internal bool IsAtCaretCharacterHit(CharacterHit characterHit, int cpFirst)
{
// TrailingLength is used as a flag to indicate whether the character
// hit is on the leading or trailing edge of the character.
if (characterHit.TrailingLength == 0)
{
CharacterHit nextHit = GetNextCaretCharacterHit(characterHit);
if (nextHit == characterHit)
{
// At this point we only know that no caret stop is available
// after the input, we caliberate the input to the end of the line.
nextHit = new CharacterHit(cpFirst + Length - 1, 1);
}
CharacterHit previousHit = GetPreviousCaretCharacterHit(nextHit);
return(previousHit == characterHit);
}
else
{
CharacterHit previousHit = GetPreviousCaretCharacterHit(characterHit);
CharacterHit nextHit = GetNextCaretCharacterHit(previousHit);
return(nextHit == characterHit);
}
}
/// <summary>
/// Client to get the distance from the beginning of the line from the specified
/// character hit.
/// </summary>
/// <param name="characterHit">character hit of the character to query the distance.</param>
/// <returns>distance in text flow direction from the beginning of the line.</returns>
public abstract double GetDistanceFromCharacterHit(
CharacterHit characterHit
);
/// <summary>
/// Client to get the previous character hit for caret navigation
/// </summary>
/// <param name="characterHit">the current character hit</param>
/// <returns>the previous character hit</returns>
public abstract CharacterHit GetPreviousCaretCharacterHit(
CharacterHit characterHit
);
/// <summary>
/// Client to get the previous character hit after backspacing
/// </summary>
/// <param name="characterHit">the current character hit</param>
/// <returns>the character hit after backspacing</returns>
public abstract CharacterHit GetBackspaceCaretCharacterHit(
CharacterHit characterHit
);
/// <summary>
/// Client to get the next character hit for caret navigation
/// </summary>
/// <param name="characterHit">the current character hit</param>
/// <returns>the next character hit</returns>
public abstract CharacterHit GetNextCaretCharacterHit(
CharacterHit characterHit
);