Album Art as Backdrop

[RockBoxFan]

Is it possible to use the %VB tag to display album art as a backdrop?

I am attempting this one a 1g Nano.  Here is a code fragment:

%V(0,0,-,-,-)%VB           
%V(0,0,-,-,-)             

%Fl(4,21-Adobe-Helvetica.fnt,50)

%Vd(A)%VB
%Vd(t)

%Vl(A,22,0,132,132,1)
%Cl(0,0,132,132,c,c)
%Cd%VB

%Vl(t,40,42,65,20,4)%Vf(000000)
%al%pc

(I am trying to write black text over the album art.)

This seems to work in the simulator, but the results are inconsistent, meaning I have to re-load the theme each time I start the simulator.  Is this concept supported, and am I doing it correctly?

Thanks!

[ploco]

Don't forget to force update the top layer after draw in backdrop.

%V(0,0,-,-,-)
%Fl(4,21-Adobe-Helvetica.fnt,50)

%Vd(A)%Vd(t)
%Vl(A,22,0,132,132,1)%VB
%Cl(0,0,132,132,c,c)
%Cd
#force update View A
%Vl(A,22,0,132,132,1)
%Vl(t,40,42,65,20,4)%Vf(000000)
%al%pc

[RockBoxFan]

Wow, that does seem to stabilize things (much more consistent, so I don't have to keep reloading the theme).

Thanks!

Can you explain why I need this extra line and what it does, or perhaps point me to some documentation?  I have been trying to work it out from the wiki:

http://www.rockbox.org/wiki/CustomWPS#Viewport_Draw_Layer

which says "Any viewports you want drawn on the backdrop need the %VB tag but otherwise code as normal."

Why do I need to force an update to the top layer (and how does your extra command force that?).

[ploco]

%VB only associate with viewports, such as %V or %Vl( not %Vd)
So whenever you want to drawn on backdrop, only need to append a %VB to the end of the %V line
however there isn't any documents record the needs of top layer overlay except from the demo script
%V(0,0,-,-,-)%VB           
%V(0,0,-,-,-)

indicates "I drawn, then I menially refresh the screen by putting a same size viewport right on top of it "

My guess is that top layer viewport always receive a screen refreshment after drawn but button layer does not get the same treatment.

I think this extra top layer is a plus
for example
%V(A,22,0,132,132,1)%VB
%Cl(0,0,132,132,c,c)
%Cd
#use a bmp with alpha channel can make really fancy photo frame.
%V(A,22,0,132,132,1)
%x(frame,frame.bmp,0,0)
 
     

[RockBoxFan]

That makes sense.  Thank you so much for your help!