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[directfb-dev] Re: Help me please! About 4bits pixel format.
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.