[Section] Enhanced Alpha Compositing [Element] container elements and graphics elements [Attribute] comp-op [Values] 
clear | src | dst | src_over | dst_over | src_in | dst_in | src_out | dst_out | src_atop | dst_atop | xor | plus | multiply | screen | overlay | darken | lighten | color_dodge | color_burn | hard_light | soft_light | difference | exclusion | inherit