Bug 5445 – [WebCoreBridge firstRectForDOMRange:] works incorrectly for visible overflowed text

• Component: HTML Editing
• Status: NEW

[Alexey Proskuryakov]

(spin-off from bug 5401)

If firstRectForDOMRange is called for text that has overflowed its box, it always returns a single-pixel 
rect at the right border of the box. As Justin has pointed out, the problem is in RenderText::caretRect
(...):

RenderBlock *cb = containingBlock();
int availableWidth = cb->lineWidth(top);
if (style()->whiteSpace() == NORMAL)
        left = kMin(left, absx + box->m_x + availableWidth - 1);

However, simply adding a check like (style()->overflow() != OVISIBLE) is not a complete solution, 
because the box itself may be nested in another box with overflow: hidden, or otherwise obscured. The 
attached test case checks for this, too.

[Alexey Proskuryakov]

Created attachment 4425 [details]
test case (for run-webkit-tests)

[Ahmad Saleem]

Created attachment 461316 [details]
Safari 15.6 matches Chrome but differs from Firefox

As can be seen from attached screenshot that in case of text overflow - Safari 15.6 matches with Chrome Canary 106 but differs from Firefox Nightly 105. I am not sure on web-spec or expected behavior but wanted to share updated results. Thanks!

[Alexey Proskuryakov]

Comment on attachment 4425 [details]
test case (for run-webkit-tests)

The fact that the test renders differently in different browsers is unexpected, but is not the point of this bug. This test relies on features that are only exposed in DumpRenderTree harness, so it needs to be run via run-webkit-tests script.

Also, even though this sounds like a Legacy WebKit API bug report, it is really about inline text input behavior, so it's not necessarily obsolete.