Remove text layer from PDF using Apache PDFBox in a Groovy script

pdftrim

#!/usr/bin/env groovy
@Grab('org.apache.pdfbox:pdfbox:1.8.8')
import org.apache.pdfbox.cos.COSArray
import org.apache.pdfbox.cos.COSString
import org.apache.pdfbox.pdfparser.PDFStreamParser
import org.apache.pdfbox.pdfwriter.ContentStreamWriter
import org.apache.pdfbox.pdmodel.PDDocument
import org.apache.pdfbox.pdmodel.PDPage
import org.apache.pdfbox.pdmodel.common.PDStream
import org.apache.pdfbox.util.PDFOperator
 
def doc = PDDocument.load(args[0])
 
doc.documentCatalog.allPages.each { PDPage page ->
    def parser = new PDFStreamParser(page.contents)
    parser.parse()
    def j = 0
    def flags = []
    parser.tokens.each { token ->
        if (token instanceof PDFOperator) {
            PDFOperator op = (PDFOperator) token;
            if (op.operation == 'Tj') {
                COSString str = (COSString) parser.tokens.get(j - 1)
                if (str.string.contains('www.it-ebooks.info')) {
                    flags << j - 1
                    flags << j
                }
            }
        }
        j++
    }
 
    List tokens = []
 
    for (int i = 0; i < parser.tokens.size(); i++) {
        if (!flags.contains(i)) {
            tokens << parser.tokens[i]
        }
    }
 
    def newContents = new PDStream(doc)
    def writer = new ContentStreamWriter(newContents.createOutputStream())
    writer.writeTokens(tokens)
    newContents.addCompression()
    page.setContents(newContents)
}
 
doc.save(args[1])
 
if (doc) {
    doc.close()
}