Function blitEscapingAbsoluteDescendants

src/ink/render-node-to-output.ts:1337–1369

(
  node: DOMElement,
  output: Output,
  prevScreen: Screen,
  px: number,
  py: number,
  pw: number,
  ph: number,
)

// to float above the prompt; a spinner tick in the ScrollBox above re-renders
// and overwrites those cells. Without this, the menu vanishes on the next frame.
function blitEscapingAbsoluteDescendants(
  node: DOMElement,
  output: Output,
  prevScreen: Screen,
  px: number,
  py: number,
  pw: number,
  ph: number,
): void {
  const pr = px + pw
  const pb = py + ph
  for (const child of node.childNodes) {
    if (child.nodeName === '#text') continue
    const elem = child as DOMElement
    if (elem.style.position === 'absolute') {
      const cached = nodeCache.get(elem)
      if (cached) {
        absoluteRectsCur.push(cached)
        const cx = Math.floor(cached.x)
        const cy = Math.floor(cached.y)
        const cw = Math.floor(cached.width)
        const ch = Math.floor(cached.height)
        // Only blit rects that extend outside the parent's layout bounds —
        // cells within the parent rect are already covered by the parent blit.
        if (cx < px || cy < py || cx + cw > pr || cy + ch > pb) {
          output.blit(prevScreen, cx, cy, cw, ch)
        }
      }
    }
    // Recurse — absolute descendants can be nested arbitrarily deep
    blitEscapingAbsoluteDescendants(elem, output, prevScreen, px, py, pw, ph)
  }
}

// Render children of a scroll container with viewport culling.
// scrollTopY..scrollBottomY are the visible window in CHILD-LOCAL Yoga coords