WKWebView shows pdf inside a border, I don't want the border

Question

I have a custom view that adds a WKWebView like this:

 override func awakeFromNib() {
    super.awakeFromNib()
    loadWebView()
}

func loadWebView() {
    pdfWebView = WKWebView(frame: .zero)

    pdfWebView.navigationDelegate = self
    pdfWebView.translatesAutoresizingMaskIntoConstraints = false
    pdfWebView.isHidden = true
    self.addSubview(pdfWebView)
    ... add constrains to self anchors - top, left, right, bottom
}

When loads finishes, I have this:

  func webView(_ webView: WKWebView, didFinish navigation: WKNavigation!) {
    DispatchQueue.main.asyncAfter(deadline: .now() + 0.8, execute: {
        SVProgressHUD.dismiss()
        webView.isHidden = false
        webView.isOpaque = true
        webView.adjustInsets()
    })
}

I had to adjust the insets, because on iPhone X, sometimes the pdf sticked to the bottom, instead to the top.

extension WKWebView {
    func adjustInsets() {
        parentViewController?.automaticallyAdjustsScrollViewInsets = false
        scrollView.contentInset = .zero
        scrollView.scrollIndicatorInsets = .zero
        scrollView.contentOffset = .zero
    }
}

The result is this:

There is a gray border.

I have tried this:

setting view's, pdfWebView and pdfWebView.scrollView background with .white or .clear
webView.isOpaque = false ( this is the single one that removes the bottom part of the gray - but not the border)

I have used an extension to set the .clear color to all child views

extension UIView {
    func clearBackgrounds() {
        self.backgroundColor = UIColor.clear
        for subview in self.subviews {
            subview.clearBackgrounds()
        }
    }
}

Nothing works to remove the border. I can not edit the pdf, because this one is downloaded from ws and used in multiple apps.

user_5935362 · Answer

Solution : I found a trick to do this, I think you can use this with pdf that has white background. It has the idea, you can manipulate this with your design.

self.view.backgroundColor = UIColor.white
let urlString = "http://www.africau.edu/images/default/sample.pdf"
let string = ""
webView.loadHTMLString(string, baseURL: nil)

Edit : If you want to use this with base64 encoded pdf data, you can use with that :

var pdfBase64String = "" //Your pdf data
if let decodedData = Data(base64Encoded: pdfBase64String, options: .ignoreUnknownCharacters) {
        pdfWebView.load(decodedData, mimeType: "application/pdf", characterEncodingName: "utf-8", baseURL: URL(fileURLWithPath: ""))
}

Old Answer : Turning off "WebKitDiskImageCacheEnabled" can be fix this problem. Can you try this before load the pdf ?

UserDefaults.standard.set(false, forKey: "WebKitDiskImageCacheEnabled")
UserDefaults.standard.synchronize()

user_4875178 · Answer

I will use PDFKit for iOS 11 + in this custom view with the fallback to WKWebView for earlier versions. PDFView does not have any gray background.

WKWebView shows pdf inside a border, I don't want the border

2 Answers