/// <summary>
/// Answer true if the box is entirely below the clip rectangle.
/// Enhance JohnT: Could refine this to skip a box if only its margin is visible.
/// Enhance JohnT: if we do separate page drawing, as in print preview, we may need
/// a more precise way to eliminate boxes not on the page.
/// Enhance JohnT: may need to include a box that is just out of sight, in case exceptionally
/// high stacked diacritics extend above the top of the box?
/// </summary>
internal override bool IsAfterVisibleBoxes(Box box, IVwGraphics vg, PaintTransform ptrans)
{
int left, top, right, bottom;
vg.GetClipRect(out left, out top, out right, out bottom);
return(ptrans.ToPaintY(box.Top) > bottom);
}