Struct SelectionHelper 

pub struct SelectionHelper { /* private fields */ }

Text-selection logic

This struct holds the index of the edit cursor and selection position, which together form a range. There is no requirement on the order of these two positions. Each may be adjusted independently.

Additionally, this struct holds the selection anchor index. This usually equals the selection index, but when using double-click or triple-click selection, the anchor represents the initially-clicked position while the selection index represents the expanded position.

Implementations

impl SelectionHelper

pub fn new(edit: usize, selection: usize) -> Self

Construct from (edit, selection) positions

The anchor position is set to the selection position.

pub fn clear(&mut self)

Reset to the default state

All positions are set to 0.

pub fn is_empty(&self) -> bool

True if the selection index equals the cursor index

pub fn set_empty(&mut self)

Clear selection without changing the edit index

pub fn set_all(&mut self, index: usize)

Set the cursor index and clear the selection

pub fn edit_index(&self) -> usize

Get the cursor index

pub fn set_edit_index(&mut self, index: usize)

Set the cursor index without adjusting the selection index

pub fn sel_index(&self) -> usize

Get the selection index

pub fn set_sel_index(&mut self, index: usize)

Set the selection index without adjusting the edit index

The anchor index is also set to the selection index.

pub fn set_sel_index_only(&mut self, index: usize)

Set the selection index only

Prefer Self::set_sel_index unless you know you don’t want to set the anchor.

pub fn set_max_len(&mut self, len: usize)

Apply new limit to the maximum length

Call this method if the string changes under the selection to ensure that the selection does not exceed the length of the new string.

pub fn range(&self) -> Range<usize>

Get the selection range

This range is from the edit index to the selection index or reversed, whichever is increasing.

pub fn set_anchor_to_range_start(&mut self)

Set the anchor position to the start of the selection range

pub fn anchor_to_edit_range(&self) -> Range<usize>

Get the range from the anchor position to the edit position

This is used following Self::set_anchor_to_range_start to get the IME pre-edit range.

pub fn action<T: FormattableText>( &mut self, text: &Text<T>, action: SelectionAction, )

Handle an action

pub fn cursor_rect(&self, text: &TextDisplay) -> Option<Rect>

Return a Rect encompassing the cursor(s) and selection

Trait Implementations

impl Clone for SelectionHelper

fn clone(&self) -> SelectionHelper

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for SelectionHelper

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

Formats the value using the given formatter.

impl Default for SelectionHelper

fn default() -> SelectionHelper

Returns the “default value” for a type.