I really don't think these two options are possible (at least not with x11vnc afaik).
The reason is that x11vnc will simply copy the contents of the current screen and send it via vnc. Therefore, vnc and the screen must be the same size and show the same thing.
Does your “show blocked” mean just show a word on the screen (I think the gnome vnc server (forgot the name) has some kind of notification about connecting connections) or to lock the screen?
yuyichao
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