Replace text with image in PDF using Telerik RadPdfProcessing

Question

I'm using Telerik RadPdfProcessing for Xamarin to customize a PDF document in a mobile application. The code must search for a "#placeholder#" inside the document and replace it with the signature hand typed by the user.

The signature image can be inserted at a given position with this code:

RadFixedPage last = document.Pages.Last();
FixedContentEditor editor = new FixedContentEditor(last);
editor.Position.Translate(400, 900);
editor.DrawImage(imageSource);

And I've found a forum saying that find in page is basically not supported by the library, since it allows only to search one character at a time:

foreach (var contentElement in last.Content) {
    if (contentElement is TextFragment) {
        TextFragment fragment = (TextFragment) contentElement;
        string text = fragment.Text;

        //** THIS DOESN'T WORK! **
        //if ("#placeholder#" == text)  {
        //    fragment.Text = "";
        //    editor.Position = fragment.Position;
        //    editor.DrawImage(imageSource);
        //}
    }
}

Does anyone have more recent news on this subject?

Answer 1

You can achieve this in the following way:

RadFixedPage lastPage = document.Pages.Last();

IPosition position = new SimplePosition();

foreach (ContentElementBase contentElement in lastPage.Content.ToList())
{
    if (contentElement is TextFragment fragment)
    {
        if (fragment.Text == "#placeholder#")
        {
            position = fragment.Position;
            lastPage.Content.Remove(fragment);
        }
    }
}

ImageSource imageSource;
using (FileStream source = File.Open("image1.jpg", FileMode.Open))
{
    imageSource = new ImageSource(source);
}

FixedContentEditor editor = new FixedContentEditor(lastPage);
editor.Position = position;
editor.DrawImage(imageSource, new Size(50, 50));

Another option could be to replace a predefined Field by searching for its name. This way you can pre-allocate space on the document's page.

RadFixedPage firstPage = document.Pages[0];

Annotation field = firstPage.Annotations.First(a => ((VariableContentWidget)a).Field.Name == "SampleField");
System.Windows.Rect fieldRect = field.Rect;

string imagePath = "image1.jpg";
ImageSource imageSource;
using (FileStream source = File.Open(imagePath, FileMode.Open))
{
    imageSource = new ImageSource(source);
}

IPosition position = new SimplePosition();
simplePosition.Translate(fieldRect.X, fieldRect.Y);

Image image = new Image
{
    ImageSource = imageSource,
    Position = position,
    Width = fieldRect.Width,
    Height = fieldRect.Height
};

firstPage.Annotations.Remove(field);
firstPage.Content.Add(image);