get image bound(x,y coordinate) on layer

HI!

    I am new at automation plug develop and I want get the Image bound(position) on layer . I try  code like:  PIUGetInfo(classOffset,keyHorizontal,...) but it is not work at all. I try the vbs code like : docRef.ArtLayers(1).Bounds  it can work. is there  function or routine in photoshop SDK can get image bound? thanks!