Bug 285282 – Account for perspective of the scroller when determining a transformed child's contribution to layout overflow

• Component: Layout and Rendering
• Status: RESOLVED FIXED

[Ahmad Saleem]

Hi Team,

While going through Blink's commit, I came across another failing test case in Safari / WebKit only.

Test Case: https://jsfiddle.net/sqnrw1v5/1/

^ Not scrollbars.

Blink Commit: https://chromium.googlesource.com/chromium/src.git/+/602f4cdf9e0944a68fe91d12ead5b2ece186b8e3

Haven't explored whether we can merge it or not but from quick look, we might be able to do it.

Just raising, so we can fix it.

Thanks!

[Radar WebKit Bug Importer]

<rdar://problem/142573993>

[Ahmad Saleem]

This compiles and progress above test case:

if (paintGeometryAffectsLayoutOverflow) {
        // If we are relatively positioned or if we have a transform, then we have to convert
        // this rectangle into physical coordinates, apply relative positioning and transforms
        // to it, and then convert it back.
        // It ensures that the overflow rect tracks the paint geometry and not the inflow layout position.
        flipForWritingMode(rect);

        LayoutSize containerOffset;
        if (isInFlowPositioned())
            containerOffset = offsetForInFlowPosition();

        auto container = this->container();
        if (shouldUseTransformFromContainer(container)) {
            TransformationMatrix t;
            getTransformFromContainer(containerOffset, t);
            rect = t.mapRect(rect);
        } else
            rect.move(offsetForInFlowPosition());

        // Now we need to flip back.
        flipForWritingMode(rect);
    }

[Ahmad Saleem]

Pull request: https://github.com/WebKit/WebKit/pull/47032

[EWS]

Committed 296652@main (7005f16aba81): <https://commits.webkit.org/296652@main>

Reviewed commits have been landed. Closing PR #47032 and removing active labels.