Denis Oliver Kropp wrote:
> Karim 'Kasi Mir' Senoucci wrote:
>> Hello everyone,
>> I want to run a DirectFB application on a bunch of stand-alone systems 
>> (using via VIA EPIA boards with DirectFB, no X11), some of which have 
>> the monitor installed upside down due to mechanical reasons that cannot 
>> be changed. Therefore I'd like a (prefarably) simple way to flip the 
>> whole output upside down, rotate it 180 degrees or whatever you like to 
>> call it. :-)
>> 
>> Is such a thing possible using DirectFB and/or the kernel module for the 
>> graphics hardware? Can anyone give me any tips for a solution that 
>> doesn't require drawing every single item on screen upside down (and at 
>> diferrent coordinates, too) explicity?
>
> I'm about to add a rotation flag. 180 degrees would be easy to use
> in the windowed mode. Front and back buffer would still have the
> same dimensions.

Hi Denis,

That's interesting news.  Will this only be useful in the windowed 
mode, or can I also use it in single-application mode?

My picture frame has a home-made orientation sensor connected to the 
modem lines of its nano-ITX board.  My code does rotation the hard way 
based on this, i.e. all co-ordinates are converted and text and JPEG 
rendering is done into a temporary image which I then rotate manually 
before copying it onto the screen.

Unfortunately it's a bit slow when orientation!=0 mainly because of the 
manual rotation.  To avoid this, I need some way to render 
pre-rotated.  In the case of JPEGs it's possible to fiddle with the raw 
JPEG data to rotate it, but to use this I need some way to supply a 
pointer to an in-memory JPEG to the ImageProvider, rather than a 
filename.  I don't think there's anything equivalent for text, which is 
unfortunate: in typical text, relatively few of the pixels are "ink" 
(say 10%), but my copy/rotate code has to look at all of them.

I was also a bit surprised to find that there is no hardware support 
for rotation.  Perhaps the 3D accelerators can do this?

So how does your rotation flag work?


Phil.





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