Bug 258550 – Determination of horizontal overflow incorrect when direction:rtl

• Status: NEW
• Component: Scrolling

[Ahmad Saleem]

Hi Team,

While going through Blink's commit, I came across another failing test case, which was fixed only in Chromium pre-fork.

Old bug 85856

Blink Commit: https://src.chromium.org/viewvc/blink?view=revision&revision=161333

^ It might be just partial fix in RenderBox.cpp and RenderLayerScrollableArea.cpp only.

From attached test case (ensure you have enabled 'scrollbar to always on' in macOS): Look at last and it does not have horizontal scrollbar in STP172.

Just wanted to raise, so we can fix it since Firefox Nightly 116 and Chrome Canary 117 works fine.

Thanks!

[Ahmad Saleem]

Following in RenderLayrScrollableArea.cpp:

int scrollableLeftOverflow = roundToInt((overflowLeft() - box->borderLeft()) - (box->style().shouldPlaceVerticalScrollbarOnLeft() ? box->verticalScrollbarWidth() : 0));

and following in RenderBox.cpp:

LayoutUnit left = borderLeft() + (style().shouldPlaceVerticalScrollbarOnLeft() ? verticalScrollbarWidth() : 0);

____

This compiles but I think 'RenderLayerScrollableArea.cpp' one is wrong since it has 'if' just below it, which might need tweaking.

[Ahmad Saleem]

Also doing this on top of this commit: https://chromium.googlesource.com/chromium/blink/+/70c32d139270f1a08a6fd46ed079b89d062590a0

^ This will improve performance.

[Radar WebKit Bug Importer]

<rdar://problem/111724008>