I use WKWebView to show svg. It's rather big and i need support of scaling it on pinch gesture. WKWebView do it out of the box. But. It has it's own constraints for min and max zoom scale. For example:
subscribe to WKWebView's scrollView delegate and implement method
optional func scrollViewDidEndZooming(_ scrollView: UIScrollView,
with view: UIView?,
atScale scale: CGFloat)
{
print(self.wkWebView.scrollView.minimumZoomScale, self.wkWebView.scrollView.maximumZoomScale)
self.wkWebView.scrollView.minimumZoomScale = 0.01
self.wkWebView.scrollView.maximumZoomScale = 20.0
}
And in next call it will print: 0.25, 5.0. My values of (0.01, 20.0) are absolutely ignored. Is it a way to correct it?
With deprecated UIWebView there was no such problem. (But there was very unpredictable scaling.)
I know this question is old now but I'm tackling what seems to be a similar problem and thought my solution might help others. I've wrapped the SVG in the following HTML:
<html>
<head>
<meta id="mw-viewport" name="viewport" content="width=device-width, minimum-scale=1, maximum-scale=1, initial-scale=1.0"/>
</head>
<body>
<svg/>
</body>
</html>
Once I've calculated my desired min/max zoom levels I execute some javascript to grab the "mw-viewport" meta tag and edit it's "content" attribute's "minimum-scale=1, maximum-scale=1" values.
来源：https://stackoverflow.com/questions/46289653/how-change-min-and-max-zoom-scale-in-wkwebview