CODEWITHSUNDEEP
iosswiftpdfuiscrollviewcore-graphics
Bastian
Bastian

Reputation: 4738

PDF from UIScrollView is blank

I have a UIScrollView which I want to export to a PDF file. The scroll view contains another view (content view) which actually contains the visible content:

scrollView : UIScrollView
-> contentView : UIView
   -> view1 : UIView
      ...
   -> view2 : UIView
      ...
   ...

The code for the PDF export is:

func generatePDFData() -> NSData {
    // I first tried to use the scroll view but the result was the same
    let bounds = contentView.bounds

    let pdfData = NSMutableData()
    UIGraphicsBeginPDFContextToData(pdfData, bounds, nil)

    let pdfContext = UIGraphicsGetCurrentContext()
    CGContextSetInterpolationQuality(pdfContext, kCGInterpolationMedium)
    CGContextSetRenderingIntent(pdfContext, kCGRenderingIntentDefault)
    CGPDFContextBeginPage(pdfContext, nil)

    // without the following two settings, the result remains the same
    CGContextScaleCTM(pdfContext,1.0,-1.0)
    CGContextTranslateCTM(pdfContext,0.0,-bounds.size.height)

    contentView.layer.renderInContext(pdfContext)

    UIGraphicsEndPDFContext()
    return pdfData
}

I then use the data to generate a PDF file. The resulting file has a size of about 120 KB, so I expect it to contain some stuff (the view does not comprise any images). However, when I try to open it, I just get a blank page.

Upvotes: 1

Views: 567

Answers (2)

Zell B.
Zell B.

Reputation: 10286

It looks like your only problem is beginning new pdf page in a context. Replace CGPDFContextBeginPage(pdfContext, nil) with UIGraphicsBeginPDFPage() and everything should work.

Upvotes: 1

rshev
rshev

Reputation: 4176

Use

contentView.drawViewHierarchyInRect(bounds, afterScreenUpdates: false)

Upvotes: 0

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