Use comonads
This commit is contained in:
parent
8833880c22
commit
7e448da839
35
src/Main.hs
35
src/Main.hs
@ -1,4 +1,5 @@
|
||||
{-# LANGUAGE DeriveAnyClass #-}
|
||||
{-# LANGUAGE DeriveFunctor #-}
|
||||
{-# LANGUAGE DeriveGeneric #-}
|
||||
{-# LANGUAGE OverloadedStrings #-}
|
||||
{-# LANGUAGE RecordWildCards #-}
|
||||
@ -9,6 +10,8 @@ module Main where
|
||||
|
||||
import Codec.Picture
|
||||
import Codec.Picture.Extra (scaleBilinear)
|
||||
import Control.Comonad (extend, extract)
|
||||
import Control.Comonad.Store (Store, experiment, seek, store)
|
||||
import Control.Exception (SomeException, try)
|
||||
import Control.Monad (forM_, void, when)
|
||||
import Data.Bits
|
||||
@ -21,7 +24,8 @@ import Pipes
|
||||
import Pipes.Files
|
||||
import qualified Pipes.Prelude as P
|
||||
import Pipes.Safe (runSafeT)
|
||||
import System.Directory (createDirectoryIfMissing, createFileLink)
|
||||
import System.Directory (createDirectoryIfMissing,
|
||||
createFileLink)
|
||||
import System.FilePath (takeFileName, (</>))
|
||||
|
||||
|
||||
@ -46,7 +50,6 @@ instance BK.Metric Fingerprint where
|
||||
let xored = a `xor` b
|
||||
in foldr (\shiftA acc -> acc + if 1 `shift` shiftA .&. xored > 0 then 1 else 0) 0 [0..63]
|
||||
|
||||
|
||||
fingerprint :: Alg -> DynamicImage -> Word64
|
||||
fingerprint alg = hash . grey . scale . convertRGB8
|
||||
where
|
||||
@ -54,17 +57,25 @@ fingerprint alg = hash . grey . scale . convertRGB8
|
||||
scale = scaleBilinear 8 8
|
||||
grey :: Image PixelRGB8 -> Image Pixel8
|
||||
grey = pixelMap (\(PixelRGB8 r g b) -> ceiling ((fromIntegral r * (0.3 :: Double)) + (fromIntegral g * 0.59) + (fromIntegral b * 0.11)))
|
||||
indexes = [(x,y) | x <- [0..7], y <- [0..7]]
|
||||
hashWith :: Image Pixel8 -> (Store (Int, Int) Pixel8 -> Bool) -> Word64
|
||||
hashWith img f =
|
||||
let s = store (uncurry (pixelAt img)) (0,0)
|
||||
img' = extend f s
|
||||
at pos = extract $ seek pos img'
|
||||
in foldr (\(shiftA, b) acc -> if b then 1 `shift` shiftA .|. acc else acc) 0 $ zip [0..] $ map at indexes
|
||||
hash :: Image Pixel8 -> Word64
|
||||
hash = case alg of
|
||||
Average -> averageHash
|
||||
DHash -> dhash
|
||||
dhash :: Image Pixel8 -> Word64
|
||||
dhash img =
|
||||
foldr (\(shiftA, b) acc -> if b then 1 `shift` shiftA .|. acc else acc) 0 $ zip [0..] [(x < 7) && (pixelAt img x y > pixelAt img (x+1) y) | x <- [0..7], y <- [0..7]]
|
||||
averageHash :: Image Pixel8 -> Word64
|
||||
averageHash img = -- the average fingerprint method
|
||||
let avg = fromIntegral (foldl' (\acc (x,y) -> acc + fromIntegral (pixelAt img x y)) (0 :: Int) [(x,y) | x <- [0..7], y <- [0..7]] `div` 64)
|
||||
in foldr (\(shiftA, b) acc -> if b then 1 `shift` shiftA .|. acc else acc) 0 $ zip [0..] [pixelAt img x y > avg | x <- [0..7], y <- [0..7]]
|
||||
hash img = case alg of
|
||||
Average ->
|
||||
let avg = fromIntegral (foldl' (\acc (x,y) -> acc + fromIntegral (pixelAt img x y)) (0 :: Int) [(x,y) | (x,y) <- indexes] `div` 64)
|
||||
in img `hashWith` (avgAlg avg)
|
||||
DHash -> img `hashWith` dAlg
|
||||
dAlg :: Store (Int, Int) Pixel8 -> Bool
|
||||
dAlg img = case experiment (\(x,y) -> [(x,y), (succ x `mod` 8, y)]) img of
|
||||
[l,r] -> l > r
|
||||
_ -> False
|
||||
avgAlg :: Pixel8 -> Store (Int, Int) Pixel8 -> Bool
|
||||
avgAlg avg img = extract img > avg
|
||||
|
||||
main :: IO ()
|
||||
main = do
|
||||
|
Loading…
Reference in New Issue
Block a user