1960755 - Incorrect rendering result if we scroll before calling startViewTranistion()

Status: NEW

(Core :: CSS Parsing and Computation, defect)

Description

[Boris Chiou [:boris]]

Attachment: testcase

When I was checking this test, snapshot-containing-block-static.html, I noticed the target element has some weird behavior after we do scrolling.

If we don't call scrollTo() before startViewTransition(), everything looks normal. However, if we scroll a little bit, and then start the view transition, the rendering result of target element looks incorrect. It seems like we use the incorrect rect to take the snapshot of it, or maybe other issues?

Steps to reproduce:

1. Run the testcase

The expected result:
we should see a 100x100 green rectangle.

The actual result:
I saw a 100x50 (or 100x45, the height looks like less than 50px) green rectangle.

Comment 1

[Boris Chiou [:boris]]

Attachment: Firefox Nightly

Comment 2

[Boris Chiou [:boris]]

Attachment: Google Chrome (the expected result I think)