pango font size failure if size it too small, it this is a bug?

["chen.shengqi" <chen shengqi connet com tw>]

Dear sirs:
    I use pango_attr_size_new ......  to set text size, it works fine if font size is bigger than 12.
     but if font size is verysmall( sush as font_size * PANGO_SCALE, and font_size<10), it will not work but 
draw text out as fontsize is 12 (magbe other size,  all small font size show in this same size),  if I use 
pango_font_description_new_from_string("courier 14") and pango_layout_set_font_description to set to 
pangolayout,  pango_layout_get_pixel_size will fail and return width=0,height=20; is this is a bug or I make 
something wrong?
    thanks.