Impact of changing default Screen depth on other XO Apps

NoiseEHC NoiseEHC at
Wed Jan 27 07:54:36 EST 2010

Since you can only blit pictures on an X server and cannot get a direct 
pointer to the video memory, I do not know what your problem is. You can 
just allocate a 32 bit offscreen buffer in the address space of your 
application and blit it via the X server to the 16 bit video memory 
(draw). The XO-1 has bit depth converter hardware so it will not be 
slower in theory.
Note that you cannot use the video overlay for this because it has only 
YUV and RGB-565 modes on the XO-1 and there is a bug in X that the 
overlay will be garbage after a suspend and it was not fixed last time I 
checked. (I have told that I would fix it but because I could not figure 
out how to compile stuff for the XO-1 - like recompiling the kernel and 
the X server - I did not fix that.)

If you need it then I could search for the code I have used but it would 
take some time...

shivaprasad javali wrote:
> Hi All,
>         We are developing an Activity for the XO. During development 
> we ran into an issue with the default screen depth on the XO. Our 
> application assumes that the screen depth is 32 and does all the draw 
> math. But as the screen depth on the XO is 16 we had to do constant 32 
> bit- 16 bit conversions which really hit performance. So we put in 
> script to run after installing our activity which changes the default 
> screen depth on the XO from 16 to 32 bit.
>         I wanted to know how much of an issue this would be for other 
> activities running on the XO. Would they be adversely affected by this 
> change?
> Thanks
> Shivaprasad
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