInputState

impl StructuralPartialEq for TextInputState