How to render a PDF to an image
iOS has built-in APIs for drawing PDFs, which means it's relatively straight forward to render a PDF to an image. I say "relatively" because there's still some boilerplate you need to worry about: figuring out the document size, filling the background in a solid color to avoid transparency, and flipping the rendering so that the PDF draws the right way up.
To make things easy for you, here's a pre-made method you can use that takes a URL to a PDF and returns either a rendered image or nil if it failed. To call it you should pull out the URL to a resource in your bundle or another local PDF file.
func drawPDFfromURL(url: URL) -> UIImage? {
guard let document = CGPDFDocument(url as CFURL) else { return nil }
guard let page = document.page(at: 1) else { return nil }
let pageRect = page.getBoxRect(.mediaBox)
let renderer = UIGraphicsImageRenderer(size: pageRect.size)
let img = renderer.image { ctx in
UIColor.white.set()
ctx.fill(pageRect)
ctx.cgContext.translateBy(x: 0.0, y: pageRect.size.height)
ctx.cgContext.scaleBy(x: 1.0, y: -1.0)
ctx.cgContext.drawPDFPage(page)
}
return img
}Available from iOS 3.0
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