Struct druid::text::TextComponent

pub struct TextComponent<T> {
    pub has_focus: bool,
    /* private fields */
}

A widget that accepts text input.

This is intended to be used as a component of other widgets.

Text input is more complicated than you think, probably. For a good overview, see druid_shell::text.

This type manages an inner EditSession that is shared with the platform. Unlike other aspects of Druid, the platform interacts with this session, not through discrete events.

This is managed through a simple ‘locking’ mechanism; the platform asks for a lock on a particular text session that it wishes to interact with, calls methods on the locked session, and then later releases the lock.

Importantly, other events may be received while the lock is held.

It is the responsibility of the user of this widget to ensure that the session is not locked before it is accessed. This can be done by checking TextComponent::can_read and TextComponent::can_write; after checking these methods the inner session can be accessed via TextComponent::borrow and TextComponent::borrow_mut.

Sementically, this functions like a RefCell; attempting to borrow while a lock is held will result in a panic.

Fields

has_focus: bool

A manual flag set by the parent to control drawing behaviour.

The parent should update this when handling LifeCycle::FocusChanged.

Implementations

impl TextComponent<()>

pub const SCROLL_TO: Selector<bool> = _

A notification sent by the component when the cursor has moved.

If the payload is true, this follows an edit, and the view will need layout before scrolling.

pub const RETURN: Selector = _

A notification sent by the component when the user hits return.

This is only sent when send_notification_on_return is true.

pub const CANCEL: Selector = _

A notification sent when the user cancels editing.

This is only sent when send_notification_on_cancel is true.

pub const TAB: Selector = _

A notification sent by the component when the user presses the tab key.

This is not sent if accepts_tabs is true.

An ancestor can handle this event in order to do things like request a focus change.

pub const BACKTAB: Selector = _

A notification sent by the component when the user inserts a backtab.

This is not sent if accepts_tabs is true.

An ancestor can handle this event in order to do things like request a focus change.

impl<T> TextComponent<T>

pub fn can_read(&self) -> bool

Returns true if the inner EditSession can be read.

pub fn can_write(&self) -> bool

Returns true if the inner EditSession can be mutated.

pub fn is_composing(&self) -> bool

Returns true if the IME is actively composing (or the text is locked.)

When text is composing, you should avoid doing things like modifying the selection or copy/pasting text.

pub fn borrow_mut(&self) -> RefMut<'_, EditSession<T>>

Attempt to mutably borrow the inner EditSession.

Panics

This method panics if there is an outstanding lock on the session.

pub fn borrow(&self) -> Ref<'_, EditSession<T>>

Attempt to borrow the inner EditSession.

Panics

This method panics if there is an outstanding write lock on the session.

impl<T: EditableText + TextStorage> TextComponent<T>

pub fn input_handler(&self) -> impl ImeHandlerRef

Returns an ImeHandlerRef that can accept platform text input.

The widget managing this component should call LifeCycleCtx::register_text_input during LifeCycle::WidgetAdded, and pass it this object.

Trait Implementations

impl<T: Clone> Clone for TextComponent<T>

fn clone(&self) -> TextComponent<T>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<T: Debug> Debug for TextComponent<T>

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

Formats the value using the given formatter.

impl<T> Default for TextComponent<T>

fn default() -> Self

Returns the “default value” for a type.

impl<T: TextStorage + EditableText> Widget<T> for TextComponent<T>

fn event( &mut self, ctx: &mut EventCtx<'_, '_>, event: &Event, data: &mut T, env: &Env )

Handle an event.

fn lifecycle( &mut self, ctx: &mut LifeCycleCtx<'_, '_>, event: &LifeCycle, data: &T, env: &Env )

Handle a life cycle notification.

fn update(&mut self, ctx: &mut UpdateCtx<'_, '_>, _old: &T, data: &T, env: &Env)

Update the widget’s appearance in response to a change in the app’s Data or Env.

fn layout( &mut self, ctx: &mut LayoutCtx<'_, '_>, bc: &BoxConstraints, _data: &T, env: &Env ) -> Size

Compute layout.

fn paint(&mut self, ctx: &mut PaintCtx<'_, '_, '_>, _data: &T, env: &Env)

Paint the widget appearance.

fn compute_max_intrinsic( &mut self, axis: Axis, ctx: &mut LayoutCtx<'_, '_>, bc: &BoxConstraints, data: &T, env: &Env ) -> f64

Computes max intrinsic/preferred dimension of a widget on the provided axis.