overview / pdfocr   0.0.12

dependencies += "org.overviewproject" %% "pdfocr" % "0.0.10"

import java.nio.file.Path
import java.util.Locale
import org.overviewproject.pdfocr.{PdfOcr,PdfOcrProgress,PdfOcrResult}
import org.overviewproject.pdfocr.exceptions._
import scala.concurrent.Future

val pdfOcr = new PdfOcr()                          // default settings: finds tesseract in your $PATH
val inPdf = new Path("/path/to/needs-ocr.pdf")     // exists
val outPdf = new Path("/path/to/ocr-finished.pdf") // doesn't exist; will be deleted if it does
val process = PdfOcr.makePdfSearchable(inPdf, outPdf, Seq(Locale("en")))

process.progress // Future[PdfOcrProgress]
  .map { progress =>
    // It's a Future because we don't know how many pages there are until
    // we begin parsing the PDF, which takes time.

    progress.value       // 0.0 ... 1.0
    progress.currentPage // 1 .. nPages
    progress.nPages      // n
  }

process.result // Future[PdfTextResult]
  .map { result =>
    // do something with outPdf now...

    // Also, since the data is handy and would otherwise take a long time
    // to compute, PdfOcr returns the text, in pages.
    val text = result.pages.map(_.text).mkString("\n")
  }
  .recover {
    // outPdf is guaranteed not to exist

    case TesseractMissingException => throw
    case TesseractLanguageMissingException => throw
    case EncryptedPdfException => throw
    case InvalidPdfException => throw
    // Other errors may happen -- PDFBox bugs, Tesseract bugs,
    // out-of-memory.... You shouldn't catch those.
  }

// Or if you got impatient, you could:
process.cancel // Future[Unit]