Bug 197105 – REGRESSION (iOS 12.2): CSS perspective property value can only be set correctly once

• Component: Compositing
• Status: RESOLVED FIXED

[Iker Jamardo Zugaza]

Since iOS 12.2 WebKit is not able to reset the perspective value correctly more than once. This issue is reproducible on both iOS 12.2 Safari and WKWebView and also in OSX Mojave Safari version 12.1. It could be that this is happening in earlier versions.

In order to reproduce, check this W3 School example: https://www.w3schools.com/cssref/trycss3_perspective_inuse.htm

Moving the slider does not correctly modify the perspective CSS value.

Tested on a MacBook Pro with OSX 10.14.4 and on an iPhone 7 Plus with iOS 12.2. It was not happening on iOS 12.0 nor in 11.4.

[Radar WebKit Bug Importer]

<rdar://problem/50068230>

[Simon Fraser (smfr)]

Created attachment 368143 [details]
Patch

[EWS Watchlist]

Comment on attachment 368143 [details]
Patch

Attachment 368143 [details] did not pass mac-ews (mac):
Output: https://webkit-queues.webkit.org/results/11985316

New failing tests:
compositing/style-change/transform-style-change.html
compositing/style-change/transform-origin-change.html
compositing/style-change/backface-visibility-change.html
compositing/style-change/perspective-change.html
compositing/style-change/perspective-origin-change.html

[EWS Watchlist]

Created attachment 368152 [details]
Archive of layout-test-results from ews102 for mac-highsierra

The attached test failures were seen while running run-webkit-tests on the mac-ews.
Bot: ews102  Port: mac-highsierra  Platform: Mac OS X 10.13.6

[EWS Watchlist]

Comment on attachment 368143 [details]
Patch

Attachment 368143 [details] did not pass ios-sim-ews (ios-simulator-wk2):
Output: https://webkit-queues.webkit.org/results/11985548

New failing tests:
editing/pasteboard/5761530-1.html

[EWS Watchlist]

Created attachment 368159 [details]
Archive of layout-test-results from ews123 for ios-simulator-wk2

The attached test failures were seen while running run-webkit-tests on the ios-sim-ews.
Bot: ews123  Port: ios-simulator-wk2  Platform: Mac OS X 10.13.6

[Simon Fraser (smfr)]

https://trac.webkit.org/r244612

[Hironori Takaryou]

I ran into the same issue on an iPhone 6 Plus with iOS 12.3.1.
And I solved it by adding the following code to force Safari to redraw,

-----------------------------------------------------
divElement.style.perspective = newPerspective + 'px';
divElement.style.overflow = 'hidden'; //ADDED
divElement.offsetHeight;              //ADDED
divElement.style.overflow = 'auto';   //ADDED
-----------------------------------------------------

I hope this will help you.

[Simon Fraser (smfr)]

*** Bug 201656 has been marked as a duplicate of this bug. ***