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[directfb-dev] Re: Help me please! About 4bits pixel format.
Then, must I remeber whether the sub surface begins at odd pixel? Or is there some way to get this information from current data structure? Regards James Su Henric Andersson wrote: >Sorry about the previous mail, wrong button combo :) > > > >>Hi, >>So sorry to bother you, but I really want to implement 4bits pixel >>format for DirectFB. The source code of DirectFB almost drives me crazy. >>Could you please give me some more hint or information? >>Until now, I did not understand the structure of DirectFB clearly, >>especially the surface memory management. In my understanding, a surface >>may occupy a block of memory itself or share a block of memory with >>other surface, ie. a sub surface. Am I right? Then, for example if I >>alloc a sub surface from an odd x coordination within the father >>surface, i.e. (3,4), the memory offset of the sub surface will be 1.5 >>bytes, but it's impossible! There are many other similar problems in >>DirectFB to prevent me implementing 4bpp format. But it is very >> >> > >It is possible to use uneven X coordinates. You have to work at a bit level >though. So, if you would highlight the first pixel of a row, you would only >manipulate the first 4 bits. The next pixel would use the higher 4 bits of >the same byte, the next (3rd) pixel would use the lower 4 bits of the second >byte, and so on. > >Hope it helps... > >/Henric > > > > > -- Info: To unsubscribe send a mail to firstname.lastname@example.org with "unsubscribe directfb-dev" as subject.