Diez B. Roggisch wrote: > beertje wrote: > >> This has me a bit stumped... >> >> I'm trying to extract pictures from a file. So far I'm successfully >> retrieved the header and what I think is the colour for each pixel. >> Here's the description: >> >> """ >> 3) The picture data format: >> The color information is 15 bit data stored in 16 bit. This means the >> most >> significant bit is unused. The data is stored line for line in little >> endian Intel format starting with top left edge to bottom right edge. >> This >> is normally called chunky format. >> >> Bit 0.. 4 blue value >> Bit 5.. 9 green value >> Bit 10..14 red value >> """ >> >> So I've got a list of 16-bit numbers, but how to extract RGB info from >> those I'm a bit lost. I thought at first I should convert the decimal >> (say 23294) into a binary (say 0101101011111110) into something like >> this: >> blue: 01011 >> green: 01011 >> red: 11111 >> >> But encountered two problems: First, I don't know what the best way is >> to do this conversion, but more importantly I don't see how every >> colour could possibly be represented like this. 65535 is presumably >> white, but converting this into chunks of 5 gives me a 31, 31, 31, a >> dark shade of grey. >> >> I guess I'm on the wrong track completely? >> >> I'm a bit unsure about how to treat what the guide calls 'UWORD'... > > ANDing and SHIFTing are your friends here: > > v = 0x0bcd > b = v & 0xf > v >>= 4 > g = v & 0xf > v >>= 4 > r = v & 0xf > print r, g, b > > Alternatively, using 5-bit colors you would use
b = v & 0x1f g = (v >> 5) & 0x1f r = (v >> 10) & 0x1f regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 Holden Web LLC/Ltd http://www.holdenweb.com Skype: holdenweb http://del.icio.us/steve.holden --------------- Asciimercial ------------------ Get on the web: Blog, lens and tag the Internet Many services currently offer free registration ----------- Thank You for Reading ------------- -- http://mail.python.org/mailman/listinfo/python-list
