Trait TextBuffer

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pub trait TextBuffer {
Show 21 methods    // Required methods
    fn is_mutable(&self) -> bool;
    fn as_str(&self) -> &str;
    fn insert_text(&mut self, text: &str, char_index: usize) -> usize;
    fn delete_char_range(&mut self, char_range: Range<usize>);
    fn type_id(&self) -> TypeId;

    // Provided methods
    fn char_range(&self, char_range: Range<usize>) -> &str { ... }
    fn byte_index_from_char_index(&self, char_index: usize) -> usize { ... }
    fn char_index_from_byte_index(&self, char_index: usize) -> usize { ... }
    fn clear(&mut self) { ... }
    fn replace_with(&mut self, text: &str) { ... }
    fn take(&mut self) -> String { ... }
    fn insert_text_at(
        &mut self,
        ccursor: &mut CCursor,
        text_to_insert: &str,
        char_limit: usize,
    ) { ... }
    fn decrease_indentation(&mut self, ccursor: &mut CCursor) { ... }
    fn delete_selected(&mut self, cursor_range: &CCursorRange) -> CCursor { ... }
    fn delete_selected_ccursor_range(
        &mut self,
        [min, max]: [CCursor; 2],
    ) -> CCursor { ... }
    fn delete_previous_char(&mut self, ccursor: CCursor) -> CCursor { ... }
    fn delete_next_char(&mut self, ccursor: CCursor) -> CCursor { ... }
    fn delete_previous_word(&mut self, max_ccursor: CCursor) -> CCursor { ... }
    fn delete_next_word(&mut self, min_ccursor: CCursor) -> CCursor { ... }
    fn delete_paragraph_before_cursor(
        &mut self,
        galley: &Galley,
        cursor_range: &CCursorRange,
    ) -> CCursor { ... }
    fn delete_paragraph_after_cursor(
        &mut self,
        galley: &Galley,
        cursor_range: &CCursorRange,
    ) -> CCursor { ... }
}

Expand description

Trait constraining what types crate::TextEdit may use as an underlying buffer.

Most likely you will use a String which implements TextBuffer.

Required Methods§

Source

fn is_mutable(&self) -> bool

Can this text be edited?

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fn as_str(&self) -> &str

Returns this buffer as a str.

Source

fn insert_text(&mut self, text: &str, char_index: usize) -> usize

Inserts text text into this buffer at character index char_index.

§Notes

char_index is a character index, not a byte index.

§Return

Returns how many characters were successfully inserted

Source

fn delete_char_range(&mut self, char_range: Range<usize>)

Deletes a range of text char_range from this buffer.

§Notes

char_range is a character range, not a byte range.

Source

fn type_id(&self) -> TypeId

Returns a unique identifier for the implementing type.

This is useful for downcasting from this trait to the implementing type. Here is an example usage:

use egui::TextBuffer;
use std::any::TypeId;

struct ExampleBuffer {}

impl TextBuffer for ExampleBuffer {
    fn is_mutable(&self) -> bool { unimplemented!() }
    fn as_str(&self) -> &str { unimplemented!() }
    fn insert_text(&mut self, text: &str, char_index: usize) -> usize { unimplemented!() }
    fn delete_char_range(&mut self, char_range: std::ops::Range<usize>) { unimplemented!() }

    // Implement it like the following:
    fn type_id(&self) -> TypeId {
        TypeId::of::<Self>()
    }
}

// Example downcast:
pub fn downcast_example(buffer: &dyn TextBuffer) -> Option<&ExampleBuffer> {
    if buffer.type_id() == TypeId::of::<ExampleBuffer>() {
        unsafe { Some(&*(buffer as *const dyn TextBuffer as *const ExampleBuffer)) }
    } else {
        None
    }
}