It seems like Radaee adds extra carriage return and new line feeds to the pdf text on iOS to render the page. When selecting the same text from PDFKit on macOS the pdf text does not contain the same carriage return and new line feeds as the text selected on iOS. Because of this the character index is not the same on Radaee for iOS and PDFKit for macOS.
Is there a way to remove the extra carriage return and new line feeds added by Radaee so that the character index is the same between Radaee for iOS and PDFKit for macOS?
PDF content is not grouped in lines, paragraphs or columns, but is a sequence of characters with defined positions.
Space characters or carriage return are interpreted by extraction algorithms but there is not a specific way to do it, as it is not a PDF spec.
You can also try using different reader like MacOS PDFKit, Acrobat Pro e Windows 10 PDF Reader, and you will get different results.
Anyway we are evaluating with developers how to handle this case