135106 2014-07-20 16:45:50 -0700 Inline box culling breaks node snapshotting 2025-04-02 16:02:31 -0700 1 1 1 Unclassified WebKit Layout and Rendering 528+ (Nightly build) Unspecified Unspecified RESOLVED CONFIGURATION CHANGED InRadar P2 Normal --- 1 mitz webkit-unassigned hyatt karlcow pangle simon.fraser webkit-bug-importer zalan oldest_to_newest 1023568 0 235193 mitz 2014-07-20 16:45:50 -0700 Created attachment 235193 Test case In the test case, when you drag the first span, the drag snapshot is correct. When you drag the second span, the snapshot is empty. The reason is that the snapshots are made by setting PaintInfo’s subtreePaintRoot to span’s RenderInline, but since the second span doesn’t have inline boxes, we never hit the (subtreePaintRoot == renderer) case in PaintInfo::updateSubtreePaintRootForChildren() when it’s called from InlineFlowBox::paint, so the subtree root is never cleared and nothing paints. 1023575 1 mitz 2014-07-20 17:28:09 -0700 My idea for fixing this is to add another RenderObject* member to PaintInfo, which will contain the nearest ancestor of the subtreePaintRoot that isn’t a RenderInline with culled boxes, and whenever we are in that object’s subtree, do a more expensive shouldPaintWithinRoot() check. 1088003 2 mitz 2015-04-23 14:30:12 -0700 To see the bug you may need to undo the workaround from <http://trac.webkit.org/r171284>. 1770448 3 webkit-bug-importer 2021-06-16 15:49:08 -0700 <rdar://problem/79420098> 2108328 4 karlcow 2025-04-02 15:46:05 -0700 I can drag on STP 125 both boxes. but I can not drag them on Firefox and Chrome. Instead a selection is done. What is the expectation? Should they be draggable at all? The testcase code relies on <span style="-webkit-user-drag: element; vertical-align: bottom;">Drag me, I have an inline box!</span> Ha this is a non documented safari only feature. https://developer.mozilla.org/en-US/docs/Web/CSS/WebKit_Extensions but fwiw with regards to this bug, the snapshot is happening on both cases. So this is "fixed". 2108342 5 mitz 2025-04-02 16:02:31 -0700 > I can drag on STP 125 both boxes. As noted in comment 3, this could be due to some form of the workaround from <http://trac.webkit.org/r171284> still being in place. However, that was undone in https://commits.webkit.org/241510@main, presumably along with fixing this bug. 235193 2014-07-20 16:45:50 -0700 2014-07-20 16:45:50 -0700 Test case scratch.html text/html 188 mitz PHA+CiAgICA8c3BhbiBzdHlsZT0iLXdlYmtpdC11c2VyLWRyYWc6IGVsZW1lbnQ7IHZlcnRpY2Fs LWFsaWduOiBib3R0b207Ij5EcmFnIG1lLCBJIGhhdmUgYW4gaW5saW5lIGJveCE8L3NwYW4+Cjwv cD4KPHA+CiAgICA8c3BhbiBzdHlsZT0iLXdlYmtpdC11c2VyLWRyYWc6IGVsZW1lbnQ7Ij5EcmFn IG1lITwvc3Bhbj4KPC9wPgo=