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Swift problem when adding annotations with regex to pdf page

I want to search for a regex in a pdf, and add annotations to it according, using the results from the regex. I have built a simple function that does this. As the amazing community (really amazing people who used their time helping me) posted I can I can use the decomposedStringWithCompatibilityMapping to search for the desired expression correctly in the pdf, but afterwards when I perform a pdf selection to find the bounds of it, I encounter a difference. I send you my code and some pictures.

func performRegex(regex:String, on pdfPage:PDFPage)  {
    guard let pdfString = pdfPage.string?.precomposedStringWithCanonicalMapping else { return }
    guard let safeRegex = try? NSRegularExpression(pattern: regex, options: .caseInsensitive) else { return }
    let results = safeRegex.matches(in: pdfString, options: .withoutAnchoringBounds, range: NSRange(pdfString.startIndex..., in: pdfString))
    pdfPage.annotations.forEach { pdfPage.removeAnnotation($0)}
    results.forEach { result in
        let bbox = pdfPage.selection(for: result.range)?.bounds(for: pdfPage)
        let annotation = PDFAnnotation(bounds: bbox!, forType: .highlight, withProperties: nil)
        annotation.color = .yellow
        annotation.contents = String(pdfString[Range(result.range, in:pdfString)!])
        pdfPage.addAnnotation(annotation)
    }
}

The problem is that when I do this and enter this expression [0-9] all my results are shifted: shifted results

While if I don't use precomposedStringWithCanonicalMapping, all my results are not shifted but I will encounter an error when I get a special character. not shifted results

The problem (I suspect) is in this line of code.

let bbox = pdfPage.selection(for: result.range)?.bounds(for: pdfPage)

But I don't know any work arround for it.

Please if anyone can give me some help!

Thanks a lot

Solution

  • The only alternative I can think right now is to use the original string and fix the malformed ranges. Try like this:

    var str = """
circular para poder realizar sus tareas laborales correspondientes a las actividades de comercialización de alimentos
"""
do {
    let regex = try NSRegularExpression(pattern: ".", options: .caseInsensitive)
    let results = regex.matches(in: str, options: .withoutAnchoringBounds, range: NSRange(location: 0, length: str.utf16.count))
    var badrange: NSRange?
    results.forEach { result in
        guard let range = Range(result.range, in: str) else {
            if badrange != nil {
                badrange!.length += 1
                if let range = Range(badrange!, in: str) {
                    let newStr = str[range]
                    print(newStr)
                }
            } else {
                badrange = result.range
            }
            return
        }
        let newStr = str[range]
        print(newStr)
        badrange = nil
    }
} catch {
    print(error)
}