Struct TextSelectionRange

Represents a range of selected text defined by an anchor (start) and an active (end) position. Used by LineScrollWindow to render selection highlights via WriteToWithSelection(StringBuilder, TextSelectionRange, string).

Implements

IEquatable<TextSelectionRange>

Inherited Members

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Namespace: Scylla.Core.Util.UI

Assembly: ScyllaCore.dll

Syntax

public readonly struct TextSelectionRange : IEquatable<TextSelectionRange>

Remarks

Start is the selection anchor - the position where the user began the selection - and does not change as the selection is extended. End is the active position, updated as the user drags or shift-clicks.

Because selections can be made in reverse (dragging upward), Start may be after End in document order. Use Normalized, NormalizedStart, and NormalizedEnd to always get document-order positions regardless of selection direction.

Constructors

TextSelectionRange(TextSelectionPosition, TextSelectionPosition)

Creates a new text selection range.

Declaration

public TextSelectionRange(TextSelectionPosition start, TextSelectionPosition end)

Parameters

Type	Name	Description
TextSelectionPosition	start	The starting position.
TextSelectionPosition	end	The ending position.

Fields

Empty

An empty/invalid selection range. Both Start and End are set to Invalid. Calling IsValid on this value returns false.

Declaration

public static readonly TextSelectionRange Empty

Field Value

Type	Description
TextSelectionRange

End

The active end of the selection: the position where the cursor currently is. This position changes as the user extends the selection by dragging or shift-clicking.

Declaration

public readonly TextSelectionPosition End

Field Value

Type	Description
TextSelectionPosition

Start

The selection anchor: the position where the user clicked or began the selection. This position does not change as the selection is extended by dragging or shift-clicking.

Declaration

public readonly TextSelectionPosition Start

Field Value

Type	Description
TextSelectionPosition

Properties

IsEmpty

Gets whether this selection range is empty. Returns true when the range is invalid OR when Start equals End (a zero-width selection representing a caret position).

Declaration

public bool IsEmpty { get; }

Property Value

Type	Description
bool

IsValid

Gets whether this selection range represents valid positions. Requires both Start and End to have LogicalLineIndex >= 0 and CharacterIndex >= 0.

Declaration

public bool IsValid { get; }

Property Value

Type	Description
bool

Normalized

Gets a normalized version of this range where Start is always at or before End in document order. Useful when iterating through selected text from top to bottom.

Declaration

public TextSelectionRange Normalized { get; }

Property Value

Type	Description
TextSelectionRange

Remarks

For a reversed selection (where the user dragged upward so that the anchor is below the cursor), returns a new TextSelectionRange with Start and End swapped so the earlier position is always Start. The original range is not modified.

NormalizedEnd

Gets the later of Start and End in document order. Uses the same comparison as Normalized but returns only the position, avoiding construction of a new range.

Declaration

public TextSelectionPosition NormalizedEnd { get; }

Property Value

Type	Description
TextSelectionPosition

NormalizedStart

Gets the earlier of Start and End in document order. Uses the same comparison as Normalized but returns only the position, avoiding construction of a new range.

Declaration

public TextSelectionPosition NormalizedStart { get; }

Property Value

Type	Description
TextSelectionPosition

Methods

Contains(TextSelectionPosition)

Checks whether the specified position falls within this selection range. The check is half-open: a position at exactly NormalizedEnd is NOT considered contained. This matches standard text selection convention where the end position is the first character after the selection.

Declaration

public bool Contains(TextSelectionPosition position)

Parameters

Type	Name	Description
TextSelectionPosition	position	The position to test.

Returns

Type	Description
bool	true if position >= NormalizedStart && position < NormalizedEnd. false if the range is invalid, empty, or position is invalid.

ContainsLine(int)

Checks whether the specified logical line index falls within the selection range. A line is considered in the selection even if only part of it is selected (i.e., the selection starts or ends mid-line).

Declaration

public bool ContainsLine(int logicalLineIndex)

Parameters

Type	Name	Description
int	logicalLineIndex	The logical line index to test. The check is inclusive: normStart.LogicalLineIndex <= logicalLineIndex <= normEnd.LogicalLineIndex.

Returns

Type	Description
bool	true if the line index falls within the selection's line range.

Equals(TextSelectionRange)

Determines whether this range equals another using raw (un-normalized) position comparison. Two selections that cover the same text extent but were made in opposite directions (different anchor/active order) are NOT considered equal.

Declaration

public bool Equals(TextSelectionRange other)

Parameters

Type	Name	Description
TextSelectionRange	other	The other range.

Returns

Type	Description
bool	true if both Start and End are equal.

Equals(object)

Declaration

public override bool Equals(object obj)

Parameters

Type	Name	Description
object	obj

Returns

Type	Description
bool

Overrides

ValueType.Equals(object)

GetHashCode()

Declaration

public override int GetHashCode()

Returns

Type	Description
int

Overrides

ValueType.GetHashCode()

GetLineSelectionRange(int, int, out int, out int)

Gets the selected character range for a specific logical line.

Declaration

public bool GetLineSelectionRange(int logicalLineIndex, int lineLength, out int startChar, out int endChar)

Parameters

Type	Name	Description
int	logicalLineIndex	The logical line index to query.
int	lineLength	The total number of characters in the line.
int	startChar	The first selected character index on this line (inclusive). For the first line of the selection, this is NormalizedStart.CharacterIndex. For lines in the middle of a multi-line selection, this is 0 (entire line selected).
int	endChar	One past the last selected character index on this line (exclusive). For the last line of the selection, this is NormalizedEnd.CharacterIndex. For lines in the middle of a multi-line selection, this is lineLength (entire line selected).

Returns

Type	Description
bool	true if at least one character on the line is selected (endChar > startChar). false if the line is not in the selection range or the selection is empty/invalid.

ToString()

Declaration

public override string ToString()

Returns

Type	Description
string

Overrides

ValueType.ToString()

Operators

operator ==(TextSelectionRange, TextSelectionRange)

Returns true if both selection ranges have identical Start and End positions.

Declaration

public static bool operator ==(TextSelectionRange left, TextSelectionRange right)

Parameters

Type	Name	Description
TextSelectionRange	left	The left operand.
TextSelectionRange	right	The right operand.

Returns

Type	Description
bool	true if the ranges are equal.

operator !=(TextSelectionRange, TextSelectionRange)

Returns true if the two selection ranges differ in Start or End.

Declaration

public static bool operator !=(TextSelectionRange left, TextSelectionRange right)

Parameters

Type	Name	Description
TextSelectionRange	left	The left operand.
TextSelectionRange	right	The right operand.

Returns

Type	Description
bool	true if the ranges are not equal.

Implements

IEquatable<T>