highlight a word in pdf

Q: I wanted to highlight a word (like markup/highlight) in the pdf.

I could able to extract the word and the rectangle coordinated of the
word from the pdf Now

Please guide me how to mark up a word by drawing a rectangle around
the word
And fill the rectangle with blue/yellow background color.
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A: There are many ways to implement text highlighting with PDFNet SDK.
Which way you go would depend on your requirements.

The following sample is creating text highlight annotations based on
the search results from TextExtractor.
     http://pdfnet-sdk.googlegroups.com/web/HighlightPDFText.cs.txt

Please note that you could further simplify the code by using built-in
text highlight annotation class (pdftron.PDF.Annots.Highlight) instead
of building highlight annotation from scratch. For example (in C#):

  Highlight h = new Highlight (doc, word_bbox);
  h.RefreshAppearance();
  page.AnnotPushBack(h);