use crate::{Bounds, InputHandler, Pixels, UTF16Selection, View, ViewContext, WindowContext};use std::ops::Range; /// Implement this trait to allow views to handle textual input when implementing an editor, field, etc.////// Once your view implements this trait, you can use it to construct an [`ElementInputHandler<V>`]./// This input handler can then be assigned during paint by calling [`WindowContext::handle_input`].////// See [`InputHandler`] for details on how to implement each method.pub trait ViewInputHandler: 'static + Sized {    /// See [`InputHandler::text_for_range`] for details    fn text_for_range(&mut self, range: Range<usize>, cx: &mut ViewContext<Self>)        -> Option<String>;     /// See [`InputHandler::selected_text_range`] for details    fn selected_text_range(        &mut self,        ignore_disabled_input: bool,        cx: &mut ViewContext<Self>,    ) -> Option<UTF16Selection>;     /// See [`InputHandler::marked_text_range`] for details    fn marked_text_range(&self, cx: &mut ViewContext<Self>) -> Option<Range<usize>>;     /// See [`InputHandler::unmark_text`] for details    fn unmark_text(&mut self, cx: &mut ViewContext<Self>);     /// See [`InputHandler::replace_text_in_range`] for details    fn replace_text_in_range(        &mut self,        range: Option<Range<usize>>,        text: &str,        cx: &mut ViewContext<Self>,    );     /// See [`InputHandler::replace_and_mark_text_in_range`] for details    fn replace_and_mark_text_in_range(        &mut self,        range: Option<Range<usize>>,        new_text: &str,        new_selected_range: Option<Range<usize>>,        cx: &mut ViewContext<Self>,    );     /// See [`InputHandler::bounds_for_range`] for details    fn bounds_for_range(        &mut self,        range_utf16: Range<usize>,        element_bounds: Bounds<Pixels>,        cx: &mut ViewContext<Self>,    ) -> Option<Bounds<Pixels>>;} /// The canonical implementation of [`PlatformInputHandler`]. Call [`WindowContext::handle_input`]/// with an instance during your element's paint.pub struct ElementInputHandler<V> {    view: View<V>,    element_bounds: Bounds<Pixels>,} impl<V: 'static> ElementInputHandler<V> {    /// Used in [`Element::paint`][element_paint] with the element's bounds and a view context for its    /// containing view.    ///    /// [element_paint]: crate::Element::paint    pub fn new(element_bounds: Bounds<Pixels>, view: View<V>) -> Self {        ElementInputHandler {            view,            element_bounds,        }    }} impl<V: ViewInputHandler> InputHandler for ElementInputHandler<V> {    fn selected_text_range(        &mut self,        ignore_disabled_input: bool,        cx: &mut WindowContext,    ) -> Option<UTF16Selection> {        self.view.update(cx, |view, cx| {            view.selected_text_range(ignore_disabled_input, cx)        })    }     fn marked_text_range(&mut self, cx: &mut WindowContext) -> Option<Range<usize>> {        self.view.update(cx, |view, cx| view.marked_text_range(cx))    }     fn text_for_range(        &mut self,        range_utf16: Range<usize>,        cx: &mut WindowContext,    ) -> Option<String> {        self.view            .update(cx, |view, cx| view.text_for_range(range_utf16, cx))    }     fn replace_text_in_range(        &mut self,        replacement_range: Option<Range<usize>>,        text: &str,        cx: &mut WindowContext,    ) {        self.view.update(cx, |view, cx| {            view.replace_text_in_range(replacement_range, text, cx)        });    }     fn replace_and_mark_text_in_range(        &mut self,        range_utf16: Option<Range<usize>>,        new_text: &str,        new_selected_range: Option<Range<usize>>,        cx: &mut WindowContext,    ) {        self.view.update(cx, |view, cx| {            view.replace_and_mark_text_in_range(range_utf16, new_text, new_selected_range, cx)        });    }     fn unmark_text(&mut self, cx: &mut WindowContext) {        self.view.update(cx, |view, cx| view.unmark_text(cx));    }     fn bounds_for_range(        &mut self,        range_utf16: Range<usize>,        cx: &mut WindowContext,    ) -> Option<Bounds<Pixels>> {        self.view.update(cx, |view, cx| {            view.bounds_for_range(range_utf16, self.element_bounds, cx)        })    }}