<html>
<head>
<base href="https://bugs.webkit.org/" />
</head>
<body>
<p>
<div>
<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - No reliable way to get a snapshot of WKWebView (macOS)"
href="https://bugs.webkit.org/show_bug.cgi?id=161450#c3">Comment # 3</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - No reliable way to get a snapshot of WKWebView (macOS)"
href="https://bugs.webkit.org/show_bug.cgi?id=161450">bug 161450</a>
from <span class="vcard"><a class="email" href="mailto:thorton@apple.com" title="Tim Horton <thorton@apple.com>"> <span class="fn">Tim Horton</span></a>
</span></b>
<pre>Comment on <span class=""><a href="attachment.cgi?id=288553&action=diff" name="attach_288553" title="Patch">attachment 288553</a> <a href="attachment.cgi?id=288553&action=edit" title="Patch">[details]</a></span>
Patch
View in context: <a href="https://bugs.webkit.org/attachment.cgi?id=288553&action=review">https://bugs.webkit.org/attachment.cgi?id=288553&action=review</a>
Thanks for the patch! Since it adds new public API, the process for getting it landed is a little... different than usual. I'll CC the appropriate people.
<span class="quote">> Source/WebKit2/ChangeLog:1
> +2016-09-11 DAN SAUNDERS <<a href="mailto:dasau@microsoft.com">dasau@microsoft.com</a>></span >
You probably want to repair the capitalization of your name.
<span class="quote">> Source/WebKit2/UIProcess/API/Cocoa/WKWebView.h:228
> +- (void)snapshotViewportWithScaleFactor:(CGFloat)scaleFactor completionHandler:(void(^)(CGImageRef _Nullable snapshotImage, NSError * _Nullable error))completionHandler WK_API_AVAILABLE(macosx(WK_MAC_TBA), ios(WK_IOS_TBA));</span >
I think I prefer something more like the API that we have for iOS WebKit:
- (void)_snapshotRect:(CGRect)rectInViewCoordinates intoImageOfWidth:(CGFloat)imageWidth completionHandler:(void(^)(CGImageRef))completionHandler;
A rect and a width instead of a scale. This has worked out well for its clients, too.
<span class="quote">> Source/WebKit2/UIProcess/API/Cocoa/WKWebView.mm:885
> + _page->takeSnapshot(snapshotRect, bitmapSize, WebKit::SnapshotOptionsInViewCoordinates, [handler](const WebKit::ShareableBitmap::Handle& imageHandle, WebKit::CallbackBase::Error errorCode) {</span >
This is a software painted snapshot, meaning that 3D transforms will be flattened and ugly, and video/WebGL may-or-may-not work. So, it's not great.
We have code (WebViewImpl::takeViewSnapshot) that shows how to do a window-server snapshot, which captures all of those things, but it has a downside: if the web view is obscured, the thing it's obscured will will end up in the snapshot as well.
_snapshotRect:intoImageOfWidth:completionHandler: gets around this, but uses functions that are only available/possible on iOS. We should definitely make use of that to implement this method on iOS, though, since it is much, much better than a software snapshot.
<span class="quote">> Tools/TestWebKitAPI/Tests/WebKit2Cocoa/WKWebViewSnapshot.mm:44
> + [webView snapshotViewportWithScaleFactor:1.0 completionHandler:^(CGImageRef snapshotImage, NSError * error) {</span >
No space between the * and 'error'
<span class="quote">> Tools/TestWebKitAPI/Tests/WebKit2Cocoa/WKWebViewSnapshot.mm:65
> + [webView snapshotViewportWithScaleFactor:1.0 completionHandler:^(CGImageRef snapshotImage, NSError * error) {</span >
Ditto.</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are the assignee for the bug.</li>
</ul>
</body>
</html>