Bug 219087 – ::first-letter styles cause Range clientRect miscalculations

• Status: RESOLVED
• Resolution: FIXED
• Component: Layout and Rendering

[Joseph Pearson]

Created attachment 414449 [details]
Example showing expected result and miscalcs

If an element has a ::first-letter style rule, creating a Range within that element and measuring its client rectangles (Range#getClientRects or Range#getBoundingClientRects) will produce incorrect dimensions.

The range itself is fine: Range#toString() shows that the correct characters have been selected. But the resulting rectangles are wrong, at least on the x axis (left, width).

Note that *any* ::first-letter declaration on the element produces the bug, even if the styles are not layout-affecting, and even if they're invalid style values.

See a quick reduction in the attached file. I don't think this is a new bug — I have observed it for years, but only got around to the reduction today.

[Smoley]

Thanks for filing. I can reproduce this with the test case on Safari 13.1.3 as well as STP 115 (14.1).

[Radar WebKit Bug Importer]

<rdar://problem/71546397>

[Ahmad Saleem]

I am able to reproduce this bug in Safari Technology Preview 154 using attached test case and both Example 2 and 3 doe snot highlight "troublemakers" like Expected Results while both Firefox Nightly 107 and Chrome Canary 108 show expected results in all cases / example. Thanks!

[alan]

Created attachment 479020 [details]
Patch

[alan]

Let's see if this works without https://github.com/WebKit/WebKit/pull/62142

[alan]

Created attachment 479024 [details]
[fast-cq]Patch

[EWS]

Committed 311085@main (625c8663227c): <https://commits.webkit.org/311085@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 479024 [details].