static _computeZoomFactor(elementRectSC, renderContainerSizeDC) {
    const targetClipToViewportRatio = 0.75;
    const zoomRatioXY = {
      x: renderContainerSizeDC.width / elementRectSC.width,
      y: renderContainerSizeDC.height / elementRectSC.height,
    };
    const zoomFactor = targetClipToViewportRatio * Math.min(zoomRatioXY.x, zoomRatioXY.y);
    return Math.min(1, zoomFactor);
  }
Given the size of the element in the screenshot and the total available size of our preview container,
compute the factor by which we need to zoom out to view the entire element with context.
@param {Rect} elementRectSC
@param {Size} renderContainerSizeDC
@return {number}