How can I programmatically generate a thumbnail of a PDF with iOS?

Question

We\'re displaying PDF content using UIWebViews at the moment. Ideally I would like to be able to display thumbnails in the UITableView without loa

Answer 1

Here is a swift 3 method for generating a UIImage thumbnail for a pdf page

static func getThumbnailForPDF(_ urlString:String, pageNumber:Int) -> UIImage? {
    let bundle = Bundle.main
    let path = bundle.path(forResource: urlString, ofType: "pdf")
    let pdfURL = URL(fileURLWithPath: path!)

    let pdf = CGPDFDocument(pdfURL as CFURL )!
    let page = pdf.page(at: pageNumber)!
    let rect = CGRect(x: 0, y: 0, width: 100.0, height: 70.0) //Image size here

    UIGraphicsBeginImageContext(rect.size)
    let context = UIGraphicsGetCurrentContext()!

    context.saveGState()
    context.translateBy(x: 0, y: rect.height)
    context.scaleBy(x: 1.0, y: -1.0)
    context.setFillColor(gray: 1.0, alpha: 1.0)
    context.fill(rect)


    let pdfTransform = page.getDrawingTransform(CGPDFBox.mediaBox, rect: rect, rotate: 0, preserveAspectRatio: true)
    context.concatenate(pdfTransform)
    context.drawPDFPage(page)

    let thumbImage = UIGraphicsGetImageFromCurrentImageContext()
    context.restoreGState()

    UIGraphicsEndImageContext()

    return thumbImage
}