Function transitionStage

src/overlay.ts:16–36

(elapsed: number, duration: number, from: Element, to: Element)

// This method calculates the animated new position of the
// stage (called for each frame by requestAnimationFrame)
export function transitionStage(elapsed: number, duration: number, from: Element, to: Element) {
  let activeStagePosition = getState("__activeStagePosition");

  const fromDefinition = activeStagePosition ? activeStagePosition : from.getBoundingClientRect();
  const toDefinition = to.getBoundingClientRect();

  const x = easeInOutQuad(elapsed, fromDefinition.x, toDefinition.x - fromDefinition.x, duration);
  const y = easeInOutQuad(elapsed, fromDefinition.y, toDefinition.y - fromDefinition.y, duration);
  const width = easeInOutQuad(elapsed, fromDefinition.width, toDefinition.width - fromDefinition.width, duration);
  const height = easeInOutQuad(elapsed, fromDefinition.height, toDefinition.height - fromDefinition.height, duration);

  activeStagePosition = {
    x,
    y,
    width,
    height,
  };

  renderOverlay(activeStagePosition);
  setState("__activeStagePosition", activeStagePosition);
}

export function trackActiveElement(element: Element) {
  if (!element) {