Function roundLayout

src/native-ts/yoga-layout/index.ts:2435–2476

(
  node: Node,
  scale: number,
  absLeft: number,
  absTop: number,
)

}

function roundLayout(
  node: Node,
  scale: number,
  absLeft: number,
  absTop: number,
): void {
  if (scale === 0) return
  const l = node.layout
  const nodeLeft = l.left
  const nodeTop = l.top
  const nodeWidth = l.width
  const nodeHeight = l.height

  const absNodeLeft = absLeft + nodeLeft
  const absNodeTop = absTop + nodeTop

  // Upstream YGRoundValueToPixelGrid: text nodes (has measureFunc) floor their
  // positions so wrapped text never starts past its allocated column. Width
  // uses ceil-if-fractional to avoid clipping the last glyph. Non-text nodes
  // use standard round. Matches yoga's PixelGrid.cpp — without this, justify
  // center/space-evenly positions are off-by-one vs WASM and flex-shrink
  // overflow places siblings at the wrong column.
  const isText = node.measureFunc !== null
  l.left = roundValue(nodeLeft, scale, false, isText)
  l.top = roundValue(nodeTop, scale, false, isText)

  // Width/height rounded via absolute edges to avoid cumulative drift
  const absRight = absNodeLeft + nodeWidth
  const absBottom = absNodeTop + nodeHeight
  const hasFracW = !isWholeNumber(nodeWidth * scale)
  const hasFracH = !isWholeNumber(nodeHeight * scale)
  l.width =
    roundValue(absRight, scale, isText && hasFracW, isText && !hasFracW) -
    roundValue(absNodeLeft, scale, false, isText)
  l.height =
    roundValue(absBottom, scale, isText && hasFracH, isText && !hasFracH) -
    roundValue(absNodeTop, scale, false, isText)

  for (const c of node.children) {
    roundLayout(c, scale, absNodeLeft, absNodeTop)
  }
}

function isWholeNumber(v: number): boolean {
  const frac = v - Math.floor(v)