How to highlight searched keyword in pdf using mvc

Jagan M

8y2.1k.NET

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

Andre Veber8y ago
What exactly library you are using to parse Pdf?
That library should be able to get access to text coordinates of text you found.
I'm using pdfium.net sdk and its viewer https://pdfium.patagames.com/c-pdf-library/
The viewer is already able to highlight the text found, but if you want to do that yoursefl, you may write something like this.
///

/// Search for a Text in a PDF File in C# With Pdfium.Net SDK Library
///
public void Search()
{
    //Open PDF document
    using (var doc = PdfDocument.Load(@"d:\0\test_big.pdf")) // Read PDF document and enumerate pages
    {
        //Enumerate pages
        foreach(var page in doc.Pages)
        {
            var found = page.Text.Find("text for search", FindFlags.MatchWholeWord, 0);
            if (found == null)
                return; //nothing found
            do
            {
                var textInfo = found.FoundText;
                foreach(var rect in textInfo.Rects)
                {
                    //The rect contains bounding box of the found text
                }
            } while (found.FindNext());

            page.Dispose();
        }
    }
}
Hope it helps you.
Leon D8y ago
Check this link:

https://www.e-iceblue.com/Tutorials/Spire.PDF/Spire.PDF-Program-Guide/Text/Find-and-Highlight-Selected-Text-in-PDF-in-C-VB.NET.html
Mohamed Abedallah8y ago
You may want to use a toolkit that supports parsing PDF text. LEADTOOLS has this feature and you can check the online working demo from this link:
https://demo.leadtools.com/JavaScript/DocumentViewer/index.html

And here is a sample code that shows how you can find and highlight text throw multiple pages:
https://www.leadtools.com/help/leadtools/v20/dh/javascript/doxui/documentviewertext-find.html

The code uses the DocumentViewerFindText Object from LEADTOOLS, and you can find it on the page beginning with these lines:
// We will find all matches of "LEAD", ignoring the case
var options = new lt.Document.Viewer.DocumentViewerFindText();
// The text
options.text = "LEAD";
// Ignore case
options.matchCase = false;
// Any word that contains the phrase
options.wholeWordsOnly = false;
// Find all results in the bounds, not just the first
options.findAll = true;
If you would like to try this, you can get a free evaluation on this page:
https://www.leadtools.com/downloads?category=main