Disable magnification gesture in WKWebView

Question

I'm looking for a way to disable the "pinch to zoom" magnification gesture on the iOS implementation of WKWebView. There is a magnification BOOL property available for OS X but it doesn't seem to be available on iOS.

WKWebView.h

#if !TARGET_OS_IPHONE
/* @abstract A Boolean value indicating whether magnify gestures will
 change the web view's magnification.
 @discussion It is possible to set the magnification property even if
 allowsMagnification is set to NO.
 The default value is NO.
 */
@property (nonatomic) BOOL allowsMagnification;

I've, also, tried look at the WKWebView's gesture recognizers but that seems to be turning up an empty array. I'm assuming the actual recognizers are bured deeper in the component's structure (fairly complex, by the looks of it) and would rather not go digging for them if at all possible.

I know of possible hacks that could potentially disable the gesture from firing (selectively passing gestures to the WebView, add child view to capture pinch gesture, etc) but I've always found those introduce lag into the event and want to keep the implementation as clean/hack free as possible.

Answer 1

You can prevent your users from zooming by setting the delegate of your WKWebKit's UIScrollView and implementing viewForZooming(in:) as in the following:

class MyClass {
    let webView = WKWebView()

    init() {
        super.init()
        webView.scrollView.delegate = self
    }

    deinit() {
        // Without this, it'll crash when your MyClass instance is deinit'd
        webView.scrollView.delegate = nil
    }
}

extension MyClass: UIScrollViewDelegate {
    func viewForZooming(in scrollView: UIScrollView) -> UIView? {
        return nil
    }
}