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//---------------------------------------------------------------------------
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
//
// Description: The CharacterHit structure represents information about a character hit
// within a glyph run - the index of the first character that got hit and the information
// about leading or trailing edge.
//
// See spec at http://team/sites/Avalon/Specs/Glyph%20Run%20hit%20testing%20and%20caret%20placement%20API.htm#CharacterHit
//
//
// History:
// 11/30/2004 : mleonov - Created
//
//---------------------------------------------------------------------------
#region Using directives
using System;
#endregion
namespace System.Windows.Media.TextFormatting
{
/// <summary>
/// The CharacterHit structure represents information about a character hit within a glyph run
/// - the index of the first character that got hit and the information about leading or trailing edge.
/// </summary>
public struct CharacterHit : IEquatable<CharacterHit>
{
/// <summary>
/// Constructs a new CharacterHit structure.
/// </summary>
/// <param name="firstCharacterIndex">Index of the first character that got hit.</param>
/// <param name="trailingLength">In case of leading edge this value is 0.
/// In case of trailing edge this value is the number of codepoints until the next valid caret position.</param>
public CharacterHit(int firstCharacterIndex, int trailingLength)
{
_firstCharacterIndex = firstCharacterIndex;
_trailingLength = trailingLength;
}
/// <summary>
/// Index of the first character that got hit.
/// </summary>
public int FirstCharacterIndex
{
get
{
return _firstCharacterIndex;
}
}
/// <summary>
/// In case of leading edge this value is 0.
/// In case of trailing edge this value is the number of codepoints until the next valid caret position.
/// </summary>
public int TrailingLength
{
get
{
return _trailingLength;
}
}
/// <summary>
/// Checks whether two character hit objects are equal.
/// </summary>
/// <param name="left">First object to compare.</param>
/// <param name="right">Second object to compare.</param>
/// <returns>Returns true when the values of FirstCharacterIndex and TrailingLength are equal for both objects,
/// and false otherwise.</returns>
public static bool operator==(CharacterHit left, CharacterHit right)
{
return left._firstCharacterIndex == right._firstCharacterIndex &&
left._trailingLength == right._trailingLength;
}
/// <summary>
/// Checks whether two character hit objects are not equal.
/// </summary>
/// <param name="left">First object to compare.</param>
/// <param name="right">Second object to compare.</param>
/// <returns>Returns false when the values of FirstCharacterIndex and TrailingLength are equal for both objects,
/// and true otherwise.</returns>
public static bool operator!=(CharacterHit left, CharacterHit right)
{
return !(left == right);
}
/// <summary>
/// Checks whether an object is equal to another character hit object.
/// </summary>
/// <param name="obj">CharacterHit object to compare with.</param>
/// <returns>Returns true when the object is equal to the input object,
/// and false otherwise.</returns>
public bool Equals(CharacterHit obj)
{
return this == obj;
}
/// <summary>
/// Checks whether an object is equal to another character hit object.
/// </summary>
/// <param name="obj">CharacterHit object to compare with.</param>
/// <returns>Returns true when the object is equal to the input object,
/// and false otherwise.</returns>
public override bool Equals(object obj)
{
if (!(obj is CharacterHit))
return false;
return this == (CharacterHit)obj;
}
/// <summary>
/// Compute hash code for this object.
/// </summary>
/// <returns>A 32-bit signed integer hash code.</returns>
public override int GetHashCode()
{
return _firstCharacterIndex.GetHashCode() ^ _trailingLength.GetHashCode();
}
private int _firstCharacterIndex;
private int _trailingLength;
}
}
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