Post without words #3

(This is my 200th post! =)

About Brent

Assistant Professor of Computer Science at Hendrix College. Functional programmer, mathematician, teacher, pianist, follower of Jesus.
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11 Responses to Post without words #3

  1. Mister Globules says:
    import Control.Monad
    import Data.Bits
    import Numeric
    import Text.Printf
    toGC n = (n `shiftR` 1) `xor` n
    base2 n = showIntAtBase 2 ("01" !!) n ""
    printGC w n = do
      let n' = toGC n
      printf "%0*s %0*s\n" w (base2 n) w (base2 n')
    main = forM_ [0..31 :: Int] $ printGC (5 :: Int)
  2. Lucas Brown says:

    The one on the left is just counting in binary. Is the one on the right a Gray code?

  3. I made something pretty using Gray code:

    • Brent says:

      Cool! Can you explain how you made it?

      • For each pixel, put its x,y coordinates in Gray code; deal out the bits to the color-channels, in one of a large number of possible ways; convert the result from Gray code. Gray code is not essential to the concept, but makes it prettier.

        Thus for example the (Gray) coordinates’ bits might be
        X = G7 B7 R6 G5 B5 R4 G3 B3 R2 G1 B1 R0
        Y = R7 G6 B6 R5 G4 B4 R3 G2 B2 R1 G0 B0
        or in other words the (Gray) color bits are
        R = Y11 X9 Y8 X6 Y5 X3 Y2 X0
        G = X11 Y10 X8 Y7 X5 Y4 X2 Y1
        B = X10 Y9 X7 Y6 X4 Y3 X1 Y0

        (I forgot that I had already posted bigger versions on G+.)

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