--- /afs/athena.mit.edu/user/k/e/kenta/.shd/www/six/snowflake/snowflake.hs	2005-01-19 03:27:15.000000002 -0500
+++ snowflake.hs	2014-10-28 06:01:15.596026084 -0400
@@ -1,36 +1,42 @@
-import Complex
-import System
+import Data.Complex
+import System.Environment(getArgs)
 
 type C = Complex(Double)
 
 mandelbrot_eval::Int->C->Int
-mandelbrot_eval max_iter c = 
-  length 
+mandelbrot_eval max_iter c =
+  length
   $ (takeWhile (\z -> (magnitude z) < 2))
-  $ (take max_iter) 
+  $ (take max_iter)
   $ (iterate (\z ->  z*z+c) (0:+0) )
 
 half_width_pixels::Int
-half_width_pixels = 400
+half_width_pixels = 10240
 scaling::Double->Int->Double
 scaling width = (* (width
             /(fromIntegral half_width_pixels)))
           . fromIntegral
 range::Double->[Double]
 range width= map (scaling width)
-    [-half_width_pixels .. half_width_pixels]
+    [1-half_width_pixels .. half_width_pixels]
 
+-- the "28" was discovered by trial and error for zoom 6.
 iterations::Int
-iterations = 200
+iterations = 310+28 -- 310;
+--  perl -plwe 'next unless /^\d+$/;if($_>255){$_=255}' fileout | xloadimage stdin
+--  perl -plwe 'next unless /^-?\d+$/;if($_>255){$_=255}elsif($_<0){$_=0}' fileout | xloadimage stdin
+
+truncrange :: Int -> Int
+truncrange i = if (i>255) then 255 else if (i<0) then 0 else i;
 
 main::IO ()
 main = do{
-   let {s = show (2*half_width_pixels+1)};
+   let {s = show (2*half_width_pixels)};
    putStrLn ("P3\n"++s++" "++s++"\n"++"255");
    args <- getArgs;
    let {side = exp(-(read (head args)))};
-   putStr $ unlines $ map show
-   $ concatMap (  (\i -> [i,i,(i+55)])
+   putStr $ unlines $ map (show.truncrange)
+   $ concatMap (   (\i -> [i-55-28,i-55-28,i-28]) -- (\i -> [i-55,i-55,i])
                 . (mandelbrot_eval iterations)
                 . (+ center) )
    $ [x:+y | x<-(range side), y<-(range side)]