/// <summary>
/// Highlights the PDF with Yellow annotation
/// </summary>
/// <param name="inputFile">File to read from</param>
/// <param name="highLightFile">File to write to</param>
/// <param name="pageno">Which page no to read</param>
/// <param name="textToAnnotate">Texts to annotate</param>
private void HighlightPDFAnnotation(string inputFile, string highLightFile, int pageno, params string[] textToAnnotate)
{
PdfReader reader = new PdfReader(inputFile);
using (FileStream fs = new FileStream(highLightFile, FileMode.Create, FileAccess.Write, FileShare.None))
{
using (PdfStamper stamper = new PdfStamper(reader, fs))
{
MyLocationTextExtractionStrategy strategy = new MyLocationTextExtractionStrategy();
strategy.UndercontentHorizontalScaling = 100;
string currentText = PdfTextExtractor.GetTextFromPage(reader, pageno, strategy);
for (int i = 0; i < textToAnnotate.Length; i++)
{
if (string.IsNullOrWhiteSpace(textToAnnotate[i]))
{
continue;
}
var lstMatches = strategy.GetTextLocations(textToAnnotate[i].Trim(), StringComparison.CurrentCultureIgnoreCase);
if (!this.chkAnnotation.Checked)
{
lstMatches = lstMatches.Take(1).ToList();
}
foreach (iTextSharp.text.Rectangle rectangle in lstMatches)
{
float[] quadPoints = { rectangle.Left - 3.0f,
rectangle.Bottom,
rectangle.Right,
rectangle.Bottom,
rectangle.Left - 3.0f,
rectangle.Top + 1.0f,
rectangle.Right,
rectangle.Top + 1.0f };
PdfAnnotation highlight = PdfAnnotation.CreateMarkup(stamper.Writer
, rectangle, null
, PdfAnnotation.MARKUP_HIGHLIGHT, quadPoints);
highlight.Color = BaseColor.YELLOW;
PdfGState state = new PdfGState();
state.BlendMode = new PdfName("Multiply");
PdfAppearance appearance = PdfAppearance.CreateAppearance(stamper.Writer, rectangle.Width, rectangle.Height);
appearance.SetGState(state);
appearance.Rectangle(0, 0, rectangle.Width, rectangle.Height);
appearance.SetColorFill(BaseColor.YELLOW);
appearance.Fill();
highlight.SetAppearance(PdfAnnotation.APPEARANCE_NORMAL, appearance);
//Add the annotation
stamper.AddAnnotation(highlight, pageno);
}
}
}
}
reader.Close();
}
