Function renderChildren

src/ink/render-node-to-output.ts:1257–1294

(
  node: DOMElement,
  output: Output,
  offsetX: number,
  offsetY: number,
  hasRemovedChild: boolean,
  prevScreen: Screen | undefined,
  inheritedBackgroundColor: Color | undefined,
)

// rects (NewMessagesPill's inner Text with backgroundColor). Opaque
// absolute siblings fill their entire rect — direct blit is safe.
function renderChildren(
  node: DOMElement,
  output: Output,
  offsetX: number,
  offsetY: number,
  hasRemovedChild: boolean,
  prevScreen: Screen | undefined,
  inheritedBackgroundColor: Color | undefined,
): void {
  let seenDirtyChild = false
  let seenDirtyClipped = false
  for (const childNode of node.childNodes) {
    const childElem = childNode as DOMElement
    // Capture dirty before rendering — renderNodeToOutput clears the flag
    const wasDirty = childElem.dirty
    const isAbsolute = childElem.style.position === 'absolute'
    renderNodeToOutput(childElem, output, {
      offsetX,
      offsetY,
      prevScreen: hasRemovedChild || seenDirtyChild ? undefined : prevScreen,
      // Short-circuits on seenDirtyClipped (false in the common case) so
      // the opaque/bg reads don't happen per-child per-frame.
      skipSelfBlit:
        seenDirtyClipped &&
        isAbsolute &&
        !childElem.style.opaque &&
        childElem.style.backgroundColor === undefined,
      inheritedBackgroundColor,
    })
    if (wasDirty && !seenDirtyChild) {
      if (!clipsBothAxes(childElem) || isAbsolute) {
        seenDirtyChild = true
      } else {
        seenDirtyClipped = true
      }
    }
  }
}

function clipsBothAxes(node: DOMElement): boolean {
  const ox = node.style.overflowX ?? node.style.overflow