module Exercise_13 where

import Transform
import Codec.Picture
import Data.Word
import Data.Number.Erf

animate :: [(String, Transform -> Transform)] -> String -> [String] 
animate = undefined

paint :: String -> String
paint = undefined


{-WETT-}
-- Add any code that generates images or videos between these tags
-- Please also include instructions on how to invoke your code
-- If you need libraries that are not available on the testserver, send your submission to fpv@in.tum.de



-- dependencies:
-- cabal install JuicyPixels
-- cabal install erf


{- HOW TO INVOKE?
 - the most simple way is just run "draw <path>" so for example: draw "winning_pic.png"
 -}

{- This minimalistic work explores the delicate balance of programming paradigms 
 - the light is functional programming, the darkness is object oriented.
 - This artwork suggests that even in the most pure functional languages,
 - there is a tiny bit of object orientation, and even in the most
 - heavy and over complicated object oriented languages, there is a
 - little bit of functional programming.
 -}

distance (x1, y1) (x2, y2) = sqrt $ fromIntegral $ (x1-x2)^2 + (y1-y2)^2
image width height = generateImage yinYang width height 
    where   yinCenter = (width*3 `div` 4, height `div` 4)
            yangCenter = (width `div` 4, height*3 `div` 4)
            probit pi = (fromIntegral $ (height `div` 4)) * ((sqrt 2) * (inverf (2*p-1)) + 2)   -- based on definition from wikipedia, shifted and scaled
                where p = ((fromIntegral pi) / (fromIntegral width)) :: Float
            yinYang x y   | distance (x,y) yinCenter < 50 = 0 :: Word8
                          | distance (x,y) yangCenter < 50 = -1 :: Word8
                          | (fromIntegral y) < probit x = -1
                          | otherwise = 0

drawDims path width height = writePng path $ image width height

-- call: draw "winning_pic.png"
draw path = drawDims path 700 700

{-TTEW-}