Function siblingSharesY

src/ink/render-node-to-output.ts:1327–1346

(node: DOMElement, yogaNode: LayoutNode)

// rounding can give h=0 while still advancing the next sibling's top
// (HelpV2's third shortcuts column), so h=0 alone isn't sufficient.
function siblingSharesY(node: DOMElement, yogaNode: LayoutNode): boolean {
  const parent = node.parentNode
  if (!parent) return false
  const myTop = yogaNode.getComputedTop()
  const siblings = parent.childNodes
  const idx = siblings.indexOf(node)
  for (let i = idx + 1; i < siblings.length; i++) {
    const sib = (siblings[i] as DOMElement).yogaNode
    if (!sib) continue
    return sib.getComputedTop() === myTop
  }
  // No next sibling with a yoga node — check previous. A run of h=0 boxes
  // at the tail would all share y with each other.
  for (let i = idx - 1; i >= 0; i--) {
    const sib = (siblings[i] as DOMElement).yogaNode
    if (!sib) continue
    return sib.getComputedTop() === myTop
  }
  return false
}

// When a node blits, its absolute-positioned descendants that paint outside
// the node's layout bounds are NOT covered by the blit (which only copies