support gtk+ about zoom in a widget

[呉永 <wuy shcore com cn>]

Hi,
First, I want to zoom in a window just like when
we use IE browser,sometime we can't  see the web page clearly,
so we will use [Ctrl]+[mouse wheel] keys to zoom the page in, in that
case we can see the web page clearly!   please tell me how to do that
in gtk!

Thanks!