function PageWordBoxes: TPdfWordBoxes;
TPdfWordBoxesWord boxes split page text on whitespace, tabs, line breaks, and NBSP characters
The component methods also union FPDFText_GetCharBox rectangles into one page-space TPdfRectangle for each word
var Words: TPdfWordBoxes;
Rects: TPdfRectangles;
begin
Words := PdfView1.PageWordBoxes;
if Length(Words) > 0 then
begin
SetLength(Rects, 1);
Rects[0] := Words[0].Rect;
PdfView1.SetReadingHighlight(Rects, Words[0].Page);
end;
end;