def adata():
    adata = ad.AnnData(np.zeros((100, 100)))
    adata.obsm["o"] = np.zeros((100, 50))
    adata.varm["o"] = np.zeros((100, 50))
    return adata
def EVT_MOUSEWHEEL(event):
  global zoomdist
  dy = event.WheelRotation
  zoomdist *= np.power(0.95, -dy)
  refresh()