Transparent background WKWebView (NSView)

Question

I am building a Mac application using Swift. Therefor, I want to make a WKWebView transparent, so it shows the text of the loaded HTML, but the background of my underlaying NSWi

Answer 1

I used this for macOS 10.12. without problems in OjbC:

[self.webView setValue:@YES forKey:@"drawsTransparentBackground"];

Under macOS 10.13.+ I got the following console warning message:

-[WKWebView _setDrawsTransparentBackground:] is deprecated and should not be used

The ONLY working solution was:

[self.webView setValue:@(NO) forKey:@"drawsBackground"];

I tried the below in many scenarios and it didn't work:

• give the webView and the enclosingScrollView a layer and edit it's properties (backgroundColor, isOpaque)
• give the webView and the enclosingScrollView a clear background color
• inject javascript without the setValue forKey: in the webview.

Additionally I did use:

- (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation
{
    if (self.isWebviewsBackgroundTransparent) {
        [self insertTransparentBackgroundTo:webView];
    }
}

- (void)insertTransparentBackgroundTo:(WKWebView *)webView
{
    NSString *transparentBackgroundJSSString = @"document.body.style = document.body.style.cssText + \";background: transparent !important;\";";
    [webView evaluateJavaScript:transparentBackgroundJSSString completionHandler:nil];
}