void RenderBoxModelObject::mapAbsoluteToLocalPoint(MapCoordinatesFlags mode, TransformState& transformState) const
{
    RenderObject* o = container();
    if (!o)
        return;

    if (o->isRenderFlowThread())
        transformState.move(o->columnOffset(LayoutPoint(transformState.mappedPoint())));

    o->mapAbsoluteToLocalPoint(mode, transformState);

    LayoutSize containerOffset = offsetFromContainer(o, LayoutPoint());

    if (!style()->hasOutOfFlowPosition() && o->hasColumns()) {
        RenderBlock* block = toRenderBlock(o);
        LayoutPoint point(roundedLayoutPoint(transformState.mappedPoint()));
        point -= containerOffset;
        block->adjustForColumnRect(containerOffset, point);
    }

    bool preserve3D = mode & UseTransforms && (o->style()->preserves3D() || style()->preserves3D());
    if (mode & UseTransforms && shouldUseTransformFromContainer(o)) {
        TransformationMatrix t;
        getTransformFromContainer(o, containerOffset, t);
        transformState.applyTransform(t, preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
    } else
        transformState.move(containerOffset.width(), containerOffset.height(), preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
}
void RenderMultiColumnFlowThread::mapAbsoluteToLocalPoint(MapCoordinatesFlags mode, TransformState& transformState) const
{
    // First get the transform state's point into the block flow thread's physical coordinate space.
    parent()->mapAbsoluteToLocalPoint(mode, transformState);
    LayoutPoint transformPoint = roundedLayoutPoint(transformState.mappedPoint());

    // Now walk through each region.
    const RenderMultiColumnSet* candidateColumnSet = nullptr;
    LayoutPoint candidatePoint;
    LayoutSize candidateContainerOffset;

    for (const auto& columnSet : childrenOfType<RenderMultiColumnSet>(*parent())) {
        candidateContainerOffset = columnSet.offsetFromContainer(parent(), LayoutPoint());

        candidatePoint = transformPoint - candidateContainerOffset;
        candidateColumnSet = &columnSet;

        // We really have no clue what to do with overflow. We'll just use the closest region to the point in that case.
        LayoutUnit pointOffset = isHorizontalWritingMode() ? candidatePoint.y() : candidatePoint.x();
        LayoutUnit regionOffset = isHorizontalWritingMode() ? columnSet.topLeftLocation().y() : columnSet.topLeftLocation().x();
        if (pointOffset < regionOffset + columnSet.logicalHeight())
            break;
    }

    // Once we have a good guess as to which region we hit tested through (and yes, this was just a heuristic, but it's
    // the best we could do), then we can map from the region into the flow thread.
    LayoutSize translationOffset = physicalTranslationFromRegionToFlow(candidateColumnSet, candidatePoint) + candidateContainerOffset;
    bool preserve3D = mode & UseTransforms && (parent()->style().preserves3D() || style().preserves3D());
    if (mode & UseTransforms && shouldUseTransformFromContainer(parent())) {
        TransformationMatrix t;
        getTransformFromContainer(parent(), translationOffset, t);
        transformState.applyTransform(t, preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
    } else
        transformState.move(translationOffset.width(), translationOffset.height(), preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform);
}