CODEWITHSUNDEEP
iosswiftpdfpdfkit
Sweet Potato
Sweet Potato

Reputation: 63

Wrong highlight annotation on apple PDFKit

I'm using PDFKit on iOS to highlight texts (PDF file). I do it by create a PDFAnnotation and add it to the selected text area. I want to highlight precisely the selected area but it always covers the whole line like the pics below. How can I create the annotation for the selected area only??

My code:

        let highlight = PDFAnnotation(bounds: selectionText.bounds(for: page), forType: PDFAnnotationSubtype.highlight, withProperties: nil)
        highlight.color = highlightColor
        page.addAnnotation(highlight)

Selected text

Highlighted text

Upvotes: 4

Views: 2950

Answers (2)

alessionossa
alessionossa

Reputation: 991

As suggested in PDFKit Highlight Annotation: quadrilateralPoints you can use quadrilateralPoints to add different lines highlights to the same annotation.

func highlight() {  
    guard let selection = pdfView.currentSelection, let currentPage = pdfView.currentPage else {return}
    let selectionBounds = selection.bounds(for: currentPage)
    let lineSelections = selection.selectionsByLine()

    let highlightAnnotation = PDFAnnotation(bounds: selectionBounds, forType: PDFAnnotationSubtype.highlight, withProperties: nil)

    highlightAnnotation.quadrilateralPoints = [NSValue]()
    for (index, lineSelection) in lineSelections.enumerated() {
        let n = index * 4
        let bounds = lineSelection.bounds(for: pdfView.currentPage!)
        let convertedBounds = bounds.convert(to: selectionBounds.origin)
        highlightAnnotation.quadrilateralPoints?.insert(NSValue(cgPoint: convertedBounds.topLeft), at: 0 + n)
        highlightAnnotation.quadrilateralPoints?.insert(NSValue(cgPoint: convertedBounds.topRight), at: 1 + n)
        highlightAnnotation.quadrilateralPoints?.insert(NSValue(cgPoint: convertedBounds.bottomLeft), at: 2 + n)
        highlightAnnotation.quadrilateralPoints?.insert(NSValue(cgPoint: convertedBounds.bottomRight), at: 3 + n)
    }

    pdfView.currentPage?.addAnnotation(highlightAnnotation)
}

extension CGRect {

    var topLeft: CGPoint {
        get {
            return CGPoint(x: self.origin.x, y: self.origin.y + self.height)
        }
    }

    var topRight: CGPoint {
        get {
            return CGPoint(x: self.origin.x + self.width, y: self.origin.y + self.height)
        }
    }

    var bottomLeft: CGPoint {
        get {
            return CGPoint(x: self.origin.x, y: self.origin.y)
        }
    }

    func convert(to origin: CGPoint) -> CGRect {
        return CGRect(x: self.origin.x - origin.x, y: self.origin.y - origin.y, width: self.width, height: self.height)
    }
}

Upvotes: 6

Rafał Rębacz
Rafał Rębacz

Reputation: 495

PDFSelection bounds(forPage:) method returns one rectangle to satisfy whole selection area. Is not the best solution in your case.

Try with selectionsByLine(), and add individual annotation for every rect, representing every single selected line in PDF. Example:

    let selections = pdfView.currentSelection?.selectionsByLine()
    // Simple scenario, assuming your pdf is single-page.
    guard let page = selections?.first?.pages.first else { return }

    selections?.forEach({ selection in
        let highlight = PDFAnnotation(bounds: selection.bounds(for: page), forType: .highlight, withProperties: nil)
        highlight.endLineStyle = .square
        highlight.color = UIColor.orange.withAlphaComponent(0.5)

        page.addAnnotation(highlight)
    })

Upvotes: 4

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