Struct TextSelection 

pub struct TextSelection {
    pub base_offset: i32,
    pub extent_offset: i32,
    pub affinity: TextAffinity,
    pub is_directional: bool,
}

A range of text that represents a selection.

Dart’s TextSelection extends TextRange: the range is range, and start / end are the normalized bounds.

Fields

base_offset: i32

The offset at which the selection originates.

Might be larger than, smaller than, or equal to extent.

extent_offset: i32

The offset at which the selection terminates.

When the user uses the arrow keys to adjust the selection, this is the value that changes. Similarly, if the current theme paints a caret on one side of the selection, this is the location at which to paint the caret.

Might be larger than, smaller than, or equal to base.

affinity: TextAffinity

If the text range is collapsed and has more than one visual location (e.g., occurs at a line break), which of the two locations to use when painting the caret.

is_directional: bool

Whether this selection has disambiguated its base and extent.

On some platforms, the base and extent are not disambiguated until the first time the user adjusts the selection. At that point, either the start or the end of the selection becomes the base and the other one becomes the extent and is adjusted.

Implementations

impl TextSelection

pub const fn new(base_offset: i32, extent_offset: i32) -> TextSelection

Creates a text selection.

pub const fn collapsed(offset: i32, affinity: TextAffinity) -> TextSelection

Creates a collapsed selection at the given offset.

A collapsed selection starts and ends at the same offset, which means it contains zero characters but instead serves as an insertion point in the text.

pub const fn from_position(position: TextPosition) -> TextSelection

Creates a collapsed selection at the given text position.

A collapsed selection starts and ends at the same offset, which means it contains zero characters but instead serves as an insertion point in the text.

pub fn range(&self) -> TextRange

The normalized range this selection covers (Dart’s TextRange superclass).

pub fn start(&self) -> i32

The index of the first character in the range.

pub fn end(&self) -> i32

The next index after the characters in this range.

pub fn is_valid(&self) -> bool

Whether this range represents a valid position in the text.

pub fn is_collapsed(&self) -> bool

Whether this range is empty (but still potentially placed inside the text).

pub fn is_normalized(&self) -> bool

Whether the start of this range precedes the end.

pub fn base(&self) -> TextPosition

The position at which the selection originates.

The TextAffinity of the resulting TextPosition is based on the relative logical position in the text to the other selection endpoint:

• if base_offset < extent_offset, base will have a TextAffinity::Downstream affinity;
• if base_offset > extent_offset, base will have a TextAffinity::Upstream affinity;
• if the selection is collapsed, the affinity is affinity.

pub fn extent(&self) -> TextPosition

The position at which the selection terminates.

When the user uses the arrow keys to adjust the selection, this is the value that changes. Similarly, if the current theme paints a caret on one side of the selection, this is the location at which to paint the caret.

pub fn copy_with(&self) -> TextSelection

Creates a new TextSelection based on the current selection, with the provided parameters overridden. Dart’s copyWith named arguments are the fluent setters that follow.

pub fn base_offset(self, base_offset: i32) -> TextSelection

Dart copyWith(baseOffset:).

pub fn extent_offset(self, extent_offset: i32) -> TextSelection

Dart copyWith(extentOffset:).

pub fn affinity(self, affinity: TextAffinity) -> TextSelection

Dart copyWith(affinity:).

pub fn is_directional(self, is_directional: bool) -> TextSelection

Dart copyWith(isDirectional:).

pub fn expand_to( &self, position: TextPosition, extent_at_index: bool, ) -> TextSelection

Returns the smallest TextSelection that this could expand to in order to include the given TextPosition.

If the given TextPosition is already inside of the selection, then returns self without change.

The returned selection will always be a strict superset of the current selection. In other words, the selection grows to include the given TextPosition.

If extent_at_index is set to true, then the extent will be placed at the given index regardless of the original order of it and the base. Otherwise, the base and extent are ordered so as to keep the original selection’s direction.

pub fn extend_to(&self, position: TextPosition) -> TextSelection

Keeping the selection’s base fixed, pivot the extent to the given TextPosition.

In some cases, the base and extent can be flipped during this operation, or the size of the selection can be reduced.

Trait Implementations

impl Clone for TextSelection

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for TextSelection

impl Debug for TextSelection

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

Formats the value using the given formatter.

impl Display for TextSelection

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

Formats the value using the given formatter.

impl Eq for TextSelection

impl From<TextSelection> for TextRange

fn from(selection: TextSelection) -> TextRange

Converts to this type from the input type.

impl Hash for TextSelection

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 TextSelection

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

Equality operator ==.

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

Inequality operator !=.