How to set and modify attr for text to drawout with pango?

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

Dear sirs:
    I use a pixmap to draw something on a drawingarea. when draw text, I want to set font/size/color/bkcolor 
for the text. I want to use PangoAttrList, should I create a PangoAttrList for each string? after modify a 
PangoAttribute(example: backgroundcolor ) of the PangoAttrList, should I use pango_layout_set_attributes() 
again ? and can the PangoAttribute(example: backgroundcolor ) be free before/after I use the PangoAttrList?
    thanks.