SelectionUnitToUTF16
Forms, interaction, unicode
Description
Converts a count of selection units into the zero-based UTF-16 index of the matching boundary within the active edit value
With fsuUTF16CodeUnit the count is returned unchanged after clamping to the value length
With fsuUnicodeCodePoint or fsuGraphemeCluster the boundary table for that unit is built on demand and looked up, so the returned index never splits a surrogate pair or a grapheme cluster and an excessive count clamps to the final boundary
A count of zero or less always converts to index zero
Declaration
function SelectionUnitToUTF16(Index: Integer;
IndexUnit: TPDFlibFormSelectionUnit): Integer;Parameters
| Index | Number of complete selection units to skip from the start of the value, clamped to the last available boundary |
|---|---|
| IndexUnit | Selection unit the count is expressed in |
Return value
Returns the UTF-16 index of the requested boundary, the value length when the count exceeds the available boundaries, or zero for counts of zero or less
Example
// Unit 2 starts after the surrogate pair, at UTF-16 index 3
Session.SetEditValue('A' + WideChar($D83D) + WideChar($DE00) + 'B');
CaretUTF16 := Session.SelectionUnitToUTF16(2, fsuUnicodeCodePoint);
// CaretUTF16 = 3See also
SelectionUTF16ToUnit, SetSelectionRange, GetVisualCaretOrder, TPDFlibFormSelectionUnit, TPDFlibFormSession