Function parseObjectPosition

packages/sdk/src/adapters/iframe.ts:195–249

* Parse a CSS object-position value into x/y offsets (top-left of the * rendered content relative to the CSS box top-left). * * Supports the common subset: keyword pairs, percentage pairs, pixel pairs, * and single-value shorthand. Mixed units (e.g. "50% 10px") are supported. * * Pure — no DOM

(
  objectPosition: string,
  box: { width: number; height: number },
  content: { width: number; height: number },
)

 * Pure — no DOM access.
 */
function parseObjectPosition(
  objectPosition: string,
  box: { width: number; height: number },
  content: { width: number; height: number },
): { x: number; y: number } {
  const raw = (objectPosition || "50% 50%").trim();
  const parts = raw.split(/\s+/);

  // Resolve a single token into a pixel offset along the given axis.
  // `available` is the "slack" (box dimension - content dimension).
  // fallow-ignore-next-line complexity
  function resolveToken(token: string, available: number): number {
    if (token === "left" || token === "top") return 0;
    if (token === "right" || token === "bottom") return available;
    if (token === "center") return available / 2;
    if (token.endsWith("%")) {
      const pct = parseFloat(token) / 100;
      return isNaN(pct) ? available / 2 : pct * available;
    }
    if (token.endsWith("px")) {
      const px = parseFloat(token);
      return isNaN(px) ? available / 2 : px;
    }
    // Bare number — treat as px
    const n = parseFloat(token);
    return isNaN(n) ? available / 2 : n;
  }

  const availX = box.width - content.width;
  const availY = box.height - content.height;

  const isVert = (t: string) => t === "top" || t === "bottom";
  const isHoriz = (t: string) => t === "left" || t === "right";

  if (parts.length === 1) {
    const tokenX = parts[0] ?? "50%";
    // Single value: if it's a vertical keyword the x defaults to center
    if (isVert(tokenX)) {
      return { x: availX / 2, y: resolveToken(tokenX, availY) };
    }
    return { x: resolveToken(tokenX, availX), y: availY / 2 };
  }

  // Keyword pairs may be given vertical-first ("bottom left"); normalize so the
  // first token addresses the x-axis and the second the y-axis.
  let xToken = parts[0] ?? "50%";
  let yToken = parts[1] ?? "50%";
  if (isVert(xToken) || isHoriz(yToken)) {
    [xToken, yToken] = [yToken, xToken];
  }
  return {
    x: resolveToken(xToken, availX),
    y: resolveToken(yToken, availY),
  };
}

function clamp(v: number, min: number, max: number): number {
  return v < min ? min : v > max ? max : v;