Enum winit::event::Ime

pub enum Ime {
    Enabled,
    Preedit(String, Option<(usize, usize)>),
    Commit(String),
    Disabled,
}

Describes input method events.

This is also called a “composition event”.

Most keypresses using a latin-like keyboard layout simply generate a WindowEvent::KeyboardInput. However, one couldn’t possibly have a key for every single unicode character that the user might want to type

• so the solution operating systems employ is to allow the user to type these using a sequence of keypresses instead.

A prominent example of this is accents - many keyboard layouts allow you to first click the “accent key”, and then the character you want to apply the accent to. In this case, some platforms will generate the following event sequence:

// Press "`" key
Ime::Preedit("`", Some((0, 0)))
// Press "E" key
Ime::Preedit("", None) // Synthetic event generated by winit to clear preedit.
Ime::Commit("é")

Additionally, certain input devices are configured to display a candidate box that allow the user to select the desired character interactively. (To properly position this box, you must use Window::set_ime_cursor_area.)

An example of a keyboard layout which uses candidate boxes is pinyin. On a latin keyboard the following event sequence could be obtained:

// Press "A" key
Ime::Preedit("a", Some((1, 1)))
// Press "B" key
Ime::Preedit("a b", Some((3, 3)))
// Press left arrow key
Ime::Preedit("a b", Some((1, 1)))
// Press space key
Ime::Preedit("啊b", Some((3, 3)))
// Press space key
Ime::Preedit("", None) // Synthetic event generated by winit to clear preedit.
Ime::Commit("啊不")

Variants

Enabled

Notifies when the IME was enabled.

After getting this event you could receive Preedit and Commit events. You should also start performing IME related requests like Window::set_ime_cursor_area.

Preedit(String, Option<(usize, usize)>)

Notifies when a new composing text should be set at the cursor position.

The value represents a pair of the preedit string and the cursor begin position and end position. When it’s None, the cursor should be hidden. When String is an empty string this indicates that preedit was cleared.

The cursor position is byte-wise indexed.

Commit(String)

Notifies when text should be inserted into the editor widget.

Right before this event winit will send empty Self::Preedit event.

Disabled

Notifies when the IME was disabled.

After receiving this event you won’t get any more Preedit or Commit events until the next Enabled event. You should also stop issuing IME related requests like Window::set_ime_cursor_area and clear pending preedit text.

Trait Implementations

impl Clone for Ime

fn clone(&self) -> Ime

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Ime

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

Formats the value using the given formatter.

impl Hash for Ime

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 Ime

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

This method tests for self and other values to be equal, and is used by ==.

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

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

impl Eq for Ime

impl StructuralEq for Ime

impl StructuralPartialEq for Ime