logischer Fehler in der Anzeige des Mandelbrot in Haskell gesetzt

Question

Ich habe ein Programm erstellt, dessen Zweck es ist, einen fraktalen Satz (die Manderbrot-Set) zu zeichnen und es enthält keinen Syntaxfehler, sondern nur ein Pixel, nicht das Set.

hier ist mein Programm:

module Main where 

import Graphics.UI.Gtk 
import Graphics.UI.Gtk.Builder() 
import Graphics.Rendering.Cairo as C 
import Control.Monad (when) 


main :: IO() 
main = do 
    _ <- initGUI 
    builder <- builderNew 
    builderAddFromFile builder "09-mandelbrot.ui" 

    window <- builderGetObject builder castToWindow "Figure de Mandelbrot" 
    canvas <- builderGetObject builder castToDrawingArea "drawingarea1" 
    _ <- onExpose canvas $ const (updateCanvas canvas) 

    widgetShowAll window 
    mainGUI 


updateCanvas :: DrawingArea -> IO Bool 
updateCanvas canvas = do 
    win <- widgetGetDrawWindow canvas 
    (width, height) <- widgetGetSize canvas 
    renderWithDrawable win $ example (fromIntegral width) (fromIntegral height) 
    return True 

k=100 

mandelbrot :: Double -> Double -> Bool 
mandelbrot a b = 
    let 
    mandelrec :: Double -> Double -> Int -> Bool 
    mandelrec x y i 
     | (x * x + y * y > 4) = False 
     | (i==k) && (x * x + y * y <= 4) = True 
     | otherwise = mandelrec x' y' (i+1) 
      where x' = x * x - y * y + a 
        y' = 2 * x * y + b 
    in mandelrec 0 0 0 

affiche :: (Double, Double) -> Render() 
affiche (a, b) = when (mandelbrot a b) $ C.rectangle a b 1 1 

colonnes w = [ t/w*4-2 | t<-[0..(w-1)] ] 
lignes h = [ t/h*4-2 | t<-[0..(h-1)] ] 


example :: Double -> Double -> C.Render() 
example width height = do 
    setSourceRGB 0 0 0 
    setLineWidth 1 

    mapM_ affiche (zip (colonnes width) (lignes height)) 
    stroke 

Ich kann Ihnen Erklärungen geben, wenn nötig. Ich testete bereits die Funktionen lignes & colones, es scheint in Ordnung.

Answer 1

Nun, es funktioniert jetzt.

Ich habe nicht alle Punkte im Bereich [-2..2] [- 2..2] gesammelt, sondern nur die in der Diagonalen.

hier ist ein gültiger Code:

module Main where 

import Graphics.UI.Gtk 
import Graphics.UI.Gtk.Builder() 
import Graphics.Rendering.Cairo as C 
import Control.Monad (when) 


main :: IO() 
main = do 
    _ <- initGUI 
    builder <- builderNew 
    builderAddFromFile builder "09-mandelbrot.ui" 

    window <- builderGetObject builder castToWindow "Figure de Mandelbrot" 
    canvas <- builderGetObject builder castToDrawingArea "drawingarea1" 
    _ <- onExpose canvas $ const (updateCanvas canvas) 

    widgetShowAll window 
    mainGUI 


updateCanvas :: DrawingArea -> IO Bool 
updateCanvas canvas = do 
    win <- widgetGetDrawWindow canvas 
    (width, height) <- widgetGetSize canvas 
    renderWithDrawable win $ example (fromIntegral width) (fromIntegral height) 
    return True 

k :: Int 
k=100 

mandelbrot :: Double -> Double -> Bool 
mandelbrot a b = 
    let 
    mandelrec :: Double -> Double -> Int -> Bool 
    mandelrec x y i 
     | (x * x + y * y > 4) = False 
     | (i==k) && (x * x + y * y <= 4) = True 
     | otherwise = mandelrec x' y' (i+1) 
      where x' = x * x - y * y + a 
        y' = 2 * x * y + b 
    in mandelrec 0 0 0 

affiche2 :: Double -> Double -> Render() 
affiche2 a b = do 
    C.rectangle a b 1 1 
    stroke 

affiche :: ((Double,Double), (Double,Double)) -> Render() 
affiche ((a0,a), (b0,b)) = when (mandelbrot a b) $ affiche2 a0 b0 

colonnes w = [ (t,t/w*4-2) | t<-[0..(w-1)] ] 
lignes h = [ (t,t/h*4-2) | t<-[0..(h-1)] ] 
points w h = [ (colonne,ligne)| colonne <- colonnes w,ligne <- lignes h] 

example :: Double -> Double -> C.Render() 
example width height = do 
    setSourceRGB 0 0 0 
    setLineWidth 1 

    mapM_ affiche (points width height) 
    stroke